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

10
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.

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4. Using the provided stickers, label each wire
according to the chart.
(If the terminals are not labeled, contact a
qualied HVAC technician.)
Note: Wire colors do not always comply with
standards, so wire color should be ignored.
Refer to the existing terminal designation for
proper identication.
*If a wire marked C is present, C may be a
Common wire and should not be used. If you have
a wire marked C, do not connect it to any terminal.
This wire is used only for non-battery powered
thermostats.
5. Do not let the wires slip back into the wall
during disconnection. You may want to secure
the wires to the wall as you disconnect them.
After all wires are labeled, disconnect each
wire and remove the existing wall plate.
UNINSTALLING THE EXISTING UNIT, CONT.
RH
G
W
W

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INSTALLING THE THERMOSTAT
INSTALLING THE THERMOSTAT
1. Remove the new thermostat from the back
plate by pulling the two halves apart.
Thermostat
Wall Plate

13
W
RH
G

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2. Position the new wall plate on the wall and pull
the labeled wires through the opening.
3. If the existing holes do not match those on the
Hunter wall plate, or if there are no existing
holes, level the wall plate and mark the wall for
two holes.
4. Remove the wall plate and drill two 3/16” holes
where marked.
5. Tap the plastic anchors into the holes until they
are ush with the wall.
6. Reposition the wall plate on the wall, pulling the
wires through the opening. Insert the mounting
screws through the mounting holes and into the
anchors. Verify that the thermostat is visually
level and securely tighten both screws.
INSTALLING THE THERMOSTAT, CONT.
INSTALLING THE WALL PLATE

15
RH
G
W

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INSTALLING THE THERMOSTAT, CONT.
CONNECTING THE WIRES
1. Loosen, but do not remove, the terminal
screws.
2. Match and connect the wires from the wall
to the terminals as shown. Wires should be
inserted behind the black terminal shields.
Tighten each screw after the connection has
been made.
(The ends of any extra wires should be wrapped in
electrical tape and carefully pushed back into the wall.)
3. Push any excess wire length back into the wall
to prevent interference.

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HE/HG Switch

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ATTACHING THE THERMOSTAT
4. Locate the HE/HG s w i t c H on the back of the
thermostat. Set the switch to HG for a gas
furnace or oil burner. Set the switch to HE for
electric furnaces.
5. Insert two fresh AA alkaline batteries.
6. Align the thermostat with the the wall plate,
and snap the two halves together.
7. Restore power at the electrical panel or
furnace.
INSTALLING THE THERMOSTAT, CONT.

19

20
Fan
Switch
System
Switch
Set Temperature
Slider
Thermometer
Battery Indicator
SYSTEM
OFF
HEAT
AUTO
ON
30
20
10
90
80
70
60
50
FC
9 0
8 0
7 0
6 0
5 0
F