We have just purchased a new property and went to try the central heating a couple of days ago. The boiler is firing up but very little heat is going to the radiators. After leaving it on for about an hour a couple of the radiators were warm, however, the majority were still cold. We have had 2 different plumbers out....the 1st said he thinks it may be the pump......the 2nd has said that he thinks the pipes going from the boiler to the radiators are too small and are only likely to be able to heat 2/3 rads. We have very little knowledge on this so really dont know what to do now......any advice would be greatly appreciated???