Grundfos Super Selectric circulator pump concerns

[Hoppers]

With only the hot water programme running, my Grundfos pump switches on and off throughout the day and night. It runs on a 4.5 minutes on and 1 minute off cycle. It only stops when the hot water programme switches off at around 10pm. This seems to have started since I had my emersion tank and expansion tank renewed a few months ago. Is this normal pump behaviour and i just hadn't noticed it running last summer or has it something to do with the PSI in the expansion vessel (think I read that somewhere as a likely cause)? My boiler is an Vaillant Eco Tech Plus, the Programmer up stairs is a Drayton LP522 and the Actuator is a Drayton MA1 Mid Position (set on W during summer).
Grateful for any advice. Thank you

 

[John.g]

No, not normal, it should only run continuously if HW cylinder stat is closed with HW programmed on. Note the cyl stat setting (normally 60C) and turn it up to get the boiler to fire & circ pump on, when the pump starts cycling on/off, turn the stat down and see if pump stops and remains off.

 

[Hoppers]

No, not normal, it should only run continuously if HW cylinder stat is closed with HW programmed on. Note the cyl stat setting (normally 60C) and turn it up to get the boiler to fire & circ pump on, when the pump starts cycling on/off, turn the stat down and see if pump stops and remains off.

Thanks for replying to my post John. Tried your suggestion but no change. I did turned it

No, not normal, it should only run continuously if HW cylinder stat is closed with HW programmed on. Note the cyl stat setting (normally 60C) and turn it up to get the boiler to fire & circ pump on, when the pump starts cycling on/off, turn the stat down and see if pump stops and remains off.

Thanks for replying to my post John. Tried your suggestion but no change. The cyl temp was already at 70 so I did turn it down to 60. Pump still ran. I noticed the led display on my boiler was showing a flashing image of a radiator (despite the CH turned off) which may have had something to do with the pump continuing to run. Using the tried and tested method of switching the whole system off and back on i seem to have reset the programmer, as the rad image has disappeared and the pump has stopped running. Fingers crossed, the pump will now behave.
Thanks again for responding. Alvin

No, not normal, it should only run continuously if HW cylinder stat is closed with HW programmed on. Note the cyl stat setting (normally 60C) and turn it up to get the boiler to fire & circ pump on, when the pump starts cycling on/off, turn the stat down and see if pump stops and remains off.

 

[ShaunCorbs]

Sounds like it’s not wired correctly or stuck port valve

 

[Hoppers]

Sounds like it’s not wired correctly or stuck port valve

seems to be working properly now, having switched the system off and then back on. Thanks

 

[king of pipes]

A possible cause would be a 2 or 3 port valve issues either sticking or failing due to wear and tear, the linkage is often a problem when operated it fails to switch the micro switch off ??
Kop

 

[Hoppers]

A possible cause would be a 2 or 3 port valve issues either sticking or failing due to wear and tear, the linkage is often a problem when operated it fails to switch the micro switch off ??
Kop

stripped the Actuator down and all parts seem to move correctly. When i turn the Temp know on the boiler to lowest setting (off) the pump stops running and the flashing radiator symbol disappears. I did think i had solved the problem earlier, but no, it still persists.

 

[king of pipes]

I'd still be leaning towards the 3 port I have had issues with 3 port valves providing a backfeed so before part swapping a electrical diagnosis needs to be carried out. Kop

 

[Hoppers]

I'd still be leaning towards the 3 port I have had issues with 3 port valves providing a backfeed so before part swapping a electrical diagnosis needs to be carried out. Kop

Photo of my MA1 3 port wiring. This wiring looks wrong to me, as it shows Grey wire to Blue (1st right). looking at on line wiring diagram, all blue wires should go together at the 8th right connector. Could this be why my pump is constantly running? I have bought a replacement MA1 but want to be sure the current configuration at the junction box is correct before swapping wiring position one for one. Alvin

 

[ShaunCorbs]

Prob using the blue core from the cylinder stat as off