Leviton Omnistat 3 RC500-2EW User manual

PK-A3099-10-02-0A-X4
omnistat™ 3
© 2015 Leviton Mfg. Co., Inc.
ENGLISH - Page 2
FRANÇAIS - Page 26
ESPAÑOL - Página 51
RC500-2EW
Thermostat Installation Instructions
Electrical rating: 24 VAC; 2 A; 50/60 Hz
Directives d’installation d’un thermostat
Valeurs nominales : 24 V c.a.; 2 A; 50/60 Hz
Instrucciones de Instalación del Termostato
Capacidad eléctrica: 24 VCA; 2 A; 50/60 Hz

WARNING AND CAUTIONS
• WARNING: TO AVOID DEATH OR SERIOUS PERSONAL INJURY never
push objects of any kind into this product through openings, as they may touch
dangerous voltages.
• WARNING: TO AVOID DEATH OR SERIOUS PERSONAL INJURY never touch
uninsulated wires or terminals unless the wiring has been disconnected at the
network interface.
• WARNING: TO AVOID DEATH OR SERIOUS PERSONAL INJURY, be sure
to disconnect the power to the control transformer before removing or installing
thermostat.
• Read and understand all instructions. Follow all warnings and instructions marked
on the product.
• Do not use this product near water - e.g., near a tub, wash basin, kitchen sink or
laundry tub, in a wet basement, or near a swimming pool.
• Never install communications wiring or components during a lightning storm.
• Never install communications components in wet locations unless the components
are designed specifically for use in wet locations.
• Use caution when installing or modifying communications wiring or components.
• SAVE THESE INSTRUCTIONS.
CAUTION:
• Do not short gas valve, fan, heat relay, or cool relay...even momentarily.
• Do not attempt to hook up to live circuits. An accidental connection to a component
on the thermostat circuit board could cause damage to the thermostat.
The following requirements must be observed for installation in Europe: CE
1. This equipment must be installed in accordance with National wiring rules for the
country in which it is installed.
2. All product labels, instructions and markings relating to safety must be translated
to a language, which is acceptable in the country in which this equipment is to be
installed.
1
DESCRIPTION
The RC500-2EW is a precision digital thermostat designed for 24 VAC heating
and cooling systems.
The RC500-2EW will support the following systems:
• Single Stage Heat/Cool Conventional
• Two Stage Conventional (2 Stage Heat / 2 Stage Cool)
• Heat Pump (2 Stage Heat / 1 Stage Cool)
• Two Speed Heat Pump (3 Stage Heat / 2 Stage Cool)
• 2-Pipe and 4-Pipe

2
INSTALLATION
Before installing this thermostat:
1. Read all of the Installation Instructions carefully.
2. Ensure that this product is suitable for your application.
3. Ensure that wiring complies with all codes and ordinances.
4. DISCONNECT POWER TO THE CONTROL TRANSFORMER to prevent
electrical shock and damage to equipment.
5. Select an appropriate location to ensure an accurate temperature reading.
Location
When replacing an existing thermostat, install the RC500-2EW in the same location. If
the existing location doesn’t meet the following criteria, choose a new location to mount
the RC500-2EW. When choosing a location for the thermostat:
1. Ensure that the thermostat is mounted 5 feet above the floor and is at least 2 feet
from an outdoor wall.
2. Ensure that the thermostat is located in an area where there is adequate air
circulation.
3. Do not mount in the path of direct sunlight or of radiant heat generated by
appliances.
4. Do not mount on an exterior-facing wall, near a fireplace, or in the path of any air
ducts.
Removing an existing thermostat
1. DISCONNECT THE POWER TO THE CONTROL TRANSFORMER.
2. Remove the cover to the existing thermostat.
3. Disconnect the wires going to each terminal on the thermostat. Label each wire
with the letter or number at the terminal.
4. Remove the existing plate or base from the wall.
NOTE: If replacing an existing thermostat that is larger than the RC500-2EW, the
Leviton®RCPLT-00W Thermostat Installation Cover Plate may be used to cover
any imperfections left by the previous thermostat. A Leviton RCPLT-00W can be
purchased from your Leviton distributor.

