Bosch Thermotechnology · Error codes
Bosch Thermotechnology error codes and alerts
Identical code numbers can mean different things on different controllers, so every entry is tied to the documented series, controller and manual version. A code is never a diagnosis.
If you smell gas
- Stop what you are doing. Do not use phones, switches, matches or anything that can spark inside.
- Go outside and leave the door open behind you.
- Call the FortisBC 24-hour emergency line at 1-800-663-9911 or dial 911.
Only after that, call ROMA about the boiler. Official guidance: FortisBC gas leaks and odour.
Bosch Greenstar wall boilers (ZBR/ZWB -3A, fault codes, I&O 6721853955)
A7
DHW temperature sensor defective. The DHW temperature sensor is defective, so check the temperature sensor and leads for interruptions or sh…
Details
A8
Communication fault. A communication fault has occurred, so check the BUS communications wiring and replace it if defective, and check the c…
Details
Ad
DHW tank temperature not detected (sensor was recognized before the connection was lost). The DHW tank temperature is not detected because t…
Details
b1
Code plug not detected. The code plug was not detected, so insert the code plug correctly and replace it if it is defective.…
Details
b2/b3/b4/b5/b6
Internal data error. An internal data error has occurred, so reset the boiler to the factory default setting using service function 8.E.…
Details
b7
Fault in the burner controls. There is a fault in the burner controls, so reset the boiler to the factory default setting.…
Details
C6
Fan not running. The fan is not running, so check the fan leads and the fan and replace them if defective.…
Details
CC
Outdoor temperature sensor not recognized. The outdoor temperature sensor is not recognized, so check the sensor and its leads for interrupt…
Details
d3
Temperature high limit defective; external guard tripped; temperature limiter locked out. The temperature high limit is defective, an extern…
Details
d5
External supply temperature sensor defective (low-loss header); sensor was recognized on the BUS and then reconnected. The external supply t…
Details
E2
Supply temperature sensor defective. The supply temperature sensor is defective, so check the temperature sensor and leads for interruptions…
Details
E3
Additional supply temperature sensor defective. The additional supply temperature sensor is defective, so check the temperature sensor and l…
Details
E9
Heat exchanger safety high limit or flue gas temperature limiter has tripped. The heat exchanger safety high limit or flue gas temperature l…
Details
EA
No flame detected (GFA safety time expired). No flame was detected and the GFA safety time expired, so check the ground lead, gas cock, inle…
Lockout
F0
Internal fault. An internal fault occurred, so press reset for 3 seconds and release, then check the electrical plug-in contacts and the ign…
Lockout
F1
Internal data error. An internal data error has occurred, so reset the boiler to the factory default setting using service function 8.E.…
Details
F7
Flame detected even when burner is off. A flame was detected even when the burner is off, so check the electrodes, the flue gas system, and …
Lockout
FA
After switching gas off: flame is detected. A flame is detected after switching the gas off, so check the gas valve, clean the condensate tr…
Details
Fd
Reset button pressed by mistake; temperature gradient limiter: temperature rise too fast. The reset button was pressed by mistake or the tem…
Details
Bosch Greenstar Combi 100p/151p (fault codes, I&O 6721853953)
A7
DHW temperature sensor defective. The DHW temperature sensor is defective, so check the temperature sensor and leads for interruptions or sh…
Details
A8
Communication fault. A communication fault has occurred, so check the BUS communications wiring and replace it if defective, and check the c…
Details
Ad
DHW tank temperature not detected (sensor was recognized before the connection was lost). The DHW tank temperature is not detected because t…
Details
b1
Code plug not detected. The code plug was not detected, so insert the code plug correctly and replace it if it is defective.…
Details
b2/b3/b4/b5/b6
Internal data error. An internal data error has occurred, so reset the boiler to the factory default setting using service function 8.E.…
Details
b7
Fault in the burner controls. There is a fault in the burner controls, so reset the boiler to the factory default setting.…
Details
C6
Fan not running. The fan is not running, so check the fan leads and the fan and replace them if defective.…
Details
CC
Outdoor temperature sensor not recognized. The outdoor temperature sensor is not recognized, so check the sensor and its leads for interrupt…
Details
d3
Temperature high limit defective; external guard tripped; temperature limiter locked out. The temperature high limit is defective, an extern…
Details
d5
External supply temperature sensor defective (low-loss header); sensor was recognized on the BUS and then reconnected. The external supply t…
Details
E2
Supply temperature sensor defective. The supply temperature sensor is defective, so check the temperature sensor and leads for interruptions…
Details
E3
Additional supply temperature sensor defective. The additional supply temperature sensor is defective, so check the temperature sensor and l…
Details
E9
Heat exchanger safety high limit or flue gas temperature limiter has tripped. The heat exchanger safety high limit or flue gas temperature l…
Details
EA
No flame detected (GFA safety time expired). No flame was detected and the GFA safety time expired, so check the ground lead, gas cock, inle…
Lockout
F0
Internal fault. An internal fault occurred, so press reset for 3 seconds and release, then check the electrical plug-in contacts and the ign…
Lockout
F1
Internal data error. An internal data error has occurred, so reset the boiler to the factory default setting using service function 8.E.…
Details
F7
Flame detected even when burner is off. A flame was detected even when the burner is off, so check the electrodes, the flue gas system, and …
Lockout
FA
After switching gas off: flame is detected. A flame is detected after switching the gas off, so check the gas valve, clean the condensate tr…
Details
Fd
Reset button pressed by mistake; temperature gradient limiter: temperature rise too fast. The reset button was pressed by mistake or the tem…
Details
Bosch Greenstar FS floor-standing (KBR/KWB, fault codes, I&O 6720810590)
A7
DHW temperature sensor defective. The DHW temperature sensor is defective, so check the temperature sensor and leads for interruptions or sh…
Details
A8
Communication fault. A communication fault has occurred, so check the BUS communications wiring and replace it if defective, and check the c…
Details
Ad
DHW tank temperature not detected (sensor was recognized before the connection was lost). The DHW tank temperature is not detected because t…
Details
b1
Code plug not detected. The code plug was not detected, so insert the code plug correctly and replace it if it is defective.…
Details
b2/b3/b4/b5/b6
Internal data error. An internal data error has occurred, so reset the boiler to the factory default setting using service function 8.E.…
