Is the wiring backwords?

[watersjc]

I give up.  

I am a pretty savvy electrical trouble shooter, but I am stumped.  I wired in the Learning Nest, and nothing I do gets the AC to come on.  The blower always works, and I've even been able to get the heater to work (when I wire it to the AC lead).

Is the wiring backwords?

[CoolingWizard · Accepted solution]

Yes, the Orange wire goes to the O/B.  And, you need to set the as type O in the nest software. 
Red Wire to Rc, Yellow wire to Y, Green wire to G, Blue wire to C, Orange wire to O/B, White wire to E/Aux.

[CoolingWizard]

Did you take a picture of the wires on the old thermostat that you can share here?

[Patrick_Caezza]

There are a couple of things that you could have done wrong.

One is wiring it as a conventional system when it is a heat pump system.

Another is if you have a heat pump system, the reversing valve control might need to be changed from O to B.

Post a picture of the original thermostat's wiring or if you don't have one. Post a picture of the terminal block on the control board in the furnace/air handler.

[watersjc]

Thanks for the interest. 

I tried to upload a picture, it says I do not have permission.  The current therm is wired with W2, G, W, C, Y & R.

[CoolingWizard]

Can you tell us the make and model of your old thermostat? The W2 wire might be 2nd stage heat or it might me programmed as O or B. Go to the outdoor unit and get the model number and the manufacturer name. I will look it up and see if it is a heat pump or not. 

[watersjc]

It is Honeywell TH522OD1029

[CoolingWizard]

With this thermostat, we can check the programming of the parameters stored.  The buttons are Up/Down on right side, and Left and Right on the bottom.  Press and hold the Left with the Up button until the display changes.  After that you will not need to touch the UP/DN buttons.  On the display, the Left will say DONE, and the right will say NEXT.  Above the the DONE will be the parameter number.   The right side of the display will be the Value of the parameter. Tap the Right button to advance to the next parameter. Get the values for these following parameters 

Parameter-1 is system type

Parameter-2  Change Over valve; 0 energize to cool (B model) , or 1 energize to heat (O model)

Parameter-3  Fan Control: 0 Gas or Oil Heat, 1 Electric Heat 

Can you check these and report back their values?

[watersjc]

Parameter 1 = 5

2 = 0

I did not see Parameter 3

[CoolingWizard]

Parameter 1 value 5, = 2 Heat, 1 Cool, (With Aux Heat) the Heat Pump is stage 1,  and Aux Heat is stage 2.

Parameter 2 value 0 = Change Over Valve energized in Cooling mode. 
Parameter 3, defaults to 0, Equipment controls fan in heating mode. 

[watersjc]

[CoolingWizard]

This looks like it is a heat pump setup with the Emergency Heat and Auxiliary heat being jumperd together.  This AUX/E jumper is normally done on a 5220D when there is No Emergency Heat in which case there also no conductor wire attached to it either. The Orange wire is on the O/B, Blue wire is on Common, the green wire is in the G, the Yellow wire is on Y, and the Red wire is on R with a jumper to Rc.  Do you feel comfortable opening the air handler and getting a picture of the control board with the thermostat wires? It would nice to see where that white wire is going.  Basically, if there is a call for Auxiliary Heat, or Emergency Heat, the white conductor will be energized.  And, what ever the white wire is controlling, it will be turned on, most likely electric heat strips in the air handler. All the other wires are straight forward Heat Pump wiring on the Nest.  Normally on a 5220D, if you jumper AUX/E, the 5220D, will detect that and sets the parameter EHR value to 0, (zero), meaning there is no Emergency Heat in this system.  Now, if indeed you have some kind of emergency heat, on the nest 3rd Generation Wall Plate, you will connect that white conductor to the W2/AUX.  

[watersjc]

It is this control board, white wire goes to W2

[CoolingWizard]

Is this in manufactured home? And this a Intertherm (Nordyme) Air handler?

[watersjc]

More info - When the original thermostat is on, and the AC is running, I detect (on the controller) 24V between the common and the R, O & Y terminals.

[CoolingWizard]

Your system defaults to heating and the O energizes the Reversing Valve to put it into Cooling mode. The Y energizes the compressor contactor and that starts the compressor, and condenser fan outside.  At the same time, the air handler control board initiates the blower relay turning it on. When in heating mode, all this will happen and the O wire will not be energized. 

it appears you have electric heat as emergency heat (W2).  So on the nest wall plate put this white wire in the W2/AUX.  

On the nest, go to the settings and then Heat Pump and set the O/B to O and all should be good now.  

[watersjc]

So the orange wire goes to the OB terminal on the nest?  This might be my screw up.  I was reading across the top of the terminal strip, and saw orange wire going to W, so I wired it to the W on the nest.

[CoolingWizard · Accepted solution]

Yes, the Orange wire goes to the O/B.  And, you need to set the as type O in the nest software. 
Red Wire to Rc, Yellow wire to Y, Green wire to G, Blue wire to C, Orange wire to O/B, White wire to E/Aux.

[watersjc]

Thanks for the help.  It works perfectly now.  I did not have to change the parameter.

[MelbaDT]

Hey folks, 

Thanks for helping again here, CoolingWizard and Patrick_Caezza. 

watersjc, that's awesome and thanks for keeping this thread updated. Glad to hear that your thermostat is now working as it should. Let us know if you have any further questions about this. 

Best, 

Melba

[MelbaDT]

Hi, 

We haven't heard from you in a while so we'll be locking this thread if there is no update within the day. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the community.

Best, 

Melba

[Patrick_Caezza · Accepted solution]

You have a simple heat pump system.

Try this wiring

White - AUX to W2 (set as AUX heat)

Green - G to G

Orange - O/B to OB

Blue - C to C

Yellow - Y to Y1

Red - R to Rc (jumper to Rc not needed)

You don't need to make any changes to the reversing valve as it defaults to O.

[watersjc]

Thanks for the help.  It works perfectly now.