On 17 Apr 2021 07:34:07 GMT, Tim+ wrote:

RJH wrote:
The condensate from my combi boiler drains via a connection at the kitchen
sink waste. Whenever the sink is emptied (etc.) this produces a bubbling sound
from the boiler, which I'd guess is caused by suction acting on the condensate
reservoir/trap inside the boiler.

I'm not sure if it's doing any harm, but was thinking about the best way to
stop this happening, short of relocating the drain pipe. Suggestions please .
.


I don’t think it’s doing any harm. I don’t think the condensate trap is
there to provide any sort of fume barrier, it’s just to turn a steady
trickle of condensate into an intermittent rush (which is much less likely
to freeze up). If it’s making a bubbling sound this would imply it’s just
drawing air through condensate that is still in the trap rather than
emptying the trap.

I could be wrong though.

Tim
I was told by the people who service my Worcester Bosch ch boiler that
the condensate trap is there to both prevent fumes (CO) escaping from
the boiler and to provide bursts rather than dribble of condensate to
resist freezing if being routed outside.