Three tanks in the loft

[Jever]

Hi,

I have a real 'beginner level' question, for which I apologise, but I have to ask as I'm itching to know.

I'm thinking about renewing my insulation and I've just been up into my loft. Whilst I was up there, I noticed three water tanks next to eachother. Two were fairly large (25 gallons each) and the third was much smaller.

The two large tanks appeared to have cold water feeds and ball-cock filling mechanisms. Some of the pipework to and from the tank is lagged, but not all of it (I assume all of the tanks are cold water so the lagging is to prevent frozen pipes?).

I'm familiar with the idea of a feed and expansion tank for the heating/hot water system, so that excess/shortfalls of water in the system can easily be compensated, but I still don't see how I need three tanks. Presumably, one of the other tanks is a holding tank for the cold water supply (not well protected, not sure I fancy drinking from it), but what the third tank is, I've no idea. Would someone please explain?

If one of the tanks is part of the cold water supply, shouldn't it be sealed in some way for better hygiene?

TIA

Jever

 

[Burnerman]

Two tanks may be used in parallel if necessary, due to the demands that the house may have.....for example, if there are two baths or there is only one mains cold tap - all the rest are fed from this gravity supply, including the toilets in some cases.
Another reason is that a separate tank is sometimes used to feed the shower, due to the reasons above.
Its always a good idea to fit tanks with lids - mandatory now.
John

 

[Armo74]

The smallest tank should be the feed and expansion tank for the central heating.
One tank maybe redundant, probably the best way to find out would be to run a hot or cold tap or even flush a toilet and see which one of the tanks starts to empty.
All tanks and pipes in the loft should be insulated to prevent freezing and also to prevent the water rising to a temperature that could be a breeding ground for legionella.
If you are thinking of insulating the loft you must not insulate underneath the tanks this allows warm air from the room below to help prevent the water in the tanks from freezing.

 

[Galoka]

No particular reason why you should only have only one CW cistern, we've got 3 for some reason - about 1000L in total, which will keep us going if we get cut off at any time

You've got three because at some point someone decided they needed more stored water than one tank would supply (or couldn't get one big tank in)

The small tank should be the F&E for the CH.

The other two tanks are both supplying cold water I imagine. Some to taps, some to the HW cyclinder. Typically with multiple tanks, you have one ballcock and the tanks are interconnected. Maybe someone fitted two ballvalves to speed the filling? and you know 25gallons isn't that much water really - run a nice deep bath and you will use up a fair chunk of that

Modern tanks are indeed fitted with proper lids, etc. to keep things out. Old tanks often didn't and so get dirt, dust and other crud in them. Which is a reason for having at least mains tap in the kitchen for drinking from. Two of ours we covered with roofing felt laid over timbers which has now all fallen into the water, I'm going to put some new covers on. Probably PIR foam sheet with a wood frame.

Actually, it's never bothered me much, and I've often drunk it, but I will be running mains into the bathroom handbasin when it's refitted. Bath/shower will still be from stored water.