Very strange overflow dripping...please help!!?

Same problem for us with overflow, but we also had a slow leak from the tank which has caused some ceiling damage. We've been quoted £500 for a new cylinder due to a hole in the coil

jk
October 2009

cylinder coils gone.
isolate the feed to the cylinder dhw and that will test if the f/e is still filling.

hi-spec plumbing & heating (essex)
September 2009

Big & Expensive are relative terms and depend on your personal wealth to a certain extent. Copper is expensive on the world market so tank prices will be relatively high.

Avoid British Gas - seek out a small independent plummer locally - an established tradesman with a reputation to maintain - personal recommendation or a small ad in yellow pages - avoid also any Large Brash super dooper outfits.

I am not a plummer and avoid this work as often as possible - I hate water engineering.

I have no absolute confidence in my original answer it's just a logical conclusion and not based on prior experience as I have none.

I would expect perhaps £200 for the tank and maybe £300 for the fitting of it but again I guess.

£500 is a lot of money to spend on a stranger's guess so you need to confirm my uneducated diagnosis before asking for a new hot water cylinder.

Good luck...

P
September 2009

Thanks Peccavi. If I do need a new hot water tank is that an expensive and big job?

Simon
September 2009

The smaller tank is the header tank for the central heating radiators - if the inlet valve is good then water may be entering this small tank through the outlet pipe you mention.

In your hot water storage tank is a heating coil that circulates water from the boiler to warm up either the radiators or the tap water in the tank - a motorised valve decides which way the water goes. Radiators and the coil are topped up by the little tank.

If the coil in the hot water tank has a split or small hole, the water in the big tank has a direct connection with the little tank. Even though the bases of your two loft tanks are level with one another each has a different height of water - with a small hole or split in the heating coil, gravity will be trying to equalise the the water levels of the two loft tanks.

Wait for the overflow to happen - make sure nobody is drawing off hot water - nip up to the loft - test the temperature of the water in the little tank (it should be quite cold) - observe the inlet of the big tank and see if any water is flowing out by the action of the inlet valve.

Alternatively - turn off the boiler and tie up the inlet of the big tank so that no water can enter it and mark the water level - wait. If the overflow stops and the level of the water in the big tank has dropped then there's a hole in the heating coil in the hot water storage tank in you airing cupboard.

You may need a new hot water tank.

Good luck...

Peccavi
September 2009