I just bought a Honeywell TH8320U1008 thermostat, and would like to install it myself if possible, but I have too many questions - so hoped you folks might be able to walk me through it.

I have a Carrier heat pump w/ auxiliary heat (electric) that also works as my air conditioner - I'm told that means I have a 2h/1c set up in my condo - the heat pump model number is FC4CNF036. I'm attaching a photo of the info plate from the heat pump, if that helps.



My current thermostat is a Lux TX9000TS - unfortunately I just found I've been using the wrong thermostat for the past 18 months. This Lux thermostat is, according to the HVAC guy who came to check my system for a different problem, turning on my emergency/auxiliary heat every time it turns on my heat pump, so both systems are always running simultaneously (at least during the winter, from what I understood), and my bills have been sky high. That also means I'm afraid to use my current thermostat's wiring as the template for wiring my new thermostat (though the new one has additional letters I don't see on my current thermostat, thus an additional reason I wanted to ask for your help. (I had a simple Carrier thermostat before that, but it was pretty basic, no programming, so I upgraded and got the wrong one.)

Here is a photo of my current thermostat setup with the Lux:



Here is a picture of the new Honeywell thermostat:



And here is a photo of the page from the installation manual that I think applies to my set up (some of the letters I don't have on my previous thermostat, but also, some of the caveats in the footnotes were a bit over my head, so I didn't want to try anything without checking with folks here):



I'm admittedly a novice at this, but have watched my HVAC guy and others change thermostats, so I understand the general concept of connecting the specific wires etc. But I don't understand the instructions in the Honeywell manual, particularly since I don't have many of the letters they refer to. And I don't want to do anything to mess up my heat pump.

I'm assuming I need advice as to the specific wires I need to connect to the new thermostat, and I would appreciate any specific advice about the setup of the thermostat installer menu (I've read the installation manual and have seen there, and in this forum, the various options you need to select in order to tell the thermostat exactly what kind of system I have, want etc) - I'd appreciate advice as to what settings to use for my specific system.

And I don't have the external sensor or anything like that - just the thermostat for a simple condo with a heat pump and auxiliary heat.

I hope this isn't asking too much, and thank you. Seriously. John.

 

No problem John, glad to help out.

I can see why your power bill was High! You even had your heat strips on when the A/C was on!

FYI, on a HP system you are best to "Set it and forget it." than using a program stat. When it comes out of temp set back/recovery, it may turn on the heat strip to help the HP recover.

This what you hook up to.

Old----------------New
W-----white-------Aux/E (Add a jumper between the two)
Y------yellow------Y1
O------orange-----O/B
R--------red--------R/Rc (jumper between the two)
C-------blue---------C


Installer set up menu.

170-7
180-1
190-0
200-0
210-0
220-2
250 to 270-3 (Some may not show up, and I know the manual says 9 for electric, but 3 is best)
280-1 (makes a great night light)
300- Up to you.
340-0
350-0
360-0

Let me know on the rest if you have questions on the settings.

 

You have got to be kidding me - it was going on with my ac too? LOL dear God. Thank you. Let me try this in the morning when I have my full wits about me, and I'll get back if something isn't making sense. Thank you so much.

 

Nope, I am afraid I am not kidding you.

The Y is your A/C, and with the jumper over to W, the W is your strip heat..

So, let us know if you need anything else.

 

Gotcha. I'll make an attempt in the morning and report back either way. Thanks again.

 

I wast just looking over the Installer options and saw the backlight option mentioned something about wired 24 Vac Common. Does that mean my main electrical system needs to be powering the thermostat? And is mine? I have no idea.

I'll hit you with my heat pump efficient, set back questions tomorrow ;-)

 

Your R and C is your power, so you are set to turn it on.

 

Dumb question ,but where do the wires go? I ask this because you'll note in the photo below that is show "heat pump" as being the outside ends of the lettered display. Does that mean you insert the wires in the outside edge, or just refer to the outside letters? Meaning in the pic below, does the C wire go into the hole in spot 1 or spot 2?



Note that there are holes on both sides where the arrows point:

 

You put the wire in the inside part, and just refer to the letters on the outside.

 

Thanks, what what I assumed, but really didn't want to risk messing up.

 

No problem. Better to ask than make a mess out of it.

