Hi all,

I've recently sealed my fairly old central heading system and I'm
experiencing a pressure loss and would appreciate your help and advice.

In brief, the system is around twenty years old with a capacity of
approximately 100 litres. Over the last twelve months I've replace the
boiler, all nine radiators and valves, the hot water cylinder and have
carried out some minor pipe work alterations. Most recently I've sealed
the system with an 18 litre kit preset at 1.5 bar and an automatic air
release valve installed at the highest point.

All appears to be fine with the working pressure up to 2.0 bar, except
I'm experience a system pressure loss of approximately 0.1 bar over a
twelve hour period with the system set at 1.0 bar and remaining cold
through out. This loss seems to increase to around 0.3 bar over the
same period but with the boiler in normal use. Having looked in the
easily accessible places I've only found two small weeps but nothing
more significant. I've not added any inhibitor yet as I didn't want to
run the risk of having to flush it away should I experience problems.

So, my questions a

- Obviously I have a fairly significant pressure loss, but how much
water would this result in?

- Could the lack of an inhibitor and the subsequent build up of
nitrogen/any trapped air in the system, and its subsequent loss through
the air release valve, result in a variation in pressure and would
topping the system up slightly continue with this cycle?

- Assuming I can't find any further water loss how effective are liquid
system leak sealers in resolving problems like mine?

Your advice/thoughts would be appreciated.

Regards,

Andrew