If the pressure keeps dropping then there must be a leak somewhere, either on the system or from the pressure relief outlet outside.
when you top the pressure up and put the heating on does the pressure gauge rise?
gary.wright53@googlemail.com
March 2008
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix home heating systems.