Lochinvar Boiler: Poor circulation
If a Lochinvar boiler fires but rooms stay cold, hot water is not circulating — a failing pump, trapped air, a closed or stuck valve, or a blocked strainer. Poor flow also makes the boiler overheat and lock out.
If a Lochinvar boiler fires but rooms stay cold, hot water is not circulating — a failing pump, trapped air, a closed or stuck valve, or a blocked strainer. Poor flow also makes the boiler overheat and lock out. On Lochinvar boilers, this is linked to 2 fault codes (Outlet High Limit, Flow Switch Open). Below are the likely causes, the safe checks you can make, and exactly what our licensed BC gas technicians do — because boiler repair in British Columbia is licensed gas work, not a DIY job.
Boiler repair is licensed gas work in BC. The checks below are the safe limit of DIY. Do not open the boiler or work on gas, combustion or safety controls — read the fault code, reset at most once, and call a licensed technician if it returns.
What you might notice
- No or weak heat
- Overheat or flow faults under load
- Pump running but rooms stay cold
- Boiler locks out under load
- Hot or burning smell near the unit
- Heat that starts then cuts out
Safe checks you can make first
These are the only steps a homeowner should take. If they don’t resolve it, stop — the rest is licensed gas work.
- 1Feel whether the pump is warm and running (a silent, cold pump may have failed)
- 2Bleed radiators that are cold at the top
- 3Check no zone or service valves have been left closed
- 4Confirm pressure is normal, then call us to test flow
Related Lochinvar fault codes
These Lochinvar codes are commonly behind “poor circulation”. Tap any code for its full meaning, causes and fix.
What our licensed technicians do
- Test circulator-pump operation and speed
- Purge trapped air and check for air-bound zones
- Inspect zone/mixing valves and strainers for blockage
- Confirm correct flow rate and stable temperatures
- Check circulation: pump operation, air-bound zones, closed valves and flow rate
- Inspect the heat exchanger and strainer for blockage or scale
Lochinvar poor circulation — FAQ
Why are my rooms cold even though my Lochinvar boiler is running?
If a Lochinvar boiler fires but rooms stay cold, hot water is not circulating — a failing pump, trapped air, a closed or stuck valve, or a blocked strainer. Poor flow also makes the boiler overheat and lock out. The related Lochinvar fault codes are Outlet High Limit, Flow Switch Open. A licensed technician confirms the true root cause with the right instruments before any repair.
Is it safe to keep resetting my Lochinvar boiler when it shows "poor circulation"?
Reset it at most once. If "poor circulation" returns, the boiler is telling you there is a real fault that needs diagnosing — continuing to reset it can make things worse. Call GasBoilers.ca at 604-359-1081 and a licensed technician will find the cause.
Can you repair a Lochinvar boiler with this problem in Greater Vancouver?
Yes. Our Red Seal–certified, TSBC gas-licensed technicians diagnose and repair Lochinvar Knight, WHN and SMART System series across Vancouver, Burnaby, Surrey, Richmond, the Tri-Cities and the rest of Greater Vancouver. Same-day appointments are often available — call 604-359-1081.
“Poor circulation” on other boiler brands
Lochinvar boiler poor circulation? We can help today.
Licensed, Red Seal–certified gas technicians across Greater Vancouver. Upfront pricing, same-day service available.