CONTENTS
Installation Instructions for
Preparations.................................................. 1
Thermostat Details ........................................ 1
Removing Old Thermostat ......................... 1-2
Mounting and Wiring .................................. 2-3
Check Thermostat Operation ..................... 4-5
Specifications ................................................ 5
Troubleshooting ......................................... 5-6
Heating & Air Conditioning
Model 500
Non- Programmable
Heat Pump Thermostat
YOUR THERMOSTAT REPLACES
PREPARATIONS
1
Assemble tools required as shown below.
Description
Heat Pump (No Aux or Emergency Heat)
Heat Pump (with Aux or Emergency Heat)
Standard Heat & Cooling Systems
Standard Heat Only Systems
Yes
Yes
No
No
No
No
No
No
No
No
FLAT BLADE SCREWDRIVER
WIRE CUTTER/STRIPPER
HAND OR POWER
DRILL WITH 3/16 INCH
DRILL BIT, IF NEEDED
Millivolt Heat Only Systems – Floor or Wall Furnaces
Standard Central Air Conditioning
Gas or Oil Heat
SPIRIT LEVEL OR PLUMB BOB AND LINE OPTIONAL—
THERMOSTAT DOES NOT NEED TO BE LEVEL TO WORK PROPERLY
Electric Furnace
Failure to follow and read all instructions carefully
before installing or operating this control could cause
personal injury and/or property damage.
Hydronic (Hot Water) Zone Heat – 2 Wires
Hydronic (Hot Water) Zone Heat – 3 Wires
THERMOSTAT DETAILS
REMOVING OLD THERMOSTAT
2
3
CAUTION
!
Mounting
hole
To prevent electrical shock and/or equipment damage,
disconnect electrical power to the system at the main
fuse or circuit breaker until installation is complete.
Before removing wires from old thermostat’s switching subbase,
label each wirewith the terminal designation it was removed from.
1. Remove Old Thermostat: A standard heat/cool thermostat
consists of three basic parts:
a. The cover, which may be either a snap-on or hinge type.
b. The base, which is removed by loosening all captive screws.
O/B
Terminal
Switches
Selection
c. The switching subbase, which is removed by unscrewing
themountingscrewsthatholditonthewalloradaptorplate.
2. Shut off electricity at the main fuse box until installation is
complete. Ensure that electrical power is disconnected.
3. Remove the front cover of the old thermostat. With wires still
attached, removewallplatefromthewall.Iftheoldthermostat
has a wall mounting plate, remove the thermostat and the wall
mounting plate as an assembly.
W906 for Emergency
Heat Second Stage
Fan Control
W904
Clip for
Celsius
Mounting
hole
W905
Clip for
Slow Cycle
4. Identifyeachwireattachedtotheoldthermostatusingthe
labels enclosed with the new thermostat.
Figure 1. Thermostat base
5. Disconnectthewiresfromtheoldthermostatoneatatime.DO
NOT LET WIRES FALL BACK INTO THE WALL.
6. Install new thermostat using the following procedures.
WHITE-RODGERS
EMERSON ELECTRIC CO.
9797 REAVIS ROAD
ST. LOUIS, MISSOURI 63123-5398
PART NO. 37-6398C
Replaces 37-6398B
Printed in U.S.A.
0341
MOUNTING AND WIRING
CONTINUED FROM SECOND PAGE
4
THERMOSTAT
SYSTEM
O/B
Y
G
W2
E
C
L
R
See Note **
SYSTEM
MONITOR
SWITCH
Changeover
Relay*
Fan
Relay
Emergency
Relay
Aux
Relay
Compressor
Contactor
(Stage 2)
Hot
24 VAC
120 VAC
Neutral
* Changeover Relay is energized in COOL when O/B switch is in the “O” position
Changeover Relay is energized in HEAT when O/B switch is in the “B” position
TRANSFORMER
(Class II)
** Jumper required to use a single Aux Heat for both Second Stage Heat and Emergency
Figure 2. Typical wiring diagram for single transformer systems
NOTE
If safety circuits are in only one of the systems, remove
the transformer of the system with NO safety circuits.
THERMOSTAT
SYSTEM
O/B
Y
G
W2
E
C
L
R
CUT AND
TAPE OFF!
