Is it normal for combi boiler to vent air for 30sec every few minutes?

[articoceanic]

I had plumbing work done in bathroom.

My boiler now keeps turning on for 25 seconds, i can hear it doing something like pumping air or gas or something out, and then stops for 8min and then repeats.

is this normal and I'm just noticing it now and hadn't before?

everything switched off in the flat. wondering if that normal behaviour for a combi boiler or an issue like water leak or trapped air from the plumbing works could be causing it?

I'm not seeing the tap led lighting up when it starts pumping the air/gas out. So not sure what it is doing or why.

 

[kidgreen61]

Sounds like hot water pre heat function may have been left on, check instructions for how to turn off.

 

[articoceanic]

Sounds like hot water pre heat function may have been left on, check instructions for how to turn off.

flame led doesn't turn on. so it isn't heating the water. so i don't think that is it. unless the preheat function doesn't light up the leds.

 

[DP]

Most likely dead leg.
Does the boiler do that each time a cold tap is run?

 

[articoceanic]

Most likely dead leg.
Does the boiler do that each time a cold tap is run?

happens with or without taps being used.
i think it's the vent fan. it spirals on for 10-30 seconds every 8min or so. whether boiler is being used or not.

preheat function is definitely off. so not that.

not sure what could be causing the Dan to come on so often.

 

[DP]

For the fan to operate, will be a boiler run demand or overheat function operating be it erroneously/ frost protection activation.
Post plumbing task, has to be dead leg sit trap

 

[Agile]

Telling us the boiler make and model might get you more useful replies!

 

[Madrab]

Could be any drop in the CW mains pressure activating the HW flow switch, if you're in a flat it could be any demand on the shared main causing enough of a drop in pressure to trip the sensor.

Mains tap fully open? Any noticeable change in the water pressure since the work?