Boiler locked out after a cold snap? Frozen condensate, frost-stat trips and overheat cut-outs are common in London winters. We diagnose, recover and prevent it happening again.
What we do for a frost-related lockout
Inspect external condensate pipe for ice plug, lag with foam insulation if missing, reset frost-stat and overheat cut-out, check expansion-vessel charge (cold weather often exposes a marginal vessel), and run a full FGA before signing off.
Common frost-related faults
F22 / FH1 / EA338 lockout overnight
Condensate pipe outside has iced up. Pour warm water on it for a temporary fix; we lag it properly to prevent recurrence.
Boiler won't fire below freezing
Frost-stat is doing its job. If it's nuisance-tripping above freezing, the sensor has drifted.
No central heating but hot water works
Diverter valve has stuck during the cold snap. Often a free recovery before quoting for replacement.
Heating cuts in and out cycling fast
Frost protection mode interfering with normal operation. Reset and recommission.
What it costs (indicative)
Most frost-related recoveries complete inside the one-hour minimum labour charge. Lagging materials charged at trade plus 30%. Full pricing.
When to call us
- ✔ Your boiler has locked out after temperatures dropped below freezing.
- ✔ The external condensate pipe is uninsulated.
- ✔ Your boiler has frost-related lockouts year after year.
- ✔ You're a landlord with tenants reporting cold-snap heat loss.