Solving Problems with Shutting Off Water Supply
When it won’t budge
When the valves responsible for shutting off the water supply haven’t been used for a while they have a nasty habit of refusing to move (gate valves, which work slightly differently, are more reliable).
In this case, the first thing to do is squirt some penetrating oil around the spindle mechanism and leave it for half an hour before trying again.
If this doesn’t work, wrap the valve in an old floor cloth and pour on boiling water; the heat may release it.
Your only other options are to apply more heat — from a blow torch or electric paint stripper — or more force. But before you use force a word of warning: if the pipes either side of the stopcock are lead, the chances are they will crack. If possible, find anothervalve further down the line rather than risk a burst.
To get extra leverage, slip a piece of pipe over one side of the handle. Alternatively, use an adjustable wrench with some cloth between the jaws to stop the handle getting chewed up. Relieve the strain on the pipework by supporting it with a piece of wood.
After freeing a stopcock you might find that it leaks slightly from around the spindle area. To cure this, loosen the top (gland) nut on the spindle and wind a few turns of plumber’s jointing tape (PTFE tape — available from anystore) round the threaded spindle body. Then retighten the nut a little over hand-tight — any more, and you won’t be able to turn the handle.
Sometimes, when you turn the water back on, you hear a hissing and gurgling in the pipes and no water comes out of the taps. Usually, the pipes affected are those fed from the storage tank, where the pressure is low.
Depending on where the problem is, you may be able to force the airlock back up the pipe by taking a damp cloth and plunging vigorously against the spout of the affected tap; when the air reaches the tank it will be able to escape.
If this doesn’t work, connect a hose between the affected tap and one that’s supplied at mains pressure (securing the ends with Jubilee clips).
Turn both taps on and leave them for about 30 seconds, then turn the mains tap off and check to see if the airlock has cleared. Sometimes it takes several goes, so be patient.
“Airlocks can take ages to clear, so wherever possible I try to avoid them. If I’ve had to drain the cold storage tank, for example, I’ll let the water back in as slowly as possible so that the air in the pipes has a chance to escape as they fill up.
If you then get persistent airlocks, the trouble may be that the storage tank isn’t filling up as quickly as it is being drained, so the pipes are sucking in air instead of water. You can check this by watching the tank while someone is filling the bath to see whether the tank empties before the bath is full. If so, the trouble may be that the stopcock hasn’t been turned back on fully or that you have a faulty ball-valve controlling the supply to the tank.”