combi closed? system but two tanks up in loft - why?

Hello All

Just bought this house. 2 storey, small end terrace. Loft. Built 1980. Very soft water area. House in occasional use (CH switched on for 30 mins each days little hot water use). Me=some experience with CH in early 90's.

The house has a combi but also two water tanks/cisterns in loft. Why? Is this just a really crappy combi install?


Detailed info:

Boiler cupboard (upstairs) plenty of evidence of there formerly being a HW cyl. that was replaced by the combi that is presently there. e.g. 22mm pipe dropping from loft is now cut and blanked off (slightly above my head). The cold mains (15mm) runs from wall near floor, T's off to supply cold feef to combi and continues on to loft.

Up in the loft are two pretty big tanks of about equal size (guessing 1.5m x 0.75m x 0.5m). Both have water in them, ball/cistern assemblies. Crudely lagged. I can lift up lids and shine torch in. Asked wife to turn on cold taps, shower (press. ball. valve). flush WC etc and observed NO drop in tank levels.

WHAT DO THESE TANKS DO (NOW)? SHOULD THEY HAVE BEEN REMOVED? I thought there was always one small tank (expansion) one big (cold storage) for the "old" HW cyl. set up

Biggest issue is that a very steady drip (seems to have got bigger) is coming out of the external wall "overflow" pipes (there are 3 which protrude like 1 inch from external wall at loft level) and soaking the external wall, mortar is weathering away etc. Damp. I assume this water is NOT the condensate fluid from the combi (as is pip outlet here is higher that the combi and pretty far away).

I assume somewhere between the T-off to the combi cold feed and the loft tanks there is a stopcock I am can turn off and then reach into the loft tanks (with a stick, etc) and eventually the drip will stop?

I am either going to sell the house in a few months or rent it. If renting WILL THESE TANKS CAUSE ME PROBLEMS LATER?

thanks for any insight

Jimbo

It would be unusual to have left the tanks connected.
It is possible you have very poor water pressure and the big tank in the loft
is supplying the hot water via the combi.
Turn the combi off and then turn a hot tap on. See if the big tank in the loft starts filling.
Is there a filling loop for the combi? If not it is still possible they are using a vented system for central heating.

thanks for quick response. Will try as you say, switch off combi and run HW when up at house tomorrow morning.

If the big tank in the loft is NOT supplying the hot water via the combi then I guess I just have a really poor installation?


Filling loop? This is what I call the "top up" to CH? Yes. Indeed, the pressure had dropped to 0.5 atm and boiler wouldn't fire up, so I just used it two days ago to top back up.

thanks again

Jimbo

It is possible you have very poor water pressure and the big tank in the loft
is supplying the hot water via the combi.

Click to expand...

How`s that work then? Never heard of a combi with a header tank.

Turn the combi off and then turn a hot tap on. See if the big tank in the loft starts filling.

Click to expand...

So you think the combi is fed by a header tank?

Is there a filling loop for the combi? If not it is still possible they are using a vented system for central heating.

Click to expand...

Which wouldn`t be a combi would it?

The house has a combi but also two water tanks/cisterns in loft. Why? Is this just a really crappy combi install?

Click to expand...

I imagine something in your home must be gravity fed from these tanks be it bathroom,or a toilet or a thermostatic shower.If you can`t drain them via an outlet and you cannot trace pipework, simply empty them manually,isolate cold supply to both tanks then test all your appliances afterwards. I take it your home/flat is not feeding other flats etc? Or unless youhave another conventional (not combi) and a hot water cylinder elsewhere in property.

Well.. after some faffing about in the loft, I found that both tanks thankfully had dedicated in line stop cocks for each cold feed. I shut off each and this has not impacted on the CH or (D)HW. The overflow leak has been stopped obviously.

The name of the plumber who originally fitted this (in 2006) is on the commissioning and hand over paperwork. Should I call him and ask if leaving 2 cold water tanks connected to the mains but otherwise "stranded" is his regular professional standard?

Thanks for the answers (even the wrong ones, I learned something from those who commented after!)