Replacing a faulty radiator valve - didn't quite work :-(

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Hi,

I replaced a radiator valve, but my replacement is leaking as well. Here's what I did:

1. Switched off my Worcester Greenstar 24i combi boiler
2. attached a hose to the drain valve by a radiator, tried draining whilst opening all valves, but this didn't quite work (look at the pic and you'll see how ridiculously low the drain valve is).
3. Opened all bleed valves and drained the water down from the radiator valve by using several buckets.
4. Once fully drained I left the old radiator tail in place, as I didn't have a hexagonal rad key to remove it.
5. Cleaned up pipework using wire wool.
6. Applied 5 loops of PTFE tape to both sides of valve and put valve in.
7. Tightened valve nuts.

Here's where it gets a bit dodgy:

1. I re-pressurised the system, but noticed the pressure gauge wasn't increasing. Wondering whether the electrical power to the boiler needs to be on before the gauge kicks in, I turned the power on (but not central heating or hot water) and continued pressuring the system. After 30 - 60 seconds I turned the boiler off and continued pressurising the system until it hit 1.5 bar.

2. Powered boiler back on and turned on central heating, then bled radiators and re-pressurised the system back to 1.5 bar.

3. After a few hours I noticed a leak in the valve, so I tightened the nuts as much as possible, but it still slightly leaks. I've now decided to put some jointing compund around the valve, but suspect this won't solve the leak.

4. I noticed something quite odd, my boiler pressure jumped up to almost 3 bars last night and I don't know why (filling loop is off)

What would you recommend? Should I have replaced the radiator tail as well?

Can I drain the water in the system from the boiler itself?


Radiator valve - http://i48.tinypic.com/21ltjpu.jpg
Low drain point - http://tinypic.com/r/2qcpe04/6
Boiler - can I drain from here? http://tinypic.com/view.php?pic=j580i1&s=6


Thanks[/img]
 
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I was only messin

Is that a cheapo valve from the likes of tool station or scewfix ?

And where is the water now leaking from ?
 
I'm not sure on it's origin - I found it in my dad's toolbox, it was clean as a whistle and the valve moved smoothly, so I'm guessing it's good.

The leak appears to be coming from the join between the valve and the radiator tail - I didn't want to tighten this anymore in case I damage something.

Any idea why the boiler pressure would have increased?

Thanks
 
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Possible faulty expansion vessel or you have recharged the system pressure to highly are you certain the filling loop isn't passing ?
 
I'm pretty sure the filling loop isn't passing, just gave it a slight turn to be sure!

Do you think turning on a partially filled boiler for 45 seconds would cause the expansion vessel to become faulty?

The boiler is 14 months old and has been looked after pretty well

Cheers
 
Hi aetius

Was it a union tail (3/4") shaped like a bell (ish) or a 15mm compression tail?

Either way it is quite common for the union to have been overtightened and once done it will forever leak and will need to be replaced.

let us know that and I will give you some possibles regarding the pressure when I have time

Hope this helps

Russ
 
The tail looked as if it needs a hexagonal key applied - I think the 15mm.

How do you know when to stop tightening?

Oh, do you know if I can drain the system from the boiler?

If not, I'm thinking of getting a freeze kit and it'll save me some time...

Thanks
 
Please clarify the situation...

So; is the leak from between the radiator and the tail?

If it is between tail and valve try tweaking it up a bit more.

What is all the ****e on the valve?!
You don't need ptfe tape on a compression joint - not that this is anything to do with it leaking or not.

When you refilled the boiler did you bleed the system properly?
No, putting power onto the boiler at the point that you did would not be a problem. The px gauge works without power - but you know that now I guess.
 
There do seem to be a lot of problems with Worcester EXVs.

I dot know why, perhaps they are supplied wrongly pressurised?

Tony
 
Cheers for the info guys,

Breesey, all that s***e over the valve is jointing compound - I'm hoping it'll harden and stop any leaks. It's not a constant leak from the valve, but a tiny trickle every now and again, almost as if the pressure gets too much and a little bit just drops out now and again.

When I have a bit more time, I'll drain the system from the boiler and check the valve again.

Thanks
 

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