Unit installation

DCN: 141-00885-16 1/26/06 TZ40 Thermostat Manual 22
TZ40 Installation
Before proceeding with removing an existing thermostat and installing the TZ40,
Read the following important steps.
1. Record existing wiring information on the enclosed wiring form.
2. Perform the TZ40 bench test
3. Check WDU wiring BEFORE applying power to control unit.
4. Be sure to install a freeze protection device as required.
Installation Overview
Standard thermostat wiring vs TZ40 in retrofit applications.
STOP
Heating &
Cooling
System
4, 5 or 6 wires
18Ga thermostat wiring
4 Wires
TZ40
Control
Unit
Heating &
Cooling
System
TZ40
Wall Display
Unit
Thermostat
Replace
Thermostat with
Wall Display Unit
Insert Control Unit into
the thermostat wiring
4,5 or 6 wires
as original
installation
OLD
NEW
Freeze Protection.
In cold climates that require the heating system to be used for building freeze protection, a mechanical
backup freeze protection device MUST be installed on the heating system. This can be a simple
mechanical heating thermostat or a preset thermoswitch installed in the heated area.
Heating
System
Red Wire 24VAC R
White Wire Heat W
40-45°
R
W
Thermostat connections
Wire across Heater R/W terminals.
Mechanical
Thermostat or
Thermoswitch