Grundfos CH pump won't stop

[johnmw]

Hi,

We have the following system:

Ideal Icos HE12 boiler
Danfoss CP715 control panel & thermostat
Heatrae Sadia Megaflo unvented indirect cylinder
Grundfos UPS 15-60 pump
Danfoss HPA2 valve (switch set to automatic - what does this even do?)

Essentially everything's working ok except that the pump doesn't shut off any more. Whilst it's still running, the boiler's LCD reads "C" and the LEDt is flashing which the boiler's manual says it does "during ignition".

I'm not averse to calling out a pro, but I just wondered whether there's any troubleshooting I can do myself?

Thanks!

 

[plumbplumb]

C means demand the boiler is registering demand.

Likely either one of the microswitches on the hot water or heating valves are stuck on or the valve is in manual position.
Check with the silver lever on the side of either valves

 

[plumbplumb]

Danfoss HPA2

Auto setting means the valve operates via the external controls. Sliding the silver level across it slots behind a little catch in the black plastic which is manual position. In manual it allows the valve to be open and will fire the pump and boiler ignoring external controls.
With the CH and HW off on the timer when you slide the levers on the valve you should feel resistance as you push against the motor.

Firstly check the valves are both in auto position.
Secondly check there is resistance on both valves when you slide the lever (with the timer off on both CH and HW) no rresistance could indicate a stuck motor.
Thirdly if the valves are on plugs try unplugging each valve in turn and seeing if the pump cuts out.

 

[johnmw]

Danfoss HPA2

Auto setting means the valve operates via the external controls. Sliding the silver level across it slots behind a little catch in the black plastic which is manual position. In manual it allows the valve to be open and will fire the pump and boiler ignoring external controls.
With the CH and HW off on the timer when you slide the levers on the valve you should feel resistance as you push against the motor.

Firstly check the valves are both in auto position.
Secondly check there is resistance on both valves when you slide the lever (with the timer off on both CH and HW) no rresistance could indicate a stuck motor.
Thirdly if the valves are on plugs try unplugging each valve in turn and seeing if the pump cuts out.

Thanks - I'll have a play when I get home, but think I'm going to have to find a plumber.