t-stat settings in "Advanced Device Configuration" will not stick

[BigAl]

I have to say, these t-stats are quite frustrating due to the lack of documentation. My dealer knows less about these things than I do, so we are on our own to try to figure this out.

I want to change the "Heating Cutoff Point" and "Heat Stage 1 Delta" settings.

Heating Cutoff Point: On 1 of my 4 stats, when I change the Heating Cutoff Point to 0, in a second or so it goes right back to the default 1. DENIED. LOL Yes, I am clicking the "Set Heat Cutoff" button. On the other 3, I've been able to change the value and it seems to be sticking.

Heat Stage 1 Delta: I change it from default 1.1 to 0.5, but there is not "save changes" button or anything. When I open the Advanced Device Configuration window again, on 3 of the 4 stats, it's gone back to the default 1.1. The change sticks on one t-stat. Interestingly enough, on THAT one, the values for Auxiliary Stage Delay and Cutoff Delay are default "Disabled". On the other 3, the default is 180 and 0. I've never touched those settings and don't know what they are.

I have a radiant floor heating system, no A/C. None of the information in the Installation Guide addresses a heating system like this, not to mention, gives ANY information about the settings in Advanced Device Configuration.

Any idea why my setting changes won't "stick"?

thanks