Issues with Nest T Stat

[Bleepster]

Google nest issue.  I can only get heat – AC isn’t even an option on the app or on the thermostat.

History:  I had a Honeywell programable Tstat, and Consumers Energy gave me a free google nest – Gen1 I believe.  the face is mirrored black, and the outer edge is white) the Honey Well worked great.  Here is how the Honeywell was hooked up:

White wire to white terminal on honey well

Green wire to green terminal on honey well

Red wire to red terminal on honey well

Red terminal had a jumper to RC terminal.

Blue Wire hoked to yellow terminal on honey well.

Google Nest Hooked up this way:

Green to Green

White to White

Red to Red

Blue to Yellow  (I put Blue to Constant tab on nest and I get error messages)

Results:

I have heat – but it acts weird – heat turns on and runs for 15 seconds, then shuts off, then 30 seconds later will kick back on and run as normal.   Repeats this every time heat turns on.  I suspect this blue wire is my issue.  Not sure if it’s a “constant” or not.

I do have a service call in to my heating guy – but he can't make it until next week.  my concerns are why don’t I have the AC option and why does the heat turn on, off then on again?

Any ideas?

[CoolingWizard]

First of all, the Nest backplate does not have colors. The terminals are labeled as letters; R,Rh,Rc are power input. Y,Y1,Y2 are for calling for Compressor On.  G is for the indoor Blower Fan, W, W1, W2 are for calling for Heat. If you have a Heat Pump HVAC system you have additionally, O, B, O/B for Changing Reversing Valve. The Aux,E is for Auxiliary and/or Emergency Heat.

Your Honeywell had:

Red wire connected to Rc with jumper to Rh.

Green wire attached to G

Blue Wire attached to Y

White wire attached to W

Your Nest Backplate should be set up the same. you have no COMMON or C wire. 
Red wire on R

Blue wire on Y

Green wire on G

White wire on W

Your HVAC system is a conventional system, Air Conditioning and a Furnace.

Ken, The AC Cooling Wizard

[Bleepster]

not to nitpick - but - on the honey well, and the nest - what does W R G Y stand for?  colors - no?  so, what I said is accurate.

thanks, for confirming what i already knew - still doesn't answer my issues - mr wizard

[CoolingWizard]

Bleepster, you have no cooling because you improperly set up the Nest thermostat. You have no cooling option because your equipment selection for cooling was not performed.  Easiest way to correct this is to Perform a reset, and set your system up as a conventional AC with a Furnace, that should correct it. The other choice is to go into the pro set up section and re-defined the AC equipment in that part. That’s a little more difficult to explain and guide so I would just do the reset approach. 

As to the so called colors.  The R, Rc and Rh are defined as Power Input. And I have yet to find a thermostat smart enough to know the colors of the thermostat wires connected to it.   The reason the letters assigned to the terminal screws match wire color was done intentionally.  So, since the true thermostat cable has conductors with insulation colors in the basic colors, why not make it easy for the techs. So yes, the R could be RED, and G could be Green etc.  however, they do not have to be.  The real key to make it work is that whatever color conductor wire you put on R at the thermostat, you must put on R at the HVAC equipment.  As I stated:

R is the power input terminal

W is the output for Heating; this wire, when energized from R, will turn on the heating cycle.

Y is the output for Cooling; this wire, when energized from R, will turn on the outdoor compressor.

G is the output for Blower Fan;  this wire, when energized from R, will turn on the indoor blower fan.

Good luck,

Ken, The AC Cooling Wizard

[Bleepster]

thanks for the reply - I will attempt your recommendations tonight.

[Bleepster]

SOLVED

I factory reset the TSTAT - re-set up and no change.  i then played with the wiring and moved my blue wire to the O/B tab and the nest gave me an error.  so, i was frustrated and put the blue wire back to yellow tab.   on my phone app, i looked at my wiring and noticed it wasn't displaying any wires.  then i saw the option to "update wires" - selected that and bingo.  i now have HEAT/AC and i also found an option to turn off "pre-fan" or something.   i turned that off and now when the heat kicks on - it runs as it should.  doesn't turn on for 15 seconds, shut off for 15, then turn back on.

thanks for the help Mr Cooling Wizard i greatly appreciate it

[Markjosephp]

Hello folks,

I wanted to ensure that everything was covered here.

Thanks for lending a hand here, @CoolingWizard. Big help!

@Bleepster, I'm glad to hear that your issue is fixed. It looks like we can consider this one complete, so I will lock the thread within 24 hours unless I can help out with anything else.

Regards,

Mark