Results 1 to 10 of 29

Thread: Mass communication loss overnight?

Threaded View

Previous Post Previous Post   Next Post Next Post
  1. #11
    Automated Home Legend
    Join Date
    Sep 2014


    Quote Originally Posted by Jemster View Post
    I cleared all the overrides then went into the Living Room and saw that the DT92 was ‘off’ (no display). I popped a battery and put it back in and it re-synced.
    Evohome is notorious for poor battery connections. You need to re-tension the battery contacts. The contacts are (probably, in my opinion) made of chrome plated mild steel rather than using proper spring steel normally used for spiral battery terminals so over time they lose their tension and become intermittent.

    Every single one of my HR92's has needed to have this done over the last 3 years because they became intermittent. Some have needed it done twice! My CS92A has needed it done, and so has one of my DTS92's which like yours decided to go blank one day even though the batteries were fine.
    What is really puzzling me is where these overrides are coming from. They have the clock symbol in the UI so aren’t coming from the phone app, they obviously aren’t coming from multiple hr92s simultaneously so how are they getting set???
    One possibility is the so called "phantom override" issue. Check for other threads about this, me and a few others have discussed this problem a few times. In essence it can cause the set point to be reverted to the previous set point. The workaround (there is no true fix) is to reboot all the HR92's in the affected zones preferably at random times in the hour, as the problem occurs when the bootup time of the HR92 within an hour clashes with set point changes.
    Got to be either the controller, or that DT92 that goes off on its own... maybe...
    The DTS92 going off is a fault but wouldn't cause all your other issues, and certainly wouldn't affect other zones.
    Quote Originally Posted by Jemster View Post
    I've exported all my data from Domoticz and here's a timeline of what happened...
    At about 11pm all the radiators go back down to 10 degrees on their schedule and at this stage everything was running normally.

    23:20 Bedroom 3 - Set point unexpectedly goes up to 20 degrees
    23:25 TV Room - Set point unexpectedly jumps to 20.5 degrees
    23:45 Living Room - Set point unexpectedly goes up to 20.5 degrees
    23:50 Computer Room - Set point mysteriously goes up to 20 degrees
    00:30 TV Room - Set point drops to 20 degrees (!?!??!)
    00:50 Living Room - Set point drops to 20 degrees (!?! like... why???? I can kind of understand a random override but this indicates more than 1 override happened)
    01:25 Bedroom 2 - Stopped reporting temperature (This is the one I got the fault message for)
    01:30 TV Room - Stopped reporting temperature
    01:40 Bedroom 1 - Set point goes up to 20 degrees
    20 degrees is the default set point for an HR92 when it boots up. If you reboot an HR92 by removing the batteries and reinserting them it will jump to 20C. This will be registered by the controller as a local override (clock icon) as if the user had turned the HR92's dial to 20.

    HR92's are very prone to random spontaneous reboots when the battery contacts start to lose their tension. You can see where I'm going with this...if an HR92 spontaneously reboots in the night you'll end up with a 20C override until your next set point in the morning. It's happened to me a few times.
    02:45 I arrived in and cleared faults and overrides...

    02:45 Computer Room - Set point goes back to 10 degrees when I cleared override
    Bedroom 1 - Set point goes back to 10 degrees when I cleared override
    Living Room - Set point goes back to 10 degrees when I cleared override
    Bedroom 3 - Set point goes back to 10 degrees when I cleared override
    TV Room - Set point goes back to 10 degrees when I cleared override

    02:50 Computer Room - Set point magically goes back to 20 degrees
    That sounds like either the Phantom override problem (which causes a revert to the previous set point) or an HR92 in the zone rebooted again - which would revert to 20C. Low battery/poor contact tension can cause spontaneous reboots when the motor tries to turn, especially if it turns all the way to the limit stop as that causes a sudden large current drain.

    Bedroom 2 - Restored temperature readings
    02:55 Computer Room - Set point goes back to 10 degrees when I cleared override for a 2nd time
    03:10 TV Room - Starts reporting temperature again (I did a battery reset of DT92 about 15 minutes earlier)

    03:20 Bedroom 3 - Set point went back up to 20 degrees!
    03:20 TV Room - Set point went back up to 20 degrees!
    03:45 Bedroom 1 - Set point went back up to 20 degrees!

    Right now, re-reading this, I am having trouble not over-reacting to what I think of EvoHome and 'fit for purpose'. This is not a simple case of interference. This is total system collapse. Bear in mind that while this was going on, 3 other zones Plus the hot water were functioning normally.

    Please... Anybody... any ideas or theories??
    I would check the status of the batteries in all your DTS92's and HR92's and then re-tension their contacts, and make sure all HR92's/DTS92 have been rebooted and then finally reboot the controller itself.

    The way I test the battery tension on the HR92 is simple but effective - remove the HR92 from it's base, hold it vertically in one hand, hold your other palm open facing up about 6" below the HR92 then bring the HR92 down with a medium force downwards "thump" into your palm. If there is any trouble with the battery contact tension the HR92 will spontaneously reboot. Often you'll find the slightest bump will reboot it and you'll wonder how it ever worked...

    To tension the contacts you'll need a small flat jewellers screwdriver or similar to bend up the middle prong of the two bottom contacts by pushing the screw driver up through the base. Bend it up a couple of millimetres. Sometimes the little shorting bar at the top needs to be bent slightly as well, (it does a really poor job and is as soft as butter) and it's helpful to fit the two security screws as that helps to hold it down as normally it relies on the pathetic clip in the middle of the bar.

    See how you go after that. Might just be a combination of many of the HR92's batteries starting to get low (but not low enough to show a fault log entry) and many of them starting to lose contact tension.
    Last edited by DBMandrake; 28th April 2019 at 10:11 PM.

Posting Permissions

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