Details
b7
Fault in the burner controls. There is a fault in the burner controls, so reset the boiler to the factory default setting.…
Details
C6
Fan not running. The fan is not running, so check the fan leads and the fan and replace them if defective.…
Details
CC
Outdoor temperature sensor not recognized. The outdoor temperature sensor is not recognized, so check the sensor and its leads for interrupt…
Details
d3
Temperature high limit defective; external guard tripped; temperature limiter locked out. The temperature high limit is defective, an extern…
Details
d5
External supply temperature sensor defective (low-loss header); sensor was recognized on the BUS and then reconnected. The external supply t…
Details
E2
Supply temperature sensor defective. The supply temperature sensor is defective, so check the temperature sensor and leads for interruptions…
Details
E3
Additional supply temperature sensor defective. The additional supply temperature sensor is defective, so check the temperature sensor and l…
Details
E9
Heat exchanger safety high limit or flue gas temperature limiter has tripped. The heat exchanger safety high limit or flue gas temperature l…
Details
EA
No flame detected (GFA safety time expired). No flame was detected and the GFA safety time expired, so check the ground lead, the gas cock, …
Lockout
F0
Internal fault. An internal fault occurred, so press reset for 3 seconds and release, then check the electrical plug-in contacts and the ign…
Lockout
F1
Internal data error. An internal data error has occurred, so reset the boiler to the factory default setting using service function 8.E.…
Details
F7
Flame detected even when burner is off. A flame was detected even when the burner is off, so check the electrodes, the flue gas system, and …
Lockout
FA
After switching gas off: flame is detected. A flame is detected after switching the gas off, so check the gas cock, clean the condensate tra…
Details
Fd
Reset button pressed by mistake; temperature gradient limiter: temperature rise too fast. The reset button was pressed by mistake or the tem…
Details
Buderus GB162 (UBA3 control, display codes and LED flags, service manual 6720614965)
-
Communication test while starting up (dash code). A communication test is carried out while starting up, and this code flashes to check the …
Details
-
Fault in communication between UBA 3 and control panel (dash code flashing). If this dash code continues to flash on the display, there is a…
Details
-A 208
Flue gas test or service mode. The boiler is in flue gas test or service mode, so the flue gas test runs the boiler in heating mode at 100 %…
Details
-H 200
Heating mode. The boiler is in heating mode, and this code may appear as any random display indication with a permanent dot in the bottom ri…
Details
-H 200
Manual operation mode. The boiler is in manual operation mode, and this code may appear as any random display indication with a flashing dot…
Details
=H 201
DHW mode. The boiler is in DHW mode, and this code may appear as any random display indication with a permanent dot in the bottom right-hand…
Details
0A 202
Switch optimization program activated. The switch optimization program is activated when a hot water request from an RC regulator or an ON/O…
Details
0A 305
Heating boiler cannot start up temporarily after DHW mode has ended. The heating boiler cannot start up temporarily after DHW mode has ended…
Details
0C 283
Boiler prepares for a burner start-up (fan and pump started, glow ignitor activated). The heating boiler prepares for a burner start-up when…
Lockout
0E 265
Time-proportional program activated. The time-proportional program is activated as soon as the required modulating control performance is lo…
Details
0H 203
Standby mode, no heat demand. The boiler is in standby mode, so no heat demand is created. The table classifies it as Operating code, UBA3 L…
Details
0L 284
Gas valve activated. The gas valve is activated during this operating code. The table classifies it as Operating code, UBA3 LED off.…
Details
0U 270
Boiler start-up after mains power supply activation or a system reset. The boiler starts up after activation of the mains power supply or co…
Details
0Y 204
Supply temperature sensor detects the supply temperature higher than the set value. The supply temperature sensor has detected that the curr…
Details
0Y 276
Supply temperature sensor measured a supply temperature higher than 203 °F (95 °C). The supply temperature sensor has measured a current hea…
Details
0Y 277
Safety temperature sensor measured a supply temperature higher than 203 °F (95 °C). The safety temperature sensor has measured a current sup…
Details
0Y 285
Return temperature sensor measured a return water temperature higher than 203 °F (95 °C). The return temperature sensor has measured a curre…
Details
1A 316
Flue gas sensor temperature too high. The flue gas sensor temperature is too high, so the cause of the fault must be remedied first, there i…
Details
1C 210
Safety temperature switch measured an excessively high temperature and is open, or no connection between contacts 50 and 78 of the UBA 3 mou…
Details
1U 317
Flue gas sensor contacts shorted. The flue gas sensor contacts have shorted, so the cause of the fault must be remedied first and there is n…
Details
1Y 318
Flue gas sensor contacts open. The flue gas sensor contacts are open, so the cause of the fault must be remedied first and there is no heati…
Details
2E 207
Heating system water pressure too low, less than 3 PSI. The heating system water pressure is too low and is less than 3 PSI, so neither the …
Details
2F 260
Supply temperature sensor did not measure any heating water temperature increase after a burner start. The supply temperature sensor has not…
Details
2F 271
Temperature difference between the supply and safety temperature sensors too high. The temperature difference of the heating water measured …
Details
2L 266
Pressure sensor failed to measure a pressure increase during any of four attempts. The pressure sensor failed to measure a pressure increase…
Details
2P 212
Supply temperature sensor measured a heating water temperature increase of more than 9 °F/sec (5 °C/sec). The supply temperature sensor has …
Details
2U 213
Temperature difference between the supply and return temperature sensors is more than 90 °F (50 °C). The temperature difference measured bet…
Details
2Y 281
Pump speed too high or too low while starting up. The pump speed was found to be too high or too low while starting up, so the modulating fu…
Details
2Y 282
Tacho signal of the pump is missing. The tacho signal of the pump is missing, so there is no heating operation and no DHW. The table classif…
Details
3A 264
Fan unit tacho signal or fan unit voltage failed during the operating phase. The fan unit tacho signal or the fan unit voltage has failed du…
Details
3C 217
Fan unit running irregularly while starting up. The fan unit is running irregularly while starting up, so the cause of the fault must be rem…
Details
3F 273
Boiler switched off for a couple of seconds after being operational for 24 hours (safety check). The boiler has been switched off for a coup…
Details
3L 214
