Gas boiler ticking

mgray

Hi, looking for some advice about my boiler. It is used for heating the rads only and when it stops there is quite a loud ticking or clicking noice(hard to explain).
The problem started over a year ago now but has got slightly worse, where it happens almost everytime the heating turns off now whereas it used to be just sometimes. Turn the heating back on and it stops..

Asked the engineer at last service and without hearing it couldn't tell but said its prob not serious. Now service is due again soon and knowing my luck the day he comes it won't make the noice..!!

So, any ideas? Thanks in advance...

shane0007

Could be a couple of things.
It could be a heat exchanger partial blockage.
If your system is zoned, there may not be an ABV installed and the pump over-run has nowhere to pump out of the boiler to as the zone valves will be closed. An ABV will also a circuit for this.
Most likely the latter if your system is zoned & you only hear it when the boiler shuts down.
Why could your engineer not hear it?

mgray

Thanks.

The last time the engineer was here the sound was pretty rare where as now it seems to be everytime the boiler shuts down. Just this afternoon the ticking noice went on for a good 2 hours after the heating turned off. Next service due in a few weeks anyway so hopefully he hears it this time and gets it sorted..

meercat

perhaps its just the pipes contracting when they are cooling down

shane0007

mgray wrote: »

Just this afternoon the ticking noice went on for a good 2 hours after the heating turned off.

2 hours!!! Maybe it's a priest you need!

On a serious note, is your system zoned with motorized valves? If you switched the mains boiler spur off when the ticking is happening, would it stop instantly?

Dtp79

meercat wrote: »

perhaps its just the pipes contracting when they are cooling down

Are the pipes going back into the wall under the boiler op?

mgray

meercat wrote: »

perhaps its just the pipes contracting when they are cooling down

This is what the engineer sugested last year. I wouldn't know for sure but I'd imagine a contracting noice would be a slow tick but this is rapid ticking.

shane0007 wrote: »

2 hours!!! Maybe it's a priest you need!

On a serious note, is your system zoned with motorized valves? If you switched the mains boiler spur off when the ticking is happening, would it stop instantly?

Going to have to pleed pure ignorance here and say I dont know. I turn it on and the house heats.:D What I do know is that it will be an old sytem, the house being my wifes grandmothers old house, i'm guessing 20-25 years?

As for turning off the mains spur, yes that stops the noice.

Dtp79 wrote: »

Are the pipes going back into the wall under the boiler op?

Not into the wall but yes out of sight into the ceiling between floors.

Dtp79

mgray wrote: »

This is what the engineer sugested last year. I wouldn't know for sure but I'd imagine a contracting noice would be a slow tick but this is rapid ticking.



Going to have to pleed pure ignorance here and say I dont know. I turn it on and the house heats.:D What I do know is that it will be an old sytem, the house being my wifes grandmothers old house, i'm guessing 20-25 years?

As for turning off the mains spur, yes that stops the noice.






Not into the wall but yes out of sight into the ceiling between floors.

If the noise stops when the main switch is off then it's not pipes contracting so

shane0007

2 hours is a bit much for pipework noise.

It is a boiler issue. To me it is a pump issue but with motorized valves but still the 2 hour over-run is confusing. Can you feel vibration/circulation in the pipework from the boiler after it is timed off? Could be a pcb issue continuously calling in pump or a faulty ntc calling in for frost protection. Would still need a motorized valve to cause noise though so I reckon they are fitted.