Cold tank overflow, cant fix it

[GiGaBaNE]

Hi all. Ok the short story is we have terrible limescale here and it keeps wrecking the water system.
the cold tank in the attic (some fibreglass jobbie) keeps overflowing.
Last time i fixed it by removing the ball and its pushrod and cleaning all the scale.

Now it seems the main part of that valve is the problem, when i try to remove it, the nut just keeps turning but does not unscrew fully.
I dont want to hire a plumber because the attic is not safe yet.

 

[GeckoGas-com]

Turn your mains supply off; removed the ballvalve and head down to B&Q and get yourself a new one...


It's bank holiday today so you have until 16:00 to buy yourself another one if you want it done today.

 

[GiGaBaNE]

well thats half my problem, i can get the external part of the ballcock off but not the brass bit with the rubber valve inside. the nut between it and the wall of the tank just keeps turning. i dont know if im missing some sort of technique for removal? =(

 

[GeckoGas-com]

You need two pair of grips... One for the locknut that's on the outside wall of the tank and one to either hold the nut connecting the body of the valve inside the tank or to grip the threaded part on the outside of the tank depending on the actual age of the valve.

If it's brass; it could be very difficult to remove; I have had only one that I gave up on and ended up making a new hole in the tank and rerouting the supply to it; but TBH - I was getting desperate and had hardly any room to grip the old valve.

 

[GiGaBaNE]

lol yeah its an evil job i jot like 6 inches of clearance to fit my head and both arms, and the way the beams and fibreglass around the tank are, i doubt i could reach inside and out.

would it be hard to drain it, demolish it and replace it with a plastic tank?
I dont really know much about joining pipe to pipe, but i was thinking of just cutting all the pipes to it and attaching flexi metal pipes from the cuts to the (new)tank.

 

[Dan Robinson]

You won't be able to use metal flexis, but you could use Polypipe of some such.

Changing tanks is not so much difficult, just often fiddly.

 

[GiGaBaNE]

Thanks, very swift and pertinant advice =)

one last thing, the current tanks is like a meter cubed and would prolly kill me if it fell on me even empty, lol.
anyway we have very high pressure here and i want to replace it with a much smaller tank like 30 litres or so..can you see any problem with that?

 

[GiGaBaNE]

oh and one more thing, we already have a small tank in the attic, its full of rust looking water. whats that for, part of the heating?

 

[GeckoGas-com]

The small tank is the feed and expansion tank from the central heating...

This larger tank should be fine if reduced, so long as you have not got a shower pump or cold water booster pump as this may drain the tank too quickly.

 

[GiGaBaNE]

thats great thanks, at full pressure the water can come into the house faster than it goes out with all taps on =)

very gratefull for your advice..

hmm on a seperate note, would you know why some of our radiators get hot when just hot water is on or should i start a new thread?

 

[GeckoGas-com]

It's not about pressure - It's about the flow rate that can actually pass through the valve; having a tank with shower pumps and multiple sets of wide bore taps creates a buffer so you don't air lock up and run dry.





As for the heating - Depends on the boiler/system/etc - Do a search; it'll normally be the diverter or motorise valve.

 

[GiGaBaNE]

much obliged =)