Page 1
Digital
Digital
Thermostat
Thermostat
residential
THERMOSTAT
900
T1
7-DAY
7-DAY
PROGRAMMABLE
PROGRAMMABLE
up to
up to
& 2-cool
3-heat
3-heat
& 2-cool
HEAT
COOL
with HUMIDITY
CONTROL
Dry Contact Equipped
Outdoor Sensor Ready with
Control up to 3 Heat &
2 Cool Stages
3 Configurable Outputs
Adjustable 2nd & 3rd Stage
Timers & Deadbands
Backlit Display & Button
Legends
Aux Heat Indicator
Use with most Air Conditioning & Heating Systems including: 1 or 2 Stage
Electric Cooling & 3 Stage Gas Heating, Heat Pump, Electric or Hydronic Heat.
INSTALLATION
INSTALLATION
INSTRUCTIONS
INSTRUCTIONS
Venstar Inc. 08/07
High/Low Readouts for the Day
Equipped with Optional Humidity
Module: Controls Humidification,
Dehumidification and Reheat
Programmable Output
Accepts EZ Programmer
Accepts Optional IR Remote Control
Accepts Comfort Call
Phone Control Accessory
HEAT
PUMP
Page 2
CAUTION
Follow the Installation Instructions before proceeding.
Set the thermostat mode to “OFF” prior to changing
settings in setup or restoring Factory Defaults.
CAUTION
NEVER PUT MORE THAN ONE
JUMPER ON THE SAME MISC
JUMPER BLOCK!
THIS MAY DAMAGE YOUR
THERMOSTAT AND VOID
YOUR WARRANTY.
MISC3
OK
NOTE: Due to variations in environmental conditions, it is not
always possible to achieve the desired humidification or
dehumidification setpoint.
This device complies with Part 15 of the FCC Rules. Operation is
subject to the following two conditions: (1) this device may not cause
harmful interference, and (2) this device must accept any interference
received, including interference that may cause undesired operation.
Thermostat T1900
Tested to Comply
c
with FCC Standards
C
F
4Z95
FOR HOME OR OFFICE USE
MISC3
Page i
Page 3
Page 4
Table of Contents
Preparation
Remove & Replace the
Old Thermostat
Configuring the MISC
Outputs
Wire Connections
Wiring Diagrams
Test Operation
Calibrating the
Thermostat Sensors
TroubleShooting
1
2
3
4
5
6
7
8
Page iii
Page 5
SECTION 1
Preparation
1
Proper installation of the thermostat will be
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accomplished by following these step by step
instructions. If you are unsure about any of these
steps, call a qualified technician for assistance.
Assemble tools
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Flat Blade
Screwdriver
Make sure your Heater/Air Conditioner is working
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properly before beginning installation of the
Wire cutter
& Stripper
thermostat.
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Carefully unpack the thermostat. Save the screws,
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HEAT
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bracket, and instructions.
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AUTO
Turn off the power to the Heating/Air Conditioning
HEAT
72
system at the main fuse panel. Most residential
systems have a separate breaker for disconnecting
power to the furnace.
Page 1.1
Page 6
SECTION 2
Remove & Replace the Old Thermostat
Remove the cover of the old thermostat.
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If it does not come off easily check for screws.
Loosen the screws holding the thermostat
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base or subbase to the wall, and lift away.
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Disconnect the wires from the old thermostat.
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Tape the ends of the wires as you disconnect
them, and mark them with the letter of the
terminal for easy reconnection to the new
thermostat.
Keep the old thermostat for reference purposes,
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until your new thermostat is functioning properly.
2
Page 2.1
Page 7
SECTION 3
Configuring the MISC Outputs
3
Section 3 Contents:
Configuring the Jumpers........3.2
Explanation of Jumper
Settings..................................3.3
Page 3.1
Page 8
Configuring the Jumpers
For additional flexibility, your thermostat has three configurable
outputs. These outputs are designed to have different functions
3
depending on how the jumpers are set (below).
