is there a plumber in the house?

[Birdseye]

Doing some alterations in the bunglaow so I have to drain down the heating system - itself a PITA since there is only one drain valve and the pipes run through the loft.

However, whilst the system is dry I need to sort out the lock shield valves. The building was put up in the 90s and now several of the lock shield valves leak from the spindle. I've taken one of the valves to bits and the design has a central flange above the archimedes screw that has two red rubber O ring seals on it.

The bungalow has solid floors and the pipes feeding the rads come up through the screed. So any new valve need to have the same dimensions as the old one if I am to avoid having to cut the riser, soldering in a new length of 15mm pipe.

Way I see it I have two alternatives. Remove every valve and replace. Or remove every valve and refit after renewing the seals. Which is the likely best way forward? Replacing the seals with O rings doesnt strike me as that easy but then how well is a new valve going to seal onto the compression fitting on the 15mm upstand pipe.

 

[VicS]

A new valve will probably seal onto the old olive just as well as the old one will reseal.

You could get an olive removing tool , pull the old olives off and fit new ones or you could fit the new valves with smear of joining compound , or your favourite boaty sealant.

 

[Giblets]

It sounds from your description of the two red o-rings that you have Belmont rad valves fitted. This is good news as not only can you replace the o-rings but this can be done with the system full. You do not need to take that valve off the radiator to do this. However be warned that the replacement o-rings are about £1 EACH and as you know you will need two rings per valve. DO NOT try and find a cheaper o-ring to fit. I have tried this over the years in the day job and the cheaper ones will fail in very short order. Whilst you are at it I would suggest if you have Belmont wheel head valves (the on/off ones at the opposite end from the lock shield valves) then you replace the o-rings in these as well.

If you could post a piccy of the parts of the valve you have taken apart this may help confirmation of the type fitted. Belmont valves are considered by some (including me) to be the Rolls Royce of rad valves.

 

[scubajohn]

Hi birdseye
repairing lockshields, id fit new you can get them with drain offs, fitting, the olives will probubly have flattened out some what just wrap the olive in ptfe tape common practise . The pain in the ar*** later is balancing the system

 

[Topcat47]

1/2" and 12mm valves are more or less interchangeable, so you can simply exchange the old valves with new ones, 3/8" and 8/10mm small bore valves are a different matter. Microbore pipes were all the rage in the 70's, not so much once the price of copper came down in the 80's.

 

[VicMallows]

DO NOT try and find a cheaper o-ring to fit. I have tried this over the years in the day job and the cheaper ones will fail in very short order.
.

Giblets, I respect your professional opinion. However I HAVE successfully replaced Belmont O-Rings with standard nitrile rings, and they have lasted well over 10 years and are on valves which are operated frequently. I would agree that very accurate sizing is essential, both diameter and thickness. And yes, easy to do 'live' with minimal spillage. (My valves are all 3/4" which are possibly more size tolerant than 1/2").

 

[MickH]

Giblets gives good advice re the Belmont Rad Valves which are the finest valves ever produced but the manufacturer
Peglar used a material rubber that was not all that long lived. I always fitted viton o rings to these valves that leaked
on a regular basis as the other contributer says. However there are nowdays plenty of opportunities to obtain viton
o rings that are tougher and will withstand the temperatures differences within any heating system. they will outlive any other industrial rubber available and it would be most prudent to measure a pair of new o rings that may be nitrile
but it must be stated that there were two different sizes of recesses (grooves) within the Peglar Belmont valves that had either red or sometimes green o rings to signify the size....... If you are confident to size the new O rings by measuring the old ones then so be it. Plenty of adverts from the Ebay sellers who list umpteen different sizes but make absolutely sure they are viton as this particular rubber is the top but some would say over the top but I would say not so why buy inferior rubber when there is a quality rubber available that is virtually fit and forget........ And don't forget a liberal smear of silicone grease on each and every cleaned and re o ringed spindle.........
No I am not a Peglar rep but I do know that only two companies in the whole of Nottingham used those valves Hiltons and myself and that was down to cost alone ie they were too dear to use on domestic systems......
Almost all lock shield and similar valves are crap these days and only one replacement locksheild is worth buying at a reasonable price & that is the Altechnic better qual one & even that needs the stuffing box nut tightening as it's usually found loose on all the new valves but to think about replacing those valves you have should be unthinkable to any engineer that is knowledgeable.

 

[Birdseye]

here are two piccies of the valves concerned https://www.dropbox.com/s/h9rkcka9u4h43i4/DSC_0117.JPG?dl=0 https://www.dropbox.com/s/7r2f8mkgnu7lfou/DSC_0118.JPG?dl=0

There are two black rubber sealing rings on the valve but dont be misled - they are ones that I dug our of my box of bits after I took the valve to pieces. I think I remember the original rubber rings being yellow or orange. I will take another one to pieces to check the colour.

So, is this the Pegler valve referred to? And if so what are the sizes of the two alternative rings?

 

[Giblets]

Yep, they are Belmont valves. Don't know the exact size of the o-rings from memory but will find one later and measure for you. It sounds like the old rings were red as the manu's replacements are either red or green.

 

[Birdseye]

Thanks Giblets. Since its a PITA to drain the system ( no drain taps and pipes through the loft) I am anxious that its a once only repair. There are 15 to do and I feel a bit more confident about replacing seals than I do about replacing valves and getting to leaks. Is this realistic?

I should add that I dug one of what I think was the old O rings out of the bin and it is red. It looks like 10mm i/d and 2mm thick but the standard rings available are 9.8mm ( no problem) but either 1.9mm thick or 2.4mm. Which?

 

[Giblets]

Sorry for the delay; having trouble finding one in the tool box as I gave most of them to #1 son when he took over. Will get one back off him if need be.

 

[nigelmercier]

the olives will probubly have flattened out some what just wrap the olive in ptfe tape common practise ...

By bodgers.