Installing your Helio T2 thermostat

Most people install the Helio T2 in about 30 minutes. You will need a small Phillips screwdriver, the wall plate and screws from the box, and your phone with the Helio app installed.

Before you start

1. Switch off power to your heating and cooling system at the breaker. Confirm the old thermostat screen is blank.
2. Take a photo of the old wiring before you remove any wires. You will use it to match labels.
3. Check you have a C-wire (common wire). The T2 needs one for reliable power. If you do not have a C-wire, see Is the Helio T2 compatible with my HVAC system?.

Mount the wall plate

1. Remove the old thermostat. Leave the wires through the wall opening.
2. Feed the wires through the centre of the Helio wall plate and screw it to the wall. Use the built-in level so the ring sits straight.
3. Insert each wire into the matching labelled terminal (R, C, W, Y, G, O/B). Push until the tab clicks. A wire should not pull out with a gentle tug.

Attach the T2 and power on

1. Line up the T2 with the plate and press until it clicks.
2. Restore power at the breaker. The ring lights white while it starts, which takes about 40 seconds.
3. Open the Helio app and tap Add device → Helio T2. The app walks you through Wi-Fi pairing and a short heating/cooling test.

Things to know

• The T2 works with 24 V low-voltage systems only. Do not connect it to line-voltage (120/240 V) baseboard heaters.
• If the ring flashes red on first boot, a wire is likely in the wrong terminal. Power down and compare against your photo.
• Keep the old thermostat until you have run the heating and cooling test successfully.