The Efficient Home Forum

Hi,

I'm looking at upgrading our current EvoHome System to include HR92s on one of the zones.

Currently we have 3 Zones controlled by T87RF with BDR91s on ZVs (Downstairs, Upstairs and a UFH Single Zone), then a Stored Hot Water Circuit. None of them are paired up as a boiler relay and just use the microswitch on the zone valve to operate the boiler.

My question is that I want to add the HR92s to the downstairs zone and operate each radiator individually but leave the other two zones seperate controlled by their T87RF. When pairing the Hr92s can you select which BDR91 it operates? (essentially selecting which zone valve to operate?)

Thanks.

No you can't nominate a BDR91. When multi zoning with HR92's all the TRV's in that zone need to be fitted with HR92's and the zone valve removed (or electrically disconnected and manually opened) and evohome then configured as a 'Figure 4' system as per page 43 of the evohome Installation Guide.

More details are in our 'customer only' area.

Thanks for the reply.

I understand the diagram but figure 4 doesn't show any control for the boiler.
To do this would I have to use to set it up as a boiler relay?

So I would only need to purchase 6 Radiator controllers,remove the zone valve for downstairs and then leave the upstairs zone the same as it currently is on a ZV.

The evohome Installation Guide Page 43 figure 4 diagram (http://www.honeywelluk.com/Documents/Al ... lation.pdf) shows the boiler connected to a BDR91 Wireless Relay Box. This is configured as the 'boiler control relay' and is the only thing that turns the boiler 'on'. The wire going to the junction box in this diagram is 3 core cable (power to the junction box from the boiler).

But yep, all rads with HR92's in the old downstairs zone and reconfigure the system to work with the boiler relay.