by htg engineer »
Tue Dec 11, 2007 8:49 pm
If it's a gravity hot water system - the pump may be faulty. Check room thermostat is turned up.
If it's a fully pumped system it could be actuator, 3 port valve, aslo check room stat is turned up.
If it's a combi, could be diverter. Room stat etc etc
Abit more info would help