3
MOUNTING
When mounting the RC500-2EW, grasp the thermostat by
the sides and unsnap the base from the face.
Holding the base to the wall so that the word “UP” is upright
and facing you:
1. Mark the two mounting holes on the wall using a pencil.
2. Drill a hole using a 3/16” bit at each mounting hole marking .
3. Install the two wall anchors supplied.
4. Slide the system wires through the opening in the base.
5. Mount the base to the wall using the two #6 x 1” self-
tapping screws supplied - See Figure 1.
Connect each wire to the terminal strip(s) on the thermostat
base per the wiring diagram for your system application -
See Figures 4 - 11. Form the thermostat wiring so that the
cable lies flat between the terminal strip(s) and the center
of the base - See Figure 2.
Upon completion of wiring the thermostat, push all excess wiring into the hole in the
wall. For best performance, Leviton recommends plugging the hole to ensure an
accurate temperature reading by the thermostat.
Align the tabs of the thermostat face with the slots of the thermostat base. Gently push
the thermostat face into the thermostat base locking it into place - See Figure 2.
NOTE: Be sure that the thermostat temperature sensor is standing up, and that it has not
been damaged during installation - See Figure 3.
Figure 2 Figure 3
TabSlot
Base
Wall
Temperature
Sensor
Figure 1

4
IMPORTANT NOTES:
1. For HVAC systems with a single transformer for heating and cooling, jumper (J3)
labeled “RH-RC” on the thermostat printed circuit board, bridges Terminal 7 (RH)
and Terminal 8 (RC) and must remain in place.
2. From the factory, the RC500-2EW is configured to control a single stage
conventional HVAC system.
• If the HVAC system is a heat pump, 2-Pipe, or 4-Pipe system that requires a
sub-base, before operating the thermostat, the “System Type” settings under
“HVAC Settings” must be configured
– See Installation Settings.
TYPICAL WIRING DIAGRAMS
CAUTION:
• WARNING: TO AVOID DEATH OR SERIOUS PERSONAL INJURY, be sure to
disconnect the power to the control transformer before removing or installing thermostat.
• Do not short gas valve, fan, heat relay, or cool relay...even momentarily.
• Do not attempt to hook up to live circuits. An accidental connection to a component
on the thermostat circuit board could cause damage to the thermostat.
This thermostat comes from the factory with a jumper (J3) labeled “RH-RC” on the
thermostat printed circuit board installed for HVAC systems with a single transformer.
The jumper bridges Terminal 7 (RH) and Terminal 8 (RC) on the terminal strip. For HVAC
systems with a single transformer, this jumper (J3) must remain in place.
Figure 4
Thermostat power-up for test or configuration purposes
12345678
(RC)
(C)
HVAC SYSTEMS
24VAC “HOT”
24VAC
CONTROL
TRANSFORMER
24VAC Common
THERMOSTAT

5
Figure 5
Connections for heat and cool transformers - applies to all systems
(RH)
(C)
(RC)
12345678
HVAC SYSTEMS
24VAC Heat “HOT”
THERMOSTAT
24VAC Common
24VAC
HEAT
TRANSFORMER
24VAC
COOL
TRANSFORMER
24VAC Cool “HOT”
TYPICAL WIRING DIAGRAMS - Continued
3. If the HVAC system is a two stage conventional or two speed heat pump, before
operating the thermostat (making a call for heat or cool), the “Cool Stages”
and “Heat Stages” settings under “HVAC Settings” must be configured – See
Installation Settings.
4. When configured as a conventional thermostat, by default this thermostat does
not turn the fan on with a call for heat. If the furnace requires the thermostat to
turn the fan on with a call for heat, configure “Fan With Heat” to “Enabled” under
“HVAC Settings”.
5. Refer to the “Configuration” steps under the wiring diagram for the respective
HVAC system type.
6. If the thermostat or HVAC system does not perform as stated in the “Power Up”
steps under the wiring diagram for the respective HVAC system, recheck all
wiring - See Troubleshooting Tips.
7. For HVAC systems with separate heating and cooling transformers, the jumper
(J3) labeled “RH-RC” on the thermostat printed circuit board must be removed –
See Figure 5.

6
For HVAC systems with separate heating and cooling
transformers, the jumper (J3) labeled “RH-RC” on the
thermostat printed circuit board must be removed.
TYPICAL WIRING DIAGRAMS - Continued

7
CONFIGURATION
• From the factory, the RC500-2EW is configured as a single stage conventional
heat/cool thermostat.
• In the default configuration, this thermostat does not turn the fan on with a call for
heat. If the furnace does not turn the fan on with a call for heat, the thermostat
must be configured to do so under “HVAC Settings”.
POWER UP
1. Double check wiring, be sure that there are no stray wires or wire strands at the
connections.
2. Connect power to the transformer and system.
3. Attach the thermostat to the base, the display will show the current temperature
reading.
4. Press [FAN]. The fan icon should display in the lower left-hand corner of the
display and the system fan should come on.
* Common wire is required in “heat only” or “cool only” applications. Also use
a common if heat, cool, or fan relay cannot supply enough current to power
thermostat, without activating.
Figure 6
Connections for single stage heat/cool thermostat
Single Stage Conventional
12345678
(RC)
(G2)
(G3)
(G1)
(W1)
(Y1)
(C)
HVAC SYSTEMS
24VAC “HOT”
THERMOSTAT
24VAC Common*
24VAC
CONTROL
TRANSFORMER
Cool
Heat
Fan Stage 1
Fan Stage 2
Fan Stage 3

