HTP EFT Combi Er:43 — Burner Overheat Switch Open
Er:43
Burner overheat switch open. Press the Power button to clear the Error Code. If Error happens again: 1. Check burner overheat switch connections. Ensure connections are secure. 2. Check switch resistance. If resistance is not zero, replace the switch. 3. If the problem persists, replace the main control. The table classifies it as Error (cleared with the Power button).
Applies to
This overheating code is displayed by the NGTX-900C / P-920C_CB-HTP control (Er:## codes) on EFT Combi models (EFTC-140W/199W wall, EFTC-140F/199F floor), as documented in EFT Combi Floor Installation Manual, LP-496 Rev. 000 Rel. 013 (10.8.19), Table 26 (LP-496 Rev. 000 Rel. 013). Codes can differ between controller generations, so always check the manual that matches your unit.
Controller: NGTX-900C / P-920C_CB-HTP control (Er:## codes). Source manual: LP-496 Rev. 000 Rel. 013 (2019-10-08).
Why a code is not a diagnosis
An over-temperature code protects the heat exchanger or venting; it does not reveal whether the cause is low water flow, a failed pump, trapped air, fouling or a sensor fault.
Safe things to observe
- Note the code and whether rooms or hot water are still working.
- If you see steam, melted wiring or smell burning, switch the appliance off at its service switch and call a technician.
Do not
- Do not reset the appliance repeatedly while the cause is unknown.
- Do not remove covers or bypass any high-limit device.
How professional service helps
- A technician checks pump operation, flow, system pressure and the cleanliness of the heat exchanger.
- 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.
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 →
Service for this alert
- Gas Boiler Repair
Licensed gas technicians from ROMA Heating & Cooling diagnose and repair residential and light-commercial gas boilers across…
Every boiler part explained — what it does, how it fails and what a technician checks.
Documented for HTP EFT Combi (discontinued).
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
- EFT Combi Floor Installation Manual, LP-496 Rev. 000 Rel. 013 (10.8.19), Table 26 · LP-496 Rev. 000 Rel. 013 · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.