Repressurising ELM Leblanc combi boiler

[ALMcKINNON]

Can anyone help?

I've just bought a flat with an ELM Leblanc combi-boiler (but haven't got a manual). I understand from the web-forums that I've visited that this should run at about 1-1.5 bar. The gauge on my boiler is currently reading 0.5 bar.

How do I repressurise the system?

I've found a lever at the back/underside of the boiler which appears to be fitted to a water pipe. Is this what I need to operate to carry out the repressurisation?

Also, a number of radiators in the flat are only hot in the bottom half. Presumably I need to "bleed" these to get rid of trapped air??

Finally, the radiator which I believe to be furthest from the boiler does not heat up at all. There does not seem to be any warmth in the pipes leading to this radiator either so I presume that the problem does not stem from the valves at either end being turned off.

 

[chrishutt]

Good thinking generally, but be careful about valves at back of boiler. One of these will be the Pressure Relief Valve and it may not have a discharge pipe attached.

ELM leblancs are pretty old now and you ought to be thinking about replacing it before long. The filling loop may not look much like the modern version, but look for some kind of link between the cold mains pipe and the CH return pipe, usually (but not always) under the boiler.

A search on this forum should give you more info on modern filling loops. Why don't you ask the previous owner of the flat where the filling loop is?

 

[ALMcKINNON]

Thanks for the advice.

I asked the previous owner where he thought the filling loop was, but he didn't have a clue.

The lever I mentioned earlier does not seem to raise the pressure when operated, but I can hear liquid moving. I guess this might be the pressure relief valve and pipe as you mentioned.

I've noticed that on two other pipes leading to the boiler there are screw valves and the end of these valves have a slot which looks like it might be for receiving a screwdriver (I can't really see any sort of link between the two pipes though). I've seen these types of valves mentioned elsewhere in this forum in relation to the filling loop but I am still unsure as to whether these are the correct parts which I need to operate to repressurise. I don't really want to operate them if I don't know what they are supposed to do!

 

[ollski]

Thanks for the advice.

I asked the previous owner where he thought the filling loop was, but he didn't have a clue.

The lever I mentioned earlier does not seem to raise the pressure when operated, but I can hear liquid moving. I guess this might be the pressure relief valve and pipe as you mentioned.

I've noticed that on two other pipes leading to the boiler there are screw valves and the end of these valves have a slot which looks like it might be for receiving a screwdriver (I can't really see any sort of link between the two pipes though). I've seen these types of valves mentioned elsewhere in this forum in relation to the filling loop but I am still unsure as to whether these are the correct parts which I need to operate to repressurise. I don't really want to operate them if I don't know what they are supposed to do!

No they are the flow and return isolation valves, filling loop could be anywhere...not necessarily near the boiler.It could be under the sink, in the airing cupboard...it may be a braided silver pipe or washing machine hose or similar. But the rule of thumb with a leblanc is 'if it works, don't touch it'. It WILL either drop the pilot, leak or crumble into pieces.

 

[ALMcKINNON]

Thanks for the advice ollski.

I finally managed to located the filling loop and have successfully increased the pressure.

However, another problem has now developed. Last night i returned from holiday to find that the central heating does not work. I had set the heating to come on twice daily when I was away so that the temperature in the house didn't drop too low.

Unfortunately, something seems to have happened whilst I was away and now I cannot get the heating to work at all. There is hot water when I turn on a hot tap, but the radiators are not getting warm no matter how much I adjust the CH dial on the boiler.

I've looked on this site to see if someone has offered advice on this before and managed to find a message from "chrishutt" posted on Monday August 29, 2005 at 7.27 pm. This is in reply to someone who couldn't get the heating working after the heating had been off for the summer and states:
"Unusually with this boiler the pump only operates in CH mode, not for DHW, so the suspicion must be that the pump has jammed through not being used over summer. To free it, open cap in head and insert screwdriver to engage in and turn spindle. A small amount of water will leak out - catch with cloth."

I'm wondering if the same problem applies to my situation, i.e. the pump is jammed. If so, could someone please explain in layman terms the steps which I've quoted above in order to solve the problem.

Also, if I'm going to proceed in taking the cover off the boiler to gain access to the pump, could someone please tell me if I need to turn the gas off first? This question may sound stupid but I'm a complete novice with boilers and would rather be safe than sorry!

 

[ollski]

Sticking microswitch on the right hand side under the pressure guage, but expect the pilot to drop out when you put the case back on....also be very careful not to knock the pressure relief valve with the case on the top right hand side as its very easy to knock it off and have several gallons of water shooting at the ceiling under pressure.

 

[ALMcKINNON]

Thanks for all your help ollski.

Unfortunately, the boiler has now finally given up and I've had to "bite the bullet" and pay for a new one.