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Cold water tank in attic , hot water tank in bedroom below, water mains is supplied to kitchen tap and then upto water tank in attic.pressure of water going into water tank is very very poor { creates problems when bath run , then water pressure from cold taps in bathroom is very poor and forms an air lock} assume air lock as the valves on the outside of the tank have been checked and are open . Any ideas how to clear the air lock . easy enough in the taps in the bathroom but not the pipe going from kitchen to water tank?

Hi
Firstly, the water supply to the tank comes straight from the water mains and will not air lock, so the low pressure to your tank must be caused by something else. Have you checked your mains stop cock in the kitchen is fully open? You should also have a stopcock on the tank supply, (should be close to the tank), which again may not not be fully open. The cold supply to the bath will be poor if the tank is not filling up quickly enough to replace the water being drawn off for bathing, hence air lock. One or both of your stop cocks mentioned above may require some maintenance such as rewashering etc. If you are doubtful about doing this yourself seek some professional help. Rewashering of mains stop cocks in particular can be a tricky business.

hi...have you tried turning up the mains water at the stopcock

OOPS,
I nearly forgot. Check that your storage tank ball valve is OK. It could be blocked or jammed and does not open fully. Best just to fit a new one.

what's the pressure like in the kitchen?

Assume that you've checked the main stopcock which may have a blockage in it, and/or you've asked the water supplier to check for pressure.

Could be a number of things including leaking/damaged mains pipe that causes low pressure.

Unfortunately, you aren't allowed to put a pump onto the rising main, which would help, although you may be able to temporarily fix one inline near the tank to "suck" the water through and clear the airlock. One way of clearing an airlock is to force water back through the pipe, as you know, but since you haven't got enough pressure to run a hose up from ground level, this won't work.

The only other thing I can think of doing to help with pressure etc in bathroom is to install a larger water tank possible at a greater height, or fix a second tank above the original one which supplies this main tank.

Many thanks gents for the advice , I have not checked the main stop cock outside as Im having difficulty locating it { not long moved into house} I am going to replace the ball and valve which look like the original I have set the valves for the supply of the hw tank and bathroom to half way rather than nearly full on and this has helped somewhat , Pressure in the kitchen is great hence the thought that the fault is in the pipe that supplies the tank in the attic.

Hi again,
As the pressure to your kitchen sink is fine then the fault is not with the mains stopcock. It is either the storage tank ball valve or the stopcock controlling the supply to this tank. Turning your other stopcocks/valves on the bath supply down a bit will help as long as you are happy with the time it takes to fill a bath. Incidentally, I would check that the main stopcock turns off properly. Just in case you ever have to do this in a hurry.
Best wishes

If the pressure to the kitchen cold tap is fine, this suggests that your stopcock is OK. So if the cold water tank in the attic is slow to fill, you probably have a restriction in the mains water pipe going up to the attic or in the ball valve in the tank. I think the ball valve is the more likely area to look.