Fan unit tacho signal or fan unit main voltage not available during the pre-operative phase. The fan unit tacho signal or the fan unit main …
Details
3P 216
Fan unit is running too slowly. The fan unit is running too slowly, so the cause of the fault must be remedied first, and when this boiler f…
Details
3Y 215
Fan unit is running too fast. The fan unit is running too fast, so the cause of the fault must be remedied first, and when this boiler fault…
Details
4A 218
Supply temperature sensor measured a heating supply temperature higher than 221 °F (105 °C). The supply temperature sensor has measured a he…
Details
4C 224
Safety temperature switch measured an excessively high temperature and is open, or no connection between contacts 22 and 24 of the UBA 3 mou…
Details
4E 278
Sensor test has failed. The sensor test has failed, so the cause of the fault must be remedied first, with no heating operation and no DHW a…
Details
4F 219
Safety temperature sensor measured a supply temperature higher than 221 °F (105 °C). The safety temperature sensor has measured a supply tem…
Details
4L 220
Safety temperature sensor contacts shorted to each other or to ground, or measured a supply water temperature over 266 °F (130 °C). The cont…
Details
4P 221
Safety temperature sensor contacts open. The contacts of the safety temperature sensor are open, so the cause of the fault must be remedied …
Details
4U 222
Supply temperature sensor contacts shorted. The contacts of the supply temperature sensor have shorted, so the cause of the fault must be re…
Details
4Y 223
Supply temperature sensor contacts open. The contacts of the supply temperature sensor are open, so the cause of the fault must be remedied …
Details
5C 268
The Service Tool was connected at the time indicated. The Service Tool was connected at the time indicated, and this code is only visible on…
Details
5H 268
Component test phase using the Service Tool. A component test phase is being carried out using the Service Tool, and this code is not visibl…
Details
5H
No communication between RCC and UBA 3. There is no communication between RCC and the UBA 3, so there is no heating operation, and this code…
Details
5L
General fault code - a blocking or locking boiler fault has occurred. A blocking or locking boiler fault has occurred, so possibly no heatin…
Details
6A 227
Insufficient flame activity (ionization current) during the first, second or third burner ignition attempt. Insufficient flame activity (ion…
Lockout
6A 227
Insufficient flame activity (ionization current) during the fourth burner ignition attempt. Insufficient flame activity (ionization current)…
Lockout
6C 228
Flames (ionization current) measured after a heat demand occurred but before opening the gas valve. Flames (ionization current) were measure…
Details
6C 306
Flames (ionization current) detected after switching off the burner. Flames (ionization current) were detected after switching off the burne…
Details
6L 229
Insufficient flame activity (ionization current) during the burner procedure. Insufficient flame activity (ionization current) was measured …
Details
6P 269
Glow ignitor activated too long (for more than 10 minutes). The glow ignitor was activated too long, for more than 10 minutes, so the cause …
Lockout
7C 231
Power supply interrupted during a locking fault. The power supply was interrupted during a locking fault such as codes 4A 218, 4C 224, 4E 27…
Details
7H 328
Main voltage has briefly been interrupted. The main voltage has briefly been interrupted, and this fault code may deactivate again automatic…
Details
7L 261
UBA 3 is defective. The UBA 3 is defective, so the cause of the fault must be remedied first, with no heating operation and no DHW and the p…
Details
7L 280
UBA 3 is defective. The UBA 3 is defective, so the cause of the fault must be remedied first, with no heating operation and no DHW and the p…
Details
8Y 232
External switch contact has opened. The external switch contact has opened, so there is no heating operation and no DHW. The table classifie…
Details
888
Display test while starting up. The display test runs while starting up, immediately after switching on the main voltage, and this code is d…
Details
9A 235
The KIM is too new for the UBA 3. The KIM is too new for the UBA 3, so the cause of the fault must be remedied first, with no heating operat…
Details
9H 237
UBA 3 or KIM is defective. The UBA 3 or the KIM is defective, so the cause of the fault must be remedied first, with no heating operation an…
Details
9H 267
UBA 3 or KIM is defective. The UBA 3 or the KIM is defective, so the cause of the fault must be remedied first, with no heating operation an…
Details
9H 272
UBA 3 or KIM is defective. The UBA 3 or the KIM is defective, so the cause of the fault must be remedied first, with no heating operation an…
Details
9L 234
Contacts of the gas valve are open. The contacts of the gas valve are open, so the cause of the fault must be remedied first, with no heatin…
Details
9L 238
UBA 3 or KIM is defective. The UBA 3 or the KIM is defective, so the cause of the fault must be remedied first, with no heating operation an…
Details
9P 239
UBA 3 or KIM is defective. The UBA 3 or the KIM is defective, so the cause of the fault must be remedied first, with no heating operation an…
Details
9U 233
UBA 3 or KIM is defective. The UBA 3 or the KIM is defective, so the cause of the fault must be remedied first, with no heating operation an…
Details
A01 800
Outdoor-temperature sensor contacts open or shorted. The contacts for the outdoor-temperature sensor are open or have shorted, so a minimum …
Details
A01 808
DHW temperature sensor contacts open or shorted. The contacts for the DHW temperature sensor are open or have shorted, so there is heating o…
Details
A01 809
DHW temperature sensor 2 contacts open or shorted. The contacts for the DHW temperature sensor 2 are open or have shorted, so there is heati…
Details
A01 810
DHW mode was active for 4 hours without interruption while a heat demand occurred. DHW mode was active for 4 hours without any interruption …
Details
A01 811
Thermal disinfection has been switched off. Thermal disinfection has been switched off, so the tank has not been disinfected. The table clas…
Details
A01 816
The UBA 3 bus is over-loaded. The UBA 3 bus is over-loaded, so there is no heating operation and no DHW. The table classifies it as Blocking…
Details
A01 828
Water pressure indication of the heating system does not work. The water pressure indication of the heating system does not work, so there i…
Details
A01 816
No communication between the room thermostat and the control panel. There is no communication between the room thermostat and the control pa…
Details
A11 806
Room thermostat sensor indicates a fault. The room thermostat sensor indicates a fault, so no reset is required and the UBA 3 LED is off. Th…
Details
A11 816
No communication with the RC35 takes place. No communication with the RC35 takes place, so no reset is required and the UBA 3 LED is off. Th…
Details
A11 840
Select RC35 as one of the heating circuit addresses. Select RC35 as one of the heating circuit addresses, so no reset is required and the UB…
Details
A11 841
