Leaking radiator valves.

20 Apr 2007
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United Kingdom
I have just replaced a radiator removed for redecorating and no matter what I try the connection into the radiator leaks. The original taps (type that fits with hex key) had a slight weep so I decided to remake the connections before refitting, the weep was now a leak. Replaced the rad with a new one and fitted the same valves, still leaked! Replaced the valves with spanner fitting type (like Honeywell) and still leaked. Gave up with PTFE tape and used jointing compound and it still leaked. All the other rads in the house have been removed and replaced with no problem.
Any suggestions?
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I like to use blue Hylomar (motor trade stuff) on the threads first, followed by loads of ptfe tape (gas stuff is thicker than standard) turning it clockwise looking at the stubs, then more Hylomar on top of the tape.
The stubs need to be tightly wound in.
John :)
You are probably not wrapping ptfe tape in the correct direction ,not enough or too much. How many turns varies from rad to rad ,but a dozen is a good starter ,and frequently need More than that.
On a standard 1/2" tail and tapping then I use 6/7 wraps of gas PTFE tape ..... while holding the tail in your left hand with the thread to your right, tape onto the thread that way wrapping over the top, going with the thread very slightly over the edge, 3 wraps up to the top of the thread and 3 back down, never had an issue.

If it still won't seal then I'd be looking at the tapping threads in the rad to see if there's an issue.
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