background image

 

Dual Fuel - 2 Stage Heat Pump, 1 Stage Heat

 

 

Label: 

Function: 

 

Y1 

Compressor Relay (Stage 1) 

Y2 

Compressor Relay (Stage 2)​

, 2nd-speed fan 

relay

 

Fan Relay* 

O/B 

Heat Pump Changeover Valve 

Rc 

24VAC power from cooling transformer 

W1 

Heat Relay (Stage 1) 

W2/AUX 

Heat Relay (Stage 2) / ​

Auxiliary Heat Relay 

24VAC Common Wire † 

Star​:​ W3,​ E​, HUM/DHUM, 3rd-speed fan relay 

Rh 

24VAC power from heating transformer ‡ 

 
 

Dual Fuel - 1 Stage Heat Pump, 2 Stage Heat 

 

Label: 

Function: 

 

Y1 

Compressor Relay (Stage 1) 

Y2 

Compressor Relay (Stage 2), 2nd-speed fan 
relay 

Fan Relay* 

O/B 

Heat Pump Changeover Valve 

Rc 

24VAC power from cooling transformer 

W1 

Heat Relay (Stage 1) 

W2/AUX 

Heat Relay (Stage 2) ​

/ Auxiliary Heat Relay 

24VAC Common Wire † 

Star:​ W3, E, HUM/DHUM, 3rd-speed fan relay 

Rh 

24VAC power from heating transformer ‡ 

 

 

15 

Summary of Contents for Learning

Page 1: ...Nest Learning Thermostat Pro Installation Configuration Guide Last updated November 2017 Version 1 1 ...

Page 2: ...ng Diagrams Heat Pump Systems 1 2 Wiring Diagrams Multi Speed Fans 1 7 Wiring Diagrams Humidifiers and Dehumidifiers 1 8 Configuring Nest Thermostat with Pro Setup 19 How to use Pro Setup 19 How to Configure Complex Systems 20 Troubleshooting 23 Handling Unusual Thermostat Wiring 2 3 Reference Materials 2 6 How To Quick Reference Guide 26 Wiring Error Quick Reference Guide 29 Troubleshooting Quick...

Page 3: ...rs and multi speed fans Pro Setup also activates a customer s extended warranty if the Nest Thermostat is purchased from and installed by a Pro Silent relays Nest Thermostats use solid state switching instead of relays so there s no noise when it switches on or off You will not hear any clicking during system testing and activation Press connectors Connecting the HVAC system wiring to the Nest The...

Page 4: ...xternal power required No common wire required with most installations Built in lithium ion battery Uses less than 1 kWh month Voltage requirement 20 30V AC Display 24 bit color LCD 480x480 resolution at 229 pixels per inch PPI 5 3 cm 2 08 in diameter Sensors Temperature 10 sensors 5 F Humidity 3 RH Near field activity Far field activity Ambient light Nest utilizes local weather data over Wi Fi in...

Page 5: ...difiers and dehumidifiers How to give your customer an extended Pro Warranty Customers who purchase a Nest Thermostat from a Nest Pro and have it installed can get an extended Pro Warranty The Pro Warranty adds an additional 3 years of coverage for a total of 5 years Entering your Pro ID in Pro Setup will automatically activate your customer s extended warranty as long as all of the following are ...

Page 6: ...g to activate the HVAC system using the existing thermostat 4 Remove the old thermostat Before removing the old thermostat take a quick picture of the wiring with your phone in case you need it for reference Disconnect the wiring and remove the old thermostat Use the wire labels included in Nest Thermostat Installation Guide if needed Be sure to leave the original thermostat hardware and any jumpe...

Page 7: ...hermostat s key features to your customer 9 Test heating and cooling This is vital to any installation in order to prevent a callback After setting up the Nest Thermostat run each part of the system for a few minutes This will ensure that the Nest Thermostat is installed correctly and there aren t any HVAC compatibility issues See page 26 for additional details on performing post installation test...

