[Closed] Help me fix a plumbing leak please

I would call it a drain valve (IANAP) I think the proper name might be a drain cock.

Not sure there is anything user servicable inside, they are only a couple of quid from screw fix so I would* just replace the whole valve - but you will need to be vaguely competent with soldering for that.

As to what it drains and why 2 - I doubt anyone can say for sure from your pic. The fact it is above the boiler suggests its not for the heating so a reasonable guess is a HW tank. One may drain the loop that takes very hot water from the boiler to the tank and the other may drain the tank itself? That may be important if you are going to disassemble because you will need to know both what to turn off and if you need to add any scale/corrosion inhibitor when refilling.

* actually I would probably be lazy and find a suitable rubber bung / balloon / tube with clip and fit on the hose barb until I got round to it (or the gassafe guy was back next year when he'd fix it in 1/4 of the time I would with none of the swearing!).

It's a drain cock, basically just a tap. There will be a replaceable rubber washer inside. Change that and make sure the seat's clean and that's about it. You'll need to drain down whatever it's on, if there's a stopcock anywhere upstream closing that will help minimise water loss and refilling.

As with anything plumbing related - what starts as a simple job/very slow drip will end up being a nightmare and involve loss of heating, angry wife and more water split than necessary.

Is it a case of, isolating the supply to it, unscrewing the innard (just keep turning anti-clockwise) and replacing a rubber seal?
Yes - but dont overtighten - this can mess with the seal (and remember to drain off first)

remember to drain off first

For sure - don't go winding the inner bit out until you have! Have a look on YouTube, there'll be plenty of vids if you search for "dripping stop cock". Probably safer not to do a similar image search on Google though.

Thanks all - replaced the rubber washer after thinking I had isolated it, but water did drain out into the sink via a hose. Now the boiler won't fire up - suspect I've drained the water supply. There's no pressure gauge or tap to fill the boiler, so guessing it has its own expansion tank in the loft???

Off to find some ladders to have a look.

What started out as a simple drip ... !!!

The boiler may be looking for a minimum pressure from the system, whether it's sealed or vented. If you have a tank in the loft it should refill the system. Odd that it didn't keep filling the system while you were draining it though.

Hmmm, boiler fired up and locked out. If I open the cold water feed, nothing comes out. It's (I think) open vent, no pressure gauge, little expansion tank in loft.

Could I have an air block?

If so, how to fix (hose from mains to cold water feed and blow back into expansion tank??)

Get your plumber back

Plumber's not interested, not his 0roblem apparently

Disclaimer, IANAP either.
Look in the back of your airing cupboard to see if there's any little sticking up stubs of pipe with a knurled bit at the top, it's called an end feed air vent cap if you Google that so you know what you're looking for. You might need to just crack them open with some pliers and bleed some air out. You might then hear a gurgling sound and the pump start pushing water to the boiler. That worked for me a while back.
Maybe...

If it's vented it'll be a header tank in your loft and that's where it'll fill from. Make sure the float valve isn't sticking. If it's not and the header's full check the exit isn't blocked and water can get to the rest of the system. Try cracking open the drain cock, is the system still empty? If not, reset the boiler trip and try again.
I've never had a problem refilling a CH/HW system but it can take a while - although you'd know something's going on by the loud gurgling.

IANAP but...
Would you have tk drain down whatever it is? I've heard it's possible to freeze a pipe to prevent leaks when doing a small repair like that,should only take a couple of minutes, really just need the pipe blocked for the duration

Plumber’s not interested, not his 0roblem apparently

He might be more interested if you offer to pay him. If not, get a different plumber and use them for your boiler servicing

No sight of the end feed vent pipe sadly.

Am I right in thinking the cold stop cock as pictured above is the gravity feed to the boiler? And if so, if I open it water should happily flow out? Because I'm getting no flow at all.

Expansion tank clear and full. No valves have been changed, nor can I find any turned off.

Am stuck and cross!

Ok, just fired up for 1 min, now flashing light lockout code = water circulation

Bled the circulation pump yet? Great big screw cap in the middle of the pump, you can't miss it, needs a big flat screwdriver. Open it until it dribbles, then close it, job done.

If you are really keen take the plug right out and reach in with a thin screwdriver to see if the pump impellor spins, after putting a bowl underneath for the dribbles.

If it is airlocked then as you said connect mains tap via hose to drain cock and push some water through. Worth being in the loft to observe proceedings, an almighty belch is a good sign, then get your lacky to turn the water off sharpish in-case the overflow can't keep up with the rate of fill.

Good luck 🙂

No water (or the sound of air) emerging from circulation pump.

Tried venting from the drain cock above the boiler (feeding to the expansion tank) but lots of water sprayed out from the collar area. But water did go up the feed pipe, how far I don't know as once it had drained, water dried up and nothing comes out again.

