expansion tank constantly overflowing

[MikePz]

does anyone have some advice on the following

I have a gravity fed system, gas bolier (20 yrs old but still going well). the loft expansion tank is constantly overflowing with a steady trickle.

the drip began soon after we had some bathroom work done (new shower, radiator, taps) last week. i have done the following -
replaced the ball valve and monitered it - all ok
isolated all mixer taps and shower - no effect

the water causing the overflow is coming back up the outlet pipe near the base of the tank. the flow back is constant whether or not the heating or hot water is on.

any advice woyld be appreciated.

 

[muggles]

Do you have a hot water cylinder? If so, is the cold water storage tank that feeds it above your F&E tank? My money is on your cylinder coil being split

 

[seco services]

My money is on your cylinder coil being split

Sounds as good as any

 

[MikePz]

the system does have a hot water cylinder and the CW storage tank is on the same level as the expansion tank.

I was dreading the responses being a split coil, after a tidy sum spent on doing up the bathroom a further expense (a big one) is not really desired.

if it is a split coil a further question is whether to replace the cylinder which is part of a 20 yr old system or do away with the tank and replace the boiler with a condensor unit. I guess more research needed!

many thanks for your quick replies. Mike

 

[seco services]

Is your cws constanly filling ?

 

[MikePz]

I haven't given any attention to the CWS. I will go in the loft tomorrow and watch it.

What does that mean if the CWS is constantly filling?

 

[seco services]

if the cws is constantly filling from the ball valve thats cause it flowing through the coil into the f/e tank.

 

[MikePz]

Hi sesco

Checked the CW tank and yes it is constantly flowing. Had someone in this morning to look at it (the plumber who fitted the bathroom) and he is of the same opinion as you, split coil.

This takes me into another area now, replace the tank or do away with it and get a condensor boiler. With it being an old system I am erring towards the boiler as it may work out more cost effective in the long run. the plumber recommeded a Bosch boiler as the best value/quality/durability - any thoughts?

in the mean time many thanks for all your help.

mike