Installation Guide
DCN: 140-02338-01 DRAFT 20619
Page 2
Use the terminal labels and not the wiring color to mark the wires
Remove the old thermostat base
Caution. Don’t let the wires slip into the wall.
Wiring colors. While the wiring terminals markings are intended to match the wire color
(R=red, G=green, W=white, Y=yellow), not all installations were correctly installed this way.
Be sure to follow the terminal marking when marking the wires, even if the wire color
doesn’t match.
The C wire. If the 24VAC Common wire (usually Blue) is present and is connect to 24VAC
common at the HVAC system end, the thermostat can be powered from the HVAC system
and batteries are not required. If there is no Common wire, batteries are required.
Mount the thermostat base
Mount the thermostat base to the wall using the wall anchors and screws provided.
Level as needed.
Connect the wires – most common connections
Single Stage Gas Heating/Cooling HVAC System Wiring to the Thermostat
R vs RC and RH Connections:
Typical HVAC installations will have a common heating and cooling system 24VAC
transformer. For these systems, there is only one 24VAC “R” wire and it can connect to
either the RC or RH terminal on the thermostat. The thermostat is supplied with an RC-RH
jumper installed. Do not remove the jumper for common transformer HVAC systems.
Some installations may have separate heating and cooling systems/transformers. For
those systems there will be a separate “R” wire for the heating (RH) and cooling
transformers (RC).
Y
C
R
W
G
Y
W
G
R
C*
Take a
Picture!
*Note: the C wire (24V common) may
not be present.
If there is no C wire, the TBZ500
must be powered by batteries.
If the C wire is present, you can
power the thermostat without
batteries
Mark the wires according to the terminal markings.
There may be additional wires. Mark these according to the
terminals. Y1, Y2, W1, W2, O, B.
W
Y
G
C*
R
Connect the wires as marked from the HVAC
system to the corresponding terminals on the
thermostat back.
*C wire (24VAC common) may not be present.
If not, batteries must be installed.
Factory installed RC and RH jumper
Thermostat
Terminal Block
W2/O W1 RH C RC G Y1 Y2