Hopefully got a plumber/CH guy coming around - took a lot of calling to get one as they're pretty busy or not interested. Fingers crossed!

How did you isolate the feed to the stop cock in the 1st instance? Did you screw win a wheel valve anywhere? They’re known to stick closed when re-opened.

Ah yes, I did screw a wheel valve shut ... is there an easy way to un-stick if stuck???

And plumber did come this afternoon - seemed a bit non-plussed. Wasn't convinced at all by an air lock. Seemed to think there's no gas getting to it. I wondered if this was because it can't call for water/no water feed to it? He's going to come back tomorrow after chatting to a few colleagues.

If of relevance, after he left, I went around the rads undoing the bleed valves, downstairs first. Lots of air came out the upstairs rads.

Went to bleed the water pump by the hot cylinder, no water came out at all, and it's spinning freely.

Hopefully tomorrow we can have a go at venting the system...

I think it is time to get a new plumber.
If he needs to ask someone else what may be wrong with it, then I'd be getting someone else in who does have a clue.
There is a fault finding flow chart for most boilers. Follow that, and it narrows down the fault. It doesnt always point to one component, it could be 2 or 3 faulty parts, but then you need to do volt checks at each component to find the fault , rather than guessing and fitting 3 new parts.

Now the boiler won’t fire up

Jeez I hate being right sometimes!
I've just had 7 rads connected to our system after a load of work had been done.
The actual pipework had been done a long time ago and I fitted the rads.... They just needed to connect the pipework sticking out of the walls to the rads.
Two weeks ago I drained down to remove a rad that was leaking and everything refilled fine.
Plumbers then came to do the rad connections and the system refilled fine again. While it was refilling they noticed a leak from the magnaclean they had just fitted so they had to drain down again to fix it.
Upon refilling there was a massive air lock (I think dur to them using a wet vac to speed up the draining down) - it took them 5 hours to get rid of it and they had to back fill the system which seems to be at least a two man job (one in the loft, one at the "tap").
Our air lock was in the coil in the hot water tank.
They also "tidied away" the copper pipe they had removed as well as all the push fit stoppers that were on the feeds to the new rads 😠

Good luck OP. Sounds like an air lock.

Ah yes, I did screw a wheel valve shut … is there an easy way to un-stick if stuck???

Sorry, forgot to check back. No, not really. It’s a replacement job usually as they’re cheap, but it’ll require a proper drain down or freeze to be able to do it.

Ah yes, I did screw a wheel valve shut … is there an easy way to un-stick if stuck???

Is the header tank full?
If so it's not that valve.

it could be 2 or 3 faulty parts, but then you need to do volt checks at each component to find the fault , rather than guessing and fitting 3 new parts.

But all he's done is drain down the system..... That's not a reason for parts to fail.

So are you wishing you’d just done a bodge job of blocking the hose barb and leaving for the plumber at the next service, yet?

Is the header tank full?
If so it’s not that valve

Sorry, just re-read and you say the tank is full so it's not the valve you closed.

Any update or has your wife had a new patio built?

Blocked cold feed to the system from the expansion cistern. Most likely caused by someone not understanding the theory behind a close coupled cold feed and vent.
If you can trace the pipe that comes from the bottom of the cistern and see where it joins the main flow from the boiler, probably just before the pump, and put a magnet on it. If it’s copper or plastic it shouldn’t be magnetic but if it is it indicates as build up of magnetite.

Thanks all for advice/pointers.

Update - so I got a second plumber around to have a look. He promptly told me the PCB had failed, so he'd replace that first, and if that didn't work, replace the gate valve from header tank and if that didn't work, he'd fully replace the whole piping from tank to boiler. and strongly hinted I replace the boiler as "it's old". Hmmmmm.

And then the first plumber phoned, asked if he could bring a colleague around who knows these systems better.

3rd plumber was much more interested in hearing the symptons, and then through a series of undoing various valves, identified a block between header tank and the circulating pump (he didn't have magnets, but undid the pipe at pupm, no water or air, then blew down the pipe from header tank to pump, and no sign of air). So he's coming back to replace that single piece of pipework and neaten it up.

I think exactly as Bear (andothers) has suggested.

So fingers crossed Monday it'll be good to go.

Sharkbait - you're right. I thought I had closed the header tank valve, but amongst the choice of 4 valves and curiously routed pipework, I hadn't!

Glad you seem to be getting a resolution to this.
As an aside I noticed this morning that one of the rads that was connected last week was weeping slightly.
Turns out the {rather expensive} plumbers actually forgot to tighten up a compression joint 🤷🏻‍♂️

OK, just an update if anyone's interested ... and can help me further.