SYSTEM
MONITOR
SWITCH
See Note **
Changeover
Relay*
Fan
Relay
Limit or
Safety
Switches
Emergency
Relay
HOT
120 VAC
NEUTRAL
24 VAC
Aux
Relay
(Stage 2)
Compressor
Contactor
Hot
24 VAC
120 VAC
Neutral
TWO COMMONS MUST
BE JUMPERED TOGETHER!
TRANSFORMER
(Class II)
* Changeover Relay is energized in COOL when O/B switch is in the “O” position
Changeover Relay is energized in HEAT when O/B switch is in the “B” position
** Jumper required to use a single Aux Heat for both Second Stage Heat and Emergency
Figure 3. Typical wiring diagram for two transformer systems with NO safety circuits
NOTE
Polarity must be observed. If the HOT side of the second transformer
is jumpered to the COMMON side of the first transformer a short will
be made. Damage to equipment will occur when power is restored.
THERMOSTAT
O/B
Y
G
W2
E
C
L
R
SYSTEM
Limit or
Safety
Limit or
Safety
See Note **
HOT
Switches
24 VAC
120 VAC
Switches
SYSTEM
MONITOR
SWITCH
Changeover
Relay*
Fan
Relay
NEUTRAL
Emergency
Relay
24 VAC
Auxiliary
Heating
NOTE
ACCESSORY
RELAY N.O.
CONTACT
Aux
Relay
(Stage 2)
Transformer
(Class II)
The accessory relay scheme
is required when safety
circuits exist in both systems.
Compressor
Contactor
COMMON
TWO COMMONS MUST
BE JUMPERED TOGETHER!
Limit or
Limit or
Safety
Switches
Safety
HOT
Switches
24 VAC
120 VAC
* Changeover Relay is energized in COOL when O/B switch is in the “O” position
Changeover Relay is energized in HEAT when O/B switch is in the “B” position
COMMON
NEUTRAL
** Jumper required to use a single Aux Heat for both Second Stage Heat and Emergency
Heat Pump Transformer
(Class II)
Figure 4. Typical wiring diagram for two transformer systems with safety circuits in BOTH systems
Cooling System
1. Move SYSTEM switch to COOL position.
CHECK THERMOSTAT OPERATION
5
2. Press
ture. The blower should come on immediately on high speed,
followed by cold air circulation.
3. Press to adjust temperature setting above room tem-
to adjust thermostat setting below room tempera-
NOTE
To prevent static discharge problems, touch side of ther-
mostattoreleasestaticbuild-upbeforetouchinganykeys.
If at any time during testing your system does not operate
properly, contact a qualified serviceperson.
perature. The cooling system should stop operating.
Before you begin programming your thermostat, you should be
familiar with its features and with the display and the location and
operation of the thermostat buttons. Your thermostat consists of
two parts: the thermostat cover and the base. To remove the
cover, gently pull it straight out from the base. To replace the
cover, line up the cover with the base and press gently until the
cover snaps onto the base.
Fan Operation
If your system does not have a G terminal connection, skip to
Heating System.
1. Turn on power to the system.
2. Move fan switch to ON position. The blower should begin to
operate.
3. Move fan switch to AUTO position. The blower should stop
The Thermostat Buttons and Switches
immediately.
1
2
3
4
(Up arrow) Raises temperature setting.
(Down arrow) Lowers temperature setting.
CAUTION
Do not allow the compressor to run unless the compres-
sor oil heaters have been operational for 6 hours and the
system has not been operational for at least 5 minutes.
!
FAN switch (ON, AUTO).
SYSTEM switch (COOL, OFF, HEAT, EMER).
The Display
Heating System
1. Move SYSTEM switch to HEAT position. If the auxiliary
5
6
Indicates a malfunction with the system.
heating system has a standing pilot, be sure to light it.
2. Press
to adjust thermostat setting to 1° above room
Flame icon ( ) is displayed when the SYSTEM switch is in
theHEATposition.Flameicon( )isdisplayedflashingwhen
2nd-stage heat (Aux or Emergency) is energized. Snow-
flakeicon( )isdisplayed(non-flashing)whentheSYSTEM
switch is in the COOL position. Snowflake and Flame icons
are displayed (flashing) if the thermostat is in lockout mode
to prevent the compressor from cycling too quickly.
temperature. The heat pump system should begin to operate.
