Glow Worm 30CXI Filling Loop Problem

21 Jul 2007
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United Kingdom
Hope you can help, I have tried to search the forum but can't seem to find the answer. . I have a Glow Worm 30CXI Condenser Boiler. Today I opened the pressure filling loop tap, as I do every now and then, just to make sure the system is properly full. However, this time, water started leaking from some sort of vent valve to the left of the tap (as you face the front of the boiler). This has never happened before and is a bit of a worry.

The boiler seems to be working perfectly well with a pressure of 1.1 Bar.

Any help is most welcome.
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Was mentioned recently. If it is an internal filling loop the filling loop is faulty - 'twill need replacing.

Unless you are talking about the safety discharge valve on the far left of the boiler.

I suspect you are talkng about the reduced pressure zone valve just to the left of the filling point.
WHY OH WHY OH WHY, (hits forehead with palm of hand)

There`s an old saying, if it aint broken then dont fix it.
Now you have fixed it and thankfully wont have broken it yet.

There is no point topping the pressure in a boiler that is working fine, with you constantly topping up "just too make sure the system is properly full" You have inadvertantly over filled. this is because the pressure guage aint reading the correct pressure and you have increased to over three bar, the water release you would have seen is from the PRV which sounds as though it is not piped to outside.

Appologies in advance for any offence causeed by my ranting, sorry muppet neighbour has just put me in a foul mood, awaiting plod now for my collar to be felt :evil: ..... neigh :evil: :evil:
LOL - Sorry to get your blood boiling CLF.... I don't think it is the PRV as I am sure that this is piped outside (it is grafted into the drainpipe). This valve is directly attached to the fill loop tap and only leaks when I open that tap.

I was unaware that the system could be overfilled and will heed your advice in the future...Once the un-broken boiler that is now broken is fixed that is...

Thanks Dan, It does sound like the valve you mention... Boiler is only 1 year old so I will get onto Glow Worm on Monday.

Thanks again.
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The grafted pipe is actually the condense drain. The safety discharge pipe is the small copper tube (15mm on the far left) that should go outside and point downards.

Your rpz valve is leaking then, aparently this is common with WB and others; although our Multi's use them - and so far none have leaked.

See, you learn something everyday!?
Again Tony sorry :oops: my rant wasnt aimed at you just typed out that way ;)

Just the pillock next door, he pranged my van and I seen him do it when I went out he said it wasnt him who smashed the light, then he let out with the verbal so I leathered him up his own path. now his wife has knocked and said he will pay for repair, and thanks for knocking him off his perch :eek: weird :confused:
Dan, Thanks again...Got the PRV pipe now..It does vent outside..

CLF - Sorry to hear about the van and arse of a neighbour. Seems to have worked out well in the end though! Looks like you have an admirer too!!!

Thanks folks...Right off to the pub ..


Pressure at 1.1 bar is fine with everything cold.

What is the pressure when system is at max running temp?

The pressure reducing zone valves on these boilers are very poor quality but so so easy to change.

Im having experience with a lot of blockages on the pipe to the ex/vessel hence pressure flutcuations, and this may be your sceanrio.

Poor installation causes this fault.

tonylott said:
Thanks Dan, It does sound like the valve you mention... Boiler is only 1 year old so I will get onto Glow Worm on Monday.

Hope it is within first year, Glow Worm are parts only 2nd year warranty and want c/c payment of £125 up front before they send an engineer :eek:

Thats one of the reasons they are cheap in the first place :rolleyes:

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