[pug_patrol]

The TH6320 is a 3 stage heat pump thermostat. However, it is designed to control 2 stages of heat pump and 1 stage of aux heat. The YTH9421 is a much better thermostat, and will stage in both the compressor and aux heat. As its a 4 stage thermostat.

I'm looking for further guidance on the Honeywell TH6320 thermostat described in these old posts.

I have this thermostat (TH6320WF1005) along with Trane XL16i heat pump (2 stage) and XV95 propane furnace (2 stage), all installed new last June. Although I have received confirmation that this t-stat is "compatible" with my heat pump/furnace setup (by the installer, Honeywell helpline, & separate HVAC company), I am wondering if, even though it "works", it is inappropriate for my HP/furnace system and I should upgrade to a better t-stat.

Problems started in Dec. during first sub-20 degree period. House dropped well below 70 F, HP was running nearly all the time. Called installer, they came, said [oops] programmed t-stat incorrectly, fixed it, house warmed up. I figured out they had the system type at #9, 2H/2C (see install manual), and changed it to system #5 (HP w/ aux heat). So old setup never switched to EM/aux heat (therefore furnace never helped heat house) and new setup resolved when too cold for HP to keep up...

...but per this post, I gather that when using EM/aux heat, this t-stat does not facilitate a 2-stage furnace as the aux source (like my setup). Reading furnace manual it seems the factory setting in this situation (furnace W1 and W2 are jumped) is for stage 1 furnace heat to run for up to 10 min, then stage 2 will kick it. So both stages of furnace will work, and it won't jump to stage 2 right away when aux heat is called for, but nonetheless it seems this type of operation is not optimal/what the high efficiency furnace was intended for.

Also, I am not confident the installer's "fix" by changing t-stat to system type #5 (HP w/ aux) was the right move. Yes, it allows furnace to kick-on and house stays at 70 F, but my interpretation from the install manual is that system #5 is for a 2H/1C HP system (plus aux) but I have a 2-stage cooling, so I am not sure how this might affect operation when switch back to "cooling" this summer. Will it only try to use 1st stage of HP for cooling? Shouldn't the installer have instead switched to system type #10 (3H/2C, facilitates aux heat)? [losing faith in installer if my understanding is correct]

Other concerns:
-Honeywell literature suggests this t-stat (FocusPRO 6000 series) is not compatible with dual fuel systems, and does not have outdoor temp measurement feature, and therefore I cannot set a compressor lockout temp. (forwardthinking.honeywell.com/related_links/thermostats/countermat/programmable_countermat)

I apologize for lengthiness of this post and appreciate any advice.

Install guide = customer.honeywell.com/resources/techlit/TechLitDocuments/69-0000s/69-2738EFS

 

[Bob Sanders]

Other concerns:
-Honeywell literature suggests this t-stat (FocusPRO 6000 series) is not compatible with dual fuel systems, and does not have outdoor temp measurement feature, and therefore I cannot set a compressor lockout temp. (forwardthinking.honeywell.com/related_links/thermostats/countermat/programmable_countermat)

You should be set on #9... 2H 2C with back up heat. The problem is that the focus pro on its own is not compatible. You need the EIM to accompany it.
Set up function number 4 list options for back up heat but it also lists "(EIM only)"

Your furnace guy is jumping some hoops because you're not properly set up.

And yes... you will have problem in the Summer with cool staging

 

[beenthere]

Should be set to 10, 3 stages heat.

But its not the proper thermostat for 4 stages of heat like you have. You could use a Bill Porter control. Thats an economical dual fuel control that can be added to your system.

You should call the installing company and remind them tht the stat is not a proper dual fuel thermostat, and thy should have either used a dual fuel stat, or an add on dual fuel control.

Is it possible they reused a dual fuel control that was connected to your old system.

 

[pug_patrol]

Will get in touch with the installing company. Good to get confirmation here that unless add-on controls are in place, this t-stat is a proper dual fuel control - everywhere else I sought advice suggested it was just fine.

My old system was conventional, air conditioner plus propane furnace, so I cannot envision that they reused a dual fuel control that may have been in place since there was no reason to have one.

 

[beenthere]

Will get in touch with the installing company. Good to get confirmation here that unless add-on controls are in place, this t-stat is a proper dual fuel control - everywhere else I sought advice suggested it was just fine.

My old system was conventional, air conditioner plus propane furnace, so I cannot envision that they reused a dual fuel control that may have been in place since there was no reason to have one.

Yep, you didn't have one then.