Advice on a JG UH3 Wiring Zone and how to stop the UF pump running when the HW timer kicks in

[hantsgaz]

Hi all. First post. I have a JG UH3 wiring zone and I've noticed that the UFH pump always comes on when the HW 'circuit/thermo' is triggered. Hence - rather than just heat the water in the tank - I also heat the UF circuits.

I can't see a way to avoid this - it may be the way the circuits work on the UH3 (as in the pump always comes on) .....

So wondering if anyone has any insights on this? My HW timer is wired to Zone 1 on the UH3, via a thermostat on the HW cylinder (providing the SL- I guess). It may be that I just need to add some actuator valves to the UF circuits to stop them being heated - but the pump will still run. So wondering if that is a solution and it's ok? I'd prefer to stop the UFH pump running completely - but if it's OK to just fit actuators then I'll do that. Many thanks.

 

[hantsgaz]

Just realised I crossed out the rads thermostat on the previous diagram.

Also there is no B2 wired connection from the HW timer (Drayton LP711).

 

[EvilDrPorkChop]

Basically you can't do what you're wanting to do with that Wiring Centre. You either need to rewire the HW & Rads separately from the UFH wiring centre or upgrade your UFH wiring centre to a model that allows you to have HW and select if zones are part of the UFH circuit (Think the new JG Speedfit one will allow you to do this)

You also need actuators or a motorised valve on your UFH circuit.

 

[hantsgaz]

Basically you can't do what you're wanting to do with that Wiring Centre. You either need to rewire the HW & Rads separately from the UFH wiring centre or upgrade your UFH wiring centre to a model that allows you to have HW and select if zones are part of the UFH circuit (Think the new JG Speedfit one will allow you to do this)

You also need actuators or a motorised valve on your UFH circuit.

Thanks -thought that might be where I'd end up. I get the actuators part, but if I fit those - what extra does the motorised valve for the UFH heating circuits give me? Thanks.

One other question if I may - what does the Yes/No switch on the wiring centre actually enable? I don't quite understand the words 'if set to no zone 8 is isolated' part. Isolated from what - the rest of the boards functions? The full text on the board reads 'If set to yes Zone 8 enables the boiler, pump and valve. If set to no Zone 8 is isolated'. Thanks again.

I wish the previous owners left the UH3 manual! Can't find that online anwhere!