User's Manual

Installation Instructions

The THERM-500 Backplate

W3 3rd stage heat circuit

W2 2nd stage heat circuit

W1/O/B 1st stage heat circuit

Y2 2nd stage compressor relay

Y1 1st stage compressor relay

G fan relay

R 24 VAC return

C 24 VAC common

SENSOR remote/outdoor/supply/return sensor connections

IMPORTANT: This thermostat requires both R (24 VAC Return) and

C (24 VAC Common) be connected to the backplate terminals.

To remove the thermostat backplate:

Using the Finger Pull Areas, pull the

front housing away from the backplate.

Look for these tabs to locate

the pull areas

Pull out with thumbs in these areas

Backplate

Front Housing

NOTE:

The backplate does not fully

cover a full size vertical junction

box. The ACC-WPLWH

OneLink Wallplate or a

single-gang, horizontally

mounted junction box would

be needed for that type of

installation

W1/O/B

SENSOR