Glowworm Flexicom 30CX Boiler losing pressure

[mcmoby69]

you might just get a new valve in if you undo the compression nut near the floor. you will need a certain amount of 'play' to get it in.

could be easier to spin the valve so it faces you. strip the gubbins out of it and make good all seals etc and reassemble.

B&Q will not be the cheapest place for a 22mm gate valve over the weekend.

most gate valves are compression, you might get away with re using the nuts and olives left on the pipe when you remove the old one. put some ptfe round the olives before you fit the new valve (not the thread)

if the nuts dont go onto the new valve easy enough do not force them, hacksaw carefully thru the old olives (without cutting the pipe) and prise off. then fit the new stuff.

 

[Steve1138]

Thanks for that, I might try to change it on Monday.

I tightened the gland nut yesterday though and since then I have not been able to feel any water around the spindle but the pressure is still dropping!

Might be a silly question but if the valve is no longer wet and the pressure is still dropping then does that mean that this leaking valve was not the cause of the pressure loss or could it still be the cause even with no visible water leaking?

I think I may have overtightened the gland nut slightly too as it started to make a cracking noise when I turned it and I think the top of the nut looks like it has started to lift away from the rest of it:

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• Steve1138
• 7 Apr 2012
• 1

 

[Steve1138]

Also, probably nothing, but there is a lot of white residue in the bottom of the boiler which looks like the remains of a leak to me. This might be normal for the inside of a boiler though, I'm not really sure:

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• Steve1138
• 7 Apr 2012
• 1

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• Steve1138
• 7 Apr 2012
• 1

 

[Steve1138]

Just giving this thread a bit of a bump

 

[mcmoby69]

most leaks have a visible clue. leave the gate valve for now.

take a some pictures of the blow off pipe and show the route it takes.
how many rads and how big in your flat?

take a picture of the condense pipe too, show the route it takes.

white residue is a common clue of internal leaks on a boiler, check all joints inside.

sounds like you have a colander fitted not a boiler !!!!

 

[Steve1138]

most leaks have a visible clue. leave the gate valve for now.

take a some pictures of the blow off pipe and show the route it takes.
how many rads and how big in your flat?

take a picture of the condense pipe too, show the route it takes.

white residue is a common clue of internal leaks on a boiler, check all joints inside.

sounds like you have a colander fitted not a boiler !!!!

Hmm

The condensate pipe comes out of the bottom left of the boiler, goes along the wall to the right and then down through the top of the work surface. It then goes along the back of a cupboard and ends at the drain pipe from the sink:

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• Steve1138
• 8 Apr 2012
• 1

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• Steve1138
• 8 Apr 2012
• 1

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• Steve1138
• 8 Apr 2012
• 1

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• Steve1138
• 8 Apr 2012
• 1

When taking these pictures just now I noticed what looked like a drop of water on one of the bends in this pipe in one of the pictures. This bend is about a full arms length away in an awkward shaped cupboard so its a bit hard to reach. I reached it though and felt what seemed like a bit of liquid then when I took another picture straight afterwards the drops were gone. Don't know if that's significant?:

Before:

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• Steve1138
• 8 Apr 2012
• 1

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• Steve1138
• 8 Apr 2012
• 1

After:

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• Steve1138
• 8 Apr 2012
• 1

I think the blow off pipe is the pressure release pipe? If so it comes out of the boiler (pipe starting in the top right corner of the first pic) bends downwards and disappears outside through the wall of the kitchen, we are 2 floors up:

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• Steve1138
• 8 Apr 2012
• 1

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• Steve1138
• 8 Apr 2012
• 1

I can see no obvious leaks inside the boiler, although once about 4 months ago there was some drops of water coming out the bottom of it but this has never happened since. We have also had 3 visits from Glowworm technicians who have not found anything either. I just spotted the white residue in the bottom of the boiler yesterday and thought it looked suspicious.

We have 6 radiators in the flat, a large one in the living room and 5 smaller ones in the bedrooms, bathrooms and hallway.

Any ideas from any of this info? I will prob still replace the gatevalve tomorrow anyway as a precaution as a little bit more water came out of it today.

 

[mcmoby69]

things to try next.
1) with the boiler running upto temperature, feel the blow off pipe where it disappears through the wall, does it get hot? can you see where it exits the building? it should be visible from outside somewhere, is there a damp patch around it or is it dripping? it will be difficult to know which is yours if there is more than one sticking out.

2)with the boiler turned off, disconnect the white condense pipe from the grey pipe under the boiler, put a bowl underneath it to catch any drips. do the drips continue? do they stop eventually?

3)is the automatic air vent working ok? is the plastic nut on top loose? does water come out if it is loosened?

 

[Steve1138]

Thanks, I'll have a look at these.

The blow off pipe doesn't get hot really when the boiler is running, certainly no where near as hot as the flow and return pipes. I have not been able to see any evidence of water dripping from the exterior end of this pipe but it is 2 floors up. There is a small ledge about 4 foot under it though which doesn't ever seem to have any damp patches on it whenever I have leaned out the living room window to look though. The PRV in the boiler was also changed as a precaution by the Glowworm tech on his last visit to us.

Where is the automatic air vent, not sure about this one?

I also changed the leaky gate valve yesterday but the pressure had still dropped to 0.3 bar this morning.

I think I'm going to have to start facing the fact that there may be a leak in the system under the floor somewhere though and call someone in to try and find it.

 

[Steve1138]

Just checking on the condensate pipe test, should I do this with the boiler at normal pressure or after it has dropped to 0.0?

Also how long should I leave the pipe disconnected for?

What results am I looking for and what would they mean?

What does the condensate pipe do, I'm not too sure?

Cheers

 

[mcmoby69]

Just checking on the condensate pipe test, should I do this with the boiler at normal pressure or after it has dropped to 0.0?

Also how long should I leave the pipe disconnected for?

What results am I looking for and what would they mean?

What does the condensate pipe do, I'm not too sure?

Cheers

AAV is behind the pump, with a little knob sticking up it should be loose to let air out. if it lets water out when loose it is faulty. only needs to be about a 1/2 turn loose from finger tight.

Pressure needs to be normal (1.5bar)
leave it disconnected for the length of time it takes for the boiler to lose pressure or the bowl overflows.
you shouldnt get near a bowl full, if you do then it means the HE has gone on the boiler.
condense pipe takes condensation away from the boiler and disposes of it.

the blow off pipe shouldnt get warm at all, but it might be heat conducted along the pipe. unless you can rule this out for definite.

i am at end stage now. two things it could be.

1) both your glowworm peeps havent repressurised the expansion vessel correctly or it needs replacing. the prv depends on the EV being correct.
2) you have eliminated all the drips on the system but still have one somewhere else. without any obvious signs it will be tricky.

good luck
moby

 

[northernguru72]

Wow how many theads for a simple problem..........
Many ways for pressure loss and a few little drips from valves will not cause a boiler to lose pressure over a 12/24 hour period. Somewhere you should have a 15mm copper pipe that goes outside ...check to see if there is any water dripping out?
If you think it might be an expansion vessel problem causing high pressure making the pressure relief valve discharge then turn on your heating until all radiators are fully hot. Turn heating off then see what the pressure is on the display. You will have to turn the heating off to see pressure reading. If heating is on it will display temperature.
White marks in your boiler could possibly be a leak from black flexible tube in the back left hand corner of the boiler. These are prone to leaking when system is cold. The flexible tube might not be fitted as it has be updated to a copper tube so problem doesn't happen on later models.
As for leakage from heatexchanger through condense pipe never known it to hapen and trust me I have worked on a hell of a lot of these boilers.
If all of the above is ok and no signs of leaks on visible pipework then you are looking at leak on hidden pipework which by the sounds of it is a possibilty.

 

[Steve1138]

Tried all the last suggested tests and still nothing.

Just a last couple of questions I think, I have taken the caps off all the lockshield valves on the rads to check them for leaks and the pins under the caps on them all have a black liquid around them.

Is this some kind of grease that gets applied to these valves or could they all be leaking?

Also, the Glow worm engineer supposedly had to recharge the expansion vessel on his last visit. Everything that I have read about this says that the system should be drained first before recharging the expansion vessel but my girlfriend is fairly sure that he did not do this, he was only here for just under an hour anyway. Is anyone able to confirm the exact process for recharging an expansion vessel please?

Thanks again for everyone's help with this!

 

[Steve1138]

Tried all the last suggested tests and still nothing.

Just a last couple of questions I think, I have taken the caps of all the lockshield valves on the rads to check them for leaks and the pins under the caps on them all have a black liquid around them.

Is this some kind of grease that gets applied to these valves or could they all be leaking?

Also, the Glow worm engineer supposedly had to recharge the expansion vessel on his last visit. Everything that I have read about this says that the system should be drained first before recharging the expansion vessel but my girlfriend is fairly sure that he did not do this, he was only here for just under an hour anyway. Is anyone able to confirm the exact process for recharging an expansion vessel please?

Thanks again for everyone's help with this!

*EDIT* Oops, didn't mean to duplicate/quote my previous post, sorry, I meant to edit it.

 

[mcmoby69]

the engineer should have isolated and drained down the boiler. with the drain valve open under the boiler he should have pumped the vessel up. any water inside the expansion vessel will have been expelled (into a bucket hopefully) depending on how full it was he could have had up to 8litres of water to get rid of.

it is a schraeder valve, like the ones on car tyres. i use a regin stirrup pump to recharge the ones i attend to.

once he has recharged it, he should have closed the drainoff, refilled/ repressurised the system and then tested it.

probably half an hour at the most.

 

[Steve1138]

I think I'm on a bit of a wild goose chase with the boiler to be honest.

I think I just keep finding new things to check on it as I was hoping it would be that instead of an underfloor leak.

Will just have to bite the bullet and call someone in I think.

Ah well, thanks for everyone's help who has replied in this thread, much appreciated!