Lochinvar Crest Fan Speed Low — Actual Fan Rpm is 30% Lower Than What is Being Called for
Fan Speed Low
Actual fan RPM is 30% lower than what is being called for. The actual fan RPM is 30% lower than what is being called for, so check that vent and air intake lengths do not exceed the maximums in the General Venting section of the Crest Installation and Operation Manual, check for obstructions in the vent and air intake pipes or at terminations, check the wiring connections at the fan and at the main control board, replace the fan, and replace fuse F2 on the control board if blown. The table classifies it as Lockout (manual reset).
If a carbon-monoxide alarm sounds
- Leave the building immediately and get fresh air.
- Call 911. Do not go back inside until emergency services say it is safe.
- Have every fuel-burning appliance inspected before use.
Only after that, call ROMA about the boiler. Official guidance: Health Canada on carbon monoxide.
Applies to
This venting or air-supply fault code is displayed by the Crest control (text faults) on Crest with Hellcat models (FCB1000 through FCB6000), as documented in Crest with Hellcat (FCB) Service Manual, 100343237 Rev D — Table 3G fault codes (100343237 Rev D). Codes can differ between controller generations, so always check the manual that matches your unit.
- Lochinvar Crest (FB / Hellcat FCB)
- Lochinvar Crest FBN0751
- Lochinvar Crest FBN1001
- Lochinvar Crest FBN1251
- Lochinvar Crest FBN1501
- Lochinvar Crest FBN1751
- Lochinvar Crest FBN2001
- Lochinvar Crest FBN2501
- Lochinvar Crest FBN3001
- Lochinvar Crest FBN3501
- Lochinvar Crest FBN4001
- Lochinvar Crest FBN5001
- Lochinvar Crest FBN6001
- Lochinvar Crest FCB1000
- Lochinvar Crest FCB1500
- Lochinvar Crest FCB2000
- Lochinvar Crest FCB2500
- Lochinvar Crest FCB3000
- Lochinvar Crest FCB4000
- Lochinvar Crest FCB5000
- Lochinvar Crest FCB6000
Controller: Crest control (text faults). Source manual: 100343237 Rev D (2025-07).
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.
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 →Vent terminal
The vent terminal is where a boiler's exhaust and combustion-air pipes meet the outdoors, and keeping it clear is one of the few combustion tasks a…
What a technician checks →Boiler venting (flue and air intake)
A condensing boiler vents cool, wet flue gases through dedicated plastic pipe that must meet ULC S636 in Canada and the boiler manufacturer's own…
What a technician checks →Control board / PCB
The control board — also called the PCB, or printed circuit board — is the boiler's main computer.
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.
Every boiler part explained — what it does, how it fails and what a technician checks.
Documented for Lochinvar Crest (FB / Hellcat FCB).
Frequently asked questions
Is this code a carbon-monoxide danger?
The code relates to combustion or venting, so treat any CO alarm as an emergency and call 911 from outside. The appliance itself should be checked by a technician before it runs again.
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
- Crest with Hellcat (FCB) Service Manual, 100343237 Rev D — Table 3G fault codes · 100343237 Rev D · accessed September 7, 2026
Facts checked September 7, 2026. Last updated September 7, 2026. Technical reviewer: not yet assigned.