Activate at least one heating circuit address via the service menu. Activate at least one heating circuit address via the service menu, so n…
Details
A11 815
Switch module sensor indicates a fault. The switch module sensor indicates a fault, so the heating system supply temperature at the heating …
Details
A11 816
No communication with the switch module. There is no communication with the switch module, so the heating circuit pump is run continuously. …
Details
A18 825
Two RC room thermostats connected and assigned the wrong heating circuit addresses. Two RC room thermostats are connected and they have been…
Details
A21 816
No communication between heating circuit address 1 and the corresponding room thermostat. There is no communication between heating circuit …
Details
A22 816
No communication between heating circuit address 2 and the corresponding room thermostat. There is no communication between heating circuit …
Details
A23 816
No communication between heating circuit address 3 and the corresponding room thermostat. There is no communication between heating circuit …
Details
A32 807
Supply temperature sensor of heating circuit address 2 indicates a fault. The supply temperature sensor of heating circuit address 2 indicat…
Details
A32 816
No communication with the mixer module of heating circuit 2. There is no communication with the mixer module of heating circuit 2 due to fau…
Details
A33 807
Supply temperature sensor of heating circuit address 3 indicates a fault. The supply temperature sensor of heating circuit address 3 indicat…
Details
A33 816
No communication with heating circuit address 3. There is no communication with heating circuit address 3, so no reset is required and the U…
Details
A51 812
The solar collector module has not been adjusted correctly. The solar collector module has not been adjusted correctly, so no reset is requi…
Details
A51 813
Solar collector sensor indicates a fault. The solar collector sensor indicates a fault, so no reset is required and the UBA 3 LED is off. Th…
Details
A51 814
Solar collector sensor indicates a fault. The solar collector sensor indicates a fault, so no reset is required and the UBA 3 LED is off. Th…
Details
A51 816
No communication with the solar collector module. There is no communication with the solar collector module, so no reset is required and the…
Details
CA 286
Return temperature sensor measured a return water temperature higher than 221 °F (105 °C). The return temperature sensor has measured a retu…
Details
C0 288
Pressure sensor contacts are open. The pressure sensor contacts are open, so the cause of the fault must be remedied first, with no heating …
Details
C0 289
Pressure sensor contacts have shorted. The pressure sensor contacts have shorted, so the cause of the fault must be remedied first, with no …
Details
CU 240
Return temperature sensor contacts shorted to each other or to ground. The contacts of the return temperature sensor have shorted to each ot…
Details
CY 241
Return temperature sensor contacts are open. The contacts of the return temperature sensor are open, so the cause of the fault must be remed…
Details
EL 290
UBA 3 or KIM is defective (code shown as E with any digit or letter). The UBA 3 or the KIM is defective, so there is no heating operation an…
Details
E 242 to 287
UBA 3 or KIM is defective (code shown as E followed by any digit or letter). The UBA 3 or the KIM is defective, and the display shows this c…
Details
H7
Heating system water pressure too low, less than 12 PSI. The heating system water pressure is too low and is less than 12 PSI, so possibly n…
Details
P-.-
Water pressure of the heating system is beyond the measuring range of the pressure sensor. The water pressure of the heating system is beyon…
Details
RE
Reset is carried out. Reset is carried out, so after pressing the Reset button this code is displayed for 5 seconds. The table classifies it…
Details
Buderus GB142 (BC10 control, boiler fault codes, service manual 7214 9400)
-
Dash code - no communication between UBA 3 and BC10. The dash code indicates no communication between the UBA 3 and the BC10, so press the R…
Details
0Y 276
Supply sensor measured a temperature higher than 203 °F (95 °C). The supply sensor has measured a temperature higher than 203 °F (95 °C), an…
Details
0Y 277
Safety sensor measured a temperature higher than 203 °F (95 °C). The safety sensor has measured a temperature higher than 203 °F (95 °C), an…
Details
0Y 285
Return sensor measured a temperature higher than 203 °F (95 °C). The return sensor has measured a temperature higher than 203 °F (95 °C), an…
Details
1L 211
UBA 3 does not register any connections to the unused contacts 78 and 50. The UBA 3 does not register any connections to the unused contacts…
Details
2E 207
The system pressure is too low. The system pressure is too low, so check whether the pressure in the heating system is at least 14.5 psi (1 …
Details
2F 260
No temperature increase after burner start or temperature difference between the supply and safety sensors is more than 27 °F (15 K). No tem…
Details
2F 271
Temperature difference between the supply and safety sensors is more than 27 °F (15 K). The temperature difference between the supply and sa…
Details
2L 266
The primary circulation pump does not generate a pressure difference. The primary circulation pump does not generate a pressure difference, …
Details
2P 212
Temperature increase of the supply sensor or safety sensor is more than 7.5 °F/sec (5 K/sec). Temperature increase of the supply sensor or s…
Details
2U 213
Temperature difference between the supply and return sensors is more than 90 °F (50 K). The temperature difference between the supply and re…
Details
3A 264
The air fan has failed during the operating phase. The air fan has failed during the operating phase, so check that both plug-and-socket con…
Details
3F 273
The blower is switched off during the safety test. The blower is switched off during the safety test, so fully switch off the heat request a…
Details
3L 214
The blower is switched off during the safety test. The blower is switched off during the safety test, so check that both plug-and-socket con…
Details
3P 216
The blower is running too slowly. The blower is running too slowly, so check to see if the blower is soiled or wet, check that the mains vol…
Details
3Y 215
The blower is running too fast. The blower is running too fast, so check the plug-and-socket connection of the tacho wire to the blower, che…
Details
4A 218
The supply sensor has measured a temperature higher than 221 °F (105 °C). The supply sensor has measured a temperature higher than 221 °F (1…
Details
CA 286
The return sensor has measured a temperature higher than 221 °F (105 °C). The return sensor has measured a temperature higher than 221 °F (1…
Details
4C 224
The UBA 3 does not register the short circuit between the unused contacts 22 and 24. The UBA 3 does not register the short circuit between t…
Details
4E 278
The sensor test has failed. The sensor test has failed, so measure the voltage to check for a possible short circuit in the supply or safety…
Details
4L 220
The safety sensor is shorted or measures temperatures higher than 266 °F (130 °C). The safety sensor is shorted or measures temperatures hig…
