Nest Thermostat E Heat Link wiring

When installing your Google Nest Thermostat E’s Heat Link, check if your current thermostat has more than 2 wires. If it does, you’ll need to identify them to finish installation. Make sure to take a picture of your current thermostat’s wiring in case you need it later. You’ll attach your current thermostat’s Common (C) wire and it’s Normally Open (NO) wire to your Heat Link and insert any extra wires into terminal blocks.

Installing your Nest Thermostat E’s Heat Link

When installing your Nest Thermostat E’s Heat Link, check if your current thermostat has more than 2 wires. If it does, you’ll need to identify them to finish installation. Make sure to take a picture of your current thermostat’s wiring in case you need it later.

You’ll only install two wires on your Heat Link, so you’ll need to find your current thermostat’s OpenTherm wires (OT1 and OT2) or its Common (C) wire and Normally Open (NO) wire.

Once you’ve found the right wires, you’ll attach them to your Heat Link and and insert any extra wires into terminal blocks.

Identifying thermostat wires

If the wires on your current thermostat have different labels, or are not labeled at all, it can be hard to tell which wires you should install on your Heat Link. Below are guides to some common thermostat models that will help you identify which wires you need to install.

Current Thermostat Brand/Model

Nest C Wire

Nest NO Wire

Busch-Jaeger Raumtemperaturregler L 1 (up arrow)
Danfoss Electronic Thermostat RET 230, 230C, 230F, 230L L 3
Danfoss Electronic Thermostat RET 230NSB, 230VF, 230VF2 2 3
Danfoss Room Thermostat RMT 230, 230T 1 2
Danfoss Programmable Room Thermostat TP9000 L* 4
Drayton (Invensys) RTS Room Thermostat RTS1, RTS2, RTS3 L 3
Drayton Combistat Room Thermostat L 3
Drayton Lifestyle ETS1 Room Thermostat 2 1
Eberle RTR-E 3502 6 2
Eberle RTR-E 6121, 6124 1 2
Eberle RTR 9121 1 2
Gira Raumtemperatur-Regler 0390, 0391, 0392, 0393, 0394, 0396, 0397 L (wave icon)
Heatmiser neoStat Thermostat A2 L
Heatmiser neoStat-12v V2 Thermostat A2 A1
Heatmiser neoStat-e V2 Thermostat Load L
Heatmiser neoStat V2 Thermostat A2 A1
Heatmiser Slimline Thermostat A2 L
Hive SLR1 Thermostat 1 3
Honeywell BDR91 Wireless Room Thermostat A B
Honeywell DT90 Digital Room Thermostat 2 1
Honeywell R6660D Wireless Room Thermostat A
(5th terminal from the left)
B
(6th terminal from the left)
Honeywell Room Thermostat T6360, T4360B, T4360E 1 3
Honeywell Room Thermostat T4360D 1* 2
Potterton PRT 2 Electronic Room Theremostat 2 3

* For these thermostat models only: If there are two wires in your old thermostat’s connector, label them both as C and attach both of them to the C connector on your Heat Link.


My thermostat isn’t listed here

If your thermostat isn’t listed above, there are still a few things you can try:

  • Call a local Nest Pro to help you finish installation
  • Contact your current thermostat’s manufacturer for help identifying your wires.
  • Search for your current thermostat’s model online to try to identify your wires.

Once you identify your NO and C wires, you’ll attach them to your Heat Link and and insert any extra wires into terminal blocks. Or if you call a Nest Pro, they’ll finish installing your thermostat, give you a demo, and answer any questions you might have about your Nest thermostat.

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