 

And the green wire I just leave dangling, don't use it?

 

My bad, I missed that one.. Green to G

 

Okay it's done. Seems to be in working order.

Any sense of how I can verify that the auxiliary heat is no longer always being used? I have a thermal leak detector from Black & Decker, any idea what the temp of the air coming out of my ducts should be with and without aux heat?

Also, I set 250 to 270 on 3 as you asked. What exactly does that do?

And finally, you mentioned that this being a heat pump, I should set it and forget it. I've done a lot of reading about whether or not to set heat pumps back, and boy opinions vary. For me, I like to set it back a few degrees at night, at least, just so I can sleep well. I can set it back further, and have a baseboard heater in my room (that came with the condo, pre-installed). I'm trying to get a sense of....

1. Do I get zero savings by setting back the temp at night during the winter? Any difference if I set it back 2-4 degrees versus ten degrees?

And if I do set it back a few degrees anyway, just to help me sleep better, is there any difference (money wise) in turning the temp down manually when I go to bed and turning it up manually when I get up, versus programming it to do so? Meaning, if I turn it down X number of degrees at night and up X degrees at morning, will the system know to use the least amount of emergency heat possible, or will it only use the least possible if I program the system to set back, so the IAQ or whatever it's called can set in and learn my environment? Or doesn't the IAQ even do anything with regards to learning to use less emergency heat?

And, how many degrees do I have to turn the temp up or down to have the emergency heat kick in - or is it more a function of the system seeing that the heat pump is running too long and it "knows" that it need to turn on the emerg heat to help?

2. I'm assuming if I go away for a weekend, or longer, I should set it back. Yes?

I've researched the heat pump issue to death online, and seriously there are a ton of varying opinions on all of this, so appreciate any feedback you can give. Thanks again for everything. JOHN

PS I set the correct setting to turn the backlight on as a nightlight, as you said, and it's not doing it - it's still off unless I touch it. I double checked, the correct number was selected. Any thoughts? it is annoying have to always touch the thing to read it.

One more thing - boy it's taking a LONG time to raise the temp one degree. It's 37 degrees out, and I dont have the best insulation - perhaps the long temp increase is the proof I needed that the emerg heat is off.

 

Good to hear!

The AUX will show up on the t-stat when it's being used. HEAT will be just the HP.

It will give a longer run time. If you left it at 9, it will be on and off too often and if you were to use the EMG heat mode, it not going to warm up enough.

If you only lower the heat a couple of degrees it wont' be too bad.. If you do 10˚, then the HP is not going to recover, so the stat is going to pull the AUX on to help out. If you had the outdoor sensor, we could of locked out the AUX at X˚ and only use the HP to recover.. But with it was wired up before, you saving will be already seen! Give it a few days to learn your house.

Watch the stat if you can when it comes into recovery mode, and see if the Aux comes on alot or long time.

Do the program mode of the set back than manualy. If you change the temp manual, the stat for sure will kick in the Aux, where program, it will start early to try bring up the temp.

The stat will learn on how long it takes to recover, and will try it best to not use the AUX, but it may use it if it sees the HP can't do it.

Yes. You can set it back Just play with it and see what happens.

Make sure C is hooked up at the stat, and at the air handler.

Yep. As I said earlier, HP are not fast recovery. Just think the money you are now saving!

 

"Make sure C is hooked up at the stat, and at the air handler"

What am I looking for, and where, on my heat pump? I'm not familiar with where those wires arrive back in the closet by my heat pump

 

Turn off the power to the air handler, follow the stat wire into the air handler, then find the blue wire and see if it tied to the C on the board.

 

your heat pump is located outside. Your air handler is the part of your system that is inside, and where you need to look for the c connection at. locate the thermostat wires going into the air handler usually on the side of the unit towards the front by the doors. Remove the doors after turning the power off to the unit at the breaker panel or if your unit has breakers at the doors then turn them off there. Look for the thermostat wires there and make sure that the blue wires is connected to common. take a picture with the doors off if you need to, in order for us to help you if you cant figure it out.

 

Here are pics of my system. I'm assuming the wires are the ones going into the top, see photo below. As for turning off the power, I did it at the fuse box, the air has turned off. Do I need to flip the switch on the unit as well - I think it's the two switches behind this plastic protector, below, it says 60 on the two switches, and then on/off below them. And finally, I assume then that I'm opening this top panel, right below where the wires go in, yes?

