Do honeywell thermostats stay lit green?

[deanbrown3d]

Hi all,

Do honeywell thermostats stay lit green? Or does the backlight only come on when you touch the pad? I'm talking about the RTH8500, but I suspect they all work the same way now.

Thanks

Dean

[Travis Jordan]

On the Vision Pro professional series (i.e. TH8110, etc.) backlight selection (continuous or key-press only) is installer option 0280. My supposition is that this option is not available on the retail version.

[deanbrown3d]

Ok thanks. Whats the big difference between the pro and the retail thermostats?

[Travis Jordan]

At the risk of not being taken seriously..... the answer is:

Features.

Such as auto changeover, the backlighting which you've already discovered, the need for batteries (optional on the trade versions), the lack of multistage capability for 3-heat, 2-cool systems, an optional humidity controller, and more that I can't recall at the moment.

[deanbrown3d]

Well, I bought the RTH8500, hoping that I could get it to use my heat pump if at all possible, instead of the electric toaster. I know its got some kind of learning algorithm, but I have no idea what it does or how it works.

Basically I want to turn off the heat pump at say 10pm, then have it come on at around 4am so its nice and warm by 7am, without using the toasters. I'm not sure it will do this if it turns on in the morning and its 60 degrees instead of my desired 74. I assume it will just turn on the electric resistance coils (toasters).

Any insight welcomed!

Dean

[Travis Jordan]

See page 53 of your owner's manual. If you REALLY want the details, here they are:

See p.20

Over time (8 days or so) the RTH8500 will learn when to turn on the HP in order to raise the setpoint temperature to 74 degrees at the time you want it. Assuming your HP is above the balance point, it will raise the setpoint a degree at a time so as to avoid heating the toaster elements.

[Travis Jordan]

The AIR algorithm does take into account both air and wall temperatures, but I don't know whether it uses them in the fashion that you describe.

[deanbrown3d]

Ok thanks all! That's great news. So the algorithm is primarily to improve efficiency, rather than comfort level, by maximizing HP use, if I'm not mistaken?

[Travis Jordan]

The algorithm is to insure that the room temperature is at the setpoint at the time you want it to be. The thermostat is just smart about how it does this.