Until recently (10-4-2026) the boiler was a Bosch 35 HRC.
On april 3rd I noticed a jump of roughy 1,5 degrees upwards of the temperature in the temperature readout in Domoticz. Next day, all of sudden it jumped back, roughly the same 1,5 degrees. See attached screenshots. All this time the temperature on the display of the thermostat is in agreement with the observed temperature in Domoticz. Also is it the temperature that is actually used to control the boiler to start heating, so it's not just "a display value" thing. I think I have seen this behaviour previously as well, but never bothered about it.
On the 10th of april the boiler was replaced with a Intergas Xtreme 30. The same thermostat is used, but at first I didn't connect the OTGW, because I wanted to make sure the installation was done and tested correctly. I had the impression that directly this same phenomenon was present, but I didn't have the Domoticz readout. After two days I connected the OTGW and I directly observed this phenomenon again, now also in Domoticz. I didn't see the jump upwards, but compared with other temperature sensors I have, I figured this must be the case. This was confirmed the next day when it made the 1,5 jump down.
So of course my questions:
Is this a phenomenon that anyone observed as well?
Who is the cullprit?
Boiler? No, because observed on two quite different boilers.
OTGW / Domoticz? No, also observed without OTGW hooked up
The thermostat then?
Any thoughts on how this can happen? Does it happen to do some sort of calibration that goes wrong, and it is being repeated at regular intervals (e.g. once a day?)
Is it just "broken down"?
Any suggestion are welcome.
- First jump upwards
- jump1.jpg (73.25 KiB) Viewed 145022 times
- Second jump downwards
- jump2.jpg (71.17 KiB) Viewed 145022 times