Hunter 40120 User manual

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Electronic/Mechanical
Thermostat
Model 40120
installation and
operation manual
44018-01 04-01-2008

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For assistance with wiring or operation, our Technical
Support Group is available from 8 am to 5 pm CST.
they may be reached toll-free at 1-888-830-1326.

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Table of Contents
Important Information ....................................... 5
Tools ................................................................. 6
Uninstalling the Existing Unit............................ 9
Installing the Thermostat ................................ 12
Installing the wall plate ................................... 14
connecting the wires........................... 15
attaching the thermostat ..................... 17
Operation........................................................ 20
Indicators & Adjustments................................ 22
Troubleshooting.............................................. 25
Wiring Diagrams............................................. 27

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Congratulations!
Thank you for choosing a Hunter thermostat.
Your new Hunter thermostat will provide years of
reliable service and year-round energy savings.
Please read this manual before beginning
installation and save this booklet for complete
operation instructions.
Electronic/Mechanical
Thermostat
Model 40120

5
This thermostat is designed to work on the following
heating and cooling systems:
Gas – Standing Pilot
Gas – Electronic Ignition
Gas – Fired Boilers
Gas – Millivolt Systems
Oil – Fired Boilers
Oil – Fired Furnace
Electric Furnace
This thermostat is not designed for heat pump
systems or 110/220 V baseboard heating systems.
If you are unsure what kind of heating and cooling
system you have, please contact a qualied HVAC
Technician for assistance.
IMPORTANT INFORMATION

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This thermostat includes two #8 slotted screws and
two wall anchors for mounting.
To install your new thermostat, you will need the
following supplies:
Flat-head screwdriver
......................................................................................
Small Phillips-head screwdriver
......................................................................................
Hammer
......................................................................................
Electric drill and 3/16” bit
......................................................................................
Two fresh 1.5 Volt (AA) size alkaline batteries
......................................................................................
TOOLS

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NOTICE! Do not disconnect the wires
from the existing thermostat before
reading these instructions. The wires
must be labeled prior to removal to
ensure proper reconnection.

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Y
RC
G
W
Y
RC
G
W

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1. Turn the system power OFF from the existing
thermostat. Turn the power to the HVAC
system OFF at the main power panel or at the
furnace.
2. Remove the existing thermostat cover to
access the wires from the wall.
(Some thermostats may have multiple covers, screws
or other locking devices that must be removed or
disengaged.)
3. Locate, but do not disconnect the wires.
(If wires are not visible, they may be connected to the
back of the wall plate. Some models may have doors
that open to expose the wires and mounting screws.)
UNINSTALLING THE EXISTING UNIT

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If your existing
thermostat is marked...
label the wire
with this sticker:
RH / R / VR / 4
RH
RH
24 Volt
W / H
W
W
heating
G / F
G
G
fan
* See page 27 for complete wiring diagram.