Details
4P 221
The safety sensor contact is interrupted. The safety sensor contact is interrupted, so press the Reset button and, if a new fault message 4P…
Details
4U 222
The supply sensor contact is shorted. The supply sensor contact is shorted, so press the Reset button and, if a new fault message 4U appears…
Details
CU 240
The return sensor contact is shorted. The return sensor contact is shorted, so press the Reset button and, if a new fault message CU appears…
Details
4Y 223
The supply sensor contact is interrupted. The supply sensor contact is interrupted, so press the Reset button and, if a new fault message 4Y…
Details
CY 241
The return sensor contact is interrupted. The return sensor contact is interrupted, so press the Reset button and, if a new fault message CY…
Details
6A 227
No ionization after four startup attempts. No ionization after four startup attempts, so press the Reset button and, if the fault message 6A…
Lockout
6C 228
An ionization current was measured before the burner start. An ionization current was measured before the burner start, so press the Reset b…
Details
6C 306
An ionization current was measured after the burner switch-off. An ionization current was measured after the burner switch-off, so check tha…
Details
6L 229
Ionization fails during the operating phase. Ionization fails during the operating phase, so measure the static inlet gas pressure, bleed th…
Details
6P 269
The hot surface ignitor activates too long. The hot surface ignitor activates too long, so press the Reset button and, if the malfunction ha…
Lockout
7C 231
The power supply was interrupted after a fault message. The power supply was interrupted after a fault message, so press the Reset button an…
Details
7L 261
The UBA 3 is defective. The UBA 3 is defective, so check the contacts between the UBA 3 and the UBA 3 mounting base, press the Reset button …
Details
7L 280
The UBA 3 is defective. The UBA 3 is defective, so check the contacts between the UBA 3 and the UBA 3 mounting base, press the Reset button …
Details
8Y 232
The external switch contact is activated. The external switch contact is activated, so check that the switch contact is connected to the boi…
Details
9A 235
KIM or UBA 3 is defective. The KIM or the UBA 3 is defective, so press the Reset button and check whether a new fault message 9A, 9H, 9P, 9U…
Details
9H 237
KIM or UBA 3 is defective. The KIM or the UBA 3 is defective, so press the Reset button and check whether a new fault message 9A, 9H, 9P, 9U…
Details
9P 239
KIM or UBA 3 is defective. The KIM or the UBA 3 is defective, so press the Reset button and check whether a new fault message 9A, 9H, 9P, 9U…
Details
9U 233
KIM or UBA 3 is defective. The KIM or the UBA 3 is defective, so press the Reset button and check whether a new fault message 9A, 9H, 9P, 9U…
Details
E 242 to 287
KIM or UBA 3 is defective (code shown with any digit or letter after the E). The KIM or the UBA 3 is defective and the code is displayed as …
Details
E 290
The UBA 3 is defective (code shown with any digit or letter after the E). The UBA 3 is defective and the code is displayed as an E followed …
Details
9L 234
The gas valve coil or the wiring to the gas valve is defective. The gas valve coil or the wiring to the gas valve is defective, so check the…
Details
9L 238
The UBA 3 is defective. The UBA 3 is defective, so check the plug-and-socket connection of the gas valve, measure the wire between the gas v…
Details
C0 288
The UBA 3 has no connection to the pressure sensor or there is a short circuit. The UBA 3 has no connection to the pressure sensor or there …
Details
C0 289
Short circuit in connection to the pressure sensor. There is a short circuit in connection to the pressure sensor, so check the plug-and-soc…
Details
Bosch Singular combi (4000/5200, fault codes, IOM table 30)
A2
Fan - abnormal operation. Abnormal operation of the fan; clean the intake air filter, check the fan connector, and contact the original inst…
Details
A3
Pump - abnormal operation. Abnormal operation of the pump; contact the original installer or licensed professional.…
Details
A4
Overheating of heat exchanger. Overheating of the heat exchanger, so turn off the system for at least 30 minutes and then restart it, and co…
Details
A5
Low water pressure. Low water pressure, so reference the built-in water filling instructions of the manual page 20, and contact the original…
Details
A6
Ignition error. Ignition error, so ensure that the main gas supply valve is open, and contact the original installer or licensed professiona…
Lockout
A7
Gas valve relay "open" - abnormal operation. Abnormal operation of the gas valve relay "open", so turn off the main gas valve and contact th…
Details
A8
Flame detection - abnormal operation. Abnormal operation of flame detection, so turn off the main gas valve and contact the original install…
Details
AA
Overheating. Overheating, so contact the original installer or licensed professional.…
Details
AB
Heat exchanger temperature sensor - abnormal operation. Abnormal operation of the heat exchanger temperature sensor, so contact the original…
Details
AC
DHW temperature sensor - abnormal operation. Abnormal operation of the DHW temperature sensor, so contact the original installer or licensed…
Details
AD
Clog of condensate trap. Clog of the condensate trap, so contact the original installer or licensed professional.…
Details
AE
Blockage of flue pipe. Blockage of the flue pipe, so clean the vent terminal and contact the original installer or licensed professional.…
Details
E0
Outdoor temperature sensor - abnormal operation. Abnormal operation of the outdoor temperature sensor, so check the outdoor temperature sens…
Details
E1
Exhaust temperature sensor - abnormal operation. Abnormal operation of the exhaust temperature sensor, so check the exhaust temperature sens…
Details
E2
Exhaust temperature overheating - abnormal operation. Abnormal operation of the exhaust temperature overheating, so contact the original ins…
Details
E3
Return water temperature sensor - abnormal operation. Abnormal operation of the return water temperature sensor, so contact the original ins…
Details
E4
Pressure sensor - abnormal operation. Abnormal operation of the pressure sensor, so contact the original installer or licensed professional.…
Details
E7
Gas valve relay "Close" - abnormal operation. Abnormal operation of the gas valve relay "Close", so contact the original installer or licens…
Details
EB
Overheating of DHW temperature sensor. Overheating of the DHW temperature sensor, so contact the original installer or licensed professional…
Details
EE
Data communication - abnormal operation. Abnormal operation of the data communication, so contact the original installer or licensed profess…
Details
EF
EEPROM error - abnormal operation. Abnormal operation of the EEPROM error, so contact the original installer or licensed professional.…
Details
Buderus Logano plus GB312 commercial condensing boilers (SAFe fault displays, IOM 6 720 806 273)
2E 207
The water pressure is < 8.7 psi (0.6 bar). Checks: Is the pressure in the heating system at least 14.5 psi (1 bar). Remedy: Adjust operating…
Details
2U 565
