Leaking valve-what do i do??

[Chris-st]

Hi. Need your help.

Just noticed a nasty leak and wondered if there would be a way to fix it. Its on a gate valve just after the pump. We seem to have inherited an old system!! An ideal system boiler with 2 22mm pipes leaving it. One of the pipes first has a pump isolation valve, then the pump, followed by another isolation valve. After this is the gate valve, originally fitted upside down and now leaking really badly. After this gate valve the 22mm pipe 't's' and goes upstairs (somewhere?). I can follow the other part of the T to the downstairs radiators. I have found a drain off point.

Thee is another 22mm pipe which follows the same route as the one just described but has no valves on it. It also 't's' off upstairs and then runs to downstairs rads.

In one of the bedrooms above is the hot water cylinder. I cant see any motorised valves.

All replies appreciated.

Chris


How can i change this leaking gate valve. I also dont want to touch the pump isolation valves as i'm sure they will leak - but if you say thats what i need to do, then i will.....

 

[nickso]

where is it leaking from?

the spindle or the body?

 

[Chris-st]

Nickso...looks like its leaking from both. Its an old valve and i suppose being fitted upside down hasnt helped. I have tried tightening it up slightly but that has made the leak worse.

 

[nickso]

its leaking worse now beacuse the fibre washer in the body was ripped when you tightened it.

it is repairable in situ....how handy are you with water and tools?

 

[Al-Glasgow]

I would isolate expansion tank, close upstairs rad valves, drain partially from downstairs radiator.

Wait until drip at faulty gate valve stops, then stop draining.

remove and refit new valve.

finish off by opening valves back up and testing/bleeding system.

Al

 

[Chris-st]

I'm pretty confident at having a go. After all its only water -

If it did go the water would go through the floor and into the cellar...

What do i need to do

 

[Chris-st]

I would isolate expansion tank, close upstairs rad valves, drain partially from downstairs radiator.

Wait until drip at faulty gate valve stops, then stop draining.

remove and refit new valve.

finish off by opening valves back up and testing/bleeding system.

Al

Wont this empty all the water out of the boiler?

 

[nickso]

i would put this at an 8 out of ten for a diyer....lots can go wrong fixing it. probably less can go wrong by replacing it.

you might be better off going for a version of glasgow als suggestion......i just prefer to fix things rather than replace myself

 

[Chris-st]

OK. So now i should isolate the cold water supply to the tank that fills the heating side. Close off all the upstairs rad valves. Then using the drain off i've found in the cellar, drain water until the leaking valve stops. Then change the valve. THen let the system fill up and bleed the radiators.

I'll use that approach.

Would have been useful to hear how you would repair it though Nickso..i'm intrigued.

 

[Al-Glasgow]

Would have been useful to hear how you would repair it though Nickso..i'm intrigued.

You have to repair it LIVE thats the risk, totally up to yourself lol

Good luck

Al

 

[nickso]

yes but by isolating the header tank he means you have to use bungs to create a vacuum.

repairing a gate valve is a caker when you have done it a few times, the first time is dodgy as you need to know when to stop unscrewing the body or the whole lot will drop out....swiftly followed by all the water in the pipes.

if you do it properly only a cup full of water will come out.

 

[Chris-st]

I think i'll drain down.

But how do you repair a gate valve. Didnt think you could. I can see it can be unscrewed - looks like it can be split in half. I can see a rubber washer half way down the valve. Then theres the spindle with a small nut below that.

What would you then do.

Obviously i'm not going to give it a go. Especially as this valve is upside down!!

PS: Do i need to buy 'bungs' then

 

[nickso]

you dont need bungs if you want to drain down.

the jist of the repair is,

screw down the spindle till it stops, unscrew the body whilst still screwing down the spindle, this is where the most water comes out. you can only unscrew the body until there is maybe 2-3mm of a gap between the fixed part of the body and the bit you are screwing out. clean the old gasket out, then make a new one with ptfe, remember to put the ptfe on the right way. then screw the body back in whilst unscrewing the spindle, more water will come out. tighten the body up hard and unscrew the spindle. tighten the spindle nut so it doesnt leak as well.

 

[Agile]

Not forgetting to put some ptfe under the spindle nut as well if that was leaking.

For a DIYer an improvised clamp to hold the gate in by applying pressure to the handle might be an advantage.

Tony

 

[Softus]

Oh. My. God.

I'm struggling to believe the fuss that's being made about this, nonsing around with pulling a vacuum and judging things that he has little chance of judging.

The easiest thing for an amateur to do is shut off the mains and open a drain cock. Then wait. Then replace the gate valve with a good quality new one.

Since the history of the system is unknown it's a good opportunity to assess it by looking at the quality of the water that comes out.

If reasonably clean, then refill with inhibitor. If not, then refill with cleaner.