I just moved into a house that has a hybrid system, heat pumps outside (Maytag DT3BA) and LP furnaces in the crawl (M10000 series C3BH-03BC-A only 80% efficient) with honeywell TH6220D thermostat. The heat pumps aren't coming on for heat, it's using gas only. When I change the settings to;
1 - 5
2 - 1
3 - 0
6 - 5
8 - 5
9 - 3

The heat pump works but the gas furnace also comes on and doesn't go off or if it goes off it keeps coming back on when the thermostat setting is below the actual temp.

I checked the wiring out on the thermostat and it looks to me like it's only wired for the conventional (1 - 0 )that the thermostat settings were originally configured for.
Current wires:
R with jumper to Rc
Y
C
W
G

I also see a orange, brown and black wire that aren't connected to anything. Shouldn't this be wired to the lower pins that say heat pump? And how should they be wired? The install guide says
Rc
Y
C
0/B
G
Aux
E
L

I think the Rc, Y, C, & G should be the same as up top, I should just move those down to where it says heat pump? How about 0/B, Aux, E and L? Which wires are those and do they need to be wired up?

Update: Do I need a separate duel fuel kit? Right now all the wiring is coming directly from the furnace/air handler to heat pump and thermostat.

 

I'd suggest 2 to 0 and 6 & 8 set to 3. (Even thou you don't have 90%, you will get better comfort.

This how it should be wired up.

T-stat-----Fur-------HP
E/Aux*----W--------W
G-----------G
O/B--------O---------O
C-----------C---------C
Y-----------Y----------Y
R/Rc-------R----------R

*= add jumper wires



No, you don't need to. But, if you use the program set back, the t-stat in recovery mode may use the gas furnace to help with the recovery, where a higher end like VisionPro or IAQ can lock out the gas heat, and/or lock out the HP if it gets too cold out where the HP is past it's savings.

I don't know off hand if this stat will run the gas Aux along with the HP at the same time?

 

I'll give that a try and report back. I did originally set 2 to 0 but the HP blew cold air, at least wired as it is now.

 

Jay,
I took a look and my furnace doesn't have an O, so I'm not sure what to connect O to. It has R, C, Y, G and W only. Also, since it's 80% it also has a squirrel cage exhaust fan connected. Here's how it's currently connected up;
TStat - Fur - HP - Fan
R ------ R ----R
C ------C-----C---- R
Y-------Y-----Y
G-------G
--------W----------W
The W from the tstat goes directly to the G on the fan and the HP has R,C, Y only.

 

Then just wirenut O from stat to O outside.

Huh!?

That's messed up....... What is this "fan" for?

Have a photo or make/model on this fan?

 

the fan is a on the exhaust vent, it requires a metal, forced vented exhaust since it's an 80% furnace. If the fan doesn't come on the furnace won't come on. I found this out the hard way, when I first moved in the fan had a dirt daubers nest and wouldn't turn. Once I cleaned that out and got the fan working the furnace worked. I can get you a picture if it will help but it's just a metal caged fan on the outside of the house to vent the exhaust from the furnace.

This is a relatively new install too, the house was built about 4 years ago but they used bottom of the line HVAC with 80% LP furnaces. I wish I could afford to replace it, I look at it and go huh too. It's crazy that they'd do all that extra install for the 80% furnace, by the time they did all that it couldn't have been much cheaper. I hope to get the heat pumps working, here in NC they should be sufficient for all but the coldest nights and LP is running 2.49 a gallon.

 

The furnace has it's own exhaust fan built in it... The exhaust then goes up and out the flue vent.


Some reason the photo is sideways...


Still huh!?

Post a photo of this if you can... I am off to bed.

Talk to you trmw.

 

My furnace is a horizontal mount. I think that's the difference in why I need another exhaust fan.

 

The house must of not had a chimney? I've never seen this around here before.

What is the brand/ model # on this fan system?