Plumber in last night who had said it was a blockage between circulation pump and FE tank. Cut the pipe out and indeed it was pretty blocked. New pipe in, opened stopcocks above the boiler and water trickled out and then flowed out nice and strongly and evenly. So good news I hoped. Boiler fired up straight away. Plumber said to leave boiler off overnight and let gravity fill the system.

Went to boiler this morning, fired up straight away and then promptly locked out. It's going through the correct firing up sequence, gas is igniting and then after 60', locking out. Lock out code = air pressure switch.

Is it as simple as that ... but just odd for a different bit to fail???

To me simple logic, there's an easy trick to get it working!

Help!

And just thinking, if the APS had failed, presumably it wouldn't light at all?

And if anybody's interested! have looked in the boiler, condensate trap(?) was full of gunk, so pulled it out, cleaned, reinstalled and boiler's firing away ... so fingers crossed, the system was just full of gunk and it blocked up. Hopefully sorted. Suspect it would be a good idea to replace the circulating pump?

Draining down could have pulled a load of crap down from the F&E tank but the tank is just a header and I'm not sure it needs a big flow in either direction (unless refilling the system).

I don't have a condensing boiler so it's new to me, but found this (replace aluminium with 'gunk':

Once the bits of aluminium block the inlet tube on the trap then it will stop the flow and the condensation will keep backing up into the bottom of the heat exchanger until it stops the appliance from breathing and suffocates it. This will stop the appliance from working altogether.

If your appliance is regularly serviced PROPERLY by someone suitable who does a good job, which includes cleaning the primary heat exchanger or the condensate trap at least, then this will probably never cause an issue.

I tend to come across this problem on appliances that haven’t been serviced properly or at all for some time. The upgraded siphon on later models is a big improvement and doesn’t tend to suffer from this issue as much but still needs cleaning from time to time.

Symptoms of this issue will include a slight gurgling noise from the boiler, also if you go outside and listen to the flue it will be make an unusual sound. The boiler will attempt to light its burner but fail and go to ignition lockout.

https://www.expert-boiler-repair.co.uk/worcester-blocked-condensate-trap/

Get bleeding those rads!

Most likely caused by someone not understanding the theory behind a close coupled cold feed and vent.

im curious as to what this means.....

btw ive recently fitted a magnacleanse to my system and the amount of stuff its pulled is incredible!

Firstly if there is a valve on the cold feed to the heating system from the cistern then remove it as it should not be there.

Close coupled cold feed and vent pipework should ideally be arranged as close as possible to the inlet of the pump, on a horizontal section of pipework, have a continuos rise back to the cistern, be correctly sized, be no more than 150mm apart, particular attention should be paid the the inlet pump valve as this may draw air into the system as it is on the negative side, think that is about it from memory.

The ‘H’ section you often see is a terrible way of doing it.

condensate trap(?) was full of gunk,

none of the people who looked at the boiler seen this?

Condensate trap shouldn't be effected by gunk from the circulating side, it's just distilled water from the combustion. Make sure the drain pipe is clear - they changed the regs a little while ago to require bigger pipe which reduces the chance of blockage.

BUT if the drain down pulled crap into the circulating side you may want to flush it with something like Fernox cleaner and add a Magnaclean or Fernox filter.

Thanks again.

OK - so the condensate trap was definitely not draining as there was dark grey silt/small pieces blocking it. After cleaning it out, the boiler ran happily.

I actually think I probably didn't drain down the system as the gate valves I closed were not from the FE tank (it's pretty chaotic pipework in the loft and my error!). However, when I open the stopcocks just above the boiler, I get a really nice flow of very clean water - I'm hoping this is a good sign.

Sounds like a clean would be good.

My faith in the plumber isn't huge and his replacement pipework looks a bit DIY to me! So really appreciate the help here.

And my next qn (and thanks for all the input) -

the FE tank in the loft is clean. It has a cold water feed via a ballcock. It then has 2 additional pipes - one to feed the system and a return(?) pipe. The return pipe has a gate valve on it.

Should this be left opened or closed???

Historically it has always been open. @Bear - is this a problem?

I am def not a plumber but I thought you should only have three pipes associated with the F&E tank:
Feed pipe to the ballcock
Feed from the tank to the CH system (I thought that this not only keeps the system topped up but the same pipe also is used for expansion - what you call the return)
Overflow from the tank to outside (or similar)

But this is based on my system with an unvented hot water system (so no header)
Is your hot water system vented or unvented - or a combi?

Historically it has always been open.

Don't change it FFS - you know what happened last time you did something simple!!

I get a really nice flow of very clean water – I’m hoping this is a good sign.

Sounds like a clean would be good.

I'd be surprised if the CH water was particularly clean - unless everything is new. I've just fitted a Magnaclean and the amount of crap it's pulling out is amazing - but then it's an old house that hasn't had much in the way of additives in the system.