Difference between supply and return temperature too great. (>72 °F; >40 K). Heat exchanger cut-out due to excessive temperature spread. Che…
Details
2U 575
Boiler sensor/ISTB sensor. The maximum permissible temperature at the ISTB has been reached. Checks: Check water flow. Check orientation of …
Details
3C 537
No speed signal. The SAFe is not receiving a speed signal even though the fan is supposed to be running. Checks: Check connecting cables bet…
Details
3C 538
Fan speed too slow. The actual speed detected is slower than the set speed. Checks: Dirt in fan. Fan defective. Remedy: Clean fan if necessa…
Details
3C 540
Fan speed too fast. The actual speed detected is faster than the set speed. Checks: Check PWM signal/SAFe connecting cable for poor contact,…
Details
4A 520
Boiler safety temperature limiter (STB). The supply temperature has reached 200 °F (93 °C) (cut-out temperature of boiler temperature limite…
Details
4U 521
Temperature difference at twin boiler sensor too great. Temperature difference between supply temperature sensors 1 and 2 too great (deviati…
Details
4U 522
Short-circuit between boiler temperature sensors 1 and 2. A temperature sensor fault was detected in test mode. Checks: Check sensor lead. C…
Details
4Y 523
Circuit break on supply temperature sensor. Temperature at supply temperature sensor. < 23 °F (< -5 °C) Checks: Check sensor lead. Check con…
Details
4U 524
Flow temperature sensor short-circuit. Current supply temperature > 266 °F (> 130 °C) Checks: Check sensor lead. Check connector. Check sens…
Details
4A 575
STB response. The boiler supply temperature has reached its maximum permissible value. Checks: High temperature safety cut-out has tripped. …
Details
5L 542
Incomplete communication with SAFe. The MC10 registers this fault if not all required data is supplied by the SAFe. Checks: Check wiring con…
Details
5L 543
No communication with SAFe. The MC10 is not receiving any data from the SAFe. Checks: Check whether the plugs on the cables (bus connecting …
Details
6L 515
Failure of the ionization signal during operation. Ionization signal is lost during burner operation. Remedy: None; the SAFe will initiate a…
Details
6L 514
Flame failure during the flame stabilization period. No flame signal was detected within the flame stabilization period. Remedy: None; the S…
Lockout
6C 576
Ionization current > 0.9 μA during preventilation. No flame signal was detected within the preventilation phase. Checks: Check ionization el…
Lockout
6A 577
No flame detected within the safety period. Ionization current < 1.1 μA during safety period. Checks: Gas supply/dynamic pressure too low. T…
Lockout
6L 561
5 power-up sequences (power supply disconnection during burner start-up). The burner control unit has switched off 5 times during the burner…
Details
7A 550
Voltage too low. The power supply voltage is too low. Checks: The power supply voltage must not drop below 102V. Remedy: Ensure adequate pow…
Details
7A 551
Power failure. There has been a brief loss of power. Checks: Check power supply cable for loose contacts. Check wiring and proper contact of…
Details
8L 579
No gas pressure. There is no gas pressure. ( Section 10.3, page 61 ff.) Checks: Check that the gas cock is turned on. Check that gas pressur…
Details
8Y 590
Pressure switch in safety assembly has tripped. Break in pressure switch safety sequence during burner operation. Checks: Check whether low …
Details
8Y 591
Faults when checking the safety sequence. SAFe pressure switch has not tripped. Checks: Check whether the gas supply pressure is > 3 inches …
Details
9Y 500/501/502/503
Internal SAFe relay fault. Internal electronic fault on SAFe. Checks: Press Reset button and wait to see if fault is eliminated. Remedy: If …
Details
CY 566
Return temperature < 23 °F (< -5 °C) (circuit break). The control unit receives unrealistic values from the return sensor. Checks: Check the…
Details
CY 567
Return temperature > 266 °F (> 130 °C) (short-circuit). The controller receives unrealistic values from the return temperature sensor. Check…
Details
CO 568
Water pressure sensor fault (cable break). Water pressure sensor break (voltage > 3.5 V). Checks: Check connection between SAFe and water pr…
Details
CO 569
Water pressure sensor fault (short-circuit). Water pressure sensor short-circuit (voltage < 0.5 V). Checks: Check connecting cable running t…
Details
CY 573
Flow temperature < 23 °F (< -5 °C) (circuit break). The control unit receives unrealistic values from the supply temperature sensor. Checks:…
Details
CY 574
Flow temperature >266°F (>130°C) (short-circuit). The control unit receives unrealistic values from the supply temperature sensor. Checks: C…
Details
LP 570
Too many resets via the interface. Too many resets have been received via the interface within a certain period. Important: this fault can b…
Details
LL 571
Too many restarts despite resetting. 15 directlly consecutive restarts have taken place. In other words, the same problem was still present …
Details
EE 601
Flow temperature sensor reading. Successive supply temperature readings fluctuate too much within range. Checks: Check the cable to the boil…
Details
EE 612
Checking the return temperature sensor. Successive return temperature readings fluctuate too much within range. Checks: Check the cable to t…
Details
EE 626
Electrode voltage incorrect. Voltage to ionization electrode too low. Checks: Check connecting cable between SAFe and electrode for breaks o…
Details
Buderus SSB85/120/160 commercial condensing boilers (service manual 6720866940)
1
Ignit Error. Three unsuccessful ignition attempts in a row Checks: a- Check gas supply pressure; b- Check ignition spark; c- Correct amount …
Lockout
2
Gv Relay Error. Failure detected in the GV (gas valve) Relay Checks: a- Check the integrity of the wire connections between gas valve and co…
Lockout
3
Gv Relay Not Open. Failure detected in the GV (gas valve) Relay Checks: a- Check the integrity of the wire connections between gas valve and…
Lockout
4
Gv Relay Not Close. Failure detected in the GV (gas valve) Relay Checks: a- Check the integrity of the wire connections between gas valve an…
Lockout
5
Safety Relay Error. Failure detected in the Safety Relay Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
6
Safety Relay Open. Failure detected in the Safety Relay Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
7
Safety Relay Closed. Failure detected in the Safety Relay Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
11
Blocking Too Long Error. Control had a blocking error for more than 20 hours in a row Checks: Press RESET button to display the Blocking err…
Lockout
12
Fan Error. Fan MF deviation for more than 60 sec Checks: a- Check for 120 Vac power connection of the fan. b- Check PWM connection of the fa…
Lockout
13
Ram Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
14
Wrong E2prom Signature. Contents of E2prom is not up-to-date Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
15
X Ram Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
16
E2Prom Error. No communication with E2prom Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
17
E2Prom Error C. Wrong safety parameters in E2prom Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
