Expansion tank back filling

[Telbert]

Hello guys and girls,

I'm really quite rubbish at this stuff so please talk to me like I'm simple.

My overflow has been running for weeks and now my boiler has stopped working properly, I suspect they related. The boiler runs for about 10 seconds then stops with pipes banging and clanking.

I went into the roof to investigate and this is what I did and know.

Trained 2 buckets from expansion tank. Sat and watched for 20 mins, the expansion tank refilled, not from ballcock or from overflow vent pipe, it appears to be back filling from the feed pipe at the bottom.

It does this slowly and seems to be in conjunction of those 10 seconds when the boiler is trying to run. The water in the expansion tanks moves about a bit and few bubbles come out from the bottom where the feed pipe is, when this happens the level rises by a few MM.

The tank in the airing cupboard is newish, about 2 years I think.

Any ideas gratefully received.

 

[ShaunCorbs]

do any of the rads get warm, as there might be a blockage

 

[Unregistered]

They did up until the boiler stopped running today. Is it worth adding the expansion tank is back filling with warm/hot water

 

[plumben]

Can you register with the forum then take pictures of your set up in the loft,

If its not filling from the ball valve then you've got a split/leak in the cylinder coil as there shouldn't be any additional water in the system to fill the tank

 

[Unregistered]

I will register now, and post pictures tomorrow.

Is the the cylinder coil the tank in the cupboard? If so should it have failed after 2 years?

Thank you you for help so far

 

[plumben]

I will register now, and post pictures tomorrow.

Is the the cylinder coil the tank in the cupboard? If so should it have failed after 2 years?

Thank you you for help so far

The cylinder is the tank in the cupboard yes, it shouldn't of failed but that all depends on system condition really, could be fault from manufacturing though, that's if it is the coil

 

[Telbert]

 

[BLOD]

Had a good few gledhil cylinder coils fail 7 or 8 years ago, never used them since !
If possible move the magnetic filter to the return before the boiler unfortunately yours isn't doing much where it is.

 

[jonnyswamp]

Did the tank completely refill when you drained two buckets full out ?

 

[AWheating]

When the heatings turned on does the pump run and does the 3 port valve move and allow heating down the heating side? Or the same when the hot water is turned on but the hot we're side

 

[Eric withy]

Sounds like coil gone in the cylinder if expansion tank overflowing

 

[joni os]

Could be coil as stated by others, but before expensive works, check non return valves on any situation where cold blends with hot water.
If it definitely is F&E tank ignore above, but your original post spoke of Tanks. The above would apply to Cold water storage tank.