Tanks in the loft....

Hey guys... I've got some questions please:
in my Loft, there are two water tanks.
#1 A kind of big tank, white, wrapped with thermo blanket, placed high and it contains clear water.

#2 A small tank, not wrapped but its top covered with plastic bag, and placed on the loft floor and not on a stand like the bigger one. I've got poor lighting in the loft so I don't know if the water was dirty or it just looked like that in the dark.

I turned the basin tap in the upstairs bathroom ON, and noticed the water level in the big one dropped and the ball valve started filling the tank.

I noticed some "mud" or sand at the bottom of the big tank.

Q1: What are these tanks for?
Q2: Are these/this tank feeds the upstairs only, or both ground and first floor?
Q3: How can I know if any tap in the house fed by mains water or the tank's?
Q3: Should I remove that mud from the big tank?
Q4: Do these tanks need some kind of annual cleaning or periodic replacement?

I would appreciate any advice regard these stuff...

Big tank is to feed upstairs bathroom and any other taps in house except Kitchen cold, Kitchen will always be mains fed cold, it also feeds your hot water tank in airing cupboard, remove sludge yes although normal, when removing sludge protect holes in bottom of tank as you don't want any to go down holes so plug them, small tank is to feed boiler, no reason why you can't annually clean them. Oh yes and never drink water out of any tap except kitchen cold tap as it is not clean or healthy to drink the water from the tank

Q1: What are these tanks for?

Click to expand...

Big one is cold water storage
Small one is probably your central heating feed and expansion tank

Q2: Are these/this tank feeds the upstairs only, or both ground and first floor?

Click to expand...

Usually feed upstairs cold taps, toilets and hot taps via hot water cylinder.

Q3: How can I know if any tap in the house fed by mains water or the tank's?

Click to expand...

Shut mains stop cock. See which taps continue to work.

Q3: Should I remove that mud from the big tank?

Click to expand...

I would - I don't like brushing my teeth with muddy water.

Q4: Do these tanks need some kind of annual cleaning or periodic replacement?

Click to expand...

Under normal operating conditions, no. If they get filthy regularly, yes. Small F & E tanks can get quite muddy after some years. If they get muddy quickly it's a sign of corrosion in your central heating.

Thank you guys for the detailed answers.

Plumbgas, do you have any idea how to plug the bottom holes?
I'm thinking of turning the shower bath tub tap ON to force the tank empty its water with forcing the ball valve on OFF, so i can easily clean the tank! what to do you think?


echoes, do I need to wrap that small central heating tank with thermo blanket or just leave it as it is?

one more thing!!! I noticed a pipe coming somewhere in the loft and had its open end in the big white tank, it looked like some water drops would come from this pipe so installers thought to have it dropping in the tank?! any idea what does that pipe do?

you can drain the tank as you've said, tie up the ball valve to stop water coming through, just beware on refilling it's possible to get air locks, the open ended pipe you speak off sounds like the vent pipe from the Hot water cylinder, do not amend in any way this pipe, it is a safety pipe of sorts. you can use rubber bungs to block the holes or similar. and No you don't need to wrap the central heating tank, no point at all

That open end sounds like the vent from your hot water cylinder. It is there to allow air to escape from the top of your tank and to provide an escape route for water in case of overheating. Normally nothing should flow from it, but that pipe will be full of water up to the level of water in that cold water storage tank.

There should be a similar one over the small F & E tank. If that flows, you have problems well worth investigating.

EDIT: One thing to look out for is the overflow from the small tank. On mine, it overflowed into the cold water storage tank. It's gone now (sealed system) but that may account for the mud you speak of.

thank you guys for giving full explanation in such simple language

many thanks