18
E2Prom Error Cal Table. Wrong calibtration table parameters Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
19
State Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
20
Rom Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
21
Rom Error C. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
22
Air Sw Not Open. Air pressure switch not working The table classifies it as lockout.…
Lockout
23
15Ms Xrl Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
24
Air Sw Not Closed. Air pressure switch not working The table classifies it as lockout.…
Lockout
25
Max. Thermostat Lock Error. The external overheat protection is activated Checks: a- Check the pump to verify the flow circulation b- Check …
Lockout
26
Stack Error. Internal error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
27
Flame Out Too Late Error. Flame still present 10 sec. after closing the gas valve Remedy: Replace the gas valve The table classifies it as l…
Lockout
28
Flame Error 1. Flame is detected before ignition Remedy: Replace the gas valve The table classifies it as lockout.…
Lockout
29
20Ms Xrl Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
30
41Ms Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
31
Too Many Flame Failures. Three times flame lost during one demand Checks: a- Check the integrity of the wire connections of the spark and th…
Lockout
32
Flow Switch Not Closed Error. Flow switch not working / No flow The table classifies it as lockout.…
Lockout
33
Flow Switch Not Open Error. Flow switch not working / No flow The table classifies it as lockout.…
Lockout
34
Flag Byte Integrity Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
35
Ad Hi Cpl Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
36
Ad Lo Cpl Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
37
Register Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
45
WD Error Ram. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
46
WD Error Rom. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
47
WD Error Stack. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
48
WD Error Register. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
49
WD Error Xrl. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
50
Refhi Too Lo Error. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
51
Refhi Too Hi Error. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
52
Reflo Too Lo Error. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
53
Reflo Too Hi Error. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
54
Flame Error 2. Flame is detected in a state in which no flame is allowed to be seen Remedy: Replace the power control board The table classi…
Lockout
55
Water Level Detect. Low water level detected The table classifies it as blocking.…
Details
56
Water Level Meas. Low water level measurement error The table classifies it as blocking.…
Details
57
Low Water Cutoff Error. Low water sensor error Checks: Check the LWCO Remedy: If the LWCO is in alarm, try to reset it. The table classifies…
Details
58
Low Water Pressure Error. Low water pressure error The table classifies it as blocking.…
Details
59
Low Water Pressure Sensor. Low water pressure The table classifies it as blocking.…
Details
60
Flue Gas Error. Flue gas pressure error Checks: a- Check the flue gas pressure switches b- Check the gas pressure Remedy: a- If the flue gas…
Details
61
Return Temp Error. Return temperature is higher than stay burning temperature Checks: a- Check the return temperature sensor b- Verify the p…
Details
62
Blocked Drain Error. Block drain switch is active The table classifies it as blocking.…
Details
64
Wd Freq Error. Incorrect Frequency signal or no communication with the WD Checks: Verify the supplied 120 V ac current Remedy: a- If the sup…
Details
65
Phase Error. Hot neutral reversed Checks: Check the supply 120 V ac connection Remedy: Reverse the supply voltage polarity The table classif…
Details
66
Net Freq Error. Net freq. error detected in the main Checks: Check the frequency of the supply 120 V ac connection Remedy: a- If the supplie…
Details
67
Faulty Earth Error. Faulty earth connection Checks: Check the earth connection to the appliance Remedy: Restore the earth connection The tab…
Details
68
WD Communication Error. Watchdog communication error Remedy: Replace the power control board The table classifies it as blocking.…
Details
70
Overheat Error. Supply temp exceed the limit Checks: a- Check the pump to verify the flow circulation b- Check if the valves on hydraulic ci…
Details
72
T Supply Open. Supply sensor open Checks: a- Check the integrity of the wire connections b- Check the supply temperature sensor Remedy: a- I…
Details
73
T Return Open. Return sensor open Checks: a- Check the integrity of the wire connections b- Check the return temperature sensor Remedy: a- I…
Details
76
T Dhw Out Open. DHW sensor open Checks: a- Check the integrity of the wire connections b- Check the DHW temperature sensor Remedy: a- If the…
Details
80
T Supply Shorted. Supply sensor shorted Checks: a- Check the integrity of the wire connections b- Check the supply temperature sensor Remedy…
Details
81
T Return Shorted. Return sensor shorted Checks: a- Check the integrity of the wire connections b- Check the return temperature sensor Remedy…
Details
84
T Dhw Out Shorted. DHW sensor shorted Checks: a- Check the integrity of the wire connections b- Check the DHW temperature sensor Remedy: a- …
Details
86
T Flue Shorted. Flue sensor shorted Checks: a- Check the integrity of the wire connections b- Check the flue temperature sensor Remedy: a- I…
Details
87
Reset Button Error. Reset button error Checks: Too many reset button pushes in a 60 sec period The table classifies it as blocking.…
Details
93
Appliance Selection. Appliance selection error Remedy: Replace the power control board The table classifies it as blocking.…
Details
107
Gas Pressure Error. Gas pressure too low or too high The table classifies it as blocking.…
Details
108
Flue Press Error. Flue gas pressure error Checks: a- Check for any obstruction in the exhaust system b- Check the condensate discharge Remed…
Details
Buderus SSB255/399/512 commercial condensing boilers (IOM 6720818454)
1
Ignit Error. Three unsuccessful ignition attempts in a row Checks: a- Check gas supply pressure; b- Check ignition spark; c- Correct amount …
Lockout
2
Gv Relay Error. Failure detected in the GV (gas valve) Relay Checks: a- Check the integrity of the wire connections between gas valve and co…
Lockout
3
Gv Relay Not Open. Failure detected in the GV (gas valve) Relay Checks: a- Check the integrity of the wire connections between gas valve and…
Lockout
4
Gv Relay Not Close. Failure detected in the GV (gas valve) Relay Checks: a- Check the integrity of the wire connections between gas valve an…
Lockout
5
Safety Relay Error. Failure detected in the Safety Relay Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
6
Safety Relay Open. Failure detected in the Safety Relay Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
7
Safety Relay Closed. Failure detected in the Safety Relay Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
11
Blocking Too Long Error. Control had a blocking error for more than 20 hours in a row Checks: Press RESET button to display the Blocking err…
