Rad valve replacement checklist

[Desi80]

I've got a rad that was leaking a decent amount of water, tried nipping things up but it didn't help. Yesterday I thought I'd quickly whip the nut off and repack the gland spindle and add a bit of PTFE when reattaching the nut.
I undid the top nut but there' s a black plastic/rubber inner that's risen up and it's stopping me reattaching the top nut. (see attachment)


So now I'm guessing it's time to replace the valve, there's another one I can do whilst I'm at it too.
I've got a pressurised combi system. My checklist is as follows:


• Make sure water feed and power to system is off
The water feed is the valve in the airing cupboard I use to top up pressure right?
• Drain system with a hose and jubilee clip, the drainage point is on the rad in question
• Replace valves
• Refill system, bleed, top up pressure, add inhibitor


I've got a couple of questions, can I get that bit of black plastic back in the valve and save me the headache of bleeding the whole system?
If I do end up replacing valves is there some kind of overflow system to stop me overfilling the system? Do you leave some bleed valves open to let the air out as it fills?
Any help would be good as I don't want to leave this too long, it's cold!

 

[Desi80]

 

[ShaunCorbs]

easier in the long run to just replace the valve (the plastic would be brittle so prob wont seal anyway)

yes

yes normally fill your system to a pressure of about 1.2bar then air a couple of rads and repeat until all rads are full

 

[Desi80]

Thanks Shaun, I'm currently looking into a pipe freezing kit from screwfix (can't post a link as I'm a new member)

 

[Riley]

Thanks Shaun, I'm currently looking into a pipe freezing kit from screwfix (can't post a link as I'm a new member)

drain it down mate. Easy to freeze microbore. Also easy to defrost microbore under pressure with water running out of the radiator

 

[dancinplumba]

Snatch it ;-)

 

[Best]

Would be really stupid to drain the system down! Why would you do that on a pressurised system? Take the pressure off the system somewhere like a draincock and then the system is dead, zero pressure. Just tighten by hand any auto vent screws to prevent air getting drawn in and after turning the other rad valve off, remove your faulty valve and replace.
Expect some water to glug out of rad - so stuff a little bit of rag temporarily in the tail while putting the new valve on.

 

[Desi80]

Thanks for the feedback everyone.

Yes, Best, I want to avoid draining down if possible, there's the hassle and the added cost of the inhibitor etc.

So if I slowly let some water out somewhere that kills the pressure in the system right? Then I can freeze up the pipe just in case and do a quick swap.

Hopefully that will be ok...

 

[ShaunCorbs]

Thanks for the feedback everyone.

Yes, Best, I want to avoid draining down if possible, there's the hassle and the added cost of the inhibitor etc.

So if I slowly let some water out somewhere that kills the pressure in the system right? Then I can freeze up the pipe just in case and do a quick swap.

Hopefully that will be ok...

it would be ok, but i wouldn't recommend it for a diyer as few things can go wrong, and draining down and putting fresh inh would help/ might be needed anyway

 

[stevetheplumber]

get a sraight swop valve shut one valve on each rad let some out of the drain off loosen both nuts on the valve then just do a quick swop

 

[Best]

Can't see why you would still feel the need to freeze a pipe once you have no pressure in the system.
Good point Shaun says about the inhibitor. You might need it anyhow, although it can be injected into system if you buy the pressurised inhibitor

 

[TFGplumbing]

Would be really stupid to drain the system down! Why would you do that on a pressurised system? Take the pressure off the system somewhere like a draincock and then the system is dead, zero pressure. Just tighten by hand any auto vent screws to prevent air getting drawn in and after turning the other rad valve off, remove your faulty valve and replace.
Expect some water to glug out of rad - so stuff a little bit of rag temporarily in the tail while putting the new valve on.

^^ This.. so much this

 

[dancinplumba]

Best bet would be to call a plumber in 🙂

 

[Riley]

Would be really stupid to drain the system down! Why would you do that on a pressurised system? Take the pressure off the system somewhere like a draincock and then the system is dead, zero pressure. Just tighten by hand any auto vent screws to prevent air getting drawn in and after turning the other rad valve off, remove your faulty valve and replace.
Expect some water to glug out of rad - so stuff a little bit of rag temporarily in the tail while putting the new valve on.

Was only saying drain as it's clearly a DIY job

 

[Best]

Was only saying drain as it's clearly a DIY job

I wasn't getting at your post Riley, so don't take offence. You are right, it gets complicated for DIY. It was just that the OP seemed to think it had to be drained or froze. Seems such a waste of time and money for a sealed system.
I rarely drain any system, sealed or open vent just to change a brass fitting.

 

[Riley]

I wasn't getting at your post Riley, so don't take offence. You are right, it gets complicated for DIY. It was just that the OP seemed to think it had to be drained or froze. Seems such a waste of time and money for a sealed system.
I rarely drain any system, sealed or open vent just to change a brass fitting.

No offence taken mate. I am much the same. It's just if you're not used to doing it you can get a bit fingers and thumbs and that's when a mess Can happen

 

[WaterTight]

When I was fresh out of the training centre and still an optimistic young scamp, a barefoot boy with cheek of tan, I told the fella I was shadowing about a similar job I had been offered. We discussed what he would do and then what I should do. The verdict was I shouldn't snatch or freeze as I was too inexperienced. So I drained down, which took longer but the chances of a disaster were slim.

 

[joni os]

On the sealed system, once the pressure is off the biggest problem will be catching water from rad.

