Geothermal, heat pump Nest install help

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Old 12-02-17, 07:46 PM
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Geothermal, heat pump Nest install help

Hey everyone, thank you so much for taking the time to read this.

I am pulling new 18/8 wire to all of my thermostats and equipment. The previous installers didn't leave any slack to any thermostat and ran the wires over my attic access where its really hard to get to.

Anyways.

This is my set up

Heat Pump Single Stage
Auxiliary heat strips Model HGL20A, Serial G14781327 Kilowatts 14.4/19.2 with 2 circuit breakers just for the heat strips
5 ton system
Geothermal
Open loop, currently set at 7.5GPM

I am using a Honeywell HZ322 control board.

How its currently wired on the control board is W1/E is jumped to W2 (HZ322 says if Emergency heat and aux use the same source to jump W1 to W2)

Nest has the following options

Yellow 1- Yellow wire attached for single stage cooling
Yellow 2 wont use because I don't have 2 stages
Green- Used for fan
OB- reversing valve, use orange- This is for my heat pump
RC- could also be used as power
W1- Do i use the white wire from the control board and attach it to W1 on the nest
W2 AUX- Attach the brown wire to W2 on circuit board that is for Auxilary heat strips
C- Common wire, using black.
Star- custom, can use it but i dont need it?
RH- Use as Red for power

I know I have something incorrect above. I also read on nest
  • Take the cover off of the thermostat and look at the wires. If you see a wire in the O, B, or O/B connector and a wire in W1, you likely have a dual fuel system (however, sometimes the wire for auxiliary strip heat is also in the W1 connector, so this is not a sure test).
Or would W1 on the nest be my Auxiliary heat, and W2 on the nest be for my emergency heat?

Or would it be W2 on my nest be for Auxiliary heat, and use the Star on the nest and program that for Emergency heat?

Im kind've confused as to why my other thermostats are wired to W2 and out to the control board it is connected wired to W1. Is this a mistake from the HVAC tech who installed it? It seems like the HZ322 board says W1 is for emergency heat, and W2 is for Auxiliary heat? Or since they're jumped it makes no difference which one goes to which one?


The HZ322 has W1E/W2

The Hvac tech wired my current thermostat W1 on the control board to W2 on the thermostat, and jumped the W2 to W1/E.

Did he install it correctly. And the way i explained the nest, is that the correct way to wire a single stage heat pump with AUX heating?

Thank you, and please ask any more assessing questions. I want to get this installed correctly.

Here is tons of pictures of my thermostats, unit, control board.

I've done my best to organize this mess of a thread, please ask any assessing questions.

Thank you so much for taking the time to read this!
 
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Old 12-02-17, 08:37 PM
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Welcome to the forums.

Or would it be W2 on my nest be for Auxiliary heat, and use the Star on the nest and program that for Emergency heat?
Yes... this would be correct.

When the nest is in heatpump mode.... the W1 (first stage) heat is the heat pump.
W2 is the AUX heat output. The * can be programmed for E heat.
 
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Old 12-02-17, 08:46 PM
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So are you saying I need 3 wires, One for W1, one for W2, one for Star for emergency heat? Or do i leave W1 blank? Isn't the heat pump O wire?

I am a little confused,

HZ322 circuit board has

W1E
W2

It has 2 slots for each

W1E is jumped to W2 because the emergency heat and heat strips are the same thing on my unit *apparently*

That means I have one option slot on W1E and W2.

On the HZ322 manual is stating W1E is for emergency heating, and W2 on the board is for auxiliary. So I would hook up W2 on the HZ322 to W2 on the Nest, and I would then use the open slot on W1E and hook that up for the star on the Nest (for my emergency heating). Because O controls my heat correct?
 
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Old 12-02-17, 09:24 PM
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W1 is not active on the nest when set to heat pump mode.
The O controls the reversing solenoid for A/C or heat refrigerant flow.

Yes.... your hookup description is correct.

You should be able to right click and do a "view picture" for larger picture.
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Old 12-02-17, 09:33 PM
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You're amazing! I know how to correctly install my Nest then.

Can you look tell at my photos and tell me if it matters that the Hvac tech installed the W2 on the thermostat to the W1E on the HZ322? Does that make a difference that he did that. If the HZ322 W1E is for Emergency heating only, and the W2 is for Auxiliary. it Seems like i need to swap the W1E to the W2? Does that make any difference though, or will my system just not use Auxiliary heat since there's no wire in the auxiliary heat terminal, since it seems to be incorrectly in the Emergency heat slot?
 
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Old 12-04-17, 04:35 AM
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More Heat pump Tstat questions

Name:  20171203_133521.jpg
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Size:  92.4 KBThis thread has been so helpful! I have a similar setup. Installing Nest is the goal. So, in the previously described setup, the white wire is simply not hooked up, right? Also, I have two wires on my O terminal, an orange and a tan. Thoughts on why this is?
 

Last edited by Cktmum1213; 12-04-17 at 06:26 AM. Reason: Adding picture
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