Nest 4th generation will only run heat pump for 5 minutes then shuts off.

[kjmike95]

I installed my new 4th generation thermostat today.  The heat pump is a dual stage and is attached to a dual stage furnace with propane backup.  When I call for heating or cooling the system starts fine and makes heating and cooling as normal but after 5 minutes the heat pump shuts off and the furnace fan keeps running.  The thermostat shows it is still heating or cooling with an eta but no heat or cool is being made as heat pump isn't running.  System was running great with old thermostat.  What do you think?

[kjmike95]

Additional info, I have tried switching from seasonal to each cycle on heat pump activation, and also tried switching from O wire to B wire.  Neither made a positive change to this issue.

[Patrick_Caezza]

@kjmike95 

Can you post a picture of the original thermostat's wiring?

[kjmike95]

Here is the original wiring.  I took closer pictures also of each side.  This is the heat pump setup. Thanks @Patrick_Caezza 

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[Patrick_Caezza]

@kjmike95 

This is my wiring recommendation.

Blue - Y2 to Y2

White - AUX to W2 (jumper to E not needed)

Black - S1 - tape off

Brown - S2 - tapeoff

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

Orange - O/B to OB

Yellow - Y to Y1

Green - G to G

[kjmike95]

Thanks.  Made one change.  Nest had me put Red on RH so I moved to RC to test and no change.  Heat pump runs for almost exactly 5 minutes and shuts off.  

One other thing I found when looking at the wiring at the furnace is although the thermostat has White on W2 the white wire in the furnace is attached to W1 and nothing is on W2.  Is that something that should change @Patrick_Caezza ?

[kjmike95]

Here is a picture of the furnace wiring. 

[bweiss48]

I have exactly the same problem.  The fact that it shuts off at 5 minutes seems to be a software problem to me.  Who can we contact to ask about this?

[kjmike95]

I had a tech come out and check the entire system.  Heat pump runs great with jumper wires and no thermostat in the system so he thought it was a faulty thermostat. I contacted Nest tech support and they sent me a new one.  I just got it and haven't installed yet to see if that cured the issue. I plan to this weekend and will let you know.  Thanks

[kjmike95]

@bweiss48 replaced the thermostat.  Didn't fix it.  Calling support tonight to see what is next.

[bweiss48]

Thanks for the info.  We have two new nest thermostats.  One works fine, the other has the same 5 minute problem you note.  We’re going to switch them tomorrow to see what happens.  I will let you know.

[bweiss48]

We switched out the thermostats and tested.  We saw no change.  That is, the system where the compressor stopped running after 5 minutes continued to function the same way.  The system that operated well continued to do so.  So, it seems the problem may not be with the thermostats....