Evohome zone constantly resetting to minimum temp after some time

[clinkadink]

Evening all.

I have the Evohome system (wifi) with boiler control, a lot of HR92's and a couple of BDR91's.

The kitchen has wet underfloor heating and is connected to one of the BDR91s via a Heatmiser DS1-E thermostat. There is also a wireless single zone thermostat on the wall of the kitchen (T87RF2033). If I turn this up, it sends the signal to the Evohome controller, and on to the BDR91, which turns the floor heating up - but the DS1-E will prevent the floor temp rising above 27 degrees. All works well and has been since it was commissioned earlier this year.

But a couple of weeks ago, the kitchen floor (zone) on the Evohome controller would randomly set itself to minimum temp (default is 5c, but I have now changed this to 15c). When I click on the zone, it just shows 'Cancel override', which I do, only to find anywhere between 10 minutes and an hour later, its on minimum temp again.

I first thought it was the Mrs or kids, but it isn't. I then thought it may be something to do with how the HR92s behave when they detect a window open, they automatically drop to minimum temp. My controller is just inside the front door, and it has been cold weather recently. That said, my house is always nice and toasty.

I am wondering if anyone out there has experienced something similar, and could help me find out what the issue is?

Many thanks in advance
Chris.

[huntajc]

Have you disabled all optimisation - window detection, optimised start and eco off - while you diagnose?

[DBMandrake]

First try rebooting the controller - remove it from the dock, prise the batteries apart enough to turn it off then put them back and put it back on the dock.

If that doesn't help, try disabling open window detection - you can do this in the zone configuration under parameters, set window open to disabled.

However if open window detection was in effect you would normally see an icon that looks like a window in the zone rather than the normal stopwatch icon. What icon do you see on the home screen within the zone ? The stopwatch icon usually means a manual override made by the user either at the controller, an HR92 (if there was one in that zone) or a wall thermostat bound to the zone.

If the change was made via the Phone app or Web API (using linked services such as IFTTT) then it will look like a mobile phone instead of a stopwatch.

[clinkadink]

Have you disabled all optimisation - window detection, optimised start and eco off - while you diagnose?

Thanks for the reply. I don't have optimisation enabled on the controller - both start and eco are off. I thought window detection was on applicable to the HR92s.

[clinkadink]

I did try taking the batteries out when it first happened a couple of weeks ago - no change.

I will try disabling window detection - i didnt even know it existed on the controller. Thanks, I will go and try this now and report back.

When it sets itself to minimum temp, there is a stopwatch overlaying the zone on the controller.

I don't have IFTTT hooked up, only bound to a T87RF2033 wall thermostat and a BDR91.

Thanks.

[clinkadink]

When I long press the settings, select the Zone Configuration, select my zone (Kitchen), my options are: Zone Name, Heating Type, Temperature Sensor, RF Binding Device, Min/Max Setpoint, and Delete Zone. There is no option for 'Parameters'.

If I go back one screen, there is a 'System Parameters' button. Within it are Internal Sensor Offset, Cycle Rate, Minimum On Time, Fail Safe, Stored Hot Water. Nothing that mentions 'Open Window Detection'.

I have now just taken the wireless thermostat off the wall, taken the batteries out - see if the problem exists. Process of elimination and all that.

[clinkadink]

I took the batteries out again last night - no change.

Also last night, I removed the wireless thermostat from the kitchen wall (so it was without power), and this morning there was a "Kitchen Sensor Fault". Which I kind of expected. But interestingly, it was back on 'minimum temp'. Wouldn't this rule the thermostat out of the equation?

Scratching my head now. Any suggestions anyone?

[mylesm]

I took the batteries out again last night - no change.

Also last night, I removed the wireless thermostat from the kitchen wall (so it was without power), and this morning there was a "Kitchen Sensor Fault". Which I kind of expected. But interestingly, it was back on 'minimum temp'. Wouldn't this rule the thermostat out of the equation?

Scratching my head now. Any suggestions anyone?

Maybe Zone got corrupted or something you could try deleting Zone clear binding on BDR and Stat and then add it again and re bind

[clinkadink]

Sounds like a plan, i'll try that and report back. Many thanks.

[clinkadink]

I deleted the zone, clear the binding on the BDR and the wireless stat, took the batteries out of the controller for 20 minutes, then re-adding zone and binding. But the problem still exists.

Not sure what else to do now, other than factory reset on the controller. It looks like I will have to get the plumbers in.

[dty]

Have you called Honeywell support?

[clinkadink]

Ok, found the issue. In case anyone else suffers the same ...

It was due to removing a surplus HR92 a few weeks back, dumping it in my 'bits' cupboard and forgetting about it. What I should have done was to fully reset the HR92 first, clearing any bindings that it had with the controller.

Just to clarify that initially, I did delete the zone on the controller at the time - but it would seem that isn't enough, you have to reset the HS92 too.

Certainly less grief from the Mrs over chrimbo

[Shwancapstan]

I had exactly the same issue, and I have no idea how the hr92 (thrown in a drawer as not needed) became bound to the ufh as well as the bdr91! Anyhow, this thread has sorted the issue out - thanks