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Thread: Evohome UFH question

  1. #11
    Automated Home Lurker
    Join Date
    Mar 2018


    Quote Originally Posted by rvb99 View Post
    Have you tried increasing the ufh mixing ( manifold ) temperature . You can usually increase to around 45-50deg , still keeping the floor temp itself to the max recommended 26-27deg. Also check the flow/s for the hydraulic circuits. As a rough guide they should be the loop length / 40. Eg 80m loop should be 2-2.5 litres/min
    Yes tried, its on maximum. My plumber says unlikely I will get more heat by adjustments. Just want to explore possibility of installing trench radiator along the patio doors which will create a warm curtain in this area, but not sure how to connect it and control by Evohome controller. I will need to connect the trench heater to the main flow of the boiler as other radiators in the house in order to get high temperature and the output, and then I can put HR92 on it and will need a separate temperature sensor. Then I will need to keep the UFH zone and this additional zone on the same program, but I am not sure whether they will work in tandem (one can switch off earlier or another, or may have some other issues). I though if I could put UFH and trench HR92 on the same zone, then they will definitely work in tandem, like multiradiator zone. Can you tell whether this mixed mode is supported?

  2. #12
    Automated Home Sr Member
    Join Date
    Oct 2017
    France & UK


    I donít believe you can mix hcc controller and HR92s in the same zone. You could I guess use one of the hcc ports to control a wired radiator actuator , rather than use the HR92. This will ensure they come on together , but the overal problem mixing ufh and radiators to have a warm floor and hot radiator will be balancing the system . The radiatior will heat up quickly and possibly heat the zone before the ufh has a chance to get going.

  3. #13
    Automated Home Lurker
    Join Date
    Apr 2016


    Quote Originally Posted by The EVOHOME Shop View Post
    Depending how evohome is configured both options are possible with the HCC80R. The BDR91 'boiler relay' approach is my preferred approach. How is your current BDR91 being used? With evohome or another Honeywell thermostat?
    Hi - I find myself in a similar situation to the OP I think. I have an Evohome setup with controller, two BDR91s (1x Boiler Relay, 1x DHW with sensor) and 8xHR92s on the rads. Following some recent building work and change to the plumbing, I am no longer able to control the DHW with Evohome (long story for a different thread) and so now have a redundant BDR91. However, I now have wet UFH installed in two newly built rooms. The UFH is to be controlled by an HCC80R, and the two rooms (as two zones) will have TR87 room temp sensors. So, do I simply need to bind the HCC80R with the controller and add the TR87s to the new zones - and the UFH will take advantage of the existing BDR91 Boiler Relay?? Or do I need to add a BDR91 just for the UFH (and I'll repurpose the 'redundant' one for that if needed).

    Am I correct to think that no additional BDR91 is needed and the existing Boiler Relay is sufficient?

    Thanks for any help you can give.

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