I have an old Potterton Prima 50F in an S Plan system and an intermittent issue.
Occassionally, becoming more frequent, the following happens:
When there is demand for CH or HW, the relevant zone valves open and the boiler fires.
However the pump (a Grundfos Alpha 2 25-60 130) does not power up (display remain off). Conesquently the boiler starts kettling.
Sometimes, the pump eventually comes on, things get moving in time and the boiler settles down.
Alternatively it will shut off, start again, & sometimes the pump begins running.
Least commonl outcome, it will cut out altogether via the overheat thermostat.
Most of the time it operates normally and I have not managed to determine how often there's a delay vs failure in the pump powering up.
It seems to me the problem lies with the boiler failing/delaying to switch power for the pump.
What are the likely causes of this intermittent issue?
The PCB or some other component in the boiler?
I plan to get a new PCB but wonder if it is actually the most likely culprit.
Occassionally, becoming more frequent, the following happens:
When there is demand for CH or HW, the relevant zone valves open and the boiler fires.
However the pump (a Grundfos Alpha 2 25-60 130) does not power up (display remain off). Conesquently the boiler starts kettling.
Sometimes, the pump eventually comes on, things get moving in time and the boiler settles down.
Alternatively it will shut off, start again, & sometimes the pump begins running.
Least commonl outcome, it will cut out altogether via the overheat thermostat.
Most of the time it operates normally and I have not managed to determine how often there's a delay vs failure in the pump powering up.
It seems to me the problem lies with the boiler failing/delaying to switch power for the pump.
What are the likely causes of this intermittent issue?
The PCB or some other component in the boiler?
I plan to get a new PCB but wonder if it is actually the most likely culprit.
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