8
Single Stage Conventional - Continued
5. Press [FAN] again. The thermostat will turn off, as evidenced by a power icon
appearing in the lower left-hand corner, no temperature displayed, and the fan
stopping.
6. Press [Fan] a third time. The thermostat will turn on, restoring the temperature
display and setting the fan to automatic mode (engage when an appropriate
heating or cooling call is made).
7. Test the “Heat” mode by performing the following steps:
a. Tap the “-“ or “+” button one time – this will bring up the raise/lower setpoint, as
well as a “flame” or “snowflake” icon below the setpoint.
b. Tap the Fan button as necessary, to change the icon below the setpoint to ”
flame” (Heat mode).
c. Use the “+” button to raise the desired heat setpoint above the current
temperature (recommend 2 degree raise). Ensure that the heating unit comes on.
d. Use the “-“ button to lower the heat setpoint back below the current temperature.
Ensure that the heating unit goes off.
8. Test the “Cool” mode by performing the following steps:
a. Tap the “-“ or “+” button one time – this will bring up the raise/lower setpoint, as
well as a “ flame” or “snowflake” icon below the setpoint.
b. Tap the Fan button as necessary, to change the icon below the setpoint to
”snowflake”
(Cool mode).
c. Use the “-” button to lower the desired cool setpoint below the current
temperature (recommend 2 degree decrease). Ensure that the cooling unit comes
on.
d. Use the “+“ button to raise the cool setpoint back above the current temperature.
Ensure that the cooling unit goes off.
****IMPORTANT****
The RC500-2EW thermostat is designed to work with most single stage conventional 4-wire HVAC
systems (without a transformer common). However, if the RC500-2EW “resets” when calling for heat
or cool, or if the heat, cool, or fan relay cannot supply enough current to power thermostat without
the relay activating, the transformer common wire or the Leviton Thermostat Power Supply Module
(Part Number: 30A00-2) is required.

CONFIGURATION
• The “System Type” for this thermostat must be set to “Conventional” under “HVAC
Settings”.
• In the default configuration, this thermostat does not turn the fan on with a call for
heat. If the furnace does not turn the fan on with a call for heat, the thermostat
must be configured to do so under “HVAC Settings”.
• The “Cool Stages” and “Heat Stages” settings must be configured under “HVAC
Settings”.
POWER UP
1. Double check wiring, be sure that there are no stray wires or wire strands at the
connections.
2. Connect power to the transformer and system.
3. Attach the thermostat to the base, the display will show the current temperature
reading.
Figure 7
Connections for two stage conventional thermostat
Two Stage Conventional (2 Stage Heat / 2 Stage Cool)
12345678
(RC)
(Y2)
(W2)
(G)
(W1)
(Y1)
(C)
HVAC SYSTEMS
24VAC “HOT”
THERMOSTAT
24VAC Common
24VAC
CONTROL
TRANSFORMER
Cool Stage 1
Heat Stage 1
Fan
Heat Stage 2
Cool Stage 2
9

10
Two Stage Conventional (2 Stage Heat / 2 Stage Cool) - Continued
4. Press [FAN]. The fan icon should display in the lower left-hand corner of the
display and the system fan should come on. NOTE: If “Fan Stages” have been
set to more than 1, a second icon depicting a staircase, with the first step
displayed in black will appear. Press [FAN] again to continue to Stage 2 and
Stage 3 (based on Fan Stages set in HVAC Settings).
5. Press [FAN] again. The thermostat will turn off, as evidenced by a power icon
appearing in the lower left-hand corner, no temperature displayed, and the fan
stopping.
6. Press [FAN] one more time. The thermostat will turn on, restoring the temperature
display and setting the fan to automatic mode (engage as necessary when an
appropriate heating or cooling call is made).
7. Test the “Heat” mode by performing the following steps:
a. Tap the “-“ or “+” button one time – this will bring up the raise/lower setpoint,
as well as a “ flame” or “snowflake” icon below the setpoint.
b. Tap the Fan button as necessary, to change the icon below the setpoint to ”
flame” (Heat mode).
c. Use the “+” button to raise the desired heat setpoint 1 degree above the
current temperature - the heating unit should come on.
d. After approximately 2-3 minutes, raise the heat setpoint to 5 degrees above
the current temperature – the second stage of heat will engage.
e. Use the “-“ button to lower the heat setpoint back below the current
temperature. Ensure that the heating unit goes off.
8. Test the “Cool” mode by performing the following steps:
a. Tap the “-“ or “+” button one time – this will bring up the raise/lower setpoint,
as well as a “ flame” or “snowflake” icon below the setpoint.
b. Tap the Fan button as necessary, to change the icon below the setpoint to
”snowflake” (Cool mode).
c. Use the “-” button to lower the desired cool setpoint 1 degree below the
current temperature - the cooling unit should come on.
d. After approximately 2-3 minutes, lower the cool setpoint to 5 degrees below
the current temperature – the second stage of cool will engage.
e. Use the “+“ button to raise the cool setpoint back above the current
temperature. Ensure that the cooling unit goes off.