Each output, labeled MISC1, MISC2, and MISC3 may be set for one
of the five choices available.
In the diagram below, the MISC3 jumper has been set for HUM
(humidification) operation, the MISC2 jumper has been set for DEHUM
(dehumidification) operation, and the MISC1 jumper has been set for
PROG (programmable) operation.
(FAN)
PROG
DEHUM
MISC2
CKGND
W3
HUM
W1
Y1
G
CK1
R
C
MISC3 MISC2 MISC1
ELEC
GAS
HP
2
4
INSTALL HUMIDITY
1
3
GAS
B
O
W2
MISC1
HUM
NO HUM
RS2
MISC3
RS+5
Z
8
6
X
Rs1
1
RSGND
Y
579
Y2
(MISC1
ONLY)
MODULE WITH SENSING
ELEMENT OUTWARD
W3
PROG
HUM
DEHUM
MISC3 MISC2 MISC1
Y2
(MISC1
ONLY)
CAUTION
NEVER PUT MORE THAN
ONE JUMPER ON THE SAME
MISC JUMPER BLOCK!
DOING SO MAY DAMAGE
YOUR THERMOSTAT AND
VOID THE WARRANTY.
Page 3.2
MISC3
OK
MISC3
Page 9
Explanation of Jumper Settings
W3 JUMPER SETTING
3
If the jumper for MISC1, MISC2, or MISC3 is set to W3, the corresponding MISC
screw terminal on the backplate will control a third stage of heat.
W3 MULTI-STAGE OPERATION EXPLAINED - SECTION 14 of the Owner’s
Manual
The 3rd Stage of Heat is turned on when:
(A) The 1st and 2nd stages have been on for the time required (steps 27
and 28, page 14.6). It is adjustable from 0-60 minutes and the default
And
is two minutes.
(B) The temperature from the setpoint is equal to or greater than: the set-
point plus the 1st stage deadband (step #24, 14.5), plus the 2nd stage
deadband (step #25, 14.5) plus the 3rd stage deadband (step #26,
14.5). This 3rd stage deadband is adjustable from 0-10 degrees and
the default is two degrees.
3rd Stage
turn on
PROG JUMPER SETTING
If the jumper for MISC1, MISC2, or MISC3 is set to PROG,
terminal on the backplate will control a pilot relay or other accessory.
Heating
Deadband Deadband DeadbandDeadbandDeadband
2nd Stage
turn on
1st Stage
turn on
DECREASE INCREASE
db 1 db 1db 2 db 2db 3
(adj. 1-6 )(adj. 0-10 )(adj. 0-10 ) (adj. 0-10 )(adj. 1-6 )
Heat
Setpoint
Setpoint
TEMPERATURE
Cool
the corresponding MISC screw
PROGRAMMABLE OUTPUT - SECTION 15 of the Owner’s Manual
This jumper setting allows the MISC outputs to control a pilot relay by time,
temperature, or a signal from the Internet/Phone. The following are three
possible scenarios:
By Time: A device that requires a start and stop time. An example
of this would be an exterior lighting system that needed to be
energized every day between the hours of 8pm and 1am.
By Temperature: An exhaust fan that needs to energize whenever
the temperature from RS2 rises above 90 degrees F.
By Remote: Remotely arming a security system through the web or phone.
Page 3.3
Cooling
1st Stage
turn on
2nd Stage
turn on
Page 10
Explanation of Jumper Settings (continued)
HUM JUMPER SETTING
If the jumper for MISC1, MISC2, or MISC3 is set to HUM,
terminal on the backplate will control a humidification system.
HUMIDIFICATION OPERATION - SECTION 9 of the Owner’s Manual
If your HVAC unit is equipped with a humidification system the thermostat will
provide power to the MISC1, MISC2, or MISC3 terminal of the thermostat when
the humidity in the home falls below the humidity setpoint you have chosen.
The value for this setpoint ranges from 0% to 60%. If no humidity is desired
or if a humidification system has not been installed, set the value to OFF.
