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Thread: Evohome Single Zone Not Working

  1. #11
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    Quote Originally Posted by g6ejd View Post
    I would wait for the problem to occur then unclip the HR92 and move it closer to the Controller and simulate a demand for heat by turning the top of the HR92 and if that works then turn it down and confirm that works takes a while. It does sound like a communication error to me. It's a fact that UHF RF is affected by air pressure, density, humidity to name a few environmental affects so for me of no surprise there is variability but only when the signal is marginal or something is in the way one day but not the next. To simulate this at 70cms or 440MHz I can hold my transceiver in one place and it receives the Amateur Radio repeater in Bath with a high signal strength, then move it 35cms and there is no signal, so at HR92 frequencies of 868Mhz half those distances and you see what's called standing waves or freznnel zones can be a real issue. My informed guess is something is diffferent in the house between working and not working; been raining; metal framed door open, usually closed; washing hanging around; clothes hangers around (seriously); pressure up; coincidentally we currently have high pressure over us in the South. It does not solve your problem but look out for something changing as to the clues to a solution.
    Thanks, I'll try to see if I can spot any consistent changes to conditions etc but this HR92 almost has line of sight to the controller, only 9m with an archway and a constantly open door between them !!

    Just to check though, I didn't think the HR92 worked if in the unclipped position ??? And if you take of and lock it again, it just constantly tries to close the valve which of course it isn't attached to ??!

  2. #12
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    Seems to be ok doing that, I had my system running on the desktop for a few days with no obvious adverse effects from turning them up and down to watch the system working.

  3. #13
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    More worryingly, I think I may have found why my boiler keeps cutting out and is related to this issue I think. Basically, as I posted earlier, tonight was one of the rare occasions that the boiler did fire up when asking for heat in conservatory. However, once I warmed up, I cancelled the override. As usual, the HR92 responded, but then the "two way communication failed" ?? so the boiler wasn't told to switch off. Therefore, will all valves closed, the boiler was still running, obviously sending water via the bypass valve but that soon heated up and my boiler cut out and started flashing red which happens to me randomly every few days. Having just watched it happen though, I'm convinced these two events are related. It would again explain why it never cuts out hen on hot water only.

    This is putting me squarely in the "this system is never going to work for me" camp. Not sure I have much option than to remove it. problem is, there are hardly any plumbers that seem t have knowledge of Evohome and it appears I need an expert to help me resolve this issue. I feel very deflated as this system cost me a fortune.

  4. #14
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    Quote Originally Posted by g6ejd View Post
    Seems to be ok doing that, I had my system running on the desktop for a few days with no obvious adverse effects from turning them up and down to watch the system working.
    What, leaving it in the unlocked position ? If it's unlocked on a desk, it's doesn't do the cycled and set the valve closed. I'll give it a try, but pretty sure when I had mine unlocked off the Rad, it didn't do anything but maybe I'm wrong.

  5. #15
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    Sorry I meant locked but not on the valve. Mine seem to be ok after their experience of doing this.

  6. #16
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    Quote Originally Posted by f1arp72 View Post
    What, leaving it in the unlocked position ? If it's unlocked on a desk, it's doesn't do the cycled and set the valve closed. I'll give it a try, but pretty sure when I had mine unlocked off the Rad, it didn't do anything but maybe I'm wrong.
    It won't call for heat if the latch is open, but you can close the latch without putting it on the radiator, then it should work.

    If it still doesn't work it might be because it can't calibrate the valve position when the valve wheel is not attached - it will try to wind the valve closed (CYCLE mode) but there is nothing to limit the rotation when it's not attached to the valve wheel - so the calibrate process will fail. I'm not sure if that will cause it to be unable to call for heat but if you want to be really certain, unscrew the white and black base off your radiator as well and fit it to the HR92 then close the latch and wait for CYCLE to finish.

    Now it will most definitely be able to calibrate and will be able to call for heat. Now you can walk with it further into your house and adjust the manual override wheel on the top to see if it calls for heat!