Page 8: ...ed W1 Stage 1 heat relay W1 Stage 1 heat relay W2 AUX Stage 2 heat relay W2 AUX Auxiliary heat relay C 24VAC common wire C 24VAC common wire Star Stage 3 heat W3 humidification HUM or dehumidification DEHUM 3rd speed fan relay Star Emergency heat E humidification HUM or dehumidification DEHUM Rh 24VAC power from heating transformer Rh 24VAC power from transformer No jumper wires required You don t...

Page 9: ... Compressor Relay Stage 1 Y2 Compressor Relay Stage 2 2nd speed fan relay G Fan Relay O B Heat Pump Changeover Valve Rc 24VAC power from cooling transformer W1 Heat Relay Stage 1 W2 AUX Heat Relay Stage 2 Auxiliary Heat Relay C 24VAC Common Wire Star W3 E HUM DHUM 3rd speed fan relay Rh 24VAC power from heating transformer Fan relay G is optional However without a G wire Nest will not be able to c...

Page 10: ... Common Wire Star W3 E HUM DHUM 3rd speed fan relay Rh 24VAC power from heating transformer Conventional 1 Stage Heating 1 Stage Cooling Label Function Y1 Compressor Relay Stage 1 Y2 Compressor Relay Stage 2 2nd speed fan relay G Fan Relay O B Heat Pump Changeover Valve Rc 24VAC power from cooling transformer W1 Heat Relay Stage 1 W2 AUX Heat Relay Stage 2 Auxiliary Heat Relay C 24VAC Common Wire ...

Page 11: ... C 24VAC Common Wire Star W3 E HUM DHUM 3rd speed fan relay Rh 24VAC power from heating transformer Conventional 2 Stage Heating 2 Stage Cooling Label Function Y1 Compressor Relay Stage 1 Y2 Compressor Relay Stage 2 2nd speed fan relay G Fan Relay O B Heat Pump Changeover Valve Rc 24VAC power from cooling transformer W1 Heat Relay Stage 1 W2 AUX Heat Relay Stage 2 Auxiliary Heat Relay C 24VAC Comm...

Page 12: ... C 24VAC Common Wire Star W3 E HUM DHUM 3rd speed fan relay Rh 24VAC power from heating transformer Conventional 1 Stage Heating 2 Stage Cooling Label Function Y1 Compressor Relay Stage 1 Y2 Compressor Relay Stage 2 2nd speed fan relay G Fan Relay O B Heat Pump Changeover Valve Rc 24VAC power from cooling transformer W1 Heat Relay Stage 1 W2 AUX Heat Relay Stage 2 Auxiliary Heat Relay C 24VAC Comm...

Page 13: ...Heat Relay C 24VAC Common Wire Star W3 E HUM DHUM 3rd speed fan relay Rh 24VAC power from heating transformer 1 Stage Heat Pump with Aux Heat Label Function Y1 Compressor Relay Stage 1 Y2 Compressor Relay Stage 2 2nd speed fan relay G Fan Relay O B Heat Pump Changeover Valve Rc 24VAC power from cooling transformer W1 Heat Relay Stage 1 W2 AUX Heat Relay Stage 2 Auxiliary Heat Relay C 24VAC Common ...

Page 14: ...liary Heat Relay C 24VAC Common Wire Star W3 E HUM DHUM 3rd speed fan relay Rh 24VAC power from heating transformer 2 Stage Heat Pump Label Function Y1 Compressor Relay Stage 1 Y2 Compressor Relay Stage 2 2nd speed fan relay G Fan Relay O B Heat Pump Changeover Valve Rc 24VAC power from cooling transformer W1 Heat Relay Stage 1 W2 AUX Heat Relay Stage 2 Auxiliary Heat Relay C 24VAC Common Wire Sta...

Page 15: ...VAC Common Wire Star W3 E HUM DHUM 3rd speed fan relay Rh 24VAC power from heating transformer Dual Fuel 1 Stage Heat Pump 1 Stage Heat Label Function Y1 Compressor Relay Stage 1 Y2 Compressor Relay Stage 2 2nd speed fan relay G Fan Relay O B Heat Pump Changeover Valve Rc 24VAC power from cooling transformer W1 Heat Relay Stage 1 W2 AUX Heat Relay Stage 2 Auxiliary Heat Relay C 24VAC Common Wire S...

