Help Combi Condensing boiler will not pressurise

springerholic

We have a Glow Worm 38cxi condensing combi boiler which has a minimum operating pressure of 1.0 bar, we usually run it at 1.2 or 1.3 and over months it gradually loses pressure and we have a valve under the boiler which we turn to top it up every now and again but its suddenly stopped topping up and we are down to 1.0 bar so as soon as it drops to 0.9 we will have no heating or hot water. Before I resort to calling out a plumber does anyone have any suggestions? Many thanks

aliEnRIK

Im not sure what model mine is without going home to look But i had 4 different guys look at mine! Last one was the only guy who had a clue. He actually took the casing off and went at the top at the back of the boiler and connected a bicycle pump (I swear this is true )
Repressured the diaphrapm with it and its worked great ever since.

HOWEVER ~ it could easily be that one of your radiators has a slight leak. Go around ALL connections and nip up anything that doesnt seem tight enough (Be VERY careful when doing this though)

MX5huggy

So what happens when you turn the tap? maybe the handle has just rounded off so does not work, try using a screw driver on the centre bit.

amersall

aliEnRIK wrote: »

Im not sure what model mine is without going home to look But i had 4 different guys look at mine! Last one was the only guy who had a clue. He actually took the casing off and went at the top at the back of the boiler and connected a bicycle pump (I swear this is true )
Repressured the diaphrapm with it and its worked great ever since.

HOWEVER ~ it could easily be that one of your radiators has a slight leak. Go around ALL connections and nip up anything that doesnt seem tight enough (Be VERY careful when doing this though)

dont know if this helps but i have a worchester combi and my pressure kept dropping we had to keep upping the pressure is there a button or something like that at the top of your boiler? mine had one and when it was depressed pressure went back up , and that helped us. alienrick is probably right could be a small leak some where as that will cause your pressure to drop. pipes from boiler could allso have small leak that has happened to us before

springerholic

Thanks guys.. when I turn valve/tap nothing happens whatsoever, it used to leak a bit of water as it topped up the water levels in the system but we just popped a towel under while we were doing it so it wasnt a problem. Im not worried about the fact it drops pressure slightly, its the fact I cant top up thats the issue, the suggestion that it may be the tap thats not tight enough sounds good, will try a screwdriver!!!!!

bluboy

If you don't have any joy try posting all your details over at screwfix plumber's forum -
http://www.screwfix.com/talk/forum.jspa?forumID=25
Be specific, clear and concise otherwise they turn nasty!;)

Robin_T_Cox

As aliEnRIK has pointed out, the expansion vessel probably needs repressurised or replaced. See:
http://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1166630630
This happened to my system a few months ago, and the engineer simply connected a car foot pump to repressurise.

tweeter

Check to see if your pressure relief valve is not leaking through its outlet pipe.

thor

I have a vaillent ecomax boiler and it drops to 0 bar within 2 or 3 weeks after being pressurised. I have searched all over for leaks but have been unable to locate one. The funny thing is that even at zero the hot water and radiators have been working fine.

aliEnRIK

Thor ~ I had a similar problem. I found that it was leaking but only when the water was that hot it was virtually steam as it escaped (Making it near impossible to locate). I ended up finding it by looking under the plastic caps that are fitted to some of the 'variable flow' connectors, and found one was wet inside where the water had been trapped . A quick 'nip' and it sealed.
Clearly its different to glowworm ones as mine doesnt work at zero. But youll probably find yours would certainly work more efficiently if you could find that damned leak
Mine certainly works at its best when fully pressurised.

worried_jim

thor wrote: »

I have a vaillent ecomax boiler and it drops to 0 bar within 2 or 3 weeks after being pressurised. I have searched all over for leaks but have been unable to locate one. The funny thing is that even at zero the hot water and radiators have been working fine.

I have exactly the same, nit a problem I hust top it up from time to time. Have had an engeener replace the diaphram a copule of years ago, and it all works fine.