In our upstairs cupboard along with the immersion heater/tank is a grundfos UPS 15-50x18 pump which is making groaning/grinding/vibrating noises and is getting EXTREMELY hot.
It would appear to be a faulty pump, but what confuses me is how the pump seems to be active when the boiler downstairs is only on the pilot?
I had to set the boiler thermostat downstairs to OFF to shut the pump up last night. This morning I put the thermostat on 3 (the maximum is 5) and the pump seems to be quiet still.
The pump electrical supply has an isolator switch, which has always been in the ON position for years - is that how it should remain? I assume with the pump not on at all if the boiler was boiling then a disaster would happen?
It would appear to be a faulty pump, but what confuses me is how the pump seems to be active when the boiler downstairs is only on the pilot?
I had to set the boiler thermostat downstairs to OFF to shut the pump up last night. This morning I put the thermostat on 3 (the maximum is 5) and the pump seems to be quiet still.
The pump electrical supply has an isolator switch, which has always been in the ON position for years - is that how it should remain? I assume with the pump not on at all if the boiler was boiling then a disaster would happen?