Why is new Nest running every 8-9min for 1.5 min?

[dianefollain]

Purchased Nest Learning Thermostat Gen 3. After what the app detected as a successful setup I have 2 issues:

1. Thermostat is on the heat setting. The thermostat is set to 66 degrees, it is about 63 in the house. Blower turns on about every 8-9 min, runs for 1.5 min and shuts off. It may not have enough time to get to heated air but the air coming from the vents is cool.
2. The system disconnected from the wifi due to low battery. It is new out of the box. I charged the battery for about an hour and the display instructs to attach to the base (so I assume it is charged enough). It reconnected to the wifi but when I check the battery power on the display it is at 3.678. I am on software version 6.2-22

I am not able to find any troubleshooting tips related to #1 above but have seen many issues reported with #2 the battery life and it seems the general concensus is the issue is likely software update related.

[sporfrog]

For issue #1

Any chance you can send photos of how your old thermostat was wired and how the Nest is wired? Maybe another set of eyes will spot something that will make a difference.  Normally, the heat should not be cycling on and off so frequently and for such short time period.

Make sure the equipment type is configured correctly for your system. For example if you have a gas forced air it will be something like fuel: gase, type: forced air.

For issue #2

Just out of curiosity does  your thermostat have a C (common) wire connected? In most cases a Nest Learning Thermostat will work without it, but in some cases it just works better with it. Often power related issues are due to lack of C. If there is no c wire, you will want to charge the thermostat 100% before connecting it.

[dianefollain]

Thanks for your response and taking the time to take a look at this.

Issue #1:  We have piped in propane and I have it configured for: Fuel: propane, type: forced air. Photos of before and after for the wiring below.

Before install (old thermostat)After (Nest Learning Gen 3)

#2. No C wire.  I charged it fully but cannot leave the face on to test because the system keeps turning on and off every 8 minutes

[sporfrog]

The wiring looks correct based on both of your images.  Thanks for attaching!

It looks like possibly there is an extra wire in the cable tucked into the wall. Maybe a brown, or blue? Not sure if I am seeing it correctly. If there is, and if you are comfortable and safe, you could open the furnace and check to see if one of those wires is connected to a C or common terminal on the circuit board. If it is, or if you can connect it to a C, then you could connect the same color wire to C on the thermostat. Adding a C has been known to fix what seems like unrelated problems. Maybe it will help in your case?

[dianefollain]

Hmmm, interesting.  I don't know how you noticed a brown or blue wire tucked in the wall (I never saw them) BUT there is a brown AND a blue wire.  Both may have corresponding wires on the furnace as you can see in the photo.  I say 'may' because that furnace is split into 2 zones and 3 thermostats (one per floor is a 3 story home).  I am only installing the nest on the main floor.  Anyway, for what it is worth below are photo's of what is in place.

I am sure this is more than you expected to get into so please don't feel obligated to continue!

[sporfrog]

I am not very knowledgeable with dual zone furnace wiring, but if it was typical furnace with one thermostat you could probably connect the blue wire to C at the furnace and the thermostat.

My guess.... NOTE, THIS IS A GUESS ... is something like this: 

You will notice in the furnace photo the brown cable going into the furnace and down into the lower section. It looks like there are two so you may have to see if it is easy to determine which goes to the thermostat you are working on. Anyway...in that lower section there is probably a circuit board with some terminals for the thermostat wires. IF you can determine which cable goes to which thermostat and IF you are comfortable and IF you are safe (turn off switch to furnace, etc) you can probably connect the blue wire to C in the furnace and the blue wire to C on the thermostat. It's possible you will find the C already has a wire or that blue has some other function for one of the 2 other thermostats. 

You may want to contact an HVAC expert.  And worth noting, this may not fix all the thermostat issues, it's just better to have a C (common) wire for Nest if possible.

Good Luck!

[dianefollain]

I think this is above my pay grade at this point but I thank you for your time and assistance.  And I learned a few things!!  Thanks again!

[Ryan_G]

Hey everyone,

I just wanted to follow up and see if anyone is still in need of help? Please let me know, as I would be happy to answer any questions you may have.

Best regards,

Ryan

[dianefollain]

This never got resolved.  The latest was that I charged the unit for 24hrs and it did get above 38 but I never connected the blue wire because I would have had to call in an HVAC person to ensure I was connect at the furnace to the appropriate place for the main floor.  I returned the Nest.  Too much time/effort and expense if I needed to pay a technician.  

[Ryan_G]

Hi dianefollain,

Thanks for the update and sorry to hear about what happened.

If you have any other questions, don't hesitate to write it up here at the Google Nest Community.

Best regards,

Ryan

[Ryan_G]

Hey folks,

Thanks for visiting the Google Nest Community. 

Since this thread hasn't had activity in a while, we're going to close it to keep content fresh.

If you have additional questions, feel free to submit another post and provide as many details as possible so that others can lend a hand. 

Hope this helps!

Kind regards,

Ryan