vaillant ecotec 831 making puffing noises

[boilerdunce2]

our vaillant combi boiler is three years old and has recently started making puffing-type noises.

It seems to happen about three times a day, first around 7am (approx half an hour after central heating comes on) then around 5pm (hour after heating comes back on, then again around 11pm

The puffing noises can be as often as every 1-2 seconds for up to 10 minutes although there are other times when it only seems to be every 3-4 seconds for less then a minute.

I've had a look for any fault code and none is showing.

Apart from these noises the boiler seems to be working oK

what could be causing this?

 

[mickyg]

I know these boilers quite well and yet I've never heard anything that I would describe as "puffing" nor can I think what it would sound like. A recording might be useful or a comparison to what else it sounds like.

 

[Netdragon]

Without digging out my Vall cd for the manual to me i would look at the condense if its frozen outside, the best way would be to check the condense trap on the boiler depending on the design one side may be full and the other should not its like a sink trap on a sink.

If its a bottle check if the bottle is full of water if so consult the manual some boilers need a basic level of water.

that can be a common cause and if the condense has frozen and back filled into the boiler it could make a gurgling or a steam engine as it moves as an example which kinda fits the problem you are having and a few hours after firing up is enough time for the boilers condense and a short length of pipe to fill up.