Secondary Grundfos ups2 on vr66 - wiring question

@stem, you have been most helpful. You are right I should create another thread for the revised question on the whole set-up which I shall do shortly.

Yes there is a control bias to this question. I guess the answer is if someone wants to wire an optional element to a vr66 (an external pump for example) they would have to do the following (please jump in if you feel this is not correct):

1. There are 5 cores in the 2-port valve cable. If you connect that 2-port valve to a wiring center only the brown (activation of the valve motor to open or close it), blue (neutral) and green (earth) are connected. Grey and orange are now free to use for something else should you wish to.

2. Grey and orange are for the internal microswitch situated inside the 2-port valve. If grey gets a permanent live, then when the valve is open, the microswitch closes and makes contact, and now orange is also live (this is what allows to turn on the boiler when the valve opens with classic relay controls).

3. Simply get a permanent live on the grey (e.g. from the supply that gives the 230v to the vr66, connect in a junction box to keep it clean and avoid stacking several cables in the 230v block of the wiring centre), then connect the orange to the live (brown) of the pump, then connect the neutral and earth of the pump on the neutral and earth in the junction box where the original power supply comes from (most likely from your fused outlet powering the boiler and controls).

Here you go: 2-port valve opens, internal microswitch closes, the live from the grey wire in the valve cable now passes a live to the orange wire of the valve cable, which passes a live to the brown of the pump, the pump runs. When the valve closes, the exact opposite happens.

That's it for this topic, as to the external pump, I am running tests with it turned off at all time (it works, yes top room rad on "2.5" floor gets a little less hot, but it works...), and will open another thread on this mystery set-up.

All the best
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