New boiler

tony863

Hi all,

I've just woke up this morning to find the pressure in my boiler has gone. Added it via the normal means and it dropped again in half an hour. Had it fixed a few months ago and the guy said it was nearly 10 years old and was on its last legs anyway. On that occasion it was leaking and he just tightened everything up, replaced a few nuts and bolts etc..

Anyway, looks like I might be needing a new boiler. I've never bought one before so have no idea where to start. I imagine most people will suggest contacting a local gas engineer via trust a trader to get at least 3 quotes?

On another note,... British gas are offering their scrappage scheme deal atm. £400 off a Worcester boiler. I've heard they're good boilers but I've heard that BG will overcharge massively. What's the general consensus with their scrappage scheme? Can anyone advise?

One more point. Can anyone recommend any other online boiler provider/fitter that might be competitive? I live in a small village and local fitters might be few and far between.


Thanks in advance

macman

Make and model? Pressure loss does not mean you need a new combi. Where is it actually leaking? Might just need a new EV or PRV. If you have a leak on the CH circuit, then changing the boiler won't fix that.
I think you need a new RGI, not a new boiler.
Many boilers will last much longer than 10 years.

tony863

Thanks and sorry for the late reply. The boiler is a Ariston micro combi 23/27 MFFI

I have no idea where the leak is. I've been round all the radiators and bled them. I've tightened all nuts and bolts that I can. With regards the PRV, I think we had a new one of those a while ago so it might not be that.

What's an RGI? Never heard of that. Thinking of calling a local plumber to come have a look. Any suggestions?

tony863

Oh and I'm not sure, but the pressure might be dropping when the heating turns off. Could this be possible and if so, what is it a sign of?

unclebulgaria

Go outside, have alook at the piping that goes out through the wall from your boiler. There should be a 15mm copper pipe poking throught the wall possibly going down to just above ground level or returning to face the wall. Is this leaking water at all? If it is then the pressure relief valve (PRV) is possibly faultyagain.
Have a look at the pressure gauge on the boiler when the boiler is working and getting hot, does the pressure climb fairly rapidly up to the number 3?
If the pressure is dropping that fast it should be pretty obvious if there's a leak.
Do you have wooden floors with some of the central heating pipes below them by any chance?

tony863

The water is leaking from outside. When the heating is on, the pressure valve rises and remains quite high whilst the heating is on but I think the bar varies.

Pressure does drop quick but I can't work out how quick. Usually notice when the room gets chilly! As for floorboards, we have them upstairs but its all concrete downstairs. Nothing leaking through the ceiling so don't think there is a leak from upstairs.

Really stumped

unclebulgaria

tony863 wrote: »

The water is leaking from outside. When the heating is on, the pressure valve rises and remains quite high whilst the heating is on but I think the bar varies.

Pressure does drop quick but I can't work out how quick. Usually notice when the room gets chilly! As for floorboards, we have them upstairs but its all concrete downstairs. Nothing leaking through the ceiling so don't think there is a leak from upstairs.

Really stumped

Ok right, if its leaking outside then the PRV is operating.
Now the PRV will operate if its faulty or forced open by central heating pressure.
If as you say the pressure is rising up to 3 bar then its more than likely the following.
Its either a flat expansion vessel (expansion vessels have two halves, one with gas or air in and the other side has water from the central heating circuit) if its flat it will not control expansion in the heating circuit and over pressurise. It could be burst, flat due to air leaking out of the valve where its refilled with air, or the small bore pipe feeding water into one half could be blocked.
If its burst then pressing the air valve on the expansion vessel will produce water.
If its flat it may hiss when pressed but will need a pressure gauge to test its pressure.
If none of these show the fault it could be blocked with debris from a dirty system.

Possetjohn

:DMight be the expansion vessel! Either it is de-pressurised or the diaphragm has failed. This item has a diaphragm with pressurised air on one side and the primary circulation heating water on the other. The air pressure can be topped up vial a Schraeder valve (like your bicycle tyre). In normal function it allows the water in the heating circuit to expand as it becomes hot while the pressure increases slowly (say 1 .1 bar to 1.7 bar). If it becomes de-pressurised on the air side, or the diaphragm fails then pressure in the water circulation will rise rapidly to the point the PRV (pressure relief valve) will open and let water out from the small copper pipe through the wall. As the system cools the pressure drops rapidly to below the safe start valve and the boiler will not restart.

Sorry Uncle Bulgaria, Wrote this as you wrote your reply. But we agree!

macman

RGI=Registered Gas Installer. 'Plumbers' are not legally qualified to work on gas appliances, unless they are RGI's.
Presumably like the cowboy who checked your boiler and failed to check or notice a discharge from the PRV overflow pipe. But was keen to suggest that you need a new boiler...
The pressure is supposed to drop when the boiler switches off.

tony863

ok, thanks guys. I think that im left with no choice but to call in a gas installer and get a check up. Would hate to risk it