Buzzing sound from Vaillant Ecotec boiler

[priceoffish]

My boiler was inspected about a month ago but tonight has suddenly started making a really loud buzzing sound (I could hear it in another room over the TV). It was on a timer so I turned the clock so it wasn't firing and after a while the buzzing stopped. I rang the guy who serviced it and he said he'd be out tomorrow and if it started buzzing again when it came on in the morning to turn it off. He thinks it's safe to leave as it is tonight (it's not due to come on again until 5am) and I've stuck a carbon monoxide monitor next to it just in case.

Just looking for any ideas as to what it could be and whether it's ok to leave it to come on in the morning?

 

[Dan Robinson]

Could be a duff solenoid in the gas valve. If it is then it is bad luck and not the guys fault.

 

[priceoffish]

Could be a duff solenoid in the gas valve. If it is then it is bad luck and not the guys fault.

Thanks. Why bad luck? Is that a big job?

 

[Dan Robinson]

Bad luck timing wise....not a big job IF it is the gas valve, but there are several other things it could be as well.

 

[priceoffish]

Great thanks. It's not buzzing when the hot water comes on demand which I guess is promising. The only thing I did differently today is have to radiators on at a slightly higher heat than usual. Oh well - at least it's not freezing outside with the heating off.

 

[Agile]

Many dumb gas people change a buzzing gas valve only to find the replacement still buzzes!

 

[GuessMan]

Sounds like the bypass on the diverter valve. Winding in the screw one an a half turns should stop it. Also, do all your Rads have TRVs? If so make sure one is left on max ( the one in the room with your room thermostat - if you have one)

 

[Dan Robinson]

Many dumb gas people change a buzzing gas valve only to find the replacement still buzzes!

Helpful.