K
KBKC
Home owner here. All was working fine this morning. Now the boiler comes on and quickly runs up to to over 100 centigrade and then cuts out for both CH and HW singly or together. I have checked the power to all the 3 port valves and there is power. There is no power to the pump (a typical red Grundfos unit). The pump does not come on. I know these pumps can fail but I am not convinced it is the pump this time due to the lack of electrical power from the boilder to the pump when the thermostat is at max and the system control is set to supply CH/HW. Does this sound like I need a new PCB or is there another component that could have failed?
The pressure gauge on the boiler is in the green and there is no discharge from the external bleed points for either the unvented cylinder or boiler. The system pressure is fine and there is no significant air in the system - radiators were bled last week and the system topped up.
The pressure gauge on the boiler is in the green and there is no discharge from the external bleed points for either the unvented cylinder or boiler. The system pressure is fine and there is no significant air in the system - radiators were bled last week and the system topped up.
