The Efficient Home Forum

We have the Evohome connected kit with the hot water kit to an unvented cylinder. This has worked well for the last 6 months. Over the last week we've noticed the hot water from the taps is far hotter than normal.The Evohome HW parameter is set to 60 degrees but the system is now reporting the hot water is at 70 degrees. I've checked that the probe is sited into the thermostat pocket on the cylinder but am unsure what else could be causing the sudden increase in hot water temperature. Any ideas? Regards.

Batteries in the CS92A? Positioning of the CS92A?

Wide angle photos may help?

Hi, I am having exactly the same problem. System works fine for the first 8 months, then we notice that the water is too hot. I have done some further investigations with the aid of a separate temperature probe placed next to the CS92a sensor. What I found was that rather than updating the Evohome controller with the hot water temperature every few minutes, the CS92a decides to take a lunch break and fails to update for 20 minutes and more. This means that the Evohome controller thinks that the water is not up to temperature yet and keeps the HW BDR91 relay on, to heat the water. When the CS92a eventually returns from lunch and sends a temperature update, the BDR91 turns the boiler off because not only has the hot water reached the desired temperature but has far overshot the target.
It is not the batteries since I put fresh ones in. However, you may find that if you take the batteries out and put them back in again the system may work again for a while.
In my view there is something clearly wrong with the CS92a, but it has not failed completely because it can be persuaded to work again.

Photos paint a thousand words! Images please...

From my near 2 year trials with a HW measured value fault at sporadic intervals of up to once every 25 day’s but as low as every day at any time of the day or night......just try taking the controller off the broadband. Silly suggestion I know but just give it a try!

Yesterday I got home to find the HW temperature Indicated on the controller as 61C. The setting temperature is 52C, and fortunately the boiler temperature is kept quite low at 65C. When I arrived the HW BD39 was not calling for heat, and the Honeywell control valve was physically off (moved it to Check spring return).
All settings have been set quite tight to keep setpoint temperature accurate without much hysteresis.
This morning system works fine, with HW being 52C.
Can’t attach pic as it’s too big...could reduce it via email but not on here unfortunately.
Internal offset 0C
hW overrun is 1min
hw differential is 1C

Does anyone have a real solution to this problem?

I have a setup as per original person's (billybob) post and an encountering same problem - HW is parameter set at 50c but reports at 70c which is boiler setting!

My system has been running perfectly for the last 18months so doubt it is the configuration. RF test shows the CS92 is working ok?!

I suspect it is a faulty insertion sensor but I don't know how to check it. I was going to swap it out but EvoHome site is currently out of stock and I cannot see where else to obtain a replacement. The suspected sensor fault may be a red herring though.

NB Please respond to me as a plumber/Evo 'know nothing'. I am a bit of an engineer and IT person that's all and definitely not a plumber. Thanks

Wide angle photos of the installation of the BDR91's/CS92A is the only way we can advise here guys...

Have a look here (https://theevohomeshop.co.uk/content/11-evo-help) as this may help too!

Update!

Have replaced afore mentioned Insertion Sensor but problem remains.

Here are requested wide angle photos:
https://photos.app.goo.gl/gv1UjgXUEb9s3o7A3 Please note that system has been up and running smoothly for 18 months up until now!

In addition-
I have included a shot of my Controller display showing the Hot Water setting (lower left hand end ) - I note the graphic is a blue coloured (hot water) cylinder and not the customary simple 'red' or 'blue' dot? What does that mean - is that an indicator of my problem?
NB I have searched and searched for a Controller Display symbols listing and their meaning but no luck. Is it possible to publish the listing somewhere, as surely someone has put some effort into creating the symbols and they must mean something - why the secret?

David,

Your BDR91's are way too close to each other and 100% will not be working correctly like this... The CS92A wireless temp sensor sends information to the evohome Controller, but if the evohome Controller cannot turn the BDR91 wireless relay off because the relay cannot get the RF comms correctly, then it will just remain on and over heat the tank...

Have a look at the information we have here - https://theevohomeshop.co.uk/content/11-evo-help

Thanks,

Richard