The behaviour that I'm observing is that the boiler fires in irregular, short intervals when I set the flow setpoint to 5C, while both outside temperature and flow temperature are > 20C. Instead of turning it off altogether, I figured it would be fine to set it to a low setpoint, but apparently it doesn't like that. This is what it looks like:
- low-temp-short-cycling.png (212.54 KiB) Viewed 5742 times
There was no DHW activity during this time and the master-OTC bit was disabled (ID1:HB3=0). I've seen the same with OTC enabled just a few hours later though:
- low-temp-short-cycling-otc.png (158.57 KiB) Viewed 5742 times
I have absolutely no idea why it would do that. "Master low-off" in the OpenTherm specification sounds related and I see ID3:HB4=0. Does that mean I'm not supposed to "go low" instead of turning CH off? The boiler also reports MaxTSet-LB = 30C (ID49:HB). Is this an attempt to tell me that it wants me to keep TSet > 30 (instead of MAX TSet)?
(Boiler is an Ideal Vogue Max Combi 32kW.)