Page 16: ... C 24VAC Common Wire Star W3 E HUM DHUM 3rd speed fan relay Rh 24VAC power from heating transformer Dual Fuel 1 Stage Heat Pump 2 Stage Heat Label Function Y1 Compressor Relay Stage 1 Y2 Compressor Relay Stage 2 2nd speed fan relay G Fan Relay O B Heat Pump Changeover Valve Rc 24VAC power from cooling transformer W1 Heat Relay Stage 1 W2 AUX Heat Relay Stage 2 Auxiliary Heat Relay C 24VAC Common W...

Page 17: ...essor Relay Stage 2 2nd speed fan relay G Fan Relay O B Heat Pump Changeover Valve Rc 24VAC power from cooling transformer W1 Heat Relay Stage 1 W2 AUX Heat Relay Stage 2 Auxiliary Heat Relay C 24VAC Common Wire Star W3 E HUM DHUM 3rd speed fan relay Rh 24VAC power from heating transformer 16 ...

Page 18: ...liary Heat Relay C 24VAC Common Wire Star W3 E HUM DHUM 3rd speed fan relay Rh 24VAC power from heating transformer 3 Speed Label Function Y1 Compressor Relay Stage 1 Y2 Compressor Relay Stage 2 2nd speed fan relay G Fan Relay O B Heat Pump Changeover Valve Rc 24VAC power from cooling transformer W1 Heat Relay Stage 1 W2 AUX Heat Relay Stage 2 Auxiliary Heat Relay C 24VAC Common Wire Star W3 E HUM...

Page 19: ...ressor Relay Stage 2 2nd speed fan relay G Fan Relay O B Heat Pump Changeover Valve Rc 24VAC power from cooling transformer W1 Heat Relay Stage 1 W2 AUX Heat Relay Stage 2 Auxiliary Heat Relay C 24VAC Common Wire Star W3 E HUM DHUM 3rd speed fan relay Rh 24VAC power from heating transformer 18 ...

Page 20: ...ways customizable Connectors that control a heating or cooling function will also have a Source setting to identify the type of fuel used to heat or cool a Delivery setting to describe how heating or cooling is distributed throughout the home and a Fan setting to activate the fan if required Depending on the wire configuration the Source or Delivery settings may have only one default option The Fa...

Page 21: ...ers that connect to it with one or two low voltage wires There are multiple Pro Setup settings for the wire in the Star connector to control a humidifier or dehumidifier Whenever a humidifier dehumidifier is attached you ll need to select whether or not the fan should activate Compatible wires have one of the following labels H Hum Hum1 H2 Hum2 D DH Dhum Dehum D2 DH2 Dhoom2 Dehum2 Regardless of wh...

Page 22: ...n or off but they won t be able to manually control the fan speed If there s more than one fan wire installed the Nest Learning Thermostat will automatically set the fan speed Your customer will also be able to select a speed in the Fan menu Not all multi speed fan wires are compatible with Nest thermostats Compatible wires will have labels similar to the following G G1 G2 G3 GL GM or GH When usin...

Page 23: ...ostat calls for heat Some systems will rely on the thermostat to activate the fan The default setting for fan control on the W1 wire is Don t activate because most forced air gas heating systems will activate the fan automatically when the furnace W1 is activated If you test the furnace and the fan doesn t activate change this option to Activate The thermostat will then call for both the furnace W...

Page 24: ... non heat pump and you see a B wire connected to the current thermostat that B is a common wire and should be connected to the C connector on the Nest base Important Note If you have a B wire that is actually a common wire not following the rules above can lead to blowing a fuse on your HVAC controller board and most likely damaging the Nest Thermostat When X W1 or W2 is an AUX wire Some heat pump...

Page 25: ...ctivate when the thermostat calls for heating Heating intermittently deactivates while the thermostat is still calling for heating There is a unusual noise coming from the customer s heating system In heat pump systems Heating or cooling is always on or on intermittently when the thermostat is not calling for it Heating or cooling does not activate when the thermostat calls for it Heating or cooli...

