I fitted new Drayton TRV4 radiator valves to all my rads about 4 years ago, and already two of them have started leaking where the valve pin projects from the valve body. Is this a common problem? Are they fixable or is the only solution to renew the whole thing? Anyone have a magic solution for doing this that avoids draining the system (it's an open vented system with a header tank)?
Most valves have a gland nut on the valve body that can be tightened slightly to stop the leak BUT not too tight to stop the pin moving.
No gland nut on thse valves, the operating pin just projects through a plastic insert in the top of the valve body (unless the nut is inside the valve body - which would be pretty useless anyway).
I guess you could turn off the rad at the other end, freeze the pipe to the TRV and then drain just that rad. But I'd prob just drain the whole thing when convenient. Not a huge amount of effort.
It probably has an O ring. Some have PTFE packing. Supposing you can get one, they can be replaced but sometimes they still leak. It's quite unusual to leak so soon. Have you got inhibitor in the water? Could be a corrosion problem. You'll likely end up replacing them. May as well wash the system out and make sure you have inhibitor in. Many inhibitors claim to have lubricators as well.
It's a good idea to "exercise" the valves by winding open and closed now and then. (Keeps the spindle clean)
The best valves BTW have a bellows not an Oring.. Expensive.
Donno about fixable but I shoul imagine you can get replacement inserts. Bit off they have started to leak after just four years. Get in touch with Drayton and see what they have to say.
They do work, I've used them when a TRV here got stuck and I wanted to take the insert out. Just make sure the system has no leaks and only open it at *one* point at *any* time. There might be a little spillage so still take precautions to protect carpets/decorations etc.
Yes system has inhibitor in. I fitted the new TRV's just before a new boiler was installed, and the whole system was power flushed at that time (by the boiler installer - qualified plumber).
Looks like I'll just have to replace them. Exercising the valves is a good tip - thanks.
I did look at the more expensive valves - OUCH! Even the TRV4s are quite a bit more expensive now than when I bought the last lot.
Ah yes, I've got a couple of these, I guess I have to plug both the feed and vent pipes at the tank. The "negative pressure" of the water won't damage anything in the boiler will it? I've heard tales of people who have seen hot water cylinders collapse when these plugs have been used on the hot water side of an open vented system and then opened a tap at the lowest point!
Usually the seal is an o ring. As a first step (they will have been unused for a few months) jiggle the pin up and down a few times. some silicone spray may help.
Yep. If air can't get in, water can't get out.
What "negative pressure"? Nothing is leaving the primary (or shouldn't...) if anything does it means some thing has got in some where. The system remains at it's static pressure determined by pure head.
Well I guess there is the "pull" from the weight of water in the pipe work below the cylinder. Which in a normal house with cylinder on first floor and taps on ground could be could be around 8' of head or
1/4 atmosphere.replying to Davidm, Skodasdad wrote: Only replying so some others may know the answer as it's now 2019. You can get a replacement seal and special key for these valves from Ebay (couldn't find them anywhere else). There is a Drayton You Tube video that shows you exactly how to do it and it takes about 5 minutes.
Found one of ours had been quietly leaking for a while. Emailed Drayton and they said the seal should be tightend an eighth of a turn every year, then replaced when it bottoms out.
I've never heard this before, but Googling a line from their email, I found it's mentioned in their FAQ.
Sadly no free seals sent - they referred me to a supplier. I'd already ordered the kit of eBay anyway.
Found one of ours had been quietly leaking for a while. Emailed Drayton and they said the seal should be tightend an eighth of a turn every year using a pair of long-nose pliers, then replaced when it bottoms out.
I've never heard this before, but Googling a line from their email, I found it's mentioned in Drayton's FAQ.
Sadly no free seals sent - they referred me to a supplier. I'd already ordered the kit off eBay anyway.
Found one of ours had been quietly leaking for a while. Emailed Drayton and they said the seal should be tightend an eighth of a turn every year using a pair of long-nose pliers, then replaced when it bottoms out.
I've never heard this before, but Googling a line from their email, I found the email was simply a cut and past of Drayton FAQ about it - but it's not in their FAQ list, you can only find it by Googling!
Sadly no free seals sent - they referred me to a supplier. I'd already ordered the kit off eBay anyway.
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