DEHUM JUMPER SETTING
If the jumper for MISC1, MISC2, or MISC3 is set to DEHUM,
terminal on the backplate will be connected to the dehumidification terminal of a furnace board.
NOTE: Not all furnaces have a dehumidification terminal.
DEHUMIDIFICATION OPERATION - SECTION 10 of the Owner’s Manual
If your HVAC unit is equipped with a dehumidification system the thermostat will
operate in one of two ways.
1) Normally Closed (NC): The thermostat will de-energize the MISC1, MISC2,
or MISC3 terminal of the thermostat (this MISC terminal is connected to the
DEHUM terminal on your furnace) to allow the fan to run in low speed when
the humidity in the home is above the dehumidify setpoint you have chosen
and there is a call for 1st stage cooling.
2) Normally Open (NO): The thermostat will energize the MISC1, MISC2, or
MISC3 terminal of the thermostat (this MISC terminal is connected to the
DEHUM terminal on your furnace) to allow the fan to run in low speed when
the humidity in the home is above the dehumidify setpoint you have chosen
and there is a call for 1st stage cooling.
the corresponding MISC screw
the corresponding MISC screw
3
Page 3.4
Page 11
Explanation of Jumper Settings (continued)
3
Y2 JUMPER SETTING
If the jumper for MISC1 is set to Y2 the
will control a second stage of cooling.
Y2 OPERATION - SECTION 14 of the Owner’s Manual
Control up to two Cool stages.
The 2nd Stage of heat or cool is turned on when:
(A) The 1st Stage has been on for the time required (step #27,
page 14.6). It is adjustable from 0-60 minutes and the default
is two minutes.
And
(B) The temperature spread from the setpoint is equal to or greater
than: the setpoint plus the deadband (step #24, page 14.5), plus
the 2nd deadband (step #25, page 14.5). This 2nd deadband is
adjustable from 0-10 degrees and the default is two degrees.
Cool
Setpoint
TEMPERATURE
MISC1 screw terminal on the backplate
Cooling
DeadbandDeadband
db 1 db 2
(adj. 0-10 )(adj. 1-6 )
1st Stage
INCREASE
turn on
2nd Stage
turn on
Page 3.5
Page 12
SECTION 4
Wire Connections
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If the terminal designations on your old thermostat
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do not match those on the new thermostat, refer
to the chart below, or the wiring diagrams
that follow.
Wire from the
old thermostat
terminal marked
G or F Fan G
Y1, Y or C
W1, W or H
C
O/B
W2
MISC1
MISC2
MISC3
RS+5
RSGND
RS2 RS2**
CK1
CKGND
Function
Cooling Y1
Heating
PowerRh, R, M, Vr, A R
Common
Rev. Valve
2nd Stage Heat
Configurable Output #1
Configurable Output #2
Configurable Output #3
Remote Sensor +5vdc
Remote Sensor Signal
Remote Sensor Ground
Remote Sensor Signal #2
Dry Contact Switch 1
Dry Contact Switch 2
Install on the
new thermostat
connector marked
W1/O/B
C
W1/O/B*
W2
MISC1
MISC2
MISC3
RS+5**
RS1**RS1
RSGND**
CK1
CKGND
4
* O/B is used if your system is a Heat Pump.
** For instructions on connecting these terminals see page 16.2
of the Owner’s Manual.
