DRAINING MY COLD WATER SYSTEM..

[les1]

I cannot seem to drain my domestic water system. I turn off the mains water & open up all cold taps but nothing comes out other than about a table spoon full of water. It has been suggested that I should blow the system. How would I do this?

Any suggestions would be gratefully received..

 

[twgas]

what type of system do you have?

 

[moggridgeplumbing]

It could be your mains stop valve (in the house) is not shutting off fully and the washer needs replacing. Failing that fit a new one. Even if you blow down the pipework if the stop valve is letting by water will return.

 

[TicklyT]

There's nothing unusual in a system not draining after the stop tap is closed. there's no way to get air into the pipework to relieve the vacuum as the water drains.

If you have a conventional cold storage cistern in the loft, run off a couple of gallons of HOT water.

Once the level in the cold cistern drops a bit, the float valve will open, breaking the vacuum that stops the cold water pipework from draining.

Other systems may drain if ALL the cold taps are left open. It may take a while before the vacuum is relieved, then it will suddenly drain all of a rush. Sodd's law states that however long you leave it, and whatever precautions you take, it will happen about 30 seconds after you cut into a pipe you thought was dry.