Page 1 of 5 12345 LastLast
Results 1 to 10 of 42

Thread: Central Heating randomly turning on when it should be off

  1. #1
    Automated Home Lurker
    Join Date
    Jan 2016
    Posts
    9

    Default Central Heating randomly turning on when it should be off

    Hi there,
    First time posting so hope can be of assistance.
    My central heating comprises a Baxi Duo-Tec Combi HE with a Honeywell Evohome Controller (latest Wifi version), wireless relay box (BDR91) and 6 Radiator Controllers (HR92).
    The problem I am experiencing, since setting up, is that when the heating switches off at the set off time, the boiler then fires randomly up again anywhere between 5-15 minutes later, despite the Controller showing the correct “off” temperature that I have set at 10C for all the rooms. Room temperatures will still be in the region of 20C so there should be no need for the boiler to fire up. Also, ambient temperature where boiler is located is not low enough to trigger frost protection.
    The boiler will then continue to cycle on/off every 5 minutes until I either push the reset button on the relay box or turn the boiler off then on again. The bathroom radiator does not have a thermostat and gets very hot during this so it appears the boiler is going into heat mode and not just the pump cycling. It seems to correct itself for a few days after a reset then starts playing up again until I reset the boiler by one of the two methods above.
    Wondering is it more likely to be the boiler or the Evohome setup?
    Any suggestions?
    Thanks

  2. #2
    Automated Home Legend
    Join Date
    Sep 2014
    Location
    Scotland
    Posts
    2,033

    Default

    Do you have "Failsafe" mode enabled in the System Installer menu ?

    Have you done a wireless signal strength test to all wireless devices and got a good result ?

    When you bound the BDR91 did you clear any pre-existing bindings by holding down the button for 15+ seconds before holding it down for 5 seconds to bind ?

    Have you seen any comms faults reported ?

  3. #3
    Automated Home Lurker
    Join Date
    Jan 2016
    Posts
    9

    Default

    Hi and thanks for your quick reply.
    In response:
    Failsafe is Disabled
    Signal stength is good (ranging between 4-5) between the HR92s and the Controller. The Controller itself is situated 5 feet from the wireless relay box and with no obstructions and no loss of signal between the two.
    All pre-existing bindings were cleared as outlined
    No Comms faults being reported
    Thanks

  4. #4
    Site Sponsor The EVOHOME Shop's Avatar
    Join Date
    Dec 2014
    Location
    Powys, Mid Wales
    Posts
    479

    Default

    Photos of the BDR91 would be handy.

  5. #5
    Automated Home Lurker
    Join Date
    Jan 2016
    Posts
    9

    Default

    Hi,
    I've attached a photo below.
    The BDR91 backplate is the original one used with a previous installation of a Honeywell CM927 Controller which was in the house when I moved in 3 years ago. I simply swapped out the fascia plate with the new one supplied with the Evohome controller as they use the same BDR91 Wireless Relay. As the previous system worked without fault this seemed logical rather than having to mess about with wiring which is as follows:
    The black wire at N goes straight to the main Neutral supply to the boiler.
    The first brown L goes to the Live out on the boiler.
    The second brown L is a loop to terminal A.
    The blue at terminal B goes to the switched live in terminal on the boiler.
    image.jpg

    I have noticed though, when taking the photo, that this wiring does not correspond to the diagram in the installation booklet, though as said above has worked without problem on the previous CM927. (The boiler requires a permanent live). Could this be the issue?
    Hope this makes sense!

  6. #6
    Site Sponsor The EVOHOME Shop's Avatar
    Join Date
    Dec 2014
    Location
    Powys, Mid Wales
    Posts
    479

    Default

    I was actually after a picture of the BDR91 in position...

  7. #7
    Automated Home Lurker
    Join Date
    Jan 2016
    Posts
    9

    Default

    The picture shows the BDR91 in position, just with the front cover off. Nothing unusual about its positioning - mounted on a blank wall with no obstructions between Controlker or boiler.

  8. #8
    Automated Home Sr Member
    Join Date
    Nov 2015
    Posts
    95

    Default

    Not wanting to cloud the water here, but I had a similar problem with my old boiler, the problem being a faulty frost stat. The thing was firing up in the middle of summer when there was no demand. Could this be a possible issue?

  9. #9
    Automated Home Lurker
    Join Date
    Jan 2016
    Posts
    9

    Default

    Hi Ccris,
    You could be right. I'm starting to realise it could be anything so thinking I'll just get the engineer out to give the system a once over.
    Thanks

  10. #10
    Automated Home Guru
    Join Date
    Dec 2012
    Posts
    128

    Default

    Jim - you may find a posting I placed what may be a year ago (I lose track of the time) I had exactly the same problem with the system appearing to have a life of its own. I tried all the suggestions and then finally did a hard reset of the Evohome controller. All was well after that! I can only conclude that the software had become corrupted. No probs since then. Steve

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •