Evohome Controller Multiple Comms faults

[robsonalan]

Ok so this is odd, since moving the controller upstairs closer to the relays and landing HR92, the controller has now lost comms and temps from all of the HR92's that are on the ground floor, but hasn't picked up any sync or temps from the relays or HR92's upstairs. I am confused, it does still seem like somethings blocking the comms.

Can a fault evohome device be causing the issue and affecting all comms?

[robsonalan]

Well would you believe it, it looked on the logs on the controller and the first device that had a comms failure yesterday was the hot water thermostat, so I took the batteries on in the Hot water tank thermostat and put in new ones, and it looks like things are coming back. Within a minute the two relays which were sold red started to flash red, and then shortly after the red LED's went off. HR92's are now coming back in and seem to be controllable.

I have a few HR92's still not quite playing ball in terms of taking updates from the controller, but I am going to leave things an hour or so to settle down, but it looks like somehow the Hot water tank thermostat was causing some system wide problem, of which I have no idea how or why.

[peterf]

Well, that's a coincidence. I've just experienced something similar.
I've also had the Evohome installed for several years - in my case the old non-wifi model - and I've also changed batteries in the HR92s at the first warning that they're getting low.
I came in last evening and the app was showing no temperature in 5 zones. Looking at the controller, it was giving a low battery warning on one zone, which I duly popped new batteries in to, and I was then presented with a low battery warning on two other zones.
Checking the log, the first comm failure occurred at 6:58pm, which was followed by comms warnings for 10 zones, the first battery low warning at 7:59pm in the zone with the initial comms failure, and 2 further by 8:43pm.
When everything had come back to normal, which it did fairly quickly once new batteries were installed, it was apparent that one zone had the radiator on full blast while in a confused state. This surprised me as I thought they'd revert to the minimum setting in the event of signal failure, but I suppose an intermittent failure may produce different behaviour. Bit worrying if one was away however and returned to an empty oil tank.
The second thing that surprised me was the seeming contagious effect of the initial comms failure. I can only assume that it caused continual and unusual activity for the other HR92s in the system thereby depleting the batteries, but perhaps someone else can come up with a better explanation.
As a result of this, I've made a mental note to go around the various units and check the battery level before I go away. Perhaps others may find it useful to do likewise.

[G4RHL]

I have only had a failure similar what has been described nearly 5 years ago when I installed the system and it was my fault for not ensuring I closely followed the sequence for installation which does mean setting up the hot water part first. Yes the manual has that but it is not obvious. A Honeywell approved installer was foxed by it and relied on me to rectify, but it was my fault initially. They say “rtfb”. I had done, but missed it. That year the Evohome Shop posted great guidance on installing set out in a much clearer way than the manual does. Over the years one learns to first question oneself as to whether things have been done right before blaming the seller etc.

As for batteries I have a diary note to change them every year and that seems to cover the concern. One HR92 needs its batteries changing every three months. That is a fault in the HR92 which I live with.

[peterf]

Just for clarity's sake, I should point out that I don't use the hot water function, but there did seem to be some similarity with robsonalan's situation.

[Jemster]

I’ve had 2 mass communication failures since installing in November. Both times the dt92 thermostat in the living room has shutdown/batteries went flat. Both times multiple zones were either demanding heat or losing contact.

I would agree with this hypothesis regarding batteries and the failures spreading out. I do think Honeywell should be investigating this issue as there is no way a low battery in one device should be allowed to affect the entire system.

We had a suspicion mine was down to the ‘phantom override’ problem but the double dt92 failure always niggled as being just too coincidental.