the builder/gucciman

[fairfield]

Re. plumbing problem. I will try to explain better. the central heating system is gas fired ducted warm air. The boiler has a double burner one for the heating and one for the hot water. in the attic I have two tanks. 1 feeds the hot water cylinder which is the large tank and also the cold water taps in bathroom this feeds in to top of the hot water cylider in addition there is much smaller tank connected to the hot water cylinder on the side. This smaller tank is filling and overflows when my heating system is on. it fills by 2/3 pints in 24 hours. the hot water cylider is a indirect cylinder. I live in very hard water area and wonder whether the tank is bloking up with sludge.

[The Builder]

Hi FF
Gucci knows a lot more about these than I do.........but, whenever I've come across this before (on conventional radiator systems - but the same thing applies).....it's often the boiler set on much too high a temp. or more likely, the boiler thermostat is faulty. This results in the boiler getting the water far too hot, and overflowing at the expansion pipe. This is usually a hook shaped pipe OVER the top of the small roof tank.
This expansion pipe is for just that type of fault.........a safety valve if you like.
With a bit of luck, Gucci will pass by soon to confirm..............or...................suggest something else :o)

[gucciman]

sorry have been too busy this last week to get on here.

the small tank will be the header tank for the coil that runs through the cylinder. is the tank refilling from the ball valve or from the expansion pipe as buildersmate suggested?