Heat pump controls

[Sparkyste86]

I’m trying to get my head around how the controls work on heat pump systems .

Usually on a s plan combi boiler let’s just say 2 zones I’ve learned that power to spur from spur to Timeclock to stat calls for heat switch live from stat on to brown on the motorised valve micro switch closes between (grey permanent live ) and orange joined to switch wire to boiler okay so I understand that.

With the heat pump no (Timeclock being used) 1.5 to spur to stat - switch live from each stat to brown on each motorised valve
The 2 oranges joined together and the (2 greys joined together not permanent feed)
Oranges together with one core to the heat pump and greys joined together to the heat pump

My question is if there’s no permanent feed on the grey when the valve micro switch operates how does this fire up the heat pump .

 

[Resu]

The microswitch is volt free. If you were to permanent live the greys like a normal S plan, you'd fire 230v down the oranges and blow something on the PCB in the heat pump.

The heat pump will be sending out a small amount of voltage through to your greys which it'll receive back via the oranges when the microswitch is activated by the valve opening.

 

[Sparkyste86]

The microswitch is volt free. If you were to permanent live the greys like a normal S plan, you'd fire 230v down the oranges and blow something on the PCB in the heat pump.

The heat pump will be sending out a small amount of voltage through to your greys which it'll receive back via the oranges when the microswitch is activated by the valve opening.

That’s great thanks I was thinking along the same lines so it’s the micro switch that creates the link .

 

[Jock from the north]

That’s great thanks I was thinking along the same lines so it’s the micro switch that creates the link .

It's not just heat pumps most boilers will give you the option for volt free or some electric boilers will only have volt free.so for s plan simply don't connect your live to the grey and the micro switch will still close once brown is energized