 

[Alex Knight]

Worst thing ever is snatching a new valve in and the threads don't match haha, then having to snatch the old one back in to stop it leaking while you drain down 🙁

 

[Desi80]

Worst thing ever is snatching a new valve in and the threads don't match haha, then having to snatch the old one back in to stop it leaking while you drain down 🙁

Yeah, that's what I've just done 😉

I drained enough out of the system so there was no pressure and just decided to go for the switch without the freezing. Got everything to hand, two vessels to swap out in case things went pear shaped and a big bucket.
Got both the nuts loose, stuck a make shift bung in the rad and then had that moment of 'WTH?!' (wrong sized valve)
I had a big bowl underneath and a towel and the leakage was minimal so no dramas there just the frustration of not having the problem sorted.

I will definitely drain down when it's warmer weather and I'm not dependent on having heating because the water was pretty black at times and I want to change the fill loop valve as the person who had the house before me ruined the screw head.

Back to using the immersion and electric heaters for now....

 

[Desi80]

I take it microbore is 8mm then?
(screwfix site) /p/angled-radiator-valve-chrome-8mm-x/60378
Still can't post links apparently

 

[ShaunCorbs]

I take it microbore is 8mm then?
(screwfix site) /p/angled-radiator-valve-chrome-8mm-x/60378
Still can't post links apparently

10mm prob bought a 15mm one

 

[Desi80]

10mm prob bought a 15mm one

Thanks Shaun, I'll get this then...
NoLinkingToThis/p/angled-radiator-valve-chrome-10mm-x/51257

 

[tamz]

Looks like an old tradesave valve. Might have an 8 x 10mm bullet in it.

 

[ShaunCorbs]

Thanks Shaun, I'll get this then...
NoLinkingToThis/p/angled-radiator-valve-chrome-10mm-x/51257

what size valve is you get? as looks like 10mm but not much difference between

 

[Desi80]

what size valve is you get? as looks like 10mm but not much difference between

No, you're right, I got a 15mm, it wasn't something I thought to check and assumed there was only one size. Live and learn 🙂

 

[ShaunCorbs]

No, you're right, I got a 15mm, it wasn't something I thought to check and assumed there was only one size. Live and learn 🙂

should be 10mm

if you could and havent got on already on your system you could put one of these on

Angled Radiator Valve & Drain Off 10mm x ½" | Manual Valves | NoLinkingToThis

if you already have

this one is fine

Angled Radiator Valve Chrome 10mm x ½" | Manual Valves | NoLinkingToThis

 

[Desi80]

Cheers Shaun, looks like I've got drain offs on pretty much all the rads so I'll go with the second one.

 

[ShaunCorbs]

Cheers Shaun, looks like I've got drain offs on pretty much all the rads so I'll go with the second one.

That's good you would be surprised how many don't have drain offs 🙂

 

[plumben]

That's good you would be surprised how many don't have drain offs 🙂

The boiler job I'm on now the only drain off is screwed into the top of the rad

 

[Desi80]

Well it wasn't 10mm either.

Tried to do another quick swap but didn't realise the system had re pressurised. If the fill loop is closed how can water be entering the system?

I turned the stopcock off last night after draining some water as an experiment and it stayed at 0 till I opened the stopcock again. After a few hours we're at 1 bar without the fill loop being touched.

This implies the fill loop valve is either not completely closed or broken right?

Trying to do a quick swap with 2 bar of pressure is not fun 🙂

 

[ShaunCorbs]

you sure ? did you measure the pipe when you took the valve off

and yes filling valve might be passing so best replace (you can tell by taking the braided hose off any much water come out/doesnt stop )

 

[Desi80]

you sure ? did you measure the pipe when you took the valve off

and yes filling valve might be passing so best replace (you can tell by taking the braided hose off any much water come out/doesnt stop )

Hehe, no I'm not sure. It was all a bit of a panic when I realized water was spurting 4ft up the wall 😉
All I know is the old nut didn't fit the new valve.

Unfortunately it's looking more likely I'm gonna have to do a drain down then to get the fill loop sorted. I assume they're compression fittings? I'll look into it.

I didn't take the 10mm valves back so when it's all emptied out I'll investigate properly.

If I'm installing a whole new valve what's the name of the plumber's mate stuff? Do I need that around the olive?

 

[ShaunCorbs]

Hehe, no I'm not sure. It was all a bit of a panic when I realized water was spurting 4ft up the wall 😉
All I know is the old nut didn't fit the new valve.

Unfortunately it's looking more likely I'm gonna have to do a drain down then to get the fill loop sorted. I assume they're compression fittings? I'll look into it.

I didn't take the 10mm valves back so when it's all emptied out I'll investigate properly.

If I'm installing a whole new valve what's the name of the plumber's mate stuff? Do I need that around the olive?

😀 the old nut might have different threads to the new one (that could be one reason)

yes they are

http://www.NoLinkingToThis/p/combi-straight-filling-loop/46605

and boss white is one but theres a few

http://www.NoLinkingToThis/p/no-nonsense-gas-water-jointing-compound-300g/52109
Fernox LS-X Leak Sealer 50ml | Sealers & Compounds | NoLinkingToThis

and always worth it saves draining down later if it leaks a bit

 

[Desi80]

Yep that's the one, I thought it was blue instead of white.

So turn the stopcock off, connect hose to rad, open fill loop, open bleed valves, drain system.

Fit new fill loop, fit new valve, close drain off, close bleed valves, stopcock on, check fill loop and fill, bleed, fill, bleed etc.

Once I'm sure everything is ok, close both valves to a rad and drain some water out and buy or make something to add inhibitor. I haven't found a good way to add inhibitor yet.

Thanks for your time on this Shaun (and everyone!) it really helps.