Figure 8
Connections for heat pump thermostat
About Heat Pump Systems
Heat Pump (2 Stage Heat / 1 Stage Cool)
1) Terminal 5 (O/B) controls the reversing valve for the heat pump.
The Reversing Valve setting is set to Cool by default. If the heat pump requires the
reversing valve to be energized for heating, configure “Reversing Valve” to “Heat”
under “HVAC Settings” (Setup and Configuration).
2) With a call for Stage 2 on a two speed heat pump, both compressor outputs Y1 and
Y2 are energized. When 2 stages of cooling and 2 stages of heating are configured
for a heat pump, Stage 2 is considered high speed on the heat pump and not auxiliary
heat. If auxiliary heat (or emergency heat) in needed, configure 3 stages of heating
under “HVAC Settings”.
3) The Emergency Heat Relay (E Terminal) and outdoor thermostats (usually
accessories to a heat pump), are not used. The RC500-2EW automatically controls
auxiliary heat efficiently. If the heat pump is equipped with an outdoor thermostat, it
should be removed from the auxiliary heat circuit.
12345678
(RC)
(AUX)
(G)
(Y1)
(O/B)
(C)
(G2)
HVAC SYSTEMS
24VAC “HOT”
THERMOSTAT
24VAC Common
24VAC
CONTROL
TRANSFORMER
Reversing Valve
Compressor
Fan
Auxiliary Heat
Fan Stage 2
11
CONFIGURATION
• The “System Type” must be set to “Heat Pump” under “HVAC Settings”.

12
POWER UP
1. Double check wiring, be sure that there are no stray wires or wire strands at the
connections.
2. Connect power to the transformer and system. The display will show all of the
temperature reading.
3. Press [FAN]. The fan icon should display in the lower left-hand corner of the display
and the system fan should come on.
4. Press [FAN] again. The thermostat will turn off, as evidenced by a power icon
appearing in the lower left-hand corner, no temperature displayed, and the fan
stopping.
5. Press [FAN] a third time. The thermostat will turn on, restoring the temperature display
and setting the fan to automatic mode (engage when an appropriate heating or cooling
call is made).
6. Test the “Heat” mode by performing the following steps:
a. Tap the “-“ or “+” button one time – this will bring up the raise/lower setpoint, as
well as a “ flame” or “snowflake” icon below the setpoint.
b. Tap the Fan button as necessary, to change the icon below the setpoint to ”
flame” (Heat mode).
c. Use the “+” button to raise the desired heat setpoint 1 degree above the current
temperature - the heating unit should come on. NOTE: Ensure that the heating
system is actually heating.
d. After approximately 2-3 minutes, raise the heat setpoint to 3 degrees above the
current temperature – the second stage of heat will engage.
e. Use the “-“ button to lower the heat setpoint back below the current temperature.
Ensure that the heating unit goes off.
7. Test the “Cool” mode by performing the following steps:
a. Tap the “-“ or “+” button one time – this will bring up the raise/lower setpoint, as
well as a “ flame” or “snowflake” icon below the setpoint.
b. Tap the Fan button as necessary, to change the icon below the setpoint to
”snowflake” (Cool mode).
c. Use the “-” button to lower the desired cool setpoint 1 degree below the current
temperature - the cooling unit should come on.
d. After approximately 2-3 minutes, lower the cool setpoint to 3 degrees below the
current temperature – the second stage of cool will engage.
e. Use the “+“ button to raise the cool setpoint back above the current temperature.
Ensure that the cooling unit goes off.
Heat Pump (2 Stage Heat / 1 Stage Cool) - Continued

CONFIGURATION
• The “System Type” must be set to “Heat Pump” under “HVAC Settings”.
• The “Cool Stages” and “Heat Stages” settings must be configured under “HVAC
