Removing 2 radiators for gas central heating for decorating. Turned off thermo valve, turned off lock shield valve. I then checked with the air valve and all ok. I then removed the the thermo valves. And when the heating came on water pissed out the thermo valves. Did I incorrectly remove the thermo valves and should I have kept them in place to keep that valve shut off?
Checking before I let the heating run tonight.
I should have mentioned I had removed the radiators at this point and the pipes at the valves didnt leak until the heating came on.
Did you shut off the thermo valve with the service caps provided? you need to remove the thermo heads and put the caps on instead which presses the pin down manually.
I dont have service caps and not near a plumb shop, would replacing the thermo valves and turned to off suffice?
I did the same, late one afternoon. Went to bed and woke up to the sound of running water. Guess what the thermostatic valve had released, took me a while to mop up the water. Now I always put a cap on the valves, which are supplied with the valves.
The way the head works is it pushes down on the pin in the valve to shut off the flow. So with no head on at all, the valve is fully "open". If you don't have a service cap you can sometimes get away with just leaving the head on and turned down to the minimum temperature (although if it gets cold enough in the room they will open). The quick hack way round the problem is to remove the thermostatic cap, and place a small coin under it and screw the cap back on. That will trap the coin and push down the pin keeping the valve off.
Some actually go down to "off" others only go down to "low" and they come with a "commissioning cap" you can install to full depress the pin.
You were lucky. If I read this right, you took the valves off the pipe? I would expect water to come pouring out as soon as that was done. I know of one case where it doesn't - that's a towel rail slightly above the expansion tank which actually needs the pump on to force the air out when bleeding it.
Yip valves were off, it was only when I turned on the CH to test all was ok when the water came shooting out. Stopped when I put the heating off. Probably minimum pressure as I would have lost most taking the rads off (I think) I have now put the therm valves back on turned to off.
Valves off, or just the heads off the valves?
The heads.
My valves came with a maintenance cap. To use the thermo head comes off the valve and then the maintenance screws on which fully depresses the valve plunger to fully shut the valve.
In the past I have resorted to unscrewing the head and then placing a spacer (5p piece) between the plunger and the head to make sure that the plunger is fully down.
This should leave the valve open unless the plunger is stuck in an almost closed position.
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