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Thread: Evo home boiler relay faut

  1. #1
    Automated Home Jr Member
    Join Date
    Nov 2015

    Default Evo home boiler relay faut


    I am a gas engineer(no electrical experience) who has just installed a

    worcester 35 cdi
    worcester 300 ltr unvented cylinder
    s plan
    underfloor heating with 5 zones
    currently 3 radiators with hr92
    zone valve to underfloor heating manifold
    zone valve to hot water
    hr92's controlling upstairs radiators

    I have
    honeywell evohome
    honeywell underfloor heating controller
    boiler relay
    hot water pack
    network pack

    An experienced boiler electrician did the installation for me although he is not experienced with evo home but had some advice by a kind chap from the evohome shop

    My issue is i get a lot of coms faults (daily) mainly boiler relay which is becoming frustrating

    The bdr's are 300mm apart and at least 300mm away from boiler cylinder and pipework.

    Anyone have any suggestions or know any evo home experts that work in kent I could get round

    One other thing is i went into advanced settings do an rf test. if i do rf test on heating both bdr's flash red, is that correct.

    I will upload some pics of my installation shortly

    Thanks for any advice


  2. #2
    Automated Home Sr Member
    Join Date
    Nov 2015


    Hi Darren,

    I am also suffering comms faults, but I believe mine is down to distance from the controller and possibly the construction of the house (lots of solid walls and several steel beams).

    Upon first installation we also had issues with comms faults to the boiler, so we moved the location of the relays closer to the controller by extending the wiring considerably. Obviously this solution isnt for everyone, but it fixed out issues with comms faults to the relays for us at least.

    Im currently trying a variety of possible fixes - my 868mhz repeater should arrive today or Monday.

    Ive noticed that the orientation of the controller also seems to play a part in the strength of communication - the front or rear is directly facing toward the relay, you may find this improves it. If my controller is at an angle to a particular zone, it does lose communication from time to time. This may also be the case with the relays.

    A plan layout may help.

    You can have a read of my thread discussing communication/range issues here:

    Again, Im amazed that Honeywell dont make a simple plug in range extender. The system is just crying out for one.

  3. #3
    Automated Home Sr Member
    Join Date
    Sep 2015


    How did you originally configure the system? Being an S plan setup, you have 2 motorised valves, one for HW loop the other for Central Heating?? Try this...

    1) Perform full Factory Reset
    2) Choose 'Guided Setup'
    3) Select 'No' to require a Boiler Relay/Heat Demand Relay
    4) Select 'Yes' to Hot Water Kit
    i) Bind CS92
    ii) Bind DHW BDR91
    iii) Bind CH BDR91
    5) Create Zones
    6) Have some cake

    If choosing 'Yes' to the Boiler Relay, then it will effectively double-bind the Central Heating loop BDR91, which at first will cause the hot water event to also open the Central heating valve, however, it will be plagued with comms fault, as it will be fighting itself and get confused.

  4. #4
    Automated Home Jr Member
    Join Date
    Nov 2015


    Thanks for your time guys

    If I select no to require a boiler relay what will tell the underfloor heating zone valve to open so it can flow to my manifold?

    Currently I have

    Two port on hot water
    Two port to underfloor heating manifold
    Hr92 on radiators upstairs which act as the zone valves and obviously no two port on this loop

    What would be the correct order to install these to the evohome?



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