Lockout
12
Fan Error. Fan MF deviation for more than 60 sec Checks: a- Check for 120 Vac power connection of the fan. b- Check PWM connection of the fa…
Lockout
13
Ram Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
14
Wrong E2prom Signature. Contents of E2prom is not up-to-date Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
15
X Ram Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
16
E2Prom Error. No communication with E2prom Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
17
E2Prom Error C. Wrong safety parameters in E2prom Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
18
E2Prom Error Cal Table. Wrong calibtration table parameters Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
19
State Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
20
Rom Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
21
Rom Error C. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
22
Air Sw Not Open. Air pressure switch not working The table classifies it as lockout.…
Lockout
23
15Ms Xrl Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
24
Air Sw Not Closed. Air pressure switch not working The table classifies it as lockout.…
Lockout
25
Max. Thermostat Lock Error. The external overheat protection is activated Checks: a- Check the pump to verify the flow circulation b- Check …
Lockout
26
Stack Error. Internal error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
27
Flame Out Too Late Error. Flame still present 10 sec. after closing the gas valve Remedy: Replace the gas valve The table classifies it as l…
Lockout
28
Flame Error 1. Flame is detected before ignition Remedy: Replace the gas valve The table classifies it as lockout.…
Lockout
29
20Ms Xrl Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
30
41Ms Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
31
Too Many Flame Failures. Three times flame lost during one demand Checks: a- Check the integrity of the wire connections of the spark and th…
Lockout
32
Flow Switch Not Closed Error. Flow switch not working / No flow The table classifies it as lockout.…
Lockout
33
Flow Switch Not Open Error. Flow switch not working / No flow The table classifies it as lockout.…
Lockout
34
Flag Byte Integrity Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
35
Ad Hi Cpl Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
36
Ad Lo Cpl Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
37
Register Error. Internal software error Remedy: Replace the power control board The table classifies it as lockout.…
Lockout
38
Flue temperatire not rising. Three times no flue temperature variation for 5 minutes each Checks: Check the integrity of the flue sensor Rem…
Lockout
45
WD Error Ram. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
46
WD Error Rom. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
47
WD Error Stack. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
48
WD Error Register. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
49
WD Error Xrl. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
50
Refhi Too Lo Error. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
51
Refhi Too Hi Error. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
52
Reflo Too Lo Error. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
53
Reflo Too Hi Error. Internal software error Remedy: Replace the power control board The table classifies it as blocking.…
Details
54
Flame Error 2. Flame is detected in a state in which no flame is allowed to be seen Remedy: Replace the power control board The table classi…
Lockout
55
Water Level Detect. Low water level detected The table classifies it as blocking.…
Details
56
Water Level Meas. Low water level measurement error The table classifies it as blocking.…
Details
57
Low Water Cutoff Error. Low water sensor error Checks: Check the LWCO Remedy: If the LWCO is in alarm, try to reset it. The table classifies…
Details
58
Low Water Pressure Error. Low water pressure error The table classifies it as blocking.…
Details
59
Low Water Pressure Sensor. Low water pressure The table classifies it as blocking.…
Details
60
Flue Gas Error. Flue gas pressure error Checks: a- Check the flue gas pressure switches b- Check the gas pressure Remedy: a- If the flue gas…
Details
61
Return Temp Error. Return temperature is higher than stay burning temperature Checks: a- Check the return temperature sensor b- Verify the p…
Details
62
Blocked Drain Error. Block drain switch is active The table classifies it as blocking.…
Details
64
Wd Freq Error. Incorrect Frequency signal or no communication with the WD Checks: Verify the supplied 120 V ac current Remedy: a- If the sup…
Details
65
Phase Error. Hot neutral reversed Checks: Check the supply 120 V ac connection Remedy: Reverse the supply voltage polarity The table classif…
Details
66
Net Freq Error. Net freq. error detected in the main Checks: Check the frequency of the supply 120 V ac connection Remedy: a- If the supplie…
Details
67
Faulty Earth Error. Faulty earth connection Checks: Check the earth connection to the appliance Remedy: Restore the earth connection The tab…
Details
68
WD Communication Error. Watchdog communication error Remedy: Replace the power control board The table classifies it as blocking.…
Details
70
Overheat Error. Supply temp exceed the limit Checks: a- Check the pump to verify the flow circulation b- Check if the valves on hydraulic ci…
Details
72
T Supply Open. Supply sensor open Checks: a- Check the integrity of the wire connections b- Check the supply temperature sensor Remedy: a- I…
Details
73
T Return Open. Return sensor open Checks: a- Check the integrity of the wire connections b- Check the return temperature sensor Remedy: a- I…
Details
76
T Dhw Out Open. DHW sensor open Checks: a- Check the integrity of the wire connections b- Check the DHW temperature sensor Remedy: a- If the…
Details
80
T Supply Shorted. Supply sensor shorted Checks: a- Check the integrity of the wire connections b- Check the supply temperature sensor Remedy…
Details
81
T Return Shorted. Return sensor shorted Checks: a- Check the integrity of the wire connections b- Check the return temperature sensor Remedy…
Details
84
T Dhw Out Shorted. DHW sensor shorted Checks: a- Check the integrity of the wire connections b- Check the DHW temperature sensor Remedy: a- …
Details
86
T Flue Shorted. Flue sensor shorted Checks: a- Check the integrity of the wire connections b- Check the flue temperature sensor Remedy: a- I…
Details
87
Reset Button Error. Reset button error Checks: Too many reset button pushes in a 60 sec period The table classifies it as blocking.…
Details
93
Appliance Selection. Appliance selection error Remedy: Replace the power control board The table classifies it as blocking.…
Details
107
Gas Pressure Error. Gas pressure too low or too high The table classifies it as blocking.…
Details
108
Flue Press Error. Flue gas pressure error Checks: a- Check for any obstruction in the exhaust system b- Check the condensate discharge Remed…
Details
Talk to a boiler technician
Describe what the boiler is doing and get a straight answer about the next step.
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