Page 1 of 5 12345 LastLast
Results 1 to 10 of 45

Thread: Balancing EvoHome zone with multiple HR92s

  1. #1
    Automated Home Guru
    Join Date
    Dec 2014
    Location
    Northern Italy
    Posts
    103

    Question Balancing EvoHome zone with multiple HR92s

    Hi all,

    I recently added a few HR92s to my heating system and I came across a behaviour I can't explain.

    There are two radiators in my bedroom: one (medium/large) under the window, valve being just under the windowsill, partly covered by curtains. Surely not a great spot for a temperature sensor. The other is a smaller one, "ladder" shape, valve very close to the floor, the opposite side of the window. It's not covered, but the floor is rather cold (downstairs there's an unheated cellar), so the measured temperature isn't the best either. Waiting for a wireless thermostat that I ordered to arrive, I configured the small radiator as the zone "master" (temperature sensing).

    Now I can actually heat the room to a decent level, but after reaching the programmed setpoint the "master" radiator stays warm, while the other closes and cools down. That doesn't feel very comfortable, since one side of the room stays warm while the opposite side is cooling down (I sleep on the cold side... ).

    Can anyone explain why this happens? Any suggestion how to fix it?

    Thanks!

  2. #2
    Automated Home Guru
    Join Date
    Feb 2015
    Location
    Netherlands, the
    Posts
    244

    Default

    Do you have the multi room parameter for the zone set to multiple rooms? Or to single room?

  3. #3
    Automated Home Legend
    Join Date
    Jan 2015
    Location
    NE UK
    Posts
    1,022

    Default

    Does sound like it has not been set to one single zone but if the ladder radiator is in an enclosed area such as an open plan en suite then that area could heat up leading the system to think all his good. Just a thought.

  4. #4
    Automated Home Guru
    Join Date
    Dec 2014
    Location
    Northern Italy
    Posts
    103

    Default

    Quote Originally Posted by erik View Post
    Do you have the multi room parameter for the zone set to multiple rooms? Or to single room?
    Good question... I had to double check but I was pretty sure it was single zone configuration, as I actually confirm.

    In a single zone/single room config there's one sensor and many actuators. In such a case, do config parameter such as temp offset or stroke or open windows sensitivity matter on slave valves (those that are not acting as a sensor)?

    Actually, at first my big radiator was master, then I couldn't achieve correct temp reading because it is recessed under the windows ledge and behind curtains, so I re-binded the zone with the ladder radiator as sensor.

    When my bedroom is heating up, both radiators work well. The unwanted behaviour I described happens after setpoint has been reached, it seems that the ladder radiator (it's not in an enclosed area actually) could heat up its own sensor enough even when the other one shuts off - chilling out half of my bedroom...

    Valves seem to behave independently, they don't always adjust at the same time (except when setpoint is changing).

    Is there a way to balance valves, or to know how they balance? Or might I delete and rebind the zone, to reset signature, and let EvoHome learn it again?

    In the future I plan to fit HR92s to other rooms in my house. Most of those rooms have two radiators. Dunno if separate wireless thermostats could fix that behaviour, but it feels a bit overkill to fit additional thermostats to every room with more than one radiator, when there's at least one that can be used as a sensor... Is there anyone that could share experience about multiple actuators in single rooms/single zones?

  5. #5
    Automated Home Guru
    Join Date
    Feb 2015
    Location
    Netherlands, the
    Posts
    244

    Default

    If it's set as single zone, it should behave like you want it to. Both actuators should basically do the same thing. You can check by checking (I think) parameter 10 to see how much % the actuator valve is open. It should be about the same percentage on both. Although the actuators don't act exactly at the same time, so there might be a 2-3% percent difference.

    It could be that 1 radiator valve is different than the other. This could mean it's closing at a certain valve percentage, while the other is still open at that same percentage. I don't think there's a way to 'calibrate' them to be balanced. You could try setting parameter 6 to 1 on the big radiator one. See if that causes it to stay open longer. Or you can re-calibrate them by taking the hr92 off, turning the black wheel all the way counter-clockwise. Then put it back on and wait for CYCLE to complete.
    Last edited by erik; 27th February 2015 at 10:18 PM.

  6. #6
    Automated Home Legend top brake's Avatar
    Join Date
    Feb 2015
    Location
    the edge of the cloud
    Posts
    827

    Default

    Quote Originally Posted by erik View Post
    If it's set as single zone, it should behave like you want it to. Both actuators should basically do the same thing. You can check by checking (I think) parameter 10 to see how much % the actuator valve is open. It should be about the same percentage on both. Although the actuators don't act exactly at the same time, so there might be a 2-3% percent difference.

    It could be that 1 radiator valve is different than the other. This could mean it's closing at a certain valve percentage, while the other is still open at that same percentage. I don't think there's a way to 'calibrate' them to be balanced. You could try setting parameter 6 to 1 on the big radiator one. See if that causes it to stay open longer. Or you can re-calibrate them by taking the hr92 off, turning the black wheel all the way counter-clockwise. Then put it back on and wait for CYCLE to complete.
    The heat output of the radiators needs to be balanced

    http://www.diyfixit.co.uk/central-he...radiators.html

    Evohome will then be able to control the room temperature in a balanced way

    The manual doesn't cover this as it assumes that the installer already did this, it is mentioned in youlearn chapter 6

    Excerpt:

    It is important to balance the heating system so that hot water is distributed evenly to all the radiators. This will ensure that the heating system operates efficiently and effectively.

    With an unbalanced system, customers may complain of cold radiators or radiators not heating up quickly enough. This is because the hot water is finding its easiest circulation path, which will normally be through those radiators closest to the boiler.
    Last edited by top brake; 27th February 2015 at 10:28 PM.
    I work for Resideo, posts are personal and my own views.

  7. #7
    Automated Home Guru
    Join Date
    Feb 2015
    Location
    Netherlands, the
    Posts
    244

    Default

    Balancing the heat output of your radiators isn't going to help AT ALL if the HR92 closes the valve on 1 radiator and not on the other. You can balance the radiators all you want, but a closed radiator valve will make it output 0 heat, no matter what.

  8. #8
    Automated Home Legend top brake's Avatar
    Join Date
    Feb 2015
    Location
    the edge of the cloud
    Posts
    827

    Default

    Quote Originally Posted by erik View Post
    Balancing the heat output of your radiators isn't going to help AT ALL if the HR92 closes the valve on 1 radiator and not on the other. You can balance the radiators all you want, but a closed radiator valve will make it output 0 heat, no matter what.
    Agreed but it does need to be balanced nonetheless

    When they are balanced (and that eliminated) if still issue I would delete the zone and bind again with a wireless thermostat on the wall as the sensor
    Last edited by top brake; 27th February 2015 at 11:05 PM.
    I work for Resideo, posts are personal and my own views.

  9. #9
    Automated Home Guru
    Join Date
    Feb 2015
    Location
    Netherlands, the
    Posts
    244

    Default

    Yes, and he needs to brush his teeth, too. But it has nothing to do with the subject.

  10. #10
    Automated Home Legend top brake's Avatar
    Join Date
    Feb 2015
    Location
    the edge of the cloud
    Posts
    827

    Default

    Quote Originally Posted by erik View Post
    Yes, and he needs to brush his teeth, too. But it has nothing to do with the subject.
    Very helpful
    I work for Resideo, posts are personal and my own views.

Posting Permissions

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