e.l.m leblanc 4.20

15 Jun 2007
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United Kingdom
I need help!!

I have an e.l.m leblanc 4.20 and the pressure slowly creeps up and then water leaks out of the bottom of the cover.
If the pressure is 1.5 or below it seems OK.

How do I manually lower the pressure?
I've been advised not to use the pressure release on the boiler as they are notorious for not reseating and then I'll have all kinds of problems.
I was told I could release some pressure by opening a bleed valve on a radiator, I've done this and released about a washing up bowl full of water but the pressure hasn't gone down at all, how much would I need to release? The pressure is currently on 2 bar.
I can't afford a new boiler just yet!!
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Use a drain cock that is on the system instead and just keep draining it out of it until pressure drops to aroung 1.2 bar. If you go too low then top up again with filling loop. why is the pressure creeping up should be the main question? Is the filling loop turned off fully?
The boiler needs replacing ideally, not sure why the pressure is increasing.
I just need to buy some time, can't afford to replace it just yet.

Where am I likely to find the drain cock?

I'll check the filling loop, does it need to be turned off completely?
steve711 said:
Where am I likely to find the drain cock?

Hopefully either under the boiler or on a flow or return pipe on a downstairs radiator.

Yes the filling loop should be fully turned off and to comply with water regs disconnected whilst not in use :rolleyes: although not many installers bother to tell customers this.
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Your filling loop will be left slightly open, but the leak from inside will usually be:
1:auto air vent on top right hand side
2:hot water spindle above pump
3:heat exchanger
I think the leak is from the auto air vent, it has been replaced once but I guess when the pressure increases it's letting water out as well.

The heating engineer that replaced the auto air vent said something about the pressure vessel but he could get to it easily due to where the boiler has been installed.
Very wise not to touch the PRV on that boiler!

It looks unique to that model and the parts are not oficially supported in the UK.

Iy might also need the boiler being taken off the wall to replace it or at least pulled forward at the front!

Much better replaced!!!

I've never even heard of this boiler/make. :eek: Just general advice I was giving. :oops: Where does it originate from :?:
gas4you said:
I've never even heard of this boiler/make. :eek: Just general advice I was giving. :oops: Where does it originate from :?:

Elm le blanc GVM 4>20 and 5>20, circa 80's Dave, not common boilers but can readily get spares, ie, PRV £110'ish.
French boilers bought out a few years ago by worcester to rip the decent parts out for their own stuff and keep parts going for a while. Most of the common parts still available but the boilers are absolute junk. Hideously expensive parts (control box 300, wilo pump 120, thermocouple 60 etc, etc), pull the case off too hard at the wrong angle you will knock the prv off, put it back on you will knock the pilot light off. Only good thing about these is the isolation valves are spot on and you can change the prv in 10 mins, you just throw 80% of it away

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