Utica Boilers · Error codes
Utica Boilers 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.
Utica Oneida residential combi and heating boilers (CO/CH; fault codes per residential IOM E93.1907.035.915.C)
0
EEPROM Read Error. Internal software error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and / or PB display unit Th…
Lockout
1
Ignition Error. Five unsuccessful ignition attempts in a row Cause: no gas, wrongly adjusted gas valve Solving: check gas supply and ad- jus…
Lockout
2
GasValve Relay Error. Failure detected in the gas valve relay Cause: short circuit in coil of the gas valve, water on wiring or gas valve So…
Lockout
3
Safety Relay Error. Failure detected in safety relay Cause: safety relay is not working correctly Solving: reset BCU or replace BCU The tabl…
Lockout
4
Blocking Too Long Error. Control had a blocking error more than 20 hours Cause: blocking code active more than 20 hours Solving: reset and c…
Lockout
5
Fan Not Running. Fan is not running for more than 60 seconds Cause: electrical wiring is not correctly connected, or fan malfunctioning Solv…
Lockout
6
Fan Too Slow. Fan runs too slow for more than 60 seconds Cause: electrical wiring is not correctly connected, or fan malfunctioning Solving:…
Lockout
7
Fan Too Fast. Fan runs too fast for more than 60 seconds Cause: electrical wiring is not correctly connected, or fan malfunctioning Solving:…
Lockout
8
RAM Error. Internal software error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and / or PB display unit The table …
Lockout
9
Wrong EEPROM Signature. Contents of E2prom is not up to date Cause: outdated E2prom Solving: reset BCU or replace BCU The table classifies i…
Lockout
10
EEPROM Error. Wrong safety parameters in E2prom Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU The table classifies i…
Lockout
11
State Error. Internal software error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU The table classifies it as lockou…
Lockout
12
ROM Error. Internal software error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU The table classifies it as lockout.…
Lockout
15
Max. Thermostat Lock Error. The external overheat protection is enabled or the T_Supply sensor measures a temp. of over Prot_Overheat_Temp -…
Lockout
16
Max. Flue Lock Error. Flue temperature exceeded the maximum flue temperature Cause: there is no water in the heat exchanger or flue gas sens…
Lockout
17
Stack Error. Internal software error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and or PB display unit The table …
Lockout
18
Instruction Error. Internal software error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and or PB display unit The …
Lockout
19
Ion Check Failed. Internal software error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and or PB display unit The t…
Lockout
20
Flame Out Too Late Error. Flame still present 10 sec. after closing the gas valve Cause: wrong earthing of BCU and boiler Solving: check ear…
Lockout
21
Flame Before Ignition. Flame is detected before ignition Cause: wrong earthing of BCU and boiler Solving: check earthing of BCU and boiler T…
Lockout
22
Too Many Flame Failures. Three times flame lost during 1 demand Cause: bad gas supply or CO2 level is not correct or bad ignition rod Solvin…
Lockout
23
Corrupted Error Number. Error code RAM byte was corrupted to an unknown error code. Cause: wrongly programmed BCU or PB Solving: reset BCU o…
Lockout
27
Filling Too Much. Too many automated filling attempts in a short time period Cause: if output is programmed as filing valve and there are to…
Lockout
28
Fill Time Error. Filling takes too long Cause: if output is programmed as filling valve and filling takes more than 10 minutes Solving: chec…
Lockout
29
PSM Error. Internal software error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and or display unit The table class…
Lockout
30
Register Error. Internal software error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and or display unit The table …
Lockout
32
T. Exchange Diff Error. The 2 exchange sensors deviate too much for more than 60 seconds Cause: there is not enough water flow through the h…
Lockout
33
LWCO/Air intake block. Low water cut off 1 error Cause: there is no water in the heat exchanger or not electrically connected Solving: check…
Lockout
34
LWCO 2 Error. Low water cut off 2 error Cause: there is no water in the heat exchanger or not electrically connected Solving: check if there…
Lockout
38
Flue pressure Locking. More than 3 flue pressure switch errors have occurred in 24 hrs. Cause: Syphon is clogged or vent is blocked Solving:…
Lockout
100
WD Error Ram. Internal software error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and / or PB display unit The tab…
Details
101
WD Error Rom. Internal software error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and / or PB display unit The tab…
