hi im new to this forum and would be thankful if anyone can explain whats wrong with a boiler i currently have... its a ravenheat combi 820/20 model boiler ...The boiler heats fine but cuts out the pilot only after running a long hot bath,...i don't know the reason for this or is there a faulty part that i could buy and replace? it have no thermostat within the house just the one built on the boiler, is there also a way to connect 2 seperate thermostats to this boiler... thanks in advance to anyone who can help me