Page 4.1
Page 13
SECTION 5
Sample Wiring Diagrams
Section 5 Contents:
HVAC Equipment Wiring............5.2
5
MISC1, MISC2, and MISC3
Wiring........................................5.6
Remote Sensor, Outdoor Sensor
and CK1-CK2 wiring for the
Time Clock................................5.8
Page 5.1
Page 14
6 Wire, 1 Stage Cooling, 1 Stage Heat
Residential & Commercial 1 Stage Cooling,
with 1st stage Gas Heat
Commercial Heat Pump 1 Stage Cooling
OR
with 2 Stage Heat
5
(FAN)
ELEC
GAS
HP
GAS
B
O
W3
PROG
HUM
DEHUM
W1
MISC2
CK1
CKGND
24 vac common
24 vac return
fan relay
compressor relay
1st stage heat circuit
2nd stage heat circuit
Y1
G
R
C
MISC3 MISC2 MISC1
W2
MISC1
RS2
MISC3
RS+5
RS1
RSGND
Y2
(MISC1
ONLY)
2
INSTALL HUMIDITY
MODULE WITH SENSING
ELEMENT OUTWARD
1
C
R
G
Y1
W1
W2
(FAN)
6 Conductor 18 gauge
ELEC
GAS
HP
GAS
unshielded cable from the
B
O
thermostat to the equipment.
W2
MISC1
HUM
NO HUM
RS2
MISC3
RS+5
Z
8
4
6
X
Rs1
1
RSGND
Y
3
579
Page 5.2
W1/O/B
MISC2
CK1
CKGND
Y1
G
R
C
Page 15
6 Wire, 1 Stage Cooling, 1 Stage Heat
Residential & Commercial 1 Stage Cooling,
with 1st stage Electric Heat
5
(FAN)
ELEC
GAS
HP
GAS
B
O
24 vac common
24 vac return
fan relay
compressor relay
1st stage heat circuit
2nd stage heat circuit
W2
MISC1
RS2
MISC3
RS+5
RS1
RSGND
(FAN)
6 Conductor 18 gauge
ELEC
W3
PROG
HUM
DEHUM
MISC3 MISC2 MISC1
W1
Y1
G
MISC2
CK1
CKGND
R
C
GAS
HP
GAS
Y2
(MISC1
ONLY)
2
4
INSTALL HUMIDITY
MODULE WITH SENSING
ELEMENT OUTWARD
1
3
unshielded cable from the
B
O
thermostat to the equipment.
W2
MISC1
HUM
NO HUM
RS2
MISC3
RS+5
Z
8
6
X
Rs1
1
RSGND
Y
579
W1/O/B
MISC2
CK1
CKGND
Y1
G
R
C
R C
G
Y1
W1
W2
Page 5.3
Page 16
6 Wire, 1 Stage Cooling, 2 Stage Heat
Residential Heat Pump with O Reversing
Valve 1 Stage Cooling, with 2 stage Heat
5
(FAN)
ELEC
GAS
HP
GAS
B
O
W3
PROG
HUM
DEHUM
W1
MISC2
CK1
CKGND
24 vac common
24 vac return
Fan Relay
Compressor Relay
Reversing Valve
2nd stage heat circuit
Y1
G
R
C
MISC3 MISC2 MISC1
W2
MISC1
RS2
MISC3
RS+5
RS1
RSGND
Y2
(MISC1
ONLY)
2
INSTALL HUMIDITY
MODULE WITH SENSING
ELEMENT OUTWARD
1
R C
G
Y1
O
W2
(FAN)
6 Conductor 18 gauge
ELEC
GAS
HP
GAS
unshielded cable from the
B
O
thermostat to the equipment.
W2
MISC1
HUM
NO HUM
RS2
MISC3
RS+5
Z
8
4
6
X
Rs1
1
RSGND
Y
3
579
Page 5.4
W1/O/B
MISC2
CK1
CKGND
Y1
G
R
C
Page 17
6 Wire, 1 Stage Cooling, 2 Stage Heat
Residential Heat Pump with b Reversing
Valve 1 Stage Cooling, with 2 stage Heat
5
(FAN)
ELEC
GAS
HP
GAS
B
O
24 vac common
24 vac return
Fan Relay
Compressor Relay
Reversing Valve
2nd stage heat circuit
W2
MISC1
RS2
MISC3
RS+5
RS1
RSGND
(FAN)
6 Conductor 18 gauge
ELEC
W3
PROG
HUM
DEHUM
MISC3 MISC2 MISC1
W1
Y1
G
MISC2
CK1
CKGND
R
C
GAS
HP
GAS
Y2
(MISC1
ONLY)
2
INSTALL HUMIDITY
MODULE WITH SENSING
ELEMENT OUTWARD
1
unshielded cable from the
B
O
thermostat to the equipment.
