Interesting BDR91 interference issue

[mdf4068]

I have an Evohome installation that has been causing me some trouble, the BDR91 used as boiler relay on a Combi system kept displaying comms error with slow flashing red light.

So I have followed all the advise do a signal check 5/5 and then move it, then move it again, again again etc etc about 12 times in different locations in the house, it would always work for a few days and then start flashing, all the time the system never missed a beat and kept working fine, and no errors appeared in the controller log or any errors for that matter.

In the end I decided to contact Resideo Support and they were really helpfull and said they have seen this issue with about 20-30 installations and they are trying to reproduce it in their lab , they suspect it is RF interference being received by the BDR91 probably by 2.4ghz Zigbee source (which might be true as I have 40+ Hue bulbs in my house ) which is triggering the error condition, they told me that as long as the system keeps working and there is nothing in the controller log then to just ignore the error light.

Of course as the signal strength is always 5/5 this issue is not easy to predict with a pre instal survey even if you test using a test rig such as the one Richard at the Evohome shop rents out.

They think it should be resolvable by a patch update but are not sure when this will be available.

Just thought I would share in case anyone else has finds the same issue.

Mark

[therealfronty]

2.4GHz is pretty congested, is your house surrounded by others as you'll be picking up interference from their devices too as well as your own? There may not be a lot you can do about it. The newer WiFi frequencies use the 5GHz band, but I have no idea if all your Hue bulbs use this. So much older legacy stuff uses 2.4GHz you're almost lucky Evohome works at all, stuff like your microwave, cordless phones, garage remote, even Bluetooth uses good old 2.4GHz. Wherever I can I've configured as many of my devices as possible to use 5GHz, my laptops, my TV, my sons PS5 etc. just trying to avoid using 2.4GHz wherever I can as so much other stuff already uses it.

[gordonb3]

...they suspect it is RF interference being received by the BDR91 probably by 2.4ghz Zigbee source (which might be true as I have 40+ Hue bulbs in my house ) which is triggering the error condition, they told me that as long as the system keeps working and there is nothing in the controller log then to just ignore the error light.

That would be highly unlikely as the Evohome components communicate over 868MHz and even a Zigbee source is spitting out harmonics these should not hit the BDR91. It is very possible however that you have other appliances running on the 868MHZ band in your home and if the message format exchanged by that other system does not contain a readable header it will become hard to distinguish between corrupted/invalid and `not for me`. Things you might consider:
- ventilation system
- weather station
- video doorbell

[G4RHL]

That would be highly unlikely as the Evohome components communicate over 868MHz and even a Zigbee source is spitting out harmonics these should not hit the BDR91. It is very possible however that you have other appliances running on the 868MHZ band in your home and if the message format exchanged by that other system does not contain a readable header it will become hard to distinguish between corrupted/invalid and `not for me`. Things you might consider:
- ventilation system
- weather station
- video doorbell

Add to this wireless alarm systems. I believe Evohome Security also runs on 868Mhz. I have had Evohome security running for a couple of years and no issues with Evohome Heating. The security system was easy to install and works very well.

[mdf4068]

That would be highly unlikely as the Evohome components communicate over 868MHz and even a Zigbee source is spitting out harmonics these should not hit the BDR91. It is very possible however that you have other appliances running on the 868MHZ band in your home and if the message format exchanged by that other system does not contain a readable header it will become hard to distinguish between corrupted/invalid and `not for me`. Things you might consider:
- ventilation system
- weather station
- video doorbell

Yep Totally agree, with your comments and I said something similar to Resideo support, and yes I have a lot of IOT in the house but one of the reasons I went evohome was that I had nothing using 868 mhz, but lots of Zigbee, WIFI, Sonos etc. also its only the BDR91 that has a problem, I put the antenna for a HCE80r in exactly the same location and it worked fine not a flicker , put the BDR91 back and issue returned almost immediately , I suspect its not very well designed to reject the harmonics, still Resideo know exactly the issue I had, hence my post for awareness.

My biggest concern is 5G low-band interference in the future.

[Mjward]

Just for comfort/sanity...I have two Evohome controllers and one of them only has repetitive comm faults.

Mostly for a single HR92 but today for first time got a BDR91 boiler relay comm fault.