Blocked Condensate Pipe
The boiler stops with a fault, sometimes with a gurgling sound, most often during a cold spell..
The boiler stops with a fault, sometimes with a gurgling sound, most often during a cold spell.
What is actually going on
The boiler stops with a fault, sometimes with a gurgling sound, most often during a cold spell.
The realistic causes, in order
Ice in an external condensate run, particularly where the pipe is undersized or has a long horizontal section Sludge or debris in the trap inside the boiler A poorly routed pipe with a section that holds water and freezes first
What we test on site
Pipe diameter, fall and route against current best practice for external runs Trap condition and cleanliness Whether an internal termination is achievable, which removes the freezing risk altogether
Questions we get asked
What causes a blocked condensate pipe on a gas boiler?
Ice in an external condensate run, particularly where the pipe is undersized or has a long horizontal section
What normally puts a blocked condensate pipe right?
Thawing restores service immediately; re-routing or upsizing the pipe prevents next winter's repeat.
Is it safe to keep using the system with a blocked condensate pipe?
Never use boiling water on a frozen pipe and never work at height on a ladder to reach one. Re-routing internally is the permanent answer where it's possible.