set-temp has no effect on AC RAC_056905_AT

[msedv]

I have three AC RAC_056905_AT and am running your great code for years (!). Everything is operation normal: turn on/off, ac-config, mon.

But: if I want to use set-temp the AC does a "dong" and I don't get any errors but the desired temperature doesn't change on the display or in the mon results. I tried fiddling around with set_celsius vs. set_fahrenheit, always the same.

Any hint how to further debug this issue?