W2
MISC1
HUM
NO HUM
RS2
MISC3
RS+5
Z
8
4
6
X
Rs1
1
RSGND
Y
3
579
W1/O/B
MISC2
CK1
CKGND
Y1
G
R
C
R C
G
Y1
b
W2
Page 5.5
Page 18
Adding a (MISC1), Sprinkler System (MISC2),
2nd Stage of Cooling
and 3rd Stage of Heating or Dual Fuel Applications (MISC3)
5
W3
PROG
HUM
DEHUM
MISC3 MISC2 MISC1
3rd Stage Heat
or Dual Fuel
2nd Stage Cooling
W2
MISC1
RS2
MISC3
RS+5
RS1
RSGND
Sprinkler System
W3
Y2
Y2
(MISC1
ONLY)
Page 5.6
W3
PROG
HUM
DEHUM
MISC2
CK1
CKGND
W1
Y1
G
MISC3 MISC2 MISC1
R
C
W1/O/B
MISC2
CK1
CKGND
Y2
(MISC1
ONLY)
2
INSTALL HUMIDITY
MODULE WITH SENSING
ELEMENT OUTWARD
1
Y1
4
3
G
R
C
(FAN)
ELEC
GAS
HP
GAS
B
O
W2
MISC1
HUM
NO HUM
RS2
MISC3
RS+5
Z
8
6
X
Rs1
1
RSGND
Y
579
Page 19
Adding a Humidification System (MISC1) and Dehumidification System (MISC2)
5
W3
PROG
HUM
DEHUM
MISC3 MISC2
Dehumidification
System
Humidification
System
W2
MISC1
RS2
MISC3
RS+5
RS1
RSGND
MISC1
W3
PROG
HUM
DEHUM
MISC3 MISC2 MISC1
W1
Y1
G
MISC2
CK1
CKGND
R
C
Y2
(MISC1
ONLY)
Page 5.7
W1/O/B
Y1
G
MISC2
CK1
CKGND
R
C
(FAN)
ELEC
GAS
HP
GAS
Y2
B
(MISC1
O
ONLY)
W2
MISC1
HUM
NO HUM
RS2
MISC3
RS+5
Z
2
8
4
6
X
Rs1
1
INSTALL HUMIDITY
MODULE WITH SENSING
RSGND
ELEMENT OUTWARD
1
Y
3
579
HUM
NO HUM
Page 20
CK1 and CK2 terminals wired to a Time Clock
For instructions on wiring the optional Remote and Outdoor
Sensors, please see page 16.2 of the Owner’s Manual
5
W2
MISC1
RS2
MISC3
RS+5
RS1
RSGND
12
11
10
9
8
7
DRY CONTACT SWITCH - The terminals are ‘normally open’ (or may be programmed for
normally closed operation, see page 17.2 of the Owner’s Manual). Closing or
completing the circuit will cause the thermostat to do one of the following:
1) If Vacation is selected in step #41 of the Advanced Setup (see page 17.3 of the
Owner’s Manual), when the dry contact is energized the thermostat will be forced into
Vacation mode (see Section 20 of the Owner’s Manual).
2) If Service Pan is selected, when the dry contact is energized the thermostat will lockout
Y1 (compressor) and write Service Pan on the display.
Page 5.8
W1/O/B
Y1
G
MISC2
CK1
CKGND
R
C
1
2
3
4
5
6
Page 21
SECTION 6
Test Operation
Turn the power on to the Heating/Air Conditioning
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system.
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Press the MODE button repeatedly until the
AUTO
HEAT
72
6
Pm
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Pm
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HEAT icon appears on the display. Press
UP or DOWN buttons until the set temperature is
10 degrees above room temperature. The
furnace should turn on.
