Can't find stopcock - is it OK to drain water tank?

[Mr Skills]

I need to to replace a shower cartridge, which means turning off the water supply. I can turn off the mains and hot water no problem, but the cold water is fed from a water tank at the top of the house. I cannot find a stopcock near this tank.

I assume the best thing to do is to turn off the mains then simply run the cold taps until the tank is drained. But I am worried about introducing air pockets in the pipes after the tank is refilled. Is this a danger, and if so, how can I avoid the problem?

Thanks

 

[PlumbBobBob]

you could bung the tank so creating a vacuum and not waste too much water and tie the ballvalve arm up to stop water entering the tank.

 

[SafeGasInstall]

as steve mention above do it that way or drain down and give cold water storage tank a clean ,if float valve is not looking healthy replace it and also fir a liver valve on down service pipe work + check mains stopcock next to tank if seems tired change it ,this way in the next 5 years will have no problems at all

 

[PlumbBobBob]

also you can put a lever valve onto the feed for the tank when you turn mains off for ease of working in the future as SGI said above

 

[dontknowitall]

Sometimes the stop tap is in the airing cupboard, but I'm assuming you've looked there too?

In these situations I make an effort to find the route of the water as it is very unusual not to have a stop tap/gate valve somewhere. I usually ask what work was done previously (e.g. washer/tap change, central heating, etc then ask where the plumber found any taps.

 

[SimonG]

To be honest I don't waste a lot of time with tanked hot and cold water, if I need to work on it, it's a quick look for iso valve, if there isn't one or if the valve looks passed it, it's mains off and throw open the bath taps. Complete the work and chuck in an iso valve for next time. Then solve any issues (airlock) if they arise.

 

[gaspastemania]

Here's how you avoid the problem ,,,,,,,,Phone in a plumber !!!

 

[SimonG]

Here's how you avoid the problem ,,,,,,,,Phone in a plumber !!!