Replacing a radiator

[sotal]

We live in a house built in 1978.

My wife noticed a bubble of paint on the top of the radiator in one of the bedrooms, pressing it caused it to burst and spray water out. We've isolated the radiator, but obviously it has rusted from the inside out. It looks like it would be the original radiator to the house.

I'm guessing I need to improve the corrosion inhibitor within the system.

I'm going to drain the whole system down as I need to work on the pipework to the radiator in the bathroom that I'm working on. I also want to replace the mid position valve as it keeps sticking.

So onto my questions...

Next to the tank in the loft there is an unopened bottle of corrosion inhibitor since before we purchased the house. Is it worth putting that in or will it have gone off in the bottle? We've lived here for 8 years.

If I need to buy a bottle - what is best to get?

The radiator I need to place is 1440mm x 600mm Single. The closest I can find locally is 1400mm x 600mm. I don't really want to mess with the pipework though as it comes through the floor. Will I be able to connect it up with it being 4cm smaller? Pipework is 15mm.

Thanks

 

[JohnD]

if you have had a radiator rust through, there will be a lot of "rust" (probably black sediment) inside the pipes, radiators and boiler. You need to clean that out before adding inhibitor. Is there some reason to think that only one of your radiators is corroding?

You could start with a simple chemical clean which is very inexpensive and an easy DIY job, see what comes out. X400 is a mild non-aggressive cleaner that you can leave circulating for a few weeks.

Bale out all the mud from the feed and expansion tank before you start, to avoid washing it down into the system.

Watch the F&E tank a few times when you first start up the boiler, and when it starts heating the cylinder. It is possible that it is "pumping over" through the vent pipe, which aerates the water and causes very fast corrosion. This is a major problem.

How often have you needed to bleed radiators?

 

[mazperks]

In answer to your question re making up the 40mm, you can get rad extensions in various sizes.
Google Toolstation radiator extensions. (Get the rigid type)

 

[sotal]

if you have had a radiator rust through, there will be a lot of "rust" (probably black sediment) inside the pipes, radiators and boiler. You need to clean that out before adding inhibitor. Is there some reason to think that only one of your radiators is corroding?

You could start with a simple chemical clean which is very inexpensive and an easy DIY job, see what comes out. X400 is a mild non-aggressive cleaner that you can leave circulating for a few weeks.

Bale out all the mud from the feed and expansion tank before you start, to avoid washing it down into the system.

Watch the F&E tank a few times when you first start up the boiler, and when it starts heating the cylinder. It is possible that it is "pumping over" through the vent pipe, which aerates the water and causes very fast corrosion. This is a major problem.

How often have you needed to bleed radiators?

Thanks, when I last removed a radiator for decorating the water inside was nice and clear. We had a new boiler fitted about 6 years ago and the fitter had to do a clean of the full system to fulfil the warranty requirements. He did it but at the time said it was a bit of a waste of money as the system was very clean. I presume but can't be 100% sure that he put some kind of inhibitor in after.

Will check the feed/expansion tank for muck.

Bleeding radiators - it is pretty much never for every radiator except the bathroom radiator. The bathroom radiator needs regular bleeding. I will be replacing the bathroom one with a tall towel radiator so would like to sort everything properly before hand. The bathroom rad is the closest to the cylinder/pump etc. No sign of corrosion on the outside of the other radiators.

 

[sotal]

Not sure if it is related at all but I'm also about to change the Y valve again, this will be the 3rd valve in the 8 years that we have lived here. They seem to seize up over the summer when we don't use the central heating.

 

[sotal]

Just been reading up on X400, looks good - will get some from screwfix. I'll put it in when I refill after replacing the rad and I'll leave it to run for a couple of weeks until I put the new rad in the bathroom - then I can drain it all out again and refill. What would be best as inhibitor after? Should I stick with the same make and put X100 in?

Are the 1L bottles enough? The house is a 4 bed detached with 10 Radiators

 

[mazperks]

1L typically does up to 10 rads, for cleaner or inhibitor, but putting extra in wont hurt, especially cleaner in a dirty system.

 

[sotal]

Well that was a fun job

Came to replace the radiator in my sons room and I re-routed the pipework for the new towel radiator in the bathroom. I was doing both together and ended up with lots of problems! The towel rad was pipework was fine, but the simple job of replacing a radiator wasn't so easy!

First off when I removed the radiator I noticed the valve on the non TRV end was loose on the end of the pipe. It looks like it was just held together with paint. Worryingly the olive hadn't bitten into the copper and would just spin. I ended up having to cut it down and use some fresh pipe lower down with a new olive - but of course that meant cutting the other pipe down too, to match.

I got 2 of the rigid 20mm extensions as recommended above, I decided that a 2cm on each end would look better than a 4cm on just one end. I put PTFE on them and installed them, filled the system to find both of them dripping very slowly, had to drain the system again, then take them off and add lots more PTFE - much more than I ever normally put on anything but it did the trick.

Then it took me an hour to bleed the system, I'd managed to get some trapped air somewhere so the boiler just kept shutting down telling me that there was a circulation issue.

House was down to about 10*C by the time I managed to get the heating going again!


Anyway - there was a good bit of black sediment in the system. I've bought the cleaner and inhibitor so will try and get the cleaner in and running through the system, I left the drain open today with the mains filling the system to try and wash the system through a bit but haven't had chance to look at the state of the F&E tank. Will post again when I've had chance to watch what happens with it.

 

[Aquaheat]

I got 2 of the rigid 20mm extensions as recommended above, I decided that a 2cm on each end would look better than a 4cm on just one end. I put PTFE on them and installed them, filled the system to find both of them dripping very slowly, had to drain the system again, then take them off and add lots more PTFE - much more than I ever normally put on anything but it did the trick.

You don't really need the PTFE on these as there should be an O ring on them that creates the seal. PTFE will stop this from pulling up properly and cause the weeps that you had.

Jon

 

[sotal]

You don't really need the PTFE on these as there should be an O ring on them that creates the seal. PTFE will stop this from pulling up properly and cause the weeps that you had.

Jon

Nope, definitely no O ring - they were the ones from toolstation - both identical both just a plain lump of metal. The inside had the hex shape to tighten it up with the allen key the outside was just smooth for 20mm, then thread for the rest. Obviously the smooth part had an internal thread - again no O ring on that side either.

 

[Aquaheat]

Oh right. Never come across the without but then I never use Toolatation. These are what I meant. So much easier if you ever have to do it again.

http://www.plumbcenter.co.uk/product/myson-stelrad-extension-tail-radiator-tappings-40mm/

Jon

 

[BigSnoopy01]

20 plus wrapps of ptfe is not uncommon with poorly made fittings and rad threads, also some ptfe tapes are alot thinner than others, for example the one with the blue outer cover which i think is eagle brand is awful tape and i refuse to use it.

 

[sotal]

Thanks, makes me feel better about the PTFE tape! I'd done it so neatly the first time! I went over the end slightly this time to give a bit of a seal against the edge as well. House is lovely and warm now and no leaks so I'm happy!