I am sorted now thanks,29 people looked at my question but one person had put themselves out to try and answer and i thank him, but all i have to say about this site ,is the so called enginers dont bother trying to give advice even if it does not help the lay man they are only conserned about always get a CORGI reg person to look at whatever the problem is as gas can kill but most people are looking for advise, not to get ripped off as there are loads out there who will,as i have the CORGI enginer who actually fixed my boiler after getting all the parts that was not the problem was sorry after costing me £262 said all i needed was a new flue seal as other seal had deteriated. So what is this site suppose to do give all enginers an ego to how superior they are i dont think so. Looking at some of the forum all it is about is trying to get one upmonship on your fellow CORGI colleagues GET A LIFE .