HTP Ultra Er:16 — CH Supply Temperature Sensor Detects Water Temperature Greater Than 200°f (auto Reset)
Er:16
CH Supply Temperature Sensor Detects Water Temperature Greater Than 200°F (Auto Reset). Over-temperature safety: Er:16 displays when the CH supply sensor measures 200°F (93.3°C), shutting down the burner and running the fan and pumps to cool the heat exchanger. The boiler restarts once temperature falls below 192°F and the programmed setpoint; at 210°F (98.8°C) a manual reset is required. Check that dip switch High Fire is OFF (switches 6 and 7), the CH inlet pipe is not blocked, and the CH outlet and operating temperature sensors are not zero resistance. The table classifies it as Soft lockout (auto reset below 192°F, manual reset at 210°F).
Applies to
This venting or air-supply fault code is displayed by the UFT control (Er:## codes) on UFT models (UFT-080W through UFT-199W), as documented in UFT Boiler Installation Start-Up Maintenance Parts Warranty, lp-542 Rev.002 (6.9.20) (lp-542 Rev.002). Codes can differ between controller generations, so always check the manual that matches your unit.
- HTP Ultra (UFT & EFTU)
- HTP UFT-80W
- HTP UFT-100W
- HTP UFT-120W
- HTP UFT-140W
- HTP UFT-175W
- HTP UFT-199W
- HTP EFTU-85WBN
- HTP EFTU-110WBN
- HTP EFTU-150WBN
- HTP EFTU-199WBN
- HTP EFTU-110WCN
- HTP EFTU-150WCN
- HTP EFTU-199WCN
Controller: UFT control (Er:## codes). Source manual: lp-542 Rev.002 (2020-06).
Why a code is not a diagnosis
A venting or air-supply code points at the combustion-air path: a blocked terminal, a restricted flue, a failed fan, or a condensate restriction. It does not say which, and running an appliance with a blocked flue is unsafe.
Safe things to observe
- If a carbon-monoxide alarm sounds anywhere in the building, leave immediately and call 911 from outside.
- From a safe distance, check that the vent terminal and combustion-air inlet are not blocked.
- Do not run the appliance while a blockage is suspected.
Do not
- Do not put anything into the vent or air-intake openings.
- Do not remove or modify vent pipe.
How professional service helps
- A technician inspects the full vent and combustion-air path, clears blockages and checks the fan.
- Combustion and safety devices are verified with an analyser and the manufacturer's procedure after any repair.
Where ROMA provides on-site service
On-site service is currently offered in Greater Vancouver, BC, including Vancouver, Burnaby, Richmond, Surrey, Coquitlam, North Vancouver, West Vancouver, New Westminster, Port Coquitlam, Port Moody, Delta, Langley, Maple Ridge, Abbotsford, Chilliwack, White Rock, Pitt Meadows, Tsawwassen, Anmore, Lions Bay, Belcarra, Bowen Island, Mission. Everything else on this site is reference information you can use anywhere in Canada.
Parts and service
Parts commonly involved
These parts appear in the documented text for this alert. A code reports a condition, not a failed part — a technician confirms the cause by testing before anything is replaced.
Heat exchanger
The heat exchanger is where a boiler transfers heat from the burner flame to the water that heats your home.
What a technician checks →Combustion fan (blower)
The combustion fan is the sealed boiler's lungs: it draws in combustion air, keeps the burner's gas-air mixture correct, and pushes flue gases out…
What a technician checks →Burner assembly
The burner assembly is where gas and air meet and burn inside a boiler, and its condition decides whether combustion is clean or makes carbon…
What a technician checks →Boiler sensors (thermistors)
Boiler sensors are small temperature probes, usually thermistors, that tell the control how hot the water and flue gases are so it can fire safely…
What a technician checks →
Service for this alert
- Gas Boiler Repair
Licensed gas technicians from ROMA Heating & Cooling diagnose and repair residential and light-commercial gas boilers across…
- Emergency Boiler Repair
Priority gas boiler repair for homes and buildings in Greater Vancouver with no heat, no hot water, a locked-out boiler or a leak.
- Gas Boiler Replacement
ROMA replaces old, failed or inefficient gas boilers in Greater Vancouver, handling removal, venting and gas-supply changes,…
Every boiler part explained — what it does, how it fails and what a technician checks.
Documented for HTP Ultra (UFT & EFTU).
Frequently asked questions
Can I clear this code myself?
Clearing a code without fixing its cause usually just brings it back. Note the code, check the safe items on this page, then call a licensed technician. If your appliance manual describes a user reset for this exact code and it stays away, no call may be needed.
Boiler locked out? Call with the alert text ready.
The brand, model and this alert are passed along when you request service online, so the technician arrives prepared.
On-site service in Greater Vancouver, BC. ROMA lists “Open 7 days” on its site; call to confirm same-day availability.
Sources and verification
- UFT Boiler Installation Start-Up Maintenance Parts Warranty, lp-542 Rev.002 (6.9.20) · lp-542 Rev.002 · accessed September 8, 2026
Facts checked September 8, 2026. Last updated September 8, 2026. Technical reviewer: not yet assigned.