Prismatic Water Cylinder - Should so much water be coming from expansion pipe?

[hztm2008]

Hi, I have a J&S warm air heating system with Eljan / Prismatic for the hot water. Over the past few weeks I have noticed a small amount of water coming from the outside overflow so I went to the loft to investigate. There is a pipe that runs up over the top of the tank so that any water coming from it will go in to the tank. I am assuming this is an expansion pipe from the prismatic water cylinder below? The water storage tank has a line of white scum around the water level which is sitting just below the overflow pipe. However, there is a patch of scum running right up to the top of the tank where the expansion pipe is, and the foam around the outside of the expansion pipe is all wet.

I am thinking that water must be coming out of the expansion pipe and splashing up the side of the tank? This would appear to be quite a lot of water if it is pushing the level up enough to cause water to come out of the overflow? The other morning I was in the bathroom when I suddenly heard what sounded like gushing water above me; the water heater was on at the time.

I just wondered if this all sounds correct. Should there be a lot of water expanding from the prismatic cylinder or should there just be the occasional trickle. I am wondering if something is wrong.

Thanks for your advice.

 

[Nige F]

Hi , it's an Elson Primatic setup It may just be the float valve filling the tank too much. Or it might be leaking internally. You need a Gas Safe plumber to have a look @ the system ( because of the J+S gas heater) You may even find someone on here who covers London ( if you post your area)