Page 26: ...all in a small number of systems The addition of a 220 Ohm resistor at the furnace provides another current path to the thermostat which reduces the voltage input at the detect circuit to prevent false heat calls Note that this resistor will draw a couple of watts during call for heat or cool if the resistor is added to Y and it will become warm Make sure to mount the resistor so that it is not in...

Page 27: ...for other types of systems such as two stage heat pumps and emergency heat It is available to installation professionals during and after installation and allows them to specify how the Nest Thermostat should control the HVAC system Testing the basic operation after installation Activate heating and cooling Simply turn the ring to set the current set point above or below the current ambient temper...

Page 28: ...TINGS 3 Turn the ring and select EQUIPMENT 4 Turn the ring and select HEAT PUMP Adjust ECO Heating and Cooling Temperatures These temperatures are set as the final step during the setup interview But if the Nest Thermostat is already configured here are the steps 1 Press the ring to bring up the menu 2 Turn the ring and select SETTINGS 3 Turn the ring and select ECO Turn the ring to set the HEAT T...

Page 29: ...struct them to tap on the included link to activate their Nest Account To pair the Nest Thermostat with the customer s account follow these steps 1 Press the thermostat s ring to open the Quick View menu 2 Choose SETTINGS 3 Turn the ring to Nest Account and press the ring to select it 4 Select Get Entry Key and write it down 5 Open the Nest App 6 From the home screen tap the Settings icon 7 Tap Ad...

Page 30: ...nnector This connector is exclusively used for heat pumps which also require a Y1 wire to be attached E78 Additional wire s required AUX W2 detected by itself The Nest Thermostat is physically detecting a wire in the AUX W2 connector Supported configurations that use this connector also include a W1 wire or an O B Y1 wire E79 No power to C wire detected The Nest Thermostat is physically detecting ...

Page 31: ...ostat may be wired incorrectly or your system may be incompatible E109 G2 detected G1 wire is also required The Nest Thermostat is physically detecting a G2 fan wire in the Y2 connector but it s not detecting a wire in the G connector Both wires are required for a multi speed fan E110 G2 wire detected Remove W2 AUX wire The Nest Thermostat is physically detecting a wire in the W1 connector a wire ...

Page 32: ...ermostat isn t electrically detecting the O B wire but one is connected to the Nest base N78 No power to Y2 wire detected The Nest Thermostat isn t electrically detecting the Y2 wire but one is connected to the Nest base N79 No power to wire detected The Nest Thermostat isn t electrically detecting the wire but one is connected to the Nest base W1 Nest can t continue to connect to your Wi Fi netwo...

Page 33: ...the Nest Thermostat First check the wiring to make sure the wires are in the right place and the wire tips are straight and fully inserted into the connectors If that doesn t work turn off HVAC breakers and pull out the Rh and the G wires Carefully hold them together with the copper ends touching for 10 20 seconds If the fan turns on there may be a hardware issue with the device so please contact ...

Page 34: ...roubles hooting Wi Fi and connection issues Forgot Lock Code Customer has forgotten the lock code to their Nest Thermostat The Nest Thermostat can be remotely unlocked by logging onto the Nest Account paired with their device from the Nest Web app or from the Nest Mobile app 33 ...

Page 35: ...o the terminal Correctly ground the other wire from the Humidifier No relay is recommended Stand Alone Humidifier 2 Wire This system has a humidifier that is separate from the HVAC system Install the 2 hum wires directly into the relay Run the single wire from the relay to the terminal Nest recommends the White Rogers 90 290Q or similar 24VAC HVAC relay 34 ...

Page 36: ...tly into the relay Run the single wire from the relay to the terminal Nest recommends the White Rogers 90 290Q or similar 24VAC HVAC relay Built in Humidifier System 1 Wire This system has a humidifier built into its HVAC system and only 1 hum wire Connect the hum wire from the built in system directly to the terminal No relay is recommended 35 ...

Page 37: ...Where to Find Additional Help Help online https nest com support thermostat Nest Pro Tech Support 1 855 VIP NEST 1 855 847 6378 Dedicated Pro Support Hours 6am 6pm pacific 9am 9pm eastern 36 ...

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