I returned from a trip abroad to find the house cold, despite having left the programmer set to run the heating every day. The upstairs radiators were hot but the downstairs not & the pump was not running. I suspected the diverter valve (Honeywell V4037A) as I've had the motor inside go before but it turned out not to be that (I fitted a new control head).
If I select CH or HW the pump has 240v across the terminals (measured on the terminal block on the top of the pump) but the pump doesn't run. I've unscrewed the vent plug & the impeller seems free to turn. There's water in the FE tank in the loft.
The pump is a Selectric MkII & it's about 20 years old. My question is: what does the capacitor inside the terminal block do? Is it necessary for the pump to run, & if so is it a replaceable item? I'd obviously like to try changing that before shelling out for a whole new pump. Is there anything else I should check first? The control system is a standard Honeywell Sundial Y plan.
If I select CH or HW the pump has 240v across the terminals (measured on the terminal block on the top of the pump) but the pump doesn't run. I've unscrewed the vent plug & the impeller seems free to turn. There's water in the FE tank in the loft.
The pump is a Selectric MkII & it's about 20 years old. My question is: what does the capacitor inside the terminal block do? Is it necessary for the pump to run, & if so is it a replaceable item? I'd obviously like to try changing that before shelling out for a whole new pump. Is there anything else I should check first? The control system is a standard Honeywell Sundial Y plan.