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Prestige IAQ 2 - more questions

943 Views 6 Replies 4 Participants Last post by  supers05
Hello. On my prior stat, I had the differential temp set at 1.5* where this HW stat is---I guess---set at 1*. The system runs more frequently, now, and I am curious about a few things:

1. On an air source HP is my understanding correct that I cannot change the differential on this stat? Any tricks to do so? It would seem logical to me that I'm consuming more energy with a narrower differential, but maybe I am wrong.

2. How do CPH values impact how often the system runs and do any of them cause the stat to raise the indoor temp ABOVE the set point temp before cycling off?

3. I feel like Nemo here but do any of you use the Commercial setting in your residential environment? And then if you do that raises additional questions like what is Throttling and integral all about?

I'd be grateful for feedback from you experts from whom I've already collected a wealth of detail regarding this stat. Thanks!
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1) You can change the differential of each stage up to 3 or 4 degrees (can't remember the actual number). I think the finest diff though is .5c (about 1F)

2) To the best of my knowledge No.

3) Never played with the "commercial" side of the stat, but the manual strongly suggests that you do not play with those settings that you're talking about unless you know exactly what they do.
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Thanks for the feedback, Bob. I am still reading to find a a temp differential setting for stage 1. Maybe differential isn't the correct term, but I was wondering if I can set to 1.5* the difference between my setpoint and actual temp before there is a call for heat (on my 1-stage compressor). The manual makes me think such an option is available only on geothermal systems.
ISU 3060
Staging Control - Compressor Heat Differential Stage 1

1.0° F to 4.0° F from setpoint (in
0.5° F increments)

ISU 3010 Temperature Control Options must be set to Advanced to view or adjust this ISU.
This ISU is only displayed if ISU 2010 Heating Equipment Type is Geothermal Radiant Heat and ISU 2050 Geothermal Forced Air System is set to Used for Heating and Cooling.
The indoor temperature must drop to the selected differential setting before the thermostat will turn on the stage of heating. For example, if stage 1 is set to 2° F (1.0° C), the indoor temperature must be 2° F (1.0° C) away from the setpoint before stage 1 turns on. When set to Comfort, the thermostat will use the stage of heating as needed to keep the indoor temperature within 1° F (0.5° C) degree of the setpoint.

(I haven't checked mine but if you look at the first couple of lines in the description, it may not be available for air to air heat pump.)

Backup heat stage one differential is ISU 3080 and 3090

I just checked mine. Stage one differential is not available in air to air HP mode... only stage 2.
Don't ask me why!?!
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Yeah, I'm mystified that it isn't offered for an air source HP.
Set your CPH to 2, or 1 if you want longer run times.
Throttling and integral are related to the PI of PID settings. It directly opposes differential temperature staging. You use one or the other, not both.

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