    The best most conclusive way to do this is set all of your other zones to a 5 degree override and hot water off (if applicable) and give that a few minutes to take effect so that there is no other demand and the boiler relay is off, then alternatively turn the HR92 you are carrying right down to 5 and right up to 30. Remember it takes up to 30 seconds for the motor to turn the valve head from one extreme to the other, and it waits until after it finishes turning before it sends a new wireless heat demand.

    So turn the temperature to one extreme and wait for the motor to stop turning before deciding whether it worked or not. You should be able to bring the boiler relay on by turning it right up and off by turning it right down. If that works when you are in the house but not when you are in the conservatory it must be a signal issue! If it still doesn't work when you're near the Evotouch then there is some sort of binding issue or possibly even a hardware fault.

    In that case I would try a reboot of the HR92 first and then the controller if still not working. I have occasionally had to reboot an HR92 by removing the batteries due to odd behaviour.
    Last edited by DBMandrake; 3rd November 2016 at 01:50 PM.

  7. #17
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    Hi, I have only recently installed Evohome, so not an expert. But I have spent about 25 years diagnosing bugs in computer systems. In that time I have learnt (1) not to take anything for granted (2) narrow down a problem systematically by only changing one thing at a time.

    So I apologise if I have got this wrong, but I have noticed that several times you say "the boiler does not fire" without actually saying you have checked the boiler. What you seem to mean is "the radiator does not get hot". These are not the same thing. The boiler not firing is only one possible explanation of the radiator not getting hot.

    You have said that the HR92 from the conservatory works ok on another radiator. You have also said that the signal strength in the conservatory is 5.
    So it's hard to see how the HR92 is the problem.
    It seems to me the symptoms you describe are most likely caused by the TRV pin sticking in the closed position. (Even if I am wrong it's worth eliminating from your investigation).

    A TRV valve body has a pin that can move up and down about 2mm. Down is closed. Up is open. It is pushed open by a spring. It is held closed (or released to open) by the head (whether a trad TRV or a motorised one like HR92). If it is sticking the HR92 will try to release the pin, but the pin will stay closed. Then obviously the radiator will not get warm. The easiest way to test this is to remove the HR92 entirely - so the pin should be fully open.
    Then turn up the temp at any other zone. This will fire up the boiler. In this scenario the other zone's radiator should warm up. AND so should the one in your conservatory. If not, there is something wrong with the rad - not the HR92.

    Also this would probably explain your boiler occasionally overheating and locking out. If the conservatory HR92 "thinks" it is open and fires the boiler, but actually the valve is stuck closed.

    If your conservatory rad does heat up when other zones call for heat, then I am wrong, but at least that's one problem eliminated!

  8. #18
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    On a more general note, I think anyone with a problem should check certain basics before assuming the problem must lie with Evohome.
    E.G balancing your radiators is important whether you have manual wheel-heads, standard TRV's or HR92's.

  9. #19
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    I know this is a very old thread, but I think it's just as relevant today. I've had this issue, and never been able to track it down. I believe it to be a bug in EvoHome ( a pretty serious one really ) - or, some strange operation parameter that is counter-intuitive. The evidence was always there and pretty obvious really ( at least in my case. ) The zone in question has a DT92 detecting the temperature, and a HR92 on a single rad. The boiler isn't fired up when the zone should be calling for heat, so unless another zone needs heating nothing happens, heat wise. The salient points are:
    • Comms test for both the HR92 and DT92 are fine, but anyway....
    • Turning the temperature control on the HR92 changes the setting on the controller
    • Changing the temperature on the DT92 changes the temperature on the controller... so....
    • Whatever the case with the other hardware, the controller KNOWS there should be demand for heat, and...
    • I know the controller can control the BDR91 for other zones.


    So given this, then assuming the controller is what "decides" when the boiler should be firing up, and I know the hardware works, there must be a problem with the software in the controller.

    Now there's info on the boiler demand for each zone, surely these two pictures summarise the fact:

    20181109_095733.jpg
    20181109_095748.jpg

    The controller knows the temperature is currently 18 degrees. The controller knows the zone temperature requested is 30 degrees. The zone heat demand should surely be 100%, but is actually 11%. Ergo, software problem. Or am I missing something obvious here???

  10. #20
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    Depends... what target temperature is showing in the HR92?

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