HR92 and BDR91 as actuators in same zone?

[PWortley]

Hi - I’d be very grateful for any advice on an issue. My Evohome controller recently failed and I have had to purchase another and configure the system all over again (thank you Smart Thermostat Shop for excellent service). Most of this I have managed to do without issue - I have one BDR91 which controls the hot water with linked sensor, and another which controls the system boiler - all fine. I have various zones which each contain a radiator with an HR92, all bound fine.

My issue is that I have one zone/room which contains one radiator with an HR92, but also a wet under floor heating circuit which is connected to a separate BDR91 (no Evohome UFH device). The way the system was set up prior to controller failure, both the radiator and the UFH were part of the one zone, the sensor for which is a wall mounted T87RF thermostat. So if the temperature fell below the desired level in the zone, both the radiator and UFH came on (and then turned off together as well).

I am struggling with how to achieve this when setting up the zone afresh. My research suggests I am supposed to connect the UFH BDR91 as a “zone valve” actuator for the zone. I can see how to do that, but then how do I also bind the HR92 on the radiator for the same zone? It looks like a zone can either be a “zone valve” zone or a “radiator valve”, but not both?

I know this set up is possible because I have had it for years, but cannot work out how to achieve it. I can see that on the failed controller, this zone was previously set up as a “zone valve”, but I can’t see how the HR92 was also linked.

Thank you for reading and I would appreciate any ideas anyone has!

[Richard]

I can't see how you set this up, as its not supposed to work that way. Heating systems aren't supposed to have mixed technologies in the same zone with evohome. So, its either UFH controlled by evohome or radiator with a HR91/92 controlled by evohome you cannot do both.

[PWortley]

Thank you for the reply. I obviously cannot argue with your superior knowledge about how Evohome works, but I know that somehow my installer pulled this off, because I tested the system at least once per year to make sure the HR92 and the UFH worked in unison! A real puzzle. I think I had better get back in touch with the installer to work it out. Thanks again for your reply.