I have had my Danesmoor for approx 3 years; not a moments problem. Yesterday I had it serviced and, almost immediately, I started to lose pressure. When heating/hot water on it drops very slowly. When heating/hot water off, it drops quite quickly. Have checked outside valve. Cannot readily see any rad leaks. Have been told(?) that expansion tank is OK. if anyone can help, please, I would be grateful. I am extremely suspicious as previously said, before service boiler was working perfectly

Tiff, November 2008

As part of a standard service procedure, the pressure releif valve is required to be operated to ensure it is opening easily. This is an important check as it prevents the boiler bursting due to over pressurisation,
This is a frightening thing to witness and potentialy can destroy the boiler.
That said, the drawback is, when the engineer opens the valve, it is very common for a piece of crud from the system to jam in the valve and prevent it closing properly again, thus causing a leak from the pressure releif outlet.
Pop a small plastic bag over the end of the pressure releif outlet, tie it with an elastic band and see if any water comes out and fills the bag.
You sound like you have lost confidence in your engineer. Your gut feeling is very important, if you are unsure I would advise you not continue with your exsisting engineer, or to DIY.
Ask around your friends to recomend someone they trust.Danesmore is oil so phone "OFTEC" for local professionals. If its gas "CORGI " has a good website. Employing a trustworthy professional is always the most cost efective option. It is much more common to get the job botched for £50 by a bloke down the boozer. But it will cost in the end and that £50 will have only caused problems.

HELP, November 2008