Help & Diagnosis
Frozen condensate pipe? Thaw it safely in 10 minutes
A boiler locking out in cold weather with an error code in the F1/E1 range is almost always a frozen condensate pipe. You can usually thaw it yourself — but only with warm water, never boiling.
Common causes
1. Cold snap below freezing
Condensate pipes routed outside are vulnerable any time temperatures drop below zero.
2. Long external pipe runs
Pipes that travel a long way before discharging are more prone — proper insulation or rerouting fixes it.
3. Undersized pipework
22mm pipework holds heat better than 21.5mm. An engineer can upgrade it for you.
Try these first
- Locate the white plastic pipe leaving the boiler (usually exits to a drain outside).
- Pour warm — not boiling — water over the most exposed section.
- Once thawed, reset the boiler from the front panel.
- Insulate the pipe with foam lagging to prevent it happening again.
Still stuck?
If it keeps freezing every winter, we can reroute or upsize the condensate run. Call 07508 207 799 — we cover Dereham, Norwich and all of Norfolk.
Call 07508 207 799