Keston C36 boiler vibrations

[Scrumking]

Hello everyone,

I hope some one can help as even my corgi gas man is stumped.
I have a Keston C36 installed nearly 2 years ago. The first year was fine and then the vibrating started. When the heating is called for it makes generally three to four vibrations and then everything is fine. This is totally random and othertimes it`s quiet and also this does not affect the hot water as this is always quiet too. I even made video footage of it happening as it could be fine for days and then suddenly in the middle of the night it would happen. My corgiman has striped it down and put it back together and you think it`s fine and then it happens again.
Any suggestions would be greatly appreciated as i have a one year old who is woken up during the night due to this.

Many Thanks,

Dave

 

[simond]

My corgiman has striped it

Really? What colours did he use?

Are you sure it isn't a wayward TRV? Do you have TRVs on every rad and is an auto bypass fitted?

 

[ChrisR]

Has your Corgi man checked its combustion with a flue gas analyser?

 

[Scrumking]

I have new thermostatic trv`s fitted on every radiator when the boiler was first installed and also a bypass valve fitted ( like a small loop in the system ) if all the thermostatic valves were shut but they never have been and this is set half way at 3 , the range is between 0 and 6.

Also my corgiman has checked its combustion with a flue gas analyser and found nothing wrong which puzzled him as he felt the noise was probably due to a lack of gas at the initial firing stage.

I can email video footage with sound if anyone wishes.

Thanks for any help

Cheers Dave

 

[BigBurner]

It could be a sticking zone valve on the CH. It make be closed and no flow through the boiler and burner on. Then valve open with pressure.