(Another) leaking rad valve question

27 Oct 2003
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United Kingdom

I have a leaking rad valve on a radiator that will be torn out and replaced when I have building work done next year. So, I RTFF and found guidance on "packing the valve" with PTFE tape. However before I dive in and give this a go I have a few questions:

1. My valves are twin-entry micro-bore ones (see pic). Does the PTFE trick even work on this type of valve (Leak 1)?

2. When I undid the nut to test out the procedure I sprung a secondary leak around the nut itself (leak 2 in pic). I had to tighten it very aggressively to stop it dripping. Is this "normal" or should I do something else e.g. wrap the nut thread in PTFE / a bit of fernox?

3. Can a leak be "too bad" for this fix to work? If open the valve even a half-turn it literally sprays out (it's a gravity fed system too, so not much pressure). I have to close the valve very aggressively (with pliers) to stop it dripping.



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Few valves can be repacked to seal their spindles.
It probably uses o rings in which case a new valve is required.
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When you undo that nut, you will spring a leak at leak point 2 and 1 unless the system is empty.

i successfully applied ptfe tape to the threads on the stuffing gland on the twin entry valves at my old house but did it with the system empty of course. This lasted me until I replaced the valves with conventional types about 2 years later. However as there are literally no spares available for these I’d leave well alone now since you’re replacing next year unless the leak is bad and can’t be managed.

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