Opentherm Rrom Temp Issue.

[Archie32]

Hi all,

I've had Opentherm running relatively smoothly for several years and then late Spring this year, I noticed one room started to regularly drop from the setpoint temperature, whereas it had always been very good at maintaining a steady room temperature prior to this.

Unfortunately it was becoming too warm to investigate during late Spring but having started to use the heating again, the regular drops in temperature and then inactivity from the system now need investigating as it's quite noticeable. .

As I write this, Evohome has been showing the room at 0.5°c below the setpoint for around 25 minutes (0.7°c according to very accurate thermometer located near Evotouch), system summary is showing the room at 16% demand, the radiators are stone cold, the boiler is off and water in the flow pipe is 21c.

The room has two very large HR92 equipped radiators, with Honeywell Valencia lockshields, all less than two years old. The HR92s are set to normal stroke which I believe is correct with these lockshields, and the Evotouch is used as the temperature sensor. I wish Honeywell would add the system summary to the app as it would make life so much easier.

Anyone have any ideas please?

[kevinsmart]

The change you observed in Spring could have been after you were updated to the latest firmware.

The boiler demand calculation appears to have changed. Mostly I see larger % demand than before, including 100% when there is 0% zone demand! But sometimes I see lower boiler demand and this can last over an hour as it appears the boiler demand is updated less frequently as well.

Best to contact Resideo support as they seem to think there is nothing wrong with the new firmware’s behaviour.