However, if the Flame icon ( ) and Snowflake icon ( ) are
flashing, the compressor lockout feature is operating (see
Configuration menu, item 3.)
3. Adjusttemperaturesettingto4° aboveroomtemperature.The
auxiliary heat system should begin to operate and the Flame
icon ( ) will be flashing.
7
8
EMER is displayed flashing when the system switch is in
EMER position.
4. Press
to adjust thermostat setting below room tempera-
ture. The heating system should stop operating.
Displays current temperature.
Emergency System
EMER bypasses the Heat Pump to use the heat source wired
to terminal E on the thermostat. EMER is typically used when
compressor operation is not desired, or you prefer back-up
heat only.
1. Move SYSTEM switch to EMER position. EMER will flash on
the display.
2. Press
toadjustthermostatsettingaboveroomtempera-
ture. The Aux heating system will begin to operate. The
Flame icon ( ) will display flashing to indicate that the Aux
system is operating.
3. Press
to adjust the thermostat below room temperature.
The Aux heating system should stop operating.
CAUTION
!
To prevent compressor and/or property damage, if the
outdoor temperature is below 50°F, DO NOT operate the
cooling system
CHECK THERMOSTAT OPERATION
CONTINUED FROM FOURTH PAGE
Configuration Menu
5
Step
Press Button(s)
Displayed
Press
or
(Factory Default)
to select:
Set SYSTEM
switch to OFF
and
9
1
2
Displays currently programmed set temperature (this is blank
when SYSTEM switch is in the OFF position).
FA
(ON)
OFF
ON
for at least 2 seconds
10
“BATT” is displayed when 2 “AAA” batteries are low and
should be replaced.
CL
(OFF)
and
momentarily
3
4
and
momentarily
0 HI
(0)
3 LO TO
3 HI
Configuration Menu
dL
(ON)
The configuration menu allows you to set certain thermostat
operating characteristics to your system or personal requirements.
To enter the configuration menu, with SYSTEM switch in OFF
and
momentarily
5*
6
OFF
Move SYSTEM
switch from OFF
Return to normal operation
position, hold
and
for at least two seconds. To exit the
configuration menu, move the SYSTEM switch from the OFF
position.
* Not available on earlier models
2. In the run mode, if the setpoint temperature is manually raised
by 3°F (2°C) or more above the actual temperature with the
TEMPERATURE UP key, and the fast second stage feature is
enabled, FA on, the second stage will energize immediately.
With FA off, second stage will not energize until the setpoint
temperature is 1°F or more above actual temperature for more
than ten minutes.
5. SelectBacklitDisplay–(Notavailableonearliermodels)The
display backlight improves display contrast in low lighting
conditions. Selecting backlight ON will keep the light on
continuously. Selecting Backlight OFF will keep the light off.
SPECIFICATIONS
6
3. Select Compressor Lockout CL OFF or ON – Selecting CL
ON will cause the thermostat to wait 5 minutes before turning
on the compressor if the heating and cooling system loses
power.Itwillalsowait5minutesminimumbetweencoolingand
heating cycles. This is intended to help protect the compressor
from short cycling. Some newer compressors already have a
time delay built in and do not require this feature. Your com-
pressor manufacturer can tell you if the lockout feature is
alreadypresentintheirsystem.Whenthethermostatcompres-
sor time delay occurs it will flash the Snowflake and Flame
Icons for about five minutes.
ELECTRICAL DATA
Electrical Rating:
20 to 30 VAC 50/60 Hz.
0.05 to 1.0 Amps (Load per terminal)
1.5 Amps Maximum Total Load (All terminals combined)
THERMAL DATA
Setpoint Temperature Range:
45°F to 90°F (7°C to 32°C)
Operating Ambient Temperature Range:
32°F to 105°F
Operating Humidity Range:
0 to 90% RH (non-condensing)
Shipping Temperature Range:
-40°F to 150°F
4. Select Temperature Display Adjustment 3 LO to 3 HI –
Allowsyoutoadjusttheroomtemperaturedisplayupto3° higher
or lower. Your thermostat was accurately calibrated at the
factory but you have the option to change the display temperature
to match your previous thermostat. The current or adjusted
roomtemperaturewillbedisplayedontheleftsideofthedisplay.
