Nest Thermostat Heat Pump Wiring

This post discusses Nest Thermostat Heat Pump Wiring. We will go over the basics of how it works and provide an example wiring diagram. The Nest Thermostat is a programmable, Wi-Fi-enabled thermostat. It learns your heating and cooling preferences. It's designed to maximize energy efficiency while maintaining a high level of comfort for everyone in the household. Nest's heat pump thermostats are compatible with heat pump systems only. They won't work with furnaces.

Nest's heat pump thermostat is compatible with electric, gas, and oil systems. In order to use Nest's heat pump thermostat, you must have a 24VAC or 24VDC heating system.

Nest Thermostat Heat Pump Setup

Nest uses a variety of sensors to measure the temperature in your home and program itself. To detect whether anyone is home it has a motion sensor. It can tell if you're running a fan or an air conditioner. And it knows the difference between a light bulb and a candle.

This also uses a built-in humidity sensor. That measures how humid your home is by comparing the current humidity to the ideal level you choose. It will turn itself off if the humidity gets too high.

To connect your Nest thermostat there are three wires. The first is SPD, or "Power" wire, which goes from the thermostat to the wall. Then there's VAC, or "Voltage" wire, which carries 24 volts of power to the thermostat. The last is GND, or "Ground" wire, which should always need to connect to a ground point on your wiring system.

Here is how it works. Let's say your thermostat is currently set to 72°F. You press "Set", and put 72°F in the "Setpoint" box, and click the "Save" tab.

The Nest thermostat sends a message to your wireless router. That sends a signal to the Nest App on your Android or iOS device. The App checks to see if you've changed your settings.

If you have, it tells your thermostat to start heating. It may even ask you to confirm that you've changed the setting. If not, no changes need to make. Your temperature won't change until 30 minutes have passed.

The Nest app also sends information about the temperature on your phone to the Nest servers. The servers store this information. It's used to "learn" what the temperature should be inside your home based on data collected by sensors. Which are always hardwired into your heating system or thermostat.

The learning process starts right away and continues for the next two weeks. Your thermostat will update itself with this information every two hours. After two weeks, it knows your schedule. It has an accurate idea of how to maintain the proper temperature. It will continue to learn over time, but it won't ever forget what it has already learned.

Once you have everything hooked up, you'll see the Nest app on your phone or tablet. If you don't have the app installed already, you'll download it from the App Store or the Google Play Store. If you do have it installed, it will show up on your Home screen.

You can set schedules for your thermostat. But if they aren't confirmed, your settings won't change until 30 minutes after you've confirmed them.

You'll also see a "Current" tab that tells the current temperature of your home. A history of how it has changed in the past day, and a graph that shows you when it went up or down. On the right side is a bar with your name. The bar is empty when you first install the thermostat. But as it learns your schedule, it will be always filled in gray when all of your settings are correct. If it's blank, you can add new scenes to the app by clicking the scenes button on the left side.

Once you've confirmed your settings, click "Get started". You'll see a countdown. When it reaches zero, your heat will come on and the thermostat will program itself.

Nest Thermostat Heat Pump Problems

There are some problems with Nest's heat pump thermostat.

If you have your Nest thermostat connected to a C-wire, there is no place for it to connect to. The red wire has no connection, so the system will not work.

The Nest thermostat only shows the temperature on one screen.  Instead of two separate ones. That makes it hard to read. The temperature swings wildly on the screen, even when you're standing right in front of it.

The Nest thermostat can't be connected to a backup heating system. The Nest thermostat cannot connect to a secondary, electric forced air heater. The Nest thermostat is not compatible with electric baseboard convectors.

The Nest thermostat can't use extra power if your HVAC unit uses excess power. ( when the primary heating source fails). It will only respond to programmed settings. It's not able to use an emergency heat source even if it's available.

The Nest thermostat can't be wirelessly linked with a "dual fuel" furnace. The Nest Thermostat is not compatible with PUE-certified furnaces. That sallow for greater energy efficiency.

The Nest thermostat doesn't work with heat pumps that use oil or gas. It will work on heat pumps that use electricity, but it's not compatible with any other systems that use oil or gas.

FAQ

Can I use Nest with my furnace?

Yes, you can use Nest with any type of furnace.

Can I use Nest with my air conditioner?

No, the Nest thermostat works only with furnaces and not air conditioners.

Do I need wiring for Nest?

Yes, you will need wiring to use this product; it does not connect to Wi-Fi on its own without wiring.

Can I hook up Nest with my existing thermostat?

Yes, you can use the Nest with your existing thermostat if you want.

Can I hook up Nest to my gas furnace?

The Nest thermostat will work on gas furnaces but it’s not compatible with dual fuel or oil furnaces.

Conclusion

The Nest Learning Thermostat has been one of the hottest gadgets of 2016. The device also comes with a few heat pump wiring complications. Understanding the device's wiring system helps to overcome any difficulties that may arise.

The Nest thermostat comes with a built-in power supply. As such, it does not need any additional power supply. It has a built-in dual-band Wi-Fi system. That connects to the Internet and controls the temperature of your home. The Nest thermostat also has an internal microphone and speakers. Which makes it possible for you to talk directly to your device.