by htg engineer »
Tue Mar 11, 2008 9:11 am
Sounds like it's overheating, and the pressure relief valve could be releasing the excess pressure to outside.
Have you noticed the Pressure relief discharge pipe releasing any water ?
Is the boiler auto-air vent open, all radiators heat to the top ?(no air in system)
Get a heating engineer out to repair. Could be a faulty thermostat or sensor.