Replacing a radiator valve

[BlueStringPudding]

One of the four radiators on my boat has a knackered valve. It's the valve at the top right, the type you bleed with a key. This one, however, can't be bled because the little square knobble inside is broken. It cant even be bled using pliers. Once a plumber managed to bleed the radiator a few years ago, but he did it by loosening the whole valve off the radiator, with spanners. He said the whole valve would need replacing if I wanted to continue using the radiators. So I'm planning on doing just that.

 

So this is one of the working valves of another radiator:

 

 

And this is the kaput one by comparison:

 

 

I've been googling radiator valves but not found any that look like this, they always seem to be the ones you find at the bottom of the radiator, which have a big twiddly thermostatic knob on it. Can anyone recommend where I can find the type that I need or perhaps what they're called? Also, I assume they come in different sizes. How do I measure what size I will need?

 

Thanks

[ditchcrawler]

One of the four radiators on my boat has a knackered valve. It's the valve at the top right, the type you bleed with a key. This one, however, can't be bled because the little square knobble inside is broken. It cant even be bled using pliers. Once a plumber managed to bleed the radiator a few years ago, but he did it by loosening the whole valve off the radiator, with spanners. He said the whole valve would need replacing if I wanted to continue using the radiators. So I'm planning on doing just that.

 

So this is one of the working valves of another radiator:

 

 

And this is the kaput one by comparison:

 

 

I've been googling radiator valves but not found any that look like this, they always seem to be the ones you find at the bottom of the radiator, which have a big twiddly thermostatic knob on it. Can anyone recommend where I can find the type that I need or perhaps what they're called? Also, I assume they come in different sizes. How do I measure what size I will need?

 

Thanks

http://compare.ebay.co.uk/like/280872733777?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar&adtype=pla&crdt=0 and you wont need a key

[Bobbybass]

I bought one just like that recently in B&Q...as a set...with new sealing washer etc..

 

I had to do a similar replacement on a 'land based' radiator...

[Rod a mod from Tod]

Half inch radiator air vents is what you are after.

 

http://www.screwfix.com/p/radiator-vent-blanking-plug-chrome-bsp/40972?_requestid=167686

 

Don't know what happened to the link first time.

Edited December 9, 2012 by Rod a mod from Tod

[Guest]

Those are identical to some of ours at home - I once had to replace one and pretty sure I got it from B&Q.

[BlueStringPudding]

Thanks. How does something like this stick in place when installed? It doesn't look like it screws in, for example.

 

[Flyboy]

Radiators normally have a 1/2 inch BSP fittings. Any DIY hardware shop, B&Q, Homebase etc. will have them. Ask for a 1/2 inch radiator bleed valve. You will probably only need to drain a couple of pints of water if you unscrew the old bleed valve with a bowl underneath. Fit the new one, top up header tank & bleed radiator. 15 minute job.

Edited December 9, 2012 by Flyboy

[Rod a mod from Tod]

Screw it in hand tight and nip it up with a spanner and the "O" ring holds it in.

[Guest]

Ours did unscrew and then replacement did screw back in.

 

I can't recall the size now but I borrowed a good well fitting socket and give it a liberal spraying of ant-seize oil for a few days before to get the old one out.

 

I agree the threads are not visible in the pic. you posted.

[ditchcrawler]

Thanks. How does something like this stick in place when installed? It doesn't look like it screws in, for example.

 

Turn off the two valves, one each end of the bottom of radiator. Put a spanner on the large nut that surrounds your present broken vent and unscrew it slightly. If the two valves work OK then you will have about half a lt. of water dribble out. If the valves don't hold it will keep leaking and you will have to drain the system. Hopefully the flow will stop and you can then unscrew the bleed body and screw the new one in.

[BlueStringPudding]

Thanks, everyone

[BlueStringPudding]

Thought I'd update this thread since this very day the lovely GoodGurl and GoodBoy got my Eberspacher working on my boat for the first time in five years! Can you Adam and Eve it!?

 

Anyway, what I ended up doing to the radiator it's the busted valve was something slightly different. I bought (what I thought was) the correct parts but clearly booboo-ed. I had one of these:

 

https://www.dropbox.com/s/1khb1ryw6c5uq9a/DSC00921.jpg

 

And it came with a blanking plate to match it. But when I removed the old broken valve this much of it is what came out:

 

https://www.dropbox.com/s/7f0lg3ehsm4ve9j/DSC00922.jpg

 

The new part fit beautifully in the space left behind, but with no stopper at the end it would just keep screwing in and there was nothing the hold the rubber washer in place. As it seemed a tight fit I tried it, but as soon as I let water through the radiator, it started to drip.

 

So I've ended up using the blanking plate with the rubber washer on it instead. It fits perfectly but it does mean to bleed the radiator I have to loosen the entire valve with a spanner instead of just using a radiator key. Here it is:

 

https://www.dropbox.com/s/7okzgh5apcfh5zl/DSC00924.jpg

 

Oh well... I'm giving the Eber a good run now and the first radiator is hot, the second radiator is just starting to get luke warm, so hopefully the third radiator, which is the one with the changed valve, will start to get hot too. Soon find out...

 

And despite editing, I clearly still don't know how to do image tags without the old forum editor!

Edited May 12, 2013 by BlueStringPudding

[n.b.Goldie]

Re your first picture, it is an air-cock and provided the threads are the same as the one you removed it would have been ok. To fit it you would need an Allen wrench of suitable size and ptfe tape. Undoing the square bit in the middle by a couple of turns lets the air out.

 

Anyway, what you have fitted will work so no big deal.

 

Regards

 

Ditchdabbler

[Paul C]

I just looked at the bleed valve on my radiator and it is different to your 1st pic, in that it has a 'shoulder' the thing can sit on in the rad, to seal against a washer/seal for example.

[smileypete]

Oh well... I'm giving the Eber a good run now and the first radiator is hot, the second radiator is just starting to get luke warm, so hopefully the third radiator, which is the one with the changed valve, will start to get hot too. Soon find out...

Good to hear the Eber is working. If all the rads are on full, they should really heat up together, if they heat up one at a time the rads may be out of balance.

 

Balancing radiators ensures that all the rads have the right amount of flow through them. Otherwise the one nearest the boiler will get all the flow and can cause the boiler to cycle off too soon which is bad for the Eber.

 

When the rads are all balanced it means that when they're on full, the temperature of the water they're passing back to the boiler is the same as it is on the other radiators. This is done by adjusting the 'lockshield' valves - the ones with a cap on which pulls off to reveal a flat blade. Best way to judge it is with a cheap IR thermometer though with a bit of experience a MK1 human hand can be used OK.

 

A google or forum search on radiator balancing should turn up some more info, if it's all a bit baffling a good plumbing person should be able to explain and demonstrate it OK. I've tried to explain it as simply as I possibly can, honest!

 

cheers, Pete.

~smpt~

[David Mack]

Thought I'd update this thread since this very day the lovely GoodGurl and GoodBoy got my Eberspacher working on my boat for the first time in five years! Can you Adam and Eve it!?

 

Anyway, what I ended up doing to the radiator it's the busted valve was something slightly different. I bought (what I thought was) the correct parts but clearly booboo-ed. I had one of these:

 

https://www.dropbox.com/s/1khb1ryw6c5uq9a/DSC00921.jpg

 

 

 

That looks like a taper thread version which needs lots of ptfe tape to get a seal.

 

This would do the trick.

 

And its got your initials!