Stop caps for isolation valve?

[robodelfy]

I've just removed a towel radiator, which has isolation valves which connect the visible chrome pipes to the 15mm copper ones under the floor boards.

I plan to leave the radiator off the wall for a few weeks while I renovate, but don't trust these old isolation valves alone, should I?

I can't seem to find any caps that just screws on to the thread of the isolation valve as extra protection! The thread is about 20mm.

I also considered re attaching the chrome pipes, sawing them off and putting a push fit stop on, but apparently they aren't safe on chrome, they slip off.

Any advice would be great

 

[Madrab]

If they are 15mm pipes then a 1/2" stop blank should fit. Just need to be as tight as you can get them with your hand.

That being said, those isolation valves shouldn't be on the system in the first place, they are just about guaranteed to leak eventually. I would recommend you remove them.

 

[robodelfy]

If they are 15mm pipes then a 1/2" stop blank should fit. Just need to be as tight as you can get them with your hand.

That being said, those isolation valves shouldn't be on the system in the first place, they are just about guaranteed to leak eventually. I would recommend you remove them.

The stop blanks I saw on the Screwfix site seemed to have an olive inside for going on to copper pipes, I didn't see one that would fit this 20mm thread.

Do isolation valves fail often? I didn't know this, I thought it made sense to have them on things, I have them in my toilet, sink and towel radiator

 

[dilalio]

You want a "stop cap" not a "stop end"
Caps are one piece ends are 2 piece items.

 

[Madrab]

They are designed for potable water so on your hot and cold supplies then fine that's what they're designed for. When it comes to central heating then there's inhibitor in the system and the system water can be hotter than normal hot water so over time the expansion and contraction can affect the seals that the ball sits in.
High quality ISO valves suited for all environments are stainless steel with teflon seals but the cheaper ones for potable water and the ones they tend to use on boilers use nylon seals that aren't as robust.

 

[robodelfy]

They are designed for potable water so on your hot and cold supplies then fine that's what they're designed for. When it comes to central heating then there's inhibitor in the system and the system water can be hotter than normal hot water so over time the expansion and contraction can affect the seals that the ball sits in.
High quality ISO valves suited for all environments are stainless steel with teflon seals but the cheaper ones for potable water and the ones they tend to use on boilers use nylon seals that aren't as robust.

Thanks, great explanation. So I should remove the ones from my towel radiator then. Also, if I've turned these off would you trust them to hold if they are not attached to a radiator anymore? It worries me that if they fail, my house would be flooded!

 

[Madrab]

As long as it/they're not leaking just now then they should hold ok. They should be removed though, that's the point of having radiator valves
Seriously though, if you have a sealed system then just shut off all the rads at their valves (lockshields - count the turns so you can set them back) then just use that valve and drain the pressure out of the system, you shouldn't lose that much water, remove the valves and fit a straight coupler then the radiator valve and pipe, make sure the radiator valves are shut off too before re-pressurising.

If you have an open vent central heating (usually with a small black tank in the attic) then it's a bit more complicated.

 

[robodelfy]

As long as it/they're not leaking just now then they should hold ok. They should be removed though, that's the point of having radiator valves
Seriously though, if you have a sealed system then just shut off all the rads at their valves (lockshields - count the turns so you can set them back) then just use that valve and drain the pressure out of the system, you shouldn't lose that much water, remove the valves and fit a straight coupler then the radiator valve and pipe, make sure the radiator valves are shut off too before re-pressurising.

If you have an open vent central heating (usually with a small black tank in the attic) then it's a bit more complicated.

Thanks, yeah I'm turning the water off when I leave the house anyway, just in case!

I had planned soon to replace all the TRV and lock shield valves on every radiator, so should I do this all at once as you described, and remove these isolating valves from the towel radiator? I've never done any of this before

 

[Madrab]

Thanks, yeah I'm turning the water off when I leave the house anyway, just in case!

You don't need to turn the mains water off, that isolation valve shouldn't be connected to the house's mains water supply if you have a sealed system.
Depending on whether the system is fed from a small tank in the loft or not would dictate what water it uses and whether it keeps itself topped up or not. Do you have a loft that has a small black tank with water in it?

No reason when the system is de-pressurised/dry not to do all the valves at the same time.

 

[robodelfy]

You don't need to turn the mains water off, that isolation valve shouldn't be connected to the house's mains water supply if you have a sealed system.
Depending on whether the system is fed from a small tank in the loft or not would dictate what water it uses and whether it keeps itself topped up or not. Do you have a loft that has a small black tank with water in it?

No reason when the system is de-pressurised/dry not to do all the valves at the same time.

I have a combi boiler and no tank in the loft. So Does this mean it's sealed?

So if those isolating valves failed (worst case scenario) then they wouldn't just endlessly spurt out water, it would only be what was in the heating system? That would be a relief

 

[Madrab]

Just the ones that are on the central heating, they would just empty the CH pipework. The ones on your toilet and basin are different of course but they're designed for those situations.