I have a combi boiler that is losing pressure over a two month period I cannot find the leak and could live with that if the mains pressure was high enough to recharge the system but it is not. Is there a devise on the market that can charge the system and is small enough to be left beside the boiler for a quick connection when required?
if you've checked for leaks on the radiators, valves, boiler and pipework the next thing to look at is the pressure relief valve, this should terminate outside the property normally in 15mm copper pipe, Watch to see if there's leaks or drips of water from there, the valve may be passing. Try adding leak sealer to the system, this will seal small leaks, as the leak can only me small if losing pressure over two months. The easiest and quickest way to re-pressurise the sytem, is to fit a ballaufix valve on the mains cold water supply and a non-return valve to the boiler return pipe, these can then be connected by a flexible hose.