3-2
Step 1.
Review and record the existing thermostat wiring configuraiton:
- Remove thermostat from wall plate to expose wiring terminals
- Take a photograph or note the wire colors and connections (see wiring reference table below)
- Attach wire labels to each of the wires
Remove Thermostat (if replacing existing thermostat)
Table 3.1: Wire Designation Record
Terminal
Designation
Wire Color
Function
4-Pipe System
2-Pipe System
L
Black
120/240 VAC Line Power
120/240 VAC Line Power
N
White
120/240 Neutral
120/240 Neutral
WY
Red
Heating Valve Actuator
Heating/Cooling Valve Actuator
YA
Blue
Cooling Valve Actuator
Auxiliary Heat
Gl
Brown
Fan Signal – Low Speed
Fan Signal – Low Speed
Gm
Orange
Fan Signal – Medium Speed
Fan Signal – Medium Speed
Gh
Yellow
Fan Signal – High Speed
Fan Signal – High Speed
Ac
Accessory Contact
Accessory Contact
Ac
Accessory Contact
Accessory Contact
Tp
Supply Pipe Temperature Sensor
Supply Pipe Temperature Sensor
Tx
External Temperature Sensor
External Temperature Sensor
Ts
Temperature Setback
Temperature Setback
Tc
Tp/Tx/Ts Common
Tp/Tx/Ts Common
Before removing the existing thermostat, turn
off power to the fan coil system .
Module 5 – Connected Fan Coil Controls
ST100ZB Line Power Fan Coil Thermostat
Section 3
Step 2.
Label each wire when disconnecting them from thermostat terminals and remove the thermostat
mounting plate .
Paint the mounting surface, if desired, before mounting the new thermostat back plate to
ensure complete wall coverage .