Details
105
High Temp Error. T_Supply sensor measures over stay_Burning_Temp for a period of Max_Value_Period. Cause: not enough waterflow causes overhe…
Details
106
Refhi Too Hi Error. Internal hardware error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and / or PB display unit T…
Details
107
Refhi Too Lo Error. Internal hardware error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and / or PB display unit T…
Details
108
Reflo Too Hi Error. Internal hardware error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and / or PB display unit T…
Details
109
Reflo Too Lo Error. Internal hardware error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and / or PB display unit T…
Details
110
Refhi2 Too Hi Error. Internal hardware error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and / or PB display unit …
Details
111
Refhi2 Too Lo Error. Internal hardware error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and / or PB display unit …
Details
112
Reflo2 Too Hi Error. Internal hardware error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and / or PB display unit …
Details
113
Reflo2 Too Lo Error. Internal hardware error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and / or PB display unit …
Details
114
False Flame. Flame is detected in a state in which no flame is allowed to be seen Cause: wrong earthing of BCU and boiler Solving: check ear…
Lockout
116
Low Water Pressure Sensor. Low water pressure, occurs when the pressure drops below drops below 11.6 psi. Cause: not enough water pressure S…
Details
118
WD Communication Error. Watchdog communication error Cause: wrong programmed BCU or PB Solving: reset BCU or replace BCU and / or PB display…
Details
119
T Return Open. Return sensor open Cause: malfunctioning return sensor or not connected Solving: check connection to BCU or check resistance …
Details
120
T Supply Open. Supply sensor open Cause: malfunctioning supply sensor or not connected Solving: check connection to BCU or check resistance …
Details
122
T DHW Open. DHW sensor open Cause: malfunctioning DHW sensor or not connected Solving: check connection to BCU or check resistance NTC senso…
Details
123
T Flue Open. Flue sensor open Cause: malfunctioning or not connected flue sensor Solving: check connection to BCU or check resistance NTC se…
Details
125
T Outdoor Open. Outdoor sensor open Cause: malfunctioning or not connected outdoor sensor or wrong CH- mode programmed Solving: check connec…
Details
126
T Return Shorted. Return sensor shorted Cause: malfunctioning return sensor or short circuiting Solving: check connection to BCU or check re…
Details
127
T Supply Shorted. Supply sensor shorted Cause: malfunctioning supply sensor or short circuiting Solving: check connection to BCU or check re…
Details
129
T DHW Shorted. DHW sensor shorted Cause: malfunctioning DHW sensor or short circuiting Solving: check connection to BCU or check resistance …
Details
130
T Flue Shorted. Flue sensor shorted Cause: malfunctioning flue sensor or short circuiting Solving: check connection to BCU or check resistan…
Details
132
T Outdoor Shorted. Outdoor sensor shorted Cause: malfunctioning outdoor sensor or short circuiting Solving: check connection to BCU or check…
Details
134
Reset Button Error. Too many resets in a short time period Cause: reset too many times by user or installer Solving: wait or disconnect and …
Details
136
T_Exchange Block Error. Exchange temperature exceeded 194 ºF (90 ºC). Cause: water temperature is above 194 ºF (90 ºC). Solving: check circu…
Details
155
WD Config Error. Watchdog fan confi- guration setting error Cause: wrongly programmed BCU or PB Solving: reset BCU or replace BCU and / or P…
Details
156
Flue Pressure Error. Flue pressure switch is closed Cause: Syphon clogged or vent blocked Solving: Clean syphon. Check vent. The table class…
Details
164
Ex. Low Flow Protection. Flow is too low, demand needs to be stopped with fan at ignition speed*, but no error needed to be stored at this t…
Lockout
168
Flue Temperature too high. Flue sensor measures above 203°F Cause: Dirty combustion chamber Solving: Clean the combustion chamber, especiall…
Details
169
ADC Unstable. ADC measurements detected too many unstable measurements Cause: Defect sensor or unstable 0-10V input signal Solving: Check se…
Details
200
Comm. Lost with module. Cascade System: Managing cascade control lost communication with one of the depending. Cause: connection between cas…
Details
202
App. Selection Error. Unknown appliance model selected Cause: wrongly programmed parameters Solving: replace BCU The table classifies it as …
Details
203
Comm. Lost with boiler. Dual Cascade System: Managing cascade control lost communication with one of the depending. Cause: connection betwee…
Details