 

Yeah, no chimney. It's a Field Controls Company sidewall power venter, model # SWGII-4HD. I'm still not sure how the wires should go with the fan in the mix. I think the fan needs to be wired up to come on before the furnace comes on (like it is now) but not when the HP is running. I'm not sure how to do that. Any suggestions?

 

T-stat-----Fur-------HP
G-----------G
O/B--------O---------O
C-----------C---------C
Y-----------Y----------Y
R/Rc-------R----------R


Now the Exhaust Fan hook up.

T-stat's Aux/E (jumper together) from t-stat and W from HP goes to T1 on the exhaust fan.

T2 goes to C on furnace.

T3 goes to W on furnace.

 

Thanks! I'll give that a try tomorrow if it's not raining and get back to you.

 

Glad to help.. Give me an update when you get this taken cared of.

 

I moved your post to a new thread to advoid any confusion with the OP's post.

 

Jay,
That didn't work. I hooked it up like that except I don't have an O on my furnace so wired the O from HP directly to O from Tstat. At first my HP wouldn't come on, with setting 2 set to 1 and when I switched it to 0 it came on and wouldn't go off when the thermostat was off... I think it was also blowing cold air, hard to tell because the furnace was coming on intermittently.

Update: Double checked my wiring and noticed I don't have W on the HP connected to anything. I think I was supposed to connect that one to the Aux/E (tstat) and G (Fan). I'll connect W up tomorrow on the HP and wire it into the fan(G) & tstat(aux/e), right now it's just fan(G) to tstat(aux/e).... Also, on the fan you refer to a T1, T2, T3... I'm thinking T1 (G), T2 (R) and T3 (W) since I have 3 wires that are G,R & W....

 

HEre is the install manual for your exhaust fan. The wire up shows up on page 3.

G does NOT go to the T1 Aux/E from stat, and so does defrost W from HP. That one is telling the relay to close to turn on the fan motor.

T2 is common, that goes to C at the furnace.

T3 sends power to the W on the furnace to fire off.



If you don't have W tied to the HP's W (some may say W2 or Aux, or Def) and when the unit outside goes into defrost, it will send power back to the furnace to to turn on the gas heat while the unit outside in defrost mode. So maybe that's why at time you had cold air blowing.

 

I was referring to T1 as G because they used a green wire. If I understand you correctly I still need to have T1 (fan), wired to Aux/E (tstat) and W (HP)... which is what I need to do today. I'm pretty sure the outside unit should not have been in defrost mode, I'd just turning it on and it was around 60 degrees outside, when the furnace was cycling off and on. I'll connect the W (HP) up shortly, tie it into T1 (fan) & Aux/E (tstat) and report back.

 

Correct.

When you said the furnace cycled on and off, was it the gas part of or just the blower?

 

Both.

Was hooking up the W on the HP and noticed I had the Y & O reversed (I color matched them to the plugs after a quick look and the installer had the yellow plug on the O and the orange plug on the Y). Now the behavior I was seeing makes sense. Yesterday I kept thinking it didn't make sense that the furnace was cycling on/off and the HP not working if it was just the W not connected to the vent fan.

So right now I still haven't connected the W to the vent fan but everything else is connected and seems to be working... My only concern is that the aux heat seems to be kicking in more frequently than it should? I'm not sure what triggers the aux heat but right now my thermostat is set on 67 and the inside temp is 64 and the aux heat kicks on. This triggers the power vent fan and gas furnace (as it should) but I'm thinking the aux heat should not be coming on that easily?

Right now T1 from the vent fan is still connected to the Aux/E(tstat) only. I'm thinking connecting the W (HP) to this isn't going to change anything, am I wrong?

 

You have a "large temp" gap, so the t-stat is kicking the Aux heat to help recover, this is normal. Once temp gets near set point, then the HP will run on it's own.

That's why we say' Set it and forget" on heat pump system.

I'd hook up the W from the HP so you got some heat when the system goes into defrost, otherwise, you will be getting cold air.

 

That makes sense about the W from the HP. I couldn't figure out why I'd need that. I think I have it squared away now thanks to all your help. Thanks again!

 

Glad to help out! If you need anything, please let me know.