TROUBLESHOOTING
7
Reset Operation
If a voltage spike or static discharge blanks out the display or
causes erratic thermostat operation you can reset the thermostat
still does not function correctly contact your heating/cooling ser-
vice person or place of purchase.
by pressing
and
at the same time when system is
Batteries
switched from “OFF” to “HEAT” position. This also resets the
factory defaults. If the thermostat has power, has been reset and
For optimum performance, we recommend replacing batteries
once a year with fresh “AAA” Energizer alkaline batteries.
®
Symptom
Possible Cause
Corrective Action
No Heat/No Cool/No Fan
(common problems)
1. Blown fuse or tripped circuit breaker.
2. Furnace power switch to OFF.
Replace fuse or reset breaker.
Turn switch to ON.
3. Furnace blower compartment door or
panel loose or not properly installed.
Replace door panel in proper position to engage
safety interlock or door switch.
TROUBLESHOOTING
CONTINUED FROM FIFTH PAGE
7
Symptom
No Heat
Possible Cause
Corrective Action
1. Pilot light not lit.
Re-light pilot.
2. System Switch not set to HEAT.
Set System Switch to HEAT and raise setpoint
above room temperature.
3. Loose connection to thermostat or system.
Verify thermostat and system wires are securely
attached.
4. Furnace Lock-Out Condition. Heat may also
be intermittent.
Many furnaces have safety devices that shut
down when a lock-out condition occurs. If the
heat works intermittently contact the furnace
manufacturer or local service person for
assistance.
5. Heating system requires service or
thermostat requires replacement.
Diagnostic: Set System Switch to HEAT and raise
the setpoint above room temperature. Within a few
seconds the thermostat should make a soft click
sound. This sound usually indicates the thermo-
stat is operating properly. If the thermostat does
not click, try the reset operation listed above. If the
thermostat does not click after being reset contact
your heating and cooling service person or place
of purchase for a replacement. If the thermostat
clicks, contact the furnace manufacturer or a
service person to verify the heating is operating
correctly.
No Cool
1. System Switch not set to COOL.
Set System Switch to COOL and lower setpoint
below room temperature.
2. Loose connection to thermostat or system.
Verify thermostat and system wires are securely
attached.
3. Cooling system requires service or
thermostat requires replacement.
Same procedure as diagnostic for No Heat
condition except set the thermostat to COOL and
lower the setpoint below the room temperature.
There may be up to a five minute delay before the
thermostat clicks in Cooling.
Heat, Cool or Fan Runs Constantly.
1. Possible short in wiring.
Check each wire connection to verify they are not
shorted or touching together. No bare wire should
stick out from under terminal screws. Try resetting
the thermostat as described above. If the condition
persists the manufacturer of your system or
2. Possible short in thermostat.
3. Possible short in heat/cool/fan system.
4. Fan Switch set to Fan On.
service person can instruct you on how to test the
Heat/Cool system for correct operation. If the
system operates correctly, replace the thermostat.
Furnace (Air Conditioning) Cycles Too Fast
or Too Slow (narrow or wide temperature
swing)
1. The location of the thermostat and/or the
size of the Heating (Cooling) System may
be influencing the cycle rate.
Digital thermostats normally provide precise
temperature control and may cycle faster than
some older mechanical models. A faster cycle
rate means the unit turns on and off more
frequently but runs for a shorter time so there is
no increase in energy use. If you would like to
increase the cycle time, clip Jumper W-905 as
mentioned in the instructions for Hydronic Heating
Systems. It is not possible to shorten the cycle
time. If an acceptable cycle rate is not achieved as
received or by clipping W-905 contact a local
service person for additional suggestions.
Thermostat Setting and Thermostat
Thermometer Disagree
1. Thermostat thermometer setting requires
adjustment.
The thermometer can be adjusted +/- 3 degrees.
See Temperature Display Adjustment in the
Operation section.
Blank Display and/or Keypad Not
Responding
1. Voltage spike or static discharge.
Use the Reset Operation listed above.
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