The Efficient Home Forum

Hi,
I’ve just had underfloor heating installed downstairs at my home. Upstairs has an EvoHome system with all radiators having the evohome TRV’s. Prior to the installation of the UFH I had a two zone system (one zone being upstairs, further zoned within evohome, the other being downstairs). Each zone had a separate 2 port valve controlling it. With the addition of the HCC100 for the UFH, and retirement of the old controller that ran downstairs, how do I wire in the 2 port valve to provide isolation of the IFH when no room downstairs calls for heat?

The HCC100 has a 'Pump' terminal which gives a switched live but only operates when there is a demand for an UFH zone.

You wire it similar to how the HCC80R used to be wired (I will do a HCC100 version when I get 5 minutes)...

Ah, ok so i effectively wiring the positive from the ‘pump’ connection to trigger the 2 port calve and then have the Grey / orange wire from the valve to be permanent 240v and switched wire to the pump respectively?

Yes correct, although the above diagram shows the grey and orange made safe.