The Efficient Home Forum

Hi,
I'm having issues with my hot water set up on my evohome system. The RF COMMS FAULT for the hot water sensor comes and goes. It usually recovers after an hour or so. I have tried moving the transiever closer the the controller for a better line of sight. Approx 5m away with one brick wall to pass through into hot press. There is nothing within 300mm of the sensor.
The RF comms test comes back excellent. I have two bdr91's controlling zone valves for heating and hw. The heating side has no issues.
Thanks in advance for any ideas.

Its been bound incorrectly or its fault.

I have had the precise same problem for over a year. The frequency of occurrence can vary from once per day to once every 19 days. As you say the error self corrects over about 2 hrs, and it doesn't matter if I go on holiday and the tank temperature drops down to 24C. When faulty the temperature display shows -- and at that time when I have seen it faulty I have done an RF test which comes back as excellent.
I have moved the transducer away from all metal, and the fault does not change. The transducer has line of site over 4m with the controller.
In desperation I decided that the fault must be an intermittent thermistor, so I had to buy an entire HW kit. Changing everything made absolutely no difference and the fault reoccurred after 14 days.
I'me left with living with it, since only I live in the house and it is nothing more than an inconvenience.

....furthermore I have unbound and rebound the sensors numerous times, each time making sure when binding there is no interfering RF source from my wifi router or dect phone despite being on different bands. I have attempted to ensure that when binding it has no other frequency present which may cause the transducer to falsely lock on.

Have you cleared the actual fault log? If not could be a ghost binding and a clear down and rebind of the hot water side.

I have finally found the fault (90% likely so far). In the 46 previous failures since Feb 2016 with varying intervals between failures of from 1 daily to 1 every 25 days, it is now 28 days since the last occurrence. And what have I done?...taken the controller off the wifi. My conclusion therefore is that the data corruption was coming up the ADSL line. Some say that it is the router cycling, however I regularly cycle my router every 3 days and 50% of these times it causes an IP address to be changed which does not match with the times or intervals I see the HW temperature failures, notwithstanding the regularity of the cycling and the irregularity of the fault occurrence.
My conclusion therefore is that it is likely that hackers are causing this problem, probably via the Honeywell software "back door" that they use for firmware updates. (as they have on one occasion with changing a zone temperature up to the maximum of 35C).
I had a belief that Honeywell would stay ahead of the intrusions (hence the often imposed updates both to the app and to the controller firmware).
I am to leave the system off for another month to give a nearer 100% confidence that the cause is via the net.
I will report back if things change.

What software version are you running on your evohome?

Application V 01:00:07:01
Wifi V 01:00:06:10
Needless to say this may be out of date since I took the controller off wifi on 7/7/2017 so there may be an update waiting.
Getting on to the fault description, it isn't strictly true to call it RF comms fault I believe. The original poster, like myself, assumed it was RF caused, but there are many types of comms failure, such as thermistor failure, and the actual alarm descriptor is "Comms fault, HW, sensor".
One thing I do know is that any firmware update causes a deletion of the faults log, so until I leave it longer (while it's warm weather!!) to get a stronger link between the lack of internet and correct operation I am wary of putting it back online.

Anymore tests you would like me to do Richard?

Possibly a faulty CS92A? Not sure what more to suggest really? If it was a Wi-Fi issue, everyone's would be doing it...

The complete hot water kit has been changed Richard, together with the CS92. I changed the whole thing because I believed the thermistor had developed an intermittent fault so it was the only way of getting one. Only after I had done that and the fault had re occurred after 20 days and when I received false emails telling me the system password had been changed AND had one instance of coming home to a lounge setpoint which was raised to 35C didIfinally start to believe that Honeywell had been hacked. But as you say not with everyone....unless the users don't realise. I am obsessed with the faults log but not everyone has a past engineering background and interest.
But let's deal with numbers of user I know.....welltheres me obviously, and the original poster Barnacle Bill, and my heating engineer also has the sAme fault, and Honeywell told him it was excess router cycling! (I do that manually every 3 days)

Presently my link is under monitoring from Honeywell tier 2 engineers. They are tracing the link at their end, but have not had an occurrence of the fault yet.

I have considered that it is my BT router that is the source of the weakness IF anyone who lives near me can spend time trying to hack it...but we are all pensioners, most with no interest in anything remotely technical.
My router, like all BT routers, has a guest channel for use by any BT customer, and I am wary of even that and the separation between my SSID and the guest challenge BT-FON SSID.
One thing that struck me is that I have never changed the admin password, or SSID. I have also been looking at the website devoted to those who hard hack BT routers by forcing their way in by using every conceivable password via an automated programme. They are committed geeks determined to prove they can do it.
Anyway....watch this space. I will report back any (or none) findings.