I've read the 'Sealed System' FAQ but really need some more specific advice about why my boiler may be loosing pressure and how best to find the cause.
Here's the score:
-Vokera 20SE system boiler fitted on ground floor. Sealed system.
-2 storey semi, recently extended, boiler recommissioned September
2003.-before extension: -boiler running 10 rads and conventional copper cylinder -boiler needed represurising every 4-5 months
-after extension: -boiler running 14 rads (10 new, 4 existing) and megaflow cylinder -boiler needs repressurising every 7 to 10 days! -no visible signs of a leak
-Boiler has been checked twice recently by Vokera engineer; no visble leaks or faults found; suggested getting plumbers to 'air test' HW plumbing to find leak.
-I typically repressurise cold system to 1.5 bar. Pressure never exceeds 2 bar when hot. No sign of pressure relief valve operating.
The plumbers who did the new plumbing and recommissioned the boiler are coming to drain and air-test soon. I'm hoping that this will help ID the leak. BUT over the past week I've noticed that the presure is falling less quickly than it was before.
Questions I'd appreciate help with:
- Does this sound like a leak? If not, what could it be? Is it typical? Will it fix itself?
- Last time I adding water (filling loop beside boiler), I didn't bleed the rads, like I normally do. So far the pressure has fallen more slowly. Is this a sign things are sorting themselves out or could there be air in the rads which is somehow keeping the overall pressure up?
- Is there a good approach to doing this air test? (I'd like to know whether the plumbers are doing sensible things!) I intend being their to oversee things.
- Should they add inhibitor when they refill? If so, what type is best.
Thanks in advance,
Dave G