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07-05-2020, 10:47 AM
1

Radiator Valves - Replacement not so Easy!

As the Central Heating can now be "off" and maintenance can be done, i have now set out on the mission to do a "Do it Myself" plan to replace a dozen, or so, Thermostatic Valves with ones more likely to perform efficiently.

Lo and behold, I find that all the old valves are on adapters which connect to the heads using Imperial connections.

The modern replacements are all of Metric connection.

Great, it looks like a total drain down is required just to get the new heads up and running.

Maybe I can plug up the CH tank, in the loft, to stop water running , such that the adapters can be replaced without draining.

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07-05-2020, 11:04 AM
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Re: Radiator Valves - Replacement not so Easy!

old saying "If it ain't broke don't fix it "
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07-05-2020, 11:12 AM
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Re: Radiator Valves - Replacement not so Easy!

Even if you plug up the expansion tank in the loft (old plumber's trick is to use a carrot), there will most likely be a degree of water spillage, so the best bet is just to go for it, drain the system down and change all of the valves at once.

Assuming that you'll be changing the entire body and not just the heads, you'll have to replace the fitting that actually goes into the radiator body. Instead of ptfe, I'd strongly recommend some loctite55 which is somewhat like tooth floss, but is far easier to use.

Also, make sure that you have an appropriate allen key, since this is sometimes the only way of removing or installing the fitting.

Finally, as you'll probably want to re-use the compression nut/olive on the pipe, make sure that you have a means of trimming them down (a dremel is great and much easier than a hacksaw in such a confined space) if needs be since it has been known for the small length of pipe protuding after the olive to be a tiny bit too long for the replacement fitting.
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07-05-2020, 11:16 AM
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Re: Radiator Valves - Replacement not so Easy!

For what it's worth, while you've got the radiators empty, now is a good time to take some of them outside and flush through with fresh water from a hose. You'd be amazed how much crud is in them.

Don't forget to add rust inhibitor to the expansion tank once you're done, but only after you're sure that there are no leaks!!!
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07-05-2020, 11:55 AM
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Re: Radiator Valves - Replacement not so Easy!

Originally Posted by Dextrous63 ->
Even if you plug up the expansion tank in the loft (old plumber's trick is to use a carrot), there will most likely be a degree of water spillage, so the best bet is just to go for it, drain the system down and change all of the valves at once.

Assuming that you'll be changing the entire body and not just the heads, you'll have to replace the fitting that actually goes into the radiator body. Instead of ptfe, I'd strongly recommend some loctite55 which is somewhat like tooth floss, but is far easier to use.

Also, make sure that you have an appropriate allen key, since this is sometimes the only way of removing or installing the fitting.

Finally, as you'll probably want to re-use the compression nut/olive on the pipe, make sure that you have a means of trimming them down (a dremel is great and much easier than a hacksaw in such a confined space) if needs be since it has been known for the small length of pipe protuding after the olive to be a tiny bit too long for the replacement fitting.
Thanks for the advice, Dex.

In the last bit you say a Dremel (which I have) would be useful. Are you saying that the the pipe might need trimming or the olive?

As for draining down, I might try to miss that as the whole thing has only just been flushed & fed with Fernox.

I see that there is still a string still up in the loft with two rubber plugs on it. Used it way back when I was a lad!
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07-05-2020, 12:02 PM
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Re: Radiator Valves - Replacement not so Easy!

You certainly can plug the water tank (the small header tank) with a set of rubber bungs. I have used them many times and only once did they not work because the pipes were out of shape.




As an aside, you only need one to bung the header tank but you need two when bunging the main water tank.
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07-05-2020, 12:38 PM
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Re: Radiator Valves - Replacement not so Easy!

Originally Posted by Tedc ->
In the last bit you say a Dremel (which I have) would be useful. Are you saying that the the pipe might need trimming or the olive?
A sliver of the pipe. Wouldn't really want to start removing the olive as this might lead to having a real ballache on your hands as you've have very little play of pipework available...and the concept of replacing the 6 or so inches of it could b a real pain. (Especially if your existing pipe is imperial 1/2" and not metric 15mm).

As you don't want to drain the system down, the only realistic way of working on it with open tails would be to use a pipe freezer. I suspect you don't want to go down that route (after all, it's cheaper to buy a pot of inhibitor than to hire a freezing kit).

All in all, it's probably simplest to write it off and get a refund for those valves you've just bought. Sorry
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07-05-2020, 01:34 PM
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Re: Radiator Valves - Replacement not so Easy!

You can also get an olive puller (available from merchants or toolstation etc)



I have one somewhere but have not seen it for years. If you are careful, you can cut off with a junior hack saw and a flat screwdriver.
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07-05-2020, 02:38 PM
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Re: Radiator Valves - Replacement not so Easy!

Originally Posted by Longdogs ->
You can also get an olive puller (available from merchants or toolstation etc)
I have one somewhere but have not seen it for years. If you are careful, you can cut off with a junior hack saw and a flat screwdriver.
All true. Not sure I'd want to risk damaging the pipe though
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07-05-2020, 02:53 PM
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Re: Radiator Valves - Replacement not so Easy!

Originally Posted by Longdogs ->
You can also get an olive puller (available from merchants or toolstation etc)



I have one somewhere but have not seen it for years. If you are careful, you can cut off with a junior hack saw and a flat screwdriver.
looks good, thanks, will try to order one asap.
 
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