 

Yes to all, including shutting the breakers off behind the plastic for safety reasons.

 

Okay, here is what I see - no idea what to do. I've uploaded high-res photos so you can click and get a detailed view. There appear to be two blue wires.

 

top rt hand corner of air handler is low voltage connections where the stat wires are coming in. what are the blue wires attached to? Too many wires bunched up for me to see.

 

Follow the brown wire from "C" on the board into the box with all the low voltage wire meeting up.

There should be a wire tied to this from the outside unit.

 

That's exactly what I figured, I literally just took another shot as you were posting, check this out and see if it helps:

 

Brown is tied to the blue, here are more pics. Though one blue stops here, another is tied to the brown - both look the same color, the color blue that is in my stat.

 

Is there another wire tied the C/Brown wire from the outside set of wires?

 

IF I were a betting man, the blues both need nutted to the brown. To be for sure you would need to go to HP outside and remove panel to see that C was connected to Blue. Does brown go to ground or can you trace it to C? I'm almost certain you need to put the blues and the brown all together. The wire bundle the loose blue wire comes from.... Does it have green connected to anything? If so, connect the blues and brown all together.

 

I pulled the wires apart a bit. One blue comes in from one cord, another blue comes in from the second cord - both cords come in the top of the airhandler from other places, I can't tell which is from the roof and which is from the stat. Here are the pics. Note how one blue goes and connects to the brown, the other blue just ends (the protective plastic thing just shot off and is gone, can I use black electrical tape around it temporarily? Or do I need to the run to the store behind the 8 inches of snow falls?

click on the thumbnails, then click the images again, they're huge

 

you cant find the rubber boot?! put both blues and and the brown all together.

 

The one blue enters from the outside and stops, it's sealed (was sealed) in that cap.

the other blue enters from a different group of wires and connects to the brown, only the brown, the brown then drops down and connects to something. Pics below to show where they connect.

The green connects to a thick grey wired, photo below, and you can look at the larger photos in previous posts to see where that goes (I think) - this is the grey connecting to the green:



this is the brown dropping down from above, where it connects with the blue, and then it connects to this, with two browns coming out of it - the destination of those two browns is in the last two pics

 

ok, looks good to go. Connect both blue wires and the brown together with a wire nut. Do you follow which ones to do this to? The ones in the upper rt hand corner of the air handler that come from the HP and the Stat. Does light stay on now?!

 

Just to confirm, you mean the two blue wires that I've been talking about, in the upper right hand corner - one enters from the outside and is simply closed off in the plastic cover, the second enters from the outside (outside the air handler I mean) and connects to the brown. You're saying to take the free standing blue and connect it to the combo blue-brown, yes?

 

sounds great!.......................................................

 

Yep, tie the lose blue into the other blue tied to the brown.

 

Hey, one last thing before I do this. I just noticed that one of the red wires came out of its holder. It's not entirely clear where it came from, but it seems, from the first pics I shot below, that it was never fully pushed into the blue cap containing the other two red wires. You can tell from those early pics that it was hanging out from the cap that contained the other two - now that I moved things around it's completely out. Do I just push it back in? I want to make sure I'm right about this, but check out these pics, you can just see where the metal is showing even before I moved the wires around (it's actually much farther out now, is just hanging free)

 

those caps screw onto the wires (wire nuts) they are not push on! you can use the wire nuts and electrical tape them for added protection to keep them from pulling apart

 

Success! Back light is on, and everything appears to be working. Thank you so much, guys. And yeah, I wasn't sure about the wire nuts, but was screwing them on, half-heartedly, anyway. Just screwed them on tighter.

I cannot thank you guys enough.

 

Glad you got it. Took a few posting and what not. I take it this is your first time going this "deep" with electrical?

 

Correct :-) I also recently learned to caulk, after finding a 7 x 7 inch hole hiding behind my baseboard heater, and lots of other non-weatherproofed parts of the condo. Finally got my own condo two years ago, and my extended family is back in Chicago, so everyone who knows about this stuff, who I'd normally have come over to help, is 700 miles away. So have been learning by trial here. I'm sort of amazed this worked ;-)

 

Well we are here to help you out. We other area on this website for DIY help!