204
T Outdoor Wrong. T_Outdoor sensor measures open or shorted Cause: malfunctioning outdoor sensor or not connected or wrong CH-mode programmed…
Details
205
T System Wrong. T_System sensor measures open or shorted Cause: malfunctioning system sensor or not connected Solving: check connection to B…
Details
206
T Cascade Wrong. T_Cascade sensor measures open or shorted Cause: malfunctioning cascade sensor or not connected Solving: check connection t…
Details
207
Heat-Exchanger protection active. The heat-exchanger protection function is actively blocking the burn demand The table classifies it as war…
Details
Utica SSC condensing boilers (E-codes, IOM 240011320 Rev G)
E33
External voltage sent back to control board on DHW T-T or CH T-T terminals. E33 error code is displayed if voltage is sent back to the contr…
Details
E35
False flame detect. Blocking error E35 "False flame detect". Boiler may be running at any firing rate. Tree asks whether flame signal is gre…
Lockout
E36
Low water cutoff test message. "Low Water" LED should illuminate and burner should shut down during LWCO test; error message E36 shown on Us…
Details
E39
Flue Temperature Sensor (flue gas temperature). Shut off burner E39 "Flue Temperature Sensor". This is a soft lockout; when the flue sensor …
Details
E40
Return Water Temp (return water temperature). Shut off burner E40 "Return Water Temp". This is a soft lockout; when the water temperature dr…
Details
E44
Neutral wire fault (power supply wiring). Boiler is powered by three wires - hot, neutral and ground. E44 displays when the neutral wire is …
Details
E45
Net frequency error (power supply frequency). Blocking error E45 "Net frequency error". Is power supply between 59 and 61 Hz? Provide freque…
Details
E46
Faulty ground (grounding conductor). Blocking error E46 "Faulty ground". Is the field grounding conductor connected to the high voltage term…
Details
E51
Supply Sens Open (supply water sensor). Blocking error E51 "Supply Sens Open". Is the harness plugged into the Supply Water Sensor and into …
Details
E52
Return Sens Open (return water sensor). Blocking error E52 "Return Sens Open". Check return water sensor harness connections and sensor resi…
Details
E60
Return sens shorted (return water sensor). Blocking error E60 "Return sens shorted". Check return water sensor for short circuit; see tree p…
Details
E65
Flue Sens Shorted (flue temperature sensor). Blocking error E65 "Flue Sens Shorted". Check flue temperature sensor for short circuit; see tr…
Details
A-06
Safety Relay Error (manual reset lockout). Lockout A-06 "Safety Relay Error". Requires manual reset of the control module: press the Reset b…
Lockout
Utica MAC/MAH wall condensing boilers (fault codes, I&O 240013687 Rev A)
09
Gas valve connection fault. Check cable PCB/gas valve and gas valve plug The table classifies it as error.…
Details
10
Outdoor sensor fault. Check sensor and cable The table classifies it as error.…
Details
15
Gas valve command fault. Verify all cables. Replace PCB. The table classifies it as error.…
Details
20
Central Heating NTC sensor fault. Check sensor and cable The table classifies it as error.…
Details
28
Flue NTC heat exchanger sensor fault. Check sensor and cable The table classifies it as error.…
Details
40
Return NTC sensor fault. Check sensor and cable The table classifies it as error.…
Details
50
Domestic Hot Water NTC sensor fault. Check sensor and cable The table classifies it as error.…
Details
53
Obstruction in flue pipe, Recirculation, Out of Calibration, Poor gas quality. Check for obstruction in flue pipe. Check gas pressure, check…
Details
55
PCB not programmed. Follow instructions provided with control board replacement kit, call technical service for assistance. The table classi…
Details
E72/E92
Combustion test alarm during commissioning / calibration. Check flame sensor, check for obstruction in flue pipe, check for recirculation, c…
Details
78
Minimum gas valve IMOD current. Check gas supply pressure. Check the correct position and integrity of the sensing electrode. Check and clea…
Lockout
79
Maximum gas valve IMOD current. Auto calibrate, manual calibrate if necessary. Replace components if all else fails. The table classifies it…
Details
E83
OT Communication Failure. Check OT connection, remove power, reconnect OT connections, if problem persists replace service key. The table cl…
Details
84-85
Communication problem between boiler board and control unit. Probable short circuit on wiring. Check cable between control unit and boiler. …
Details
86-87
Communication problem between boiler board and control unit. Probable short circuit on wiring. Check cable between control unit and boiler. …
Details
109
Pre-circulation alarm (temporary fault). Check correct circulation of water and pump. Check supply and return wiring is correct. The table c…
Details
110
Safety thermostat tripped due to over temperature (pump probably blocked or air in heating circuit). Check safety thermostat and cable; chec…
Details
117
Hydraulic pressure too high. Relieve pressure via relief valve or drain. Ensure water feed is operating correctly. The table classifies it a…
Details
118
Hydraulic pressure too low. Refill heating system by opening cold water tap. The table classifies it as error.…
Details
125
No circulation of water (control performed via temperature sensor). Check correct circulation of water and pump. Check correct connection of…
Details
128
Loss of flame 8 consecutive times after flame proving stage. Check sensing electrode and cable, flue recirculation, electrical continuity be…
Details
130
NTC flue sensor tripped due to over temperature. Check thermostat, correct circulation of water and pump. Check status of primary exchanger.…
Details
131
Thermo fuse tripped due to over temperature or wire harness disconnected from thermo fuse, off the board, or wire harness may be cut. Check …
Details
133
Ignition failure. Check correct operation of condensate trap. Check sensing electrode, spark electrode and cable. Check flue recirculation, …
Lockout
134
Gas supply valve blocked. Check gas pressure, sensing electrode, spark electrode and cable, replace PCB if it necessary. The table classifie…
Lockout
135
Internal error. Verify all cables. Replace PCB. The table classifies it as error.…
Details
160
Fan fault. Check fan and cable. The table classifies it as error.…
Details
162/317
Incorrect power supply frequency. Incorrect power supply frequency. The table classifies it as error.…
Details
169
Flue pressure switch (contact open). Check pressure switch and cable. Check obstruction on flue pipe. The table classifies it as error.…
Details
164/384
Fault flame (parasitic flame). Check correct operation of T. gas valve. The table classifies it as error.…
Details
165/385
Input voltage too low. Check power supply. The table classifies it as error.…
Details
E178
Low return water temperature / anti-freeze function active. Check the return water sensor, check the circulator, check the correct circulati…
Details
E62
Anti-wind activation with increase of the minimum fan speed. Check the position of the terminal of the flue duct. The table classifies it as…
Details
E63/E65
Combustion level out of range. Check flue recirculation and combustion levels. The table classifies it as error.…
Details
E65
Maximum value of the speed reached / correction of the flame signal. Check flue recirculation on the flue duct. The table classifies it as e…
Lockout
E67
Anti-wind activation at maximum power. Check the position of the terminal of the flue duct. The table classifies it as error.…
Details
E69
Combustion level out of range. Check flue recirculation and the combustion levels. The table classifies it as error.…
Details
E70
Flame signal problem/micro interruption of the flame signal. Check cable and integrity of the sensing electrode, verify the continuity betwe…
Lockout
E73
Combustion adjustment / modified during operation. Review and monitor other codes such as E53 and E92. The table classifies it as error.…
Details
Utica cast-iron boilers MGB-K / MGC Series 4 (LED diagnostic codes)
LWCO LOW WATER (on)
Low water condition detected. The red Low Water light on solid indicates the control is not detecting water in the boiler; the Fuel Smart Hy…
Details
LWCO LOW WATER (blinking)
Low water cut-off lockout (manual reset mode). When the low water condition is sustained for 30 seconds with manual reset mode active, the L…
Lockout
LIMITS (blinking)
External limits open. The LIMITS light illuminates on a call for heat when external limits are satisfied; if the external limits are open (f…
Details
V-SW (blinking)
Vent damper end switch failed to make. The V-SW light illuminates when the vent damper switch has made; if the damper end switch fails to ma…
Details
FLAME (blinking)
Pilot flame not sensed / flame lost. The FLAME light illuminates when the pilot flame is lit; it blinks if the pilot flame is not sensed wit…
Lockout
LWCO LOW WATER (on)
Low water condition detected. The red Low Water light on solid indicates the boiler is in a low water condition; the HydroStat control preve…
Details
LWCO LOW WATER (blinking)
Low water cut-off lockout (manual reset mode). If the low water condition is sustained for 30 seconds, the LOW WATER light blinks to indicat…
Lockout
DAMPER POWER LED (blinking, burner not firing)
Vent damper circuit not proven. The DAMPER POWER LED indicates the control is energizing the vent damper (or, when the damper is not plugged…
Details
Talk to a boiler technician
Describe what the boiler is doing and get a straight answer about the next step.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.