System pressure loss - again, but different!

[DocDave]

Hi everyone. I have spent days going through previous posts but found nothing quite like my problem. I have a Halstead combi which keeps losing pressure despite being seen twice by a Corgi service engineer. I am now having to fill the system every few hours! There is definately no increased pressure as it works and the pressure release pipe is bone dry.

When it first started there was water under the boiler and as all CH pipes are in ceilings I can't believe I have any leaks losing this much water. All radiators have been checked. The CH is producing a lot of "air" though and I know it needs cleaning. The other reason I think it is the boiler / F&E tank is that the plummer repressurised the tank and the boiler was fine for 2 weeks (immediately before it was being filled every day).

Can I lose this much water by oxidation alone? Where can it be lost as "internal leaks"? If the diaphragm has gone in the F&E tank could I lose water anywhere but the PRV?

Sorry for the long post, but I have run out of ideas (and am cold!) and my plummer seems to have no ideas either. Any help would be appreciated.

Cheers
Dave

 

[gas4you]

Think you are talking about the Expansion Vessel (EV) rather than an F&E tank.

This is certainly a lot of water to keep losing.

Pressurise the boiler to about 1.5 bar and isolate by turning off the F & R valves under the boiler. Leave this as long as possible. If pressure continues to drop then it has to be somewhere on the boiler. If it doesn't it is somewhere on you system.

 

[waterworks]

Might seem stupid but Gasforyou shouldn't you be making sure op does not switch boiler on with the isolating valves turned off?.

 

[gas4you]

Yes, one of those assumptions one makes as though you were doing the job yourself

 

[DocDave]

Thanks alot, amazingly quick for Easter Sunday.

I think I do mean the EV as it is a closed system. I will go and see if I can find the valves (with out turning on the system). Each time I fill it it vents about 0.5 bar of gas, a couple of times a day. Not sure if that gives you a clue.

Thanks, again. Much appreciated.

Dave

 

[DocDave]

To feed back.

Just found a leak, who would have believed it. Dripping every second when the system is under pressure, so I guess that is enough water.

Thanks again.

Dave