74
COOL
Press the MODE button repeatedly until the
HEAT
72
COOL icon appears on the display.
or DOWN buttons until the set temperature is 10
degrees below room temperature. The air
conditioner should turn on. NOTE: Most
equipment has a time delay of 5 minutes between
cool cycles. This feature is defeatable on the
thermostat. Consult the Owner's Manual under
Setup, cycles per hour (page 14.3).
74
COOL
Press the UP button until the setpoint is equal to
HEAT
72
the room temperature. Press the FAN
button to Fan On. The fan should turn on and run
continuously.
the
Press the UP
Page 6.1
Page 22
SECTION 7
Calibrating the Thermostat Sensors
Under normal circumstances it will not be necessary to adjust the
calibration of the temperature and humidity sensors. If calibration is
required, please contact a trained HVAC technician to correctly
perform the following procedure.
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OFF
MODE
Place the thermostat in the
OFF mode.
72
Setup
Program On
and hold the MODE
MODE
FAN
PRESS
TWICE
Press the MODE button once. The
MODE
MODE
After calibration is complete, press the MODE button once to return to
normal operation.
remote sensor temperature will be
displayed and may be calibrated using the
UP or DOWN buttons. If a remote sensor
is not installed, only dashes will appear.
Press the MODE button once. The
relative humidity at the thermostat will be
displayed and may be calibrated using the
UP or DOWN buttons.
Press
button. While holding the
MODE button, press and hold
the FAN button for 5 seconds.
All icons will appear on the
display.
THERMOSTAT SENSOR
Press the UP and buttons
at the same time twice. The
thermostat temperature will be
displayed and may be calibrated
using the UP or DOWN buttons.
REMOTE SENSOR
HUMIDITY SENSOR
DOWN
Page 7.1
I8:88
SuMoTuWeThFrSa
Service Filter
Pan UV Light
AUTO
OFFON
Morning
DayNight
Evening
FanOn
Am
Pm
StartStop
DeHumidify
I88
Outside
HI
88
COOL
Outside
Vacation
AUXHEAT
LO
88
CALIBRATE
CALIBRATE
CALIBRATE
7
Page 23
SECTION 8
TroubleShooting
SYMPTOM: The air conditioning does not attempt to
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turn on.
CAUSE: The compressor timer lockout may prevent the
air conditioner from turning on for a period of time.
REMEDY: Consult the Owner's Manual in the Setup
section to defeat the cycles per hour and
compressor timeguard.
8
SYMPTOM: The display is blank.
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CAUSE: Lack of proper power.
REMEDY: Make sure power is turned on to the furnace
and that you have 24vac between R & W. If C is
used, 24vac between R & C.
SYMPTOM: The air conditioning does not attempt to
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turn on.
CAUSE: The cooling setpoint is set too high.
REMEDY: Consult the Owner's Manual in the Setup
section to lower the cooling setpoint limit.
SYMPTOM: The heating does not attempt to turn on.
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AUTO
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CAUSE: The heating setpoint is set too low.
REMEDY: Consult the Owner's Manual in the Setup
section to raise the heating setpoint limit.
Page 8.1
Page 24
TroubleShooting
Pm
I2:00
SYMPTOM: When controlling a residential heat pump,
74
COOL
AUTO
HEAT
72
and asking for cooling, the heat comes on.
CAUSE: The thermostat reversing valve jumper is set
for “b”.
REMEDY: Set the reversing valve jumper for “O”. See
pages 5.4 and 5.5.
Pm
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74
SYMPTOM: When calling for cooling, both the heat
COOL
AUTO
HEAT
72
and cool come on.
CAUSE: The thermostat equipment jumper is configured
for “HP” and the HVAC unit is a Gas/Electric.
REMEDY: Set the equipment jumper for “Gas”. See
pages 5.2 and 5.3.
Page 8.2
8
P/N 88-600
Rev. 1
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