I need help finding a thermostat.

Harvey Ramer

I am installing an air-to-water heat pump hooked to a central air duct system. The heat pump, which is a fantastic piece of technology, still does require some backup. I am putting in a 15KW backup which I will split into 3 stages. In the airhandler, W1 TERMINAL will turn on 4.8 KW. W2 TERMINAL will turn on 9.6 KW. W1 and W2 together will turn on 14.4 KW.

I want to monitor outdoor temps and be able to set thresholds for the compressor and all the stages individually.

I looked at the TH8320U1008 VISIONPRO 8000 3H/2C but the aux. lockouts aren't what I prefer with this particular HP. Also I would have to use the 2nd stage comp. terminal to power the first stage of the backup. Don't like that either.

I don't think the EcoBee will do it. I'm not sure about the Prestige IAQ YTHX9421R5069 .  The manual is not descriptive enough to tell.

I'm hoping to get the system in operation by tues.

Any help will be greatly appreciated.

Harvey

don_9

Outdoor stat

Hi Harvey.I assuming you are going for three different balance points here.The only thing i could come up with is converting back to the old ways with the remote bulb outdoor stat.Then your only worry would be the sunshine.lol

Big Ed_4

Set point themostat

Call Honeywell , most likely they have a multi stage set point thermostat .I am sure they do ..

Harvey Ramer

They do have multi stage thermostats but

in my particular situation I need to turn off 1st stage aux. when I energize 2nd stage aux. Then for the 3rd stage I am merely turning the first stage back on.

Here's what I'm thinking of doing now. I'll use the Honeywell 8000 stat. I'll use the o/b for the comp. I'll take the aux. and run it through a duct stat. the duct stat will control a set of n/c and n/o contacts. When there is a call for aux. it will run through the n/c contacts and energize the first stage. If the air temp drops to low the contacts will switch and energize the second stage. I'll use emergency then for the 3rd stage.

Not neccassarily the way i'd prefer to do it but it should work.