pump keeps running

[REDSAW]

potterton performa system boiler, potterton controls.
2 port for water, 2 port for c/h

pump continues to run after boilers off...keeps running!.

am i right in thinking the c/h 2 ports stuck on call keeping the pump on?

customer keeps telling me they think its the controler as they had a new one in the past but thats just adding to the confusion of what i think it is!!:sosp:

 

[gassafe]

If the 2 port was stuck on the boiler would be firing also...

On a system boiler with internal pump it would be fed from the pcb, it probably overruns for a set time or until a pump thermostat kicks it off?

 

[mfgs]

Not overly familiar with the boiler. But usually its the pcb which controls the pump overrun and its either for a set time or via a thermostat.

 

[REDSAW]

presurised hot water gravity c/h and pump is in airing cupboard.

pump o/r at least half hour! never turned off when i was there!!

 

[steadyon]

If the boiler has reached temperature it won't fire, but the pump will still run. I reckon your first idea was correct - stuck micro-switch in CH valve actuator. See if there's live on the orange from the CH valve with no call for heat. You'll probably have to disconnect the orange from the DHW to test properly.

 

[REDSAW]

forgot to add....
when programmer is set to auto or man and thermostat is off/low. boiler fires and stays on as too the pump.
turn prog to off, then pump still runs.

 

[Millsy 82]

Disconnect the 2 orange wires for the zone valves and put them into separate block connectors. If pump stops you have proved its not the pcb. See which one you have 240v on and bingo problem solved.

 

[REDSAW]

Disconnect the 2 orange wires for the zone valves and put them into separate block connectors. If pump stops you have proved its not the pcb. See which one you have 240v on and bingo problem solved.

not quite with you? put them into separate block connectors

 

[Harry Askham]

Take the two switch lives out of the terminal with the pump in (orange wire), put them in separate chocolate blocks. I think is what Millsy means.

 

[thompsonbrown]

Looks to me like the boilers pump overrun is faulty or its wired up wrong.