Replacement thermostat for basement Heat Pump

[jspande]

I have long wanted a programable thermostat (or at least a better quality one) for my Coleman basement heat pump (2002 Alph 5th wheel). The several threads here about Hunter thermostats did not appear to apply to this 2-stage unit.

Recently I came across an article (www://klenger.net/artic-fox/TH5220D_T-Stat/index,html) about a Honeywell thermostat, which looks like it should work - actually I'm looking at the TH6220D which is the programable version. Has anyone attempted connecting this unit to the Coleman "Two-Ton Plus" basement Heat Pump?

The main issue I worried about is the two "Freeze" connections from the Heat Pump which are not supported by the TH6220. As I understand it, these are relay contacts in the Heat Pump which open if the coils freeze up, and the thermostat uses this to prevent the Y1 and Y2 (compressor) relays from energizing. My idea is to connect one of the "F" wires to +12 and the other to the coil of a double-pole relay, with the poles connected inline with the Y1 and Y2 wires. This would block activation of the compressors when "freeze" is active, i.e., open.

Any A/C/Heat Pump experts out there care to comment?

[jspande]

I have long wanted a programable thermostat (or at least a better quality one) for my Coleman basement heat pump (2002 Alph 5th wheel). The several threads here about Hunter thermostats did not appear to apply to this 2-stage unit.

Recently I came across an article (www://klenger.net/artic-fox/TH5220D_T-Stat/index,html) about a Honeywell thermostat, which looks like it should work - actually I'm looking at the TH6220D which is the programable version. Has anyone attempted connecting this unit to the Coleman "Two-Ton Plus" basement Heat Pump?

The main issue I worried about is the two "Freeze" connections from the Heat Pump which are not supported by the TH6220. As I understand it, these are relay contacts in the Heat Pump which open if the coils freeze up, and the thermostat uses this to prevent the Y1 and Y2 (compressor) relays from energizing. My idea is to connect one of the "F" wires to +12 and the other to the coil of a double-pole relay, with the poles connected inline with the Y1 and Y2 wires. This would block activation of the compressors when "freeze" is active, i.e., open.

Any A/C/Heat Pump experts out there care to comment?

[jspande]

Since there have been a number of reads and no replies, I'm guessing that there is some interest and no experience out there. So here's a follow-up.

I went ahead an purchased the Honeywell TH6220D which is the programable unit for "up to 2 heat/2 cool systems". I thought that was the right model since the heat pump, while 2 stage in cool mode, operates as 1 stage in heat since it always turns on both compressors in heat mode. That was a mistake however, since that model then provides no means of turning it on for gas furnace only. Apparently I should have gotten the model TH6320U, which is the "3 heate/2 cool" model.

Anyway, I went ahead and installed it for just AC and gas furnace, since I'm having problems with the heat pump operation anyway (I suspect a sticking reversing valve which requires going in to the dealer 100 miles away for repair so I'm reluctant to risk any more testing - it currently works fine in AC). Also only using the AC eliminates any issue with coil freeze-up.

The good new I can report is that it works great. It's amazing how much better it is than the "RVComfort" unit. It regulates temperature much better, and the controls are easy to operate (that 4-position slide switch on the RVComfort is the pits), plus being programable. It's sooo nice to be able to set back the temp to 65 at night and still get out of bed next morning in 72 degree comfort.

[dvleemin]

Originally Posted by jspande

Since there have been a number of reads and no replies, I'm guessing that there is some interest and no experience out there. So here's a follow-up.

I went ahead an purchased the Honeywell TH6220D which is the programable unit for "up to 2 heat/2 cool systems". I thought that was the right model since the heat pump, while 2 stage in cool mode, operates as 1 stage in heat since it always turns on both compressors in heat mode. That was a mistake however, since that model then provides no means of turning it on for gas furnace only. Apparently I should have gotten the model TH6320U, which is the "3 heate/2 cool" model.

Anyway, I went ahead and installed it for just AC and gas furnace, since I'm having problems with the heat pump operation anyway (I suspect a sticking reversing valve which requires going in to the dealer 100 miles away for repair so I'm reluctant to risk any more testing - it currently works fine in AC). Also only using the AC eliminates any issue with coil freeze-up.

The good new I can report is that it works great. It's amazing how much better it is than the "RVComfort" unit. It regulates temperature much better, and the controls are easy to operate (that 4-position slide switch on the RVComfort is the pits), plus being programable. It's sooo nice to be able to set back the temp to 65 at night and still get out of bed next morning in 72 degree comfort.

I'm assuming that when you did this you wide it so the fan speed is always high, and no longer have a fan high/low setting?

[jspande]

Originally Posted by dvleemin

I'm assuming that when you did this you wide it so the fan speed is always high, and no longer have a fan high/low setting?

Yes