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Thread: Balancing EvoHome zone with multiple HR92s

  1. #11
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    Quote Originally Posted by top brake View Post
    Very helpful
    Just as helpful as your post. At least I was helpful in the post before it...

    Changing temperature sensor is questionable advise as well. The issue is not with the temperature sensing, the issue is one radiator valve closing while the other isn't closing. Another temperature sensor isn't going to change that.
    Last edited by erik; 27th February 2015 at 11:23 PM.

  2. #12
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    Just to summarize... I had to balance my heating system myself (before I installed any EvoHome component), since I realized a few months ago that my former installer didn't bother and left all lockshield fully open (I think he didn't brush his teeth as well ).

    My bedroom HR92s are not configured the same way, because the one driving the ladder radiator (the one that stays warm, and acts as as a sensor) is configured for full stroke sincee at first it didn't open enough and the radiator didn't heat up. The other valve is set for normal stroke because it doesn't need full stroke to open/close my bigger radiator properly.

    Offset also is differently set, because I configured the big radiator to -2 degrees when, in the beginning, I tried to use it as a sensor. I left it as it was when I switched to the other one, that's set to an offset of -1. But if this counts, in my opinion it would have made valves behave the opposite way than they are doing now.

    Anyway, the two valves don't show the same opening %. When the unbalanced behaviour happens, the ladder radiator valve is usually 60 - 70% open, while the big (and cold) radiator would be only 10 - 15% open - that doesn't look too close to the other.

    The difference isn't constant, either. Now the big radiator is 39% while the ladder one is 59% (different enough but the big one is not closed, at least). Earlier this evening they were both working close to 100%.

    The unbalancing appears when the room setpoint gets reduced (e.g. wnen my schedule sys I want to switch from 21 degrees to 20), but not every time - or, at least, it's not always that evident.

    And I was planning to addd an additional wireless thermostat anyway, because neither valve is in a decent position to act as a sensor. Thermostats order is takng a bit longer than expected, so I have to wait ...and I'd really like to understand how multiple valves in a single zone act together, since I'm planning to install hr92s all around my house... most rooms I'm going to fit with have two radiators, I'm afraidthat if I'll have to fit wireless thermostats everywhere I'll be spending on batteries what I'm saving on heating

  3. #13
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    I would try to reset the HR92's and remove the zone and redo it. Seems like something is wrong (the very different valve positions).

    I had 2 running in my living room and they were always almost the same.

  4. #14
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    My two in my living room always read the same and one has a settee in front of it and is in a draught free corner.

  5. #15
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    This may not help... because I've a Hometronic setup, but the HR92s are the same, so... If I had your situation with two quite different radiator locations in the same zone, I would not explicitly assign one of the HR92s to be the temperature sensor, simply bind them both to the same zone and let them get on with it. This has the positive effect that both HR92s act independently in maintaining the same setpoint locally, but in Hometronic has the negative effect of not being able to display the achieved zone temperature at the controller. Alternatively, I would buy one of the wall-mounted temperature sensors and explicitly assign that as the sensor, which would enable achieved zone temperature reporting at the controller.

  6. #16
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    Quote Originally Posted by JohnnyP View Post
    This may not help... because I've a Hometronic setup, but the HR92s are the same, so... If I had your situation with two quite different radiator locations in the same zone, I would not explicitly assign one of the HR92s to be the temperature sensor, simply bind them both to the same zone and let them get on with it. This has the positive effect that both HR92s act independently in maintaining the same setpoint locally, but in Hometronic has the negative effect of not being able to display the achieved zone temperature at the controller. Alternatively, I would buy one of the wall-mounted temperature sensors and explicitly assign that as the sensor, which would enable achieved zone temperature reporting at the controller.
    I don't think you can actually not assign an HR92 as a zone sensor. When you configure a zone, the controller asks wether you want to use the inbuilt sensor for the zone. Saying "no", it goes into binding the room sensor - that could be the first HR92 or another thermostat. So, the first HR92 bound to the zone becomes "master" and acts as a sensor for that zone. Did you find a different way to bind them? Just curious...

    Anyway, since my thermostats are not arriving any soon, I think I'll follow erik's suggestion and try recreating my bedroom zone from scratch, and see what happens then.

    Does anyone have experience of such a configuration, with valves having different stroke and offset configuration?

  7. #17
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    Quote Originally Posted by emmeesse68 View Post
    I don't think you can actually not assign an HR92 as a zone sensor. When you configure a zone, the controller asks wether you want to use the inbuilt sensor for the zone. Saying "no", it goes into binding the room sensor - that could be the first HR92 or another thermostat. So, the first HR92 bound to the zone becomes "master" and acts as a sensor for that zone. Did you find a different way to bind them? Just curious...

    Anyway, since my thermostats are not arriving any soon, I think I'll follow erik's suggestion and try recreating my bedroom zone from scratch, and see what happens then.

    Does anyone have experience of such a configuration, with valves having different stroke and offset configuration?
    I don't but I am curious, assuming all your radiators had the same TRV fitting previously, why one radiator would be different to another in the stroke length? Are they that variable?

  8. #18
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    Quote Originally Posted by jonstatt View Post
    I don't but I am curious, assuming all your radiators had the same TRV fitting previously, why one radiator would be different to another in the stroke length? Are they that variable?
    I also assumed all my valves were equal. They are the same make and model (FAR, Italian make, dunno wether they are known at all abroad) and were fitted with thermostatic heads that I replaced with HR92s, using Danfoss RA adapters (included with HR92).

    Before I installed HR92s, my thermostatic valves have been all open and nobody touched them for 15 years. So maybe one particular valve could have been ruined for the long inactivity and now needs the full stroke to work properly, while others are still OK (or the other way round).

    It appeared as the particular valve got stuck in closed position and couldn't open when the HR92 was configured for regular stroke. If I took the motor off, I could notice the valve wasn't completely open even if the HR92 reported 100%. So I tried full stroke and it actually worked.

    Tonight I plan to do another test, and set the other valve to full stroke, and see if the % shown gets closer to one another.

    Differently, I'll just try deleting/rebuilding the whole zone.

  9. #19
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    Quote Originally Posted by emmeesse68 View Post
    I don't think you can actually not assign an HR92 as a zone sensor. When you configure a zone, the controller asks wether you want to use the inbuilt sensor for the zone. Saying "no", it goes into binding the room sensor - that could be the first HR92 or another thermostat. So, the first HR92 bound to the zone becomes "master" and acts as a sensor for that zone
    I don't think the right and the subject has been covered elsewhere in the forum. The ordering of binding has no effect on priority. I think the only way to control an awkward zone is a room stat instead of relying on the HR92s.

  10. #20
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    Quote Originally Posted by G4RHL View Post
    I don't think the right and the subject has been covered elsewhere in the forum. The ordering of binding has no effect on priority. I think the only way to control an awkward zone is a room stat instead of relying on the HR92s.
    I'm not fully convinced... I can't remember being asked which HR92 to use as a sensor. Defining a zone, you can bind a single HR92 as a sensor and actuator. All the HR92 that you bind after the first act as actuator only. This would imply the first one is the sensor and others added after the first are just actuators.

    I didn't read this in any documentation, I just infer it by my experience binding valves to a zone... Am I wrong?

    And... I'm adding a room thermostat as soon as it arrives at the store!

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