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Thread: EvoHome novice... beginners help needed please!

  1. #1
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    Default EvoHome novice... beginners help needed please!

    We had an electrician wire in out BDR91 yesterday to run the HR92s on 6 of our 14 rads ( I have another 7 coming as well as T87RF2033 which I thought I might need). The HW is run off the Danfoss timer programmer and is all working fine, however the boiler kept firing up all night and any rads without HR92s on going at full tilt. Eventually I switched the whole thing of via the phone app.
    we have an oil fired boiler on a very old system that was getting through 500l of oil a month last year so we are desperately trying to reduce our costs and hoped the evohome would do that, but with some of the rads going all night that seems like it might not be our solution after all.

    Unfortunately one of the HR92s keeps being 'blown off' a Drayton RT212 and we dont know why. We also had a fault come up on the controller when we replaced a Drayton TRV4 with and HR92. (It is on a rad in a cover and has a bit of wire coming out of it to a small plastic box - could this be an external thermostat - and could this be what was causing the error)
    I've rung Honeywell but the woman wasnt able to help really - she suggested that the heating could all be linked and therefore we would need HR92s on all rads for it to work.

    What are your thoughts? And can you offer a solution with these drayton TRVs?

    Finally we have just ordered two new towel rails that are being fitted on Thursday - if the system is 'linked' as the Honeywell lady suggested then can we fit HR92s to these? And do I even need this T8&RF2033?

  2. #2
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    Quote Originally Posted by Bovrilelles View Post
    We had an electrician wire in out BDR91 yesterday to run the HR92s on 6 of our 14 rads ( I have another 7 coming as well as T87RF2033 which I thought I might need). The HW is run off the Danfoss timer programmer and is all working fine, however the boiler kept firing up all night and any rads without HR92s on going at full tilt. Eventually I switched the whole thing of via the phone app.
    we have an oil fired boiler on a very old system that was getting through 500l of oil a month last year so we are desperately trying to reduce our costs and hoped the evohome would do that, but with some of the rads going all night that seems like it might not be our solution after all.

    Unfortunately one of the HR92s keeps being 'blown off' a Drayton RT212 and we dont know why. We also had a fault come up on the controller when we replaced a Drayton TRV4 with and HR92. (It is on a rad in a cover and has a bit of wire coming out of it to a small plastic box - could this be an external thermostat - and could this be what was causing the error)


    I've rung Honeywell but the woman wasnt able to help really - she suggested that the heating could all be linked and therefore we would need HR92s on all rads for it to work.

    What are your thoughts? And can you offer a solution with these drayton TRVs?

    Finally we have just ordered two new towel rails that are being fitted on Thursday - if the system is 'linked' as the Honeywell lady suggested then can we fit HR92s to these? And do I even need this T8&RF2033?

    The good news is that the Drayton TRV4 body should be 100% compatible with the HR92 without an adapter. In my experience, there is one main reason why the HR92 head lifts off the TRV body: it hasnít been latched on properly. It needs a slide and a click. (Remember to turn the HR92 black screw fully anti-clockwise before fitting the head). It could of course be a faulty HR92. You can fault find by moving HR92s around but beware of double binding.

    You can fit HR92s onto every radiator and towel rail in the house; however, I would only do this if an ABV is fitted.

    Random boiler firings at night are not unknown. This is usually down to the setback temperature on one or more zones. For example, in my old home, I had a bedroom over an integral garage. I had to set the overnight temperature back to 5C on a cold night to stop the boiler firing. Obviously, in an all HR92 household, the only rooms that get heated are the ones calling for heat. In a mixed household, unless there are manual turned down TRVs, non HR92 rooms will also get heat when any single zone calls for it.

  3. #3
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    Hi Hengus,

    Thanks for a speedy response! Its generated some more questions though!!

    1) what is the issue with double binding ( have seen this mentioned elsewhere but I dont really understand what that is and now worried all TRVs are double bound! Is there a way to check?)
    2) The TRV4 has a remote sensor ( very old I think) attached to it - hence the fault on the controller I think - any idea how to remove that sensor ( it didnt come away with the main TRV)

    All night time temps now dropped to 5C so fingers crossed that works!

    Any thoughts on the need for the T87RF2033 single zone thermostat? had initially thought that might be good for if any rads couldnt take the TRVs - maybe useful in the bathroom with new towel rails?..

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