Carrier BWC/BWH E091 — Clean Primary Heat Exchanger
E091
Clean primary heat exchanger. The boiler calls for cleaning of the primary heat exchanger; the manual lists it as a transitional alarm with the RED and GREEN LEDs flashing and notes the maintenance interval or this alarm requires the annual service. The table classifies it as transitional.
Applies to
This maintenance or informational code is displayed by the BWC/BWH control (E-code display with MENU/RESET) on BWC/BWH models (BWCAAG000120–150 combi and BWHAAG000120–150 heating-only), as documented in Carrier/Bryant BWC/BWH Gas-Fired Wall-Hung Condensing Boiler User's Information Manual, doc OG-BWC-H-01 (07/2020), Section 3.14 boiler faults list and combustion faults list (OG-BWC-H-01). Codes can differ between controller generations, so always check the manual that matches your unit.
Controller: BWC/BWH control (E-code display with MENU/RESET). Source manual: OG-BWC-H-01 (2020-07).
Why a code is not a diagnosis
This class of message is informational or maintenance-related: the appliance keeps running (or limits output) until the service is performed. No fault may exist beyond the interval being due.
Safe things to observe
- Book the scheduled service; the appliance will tell you when the interval is reached.
Do not
- Do not clear maintenance messages without the maintenance being performed.
How professional service helps
- A technician performs the manufacturer's scheduled maintenance and resets the counter as part of the service.
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 →
Service for this alert
- Gas Boiler Repair
Licensed gas technicians from ROMA Heating & Cooling diagnose and repair residential and light-commercial gas boilers across…
- 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 Carrier Carrier BWC/BWH (legacy wall-hung condensing gas boilers).
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
- Carrier/Bryant BWC/BWH Gas-Fired Wall-Hung Condensing Boiler User's Information Manual, doc OG-BWC-H-01 (07/2020), Section 3.14 boiler faults list and combustion faults list · OG-BWC-H-01 · accessed September 9, 2026
Facts checked September 9, 2026. Last updated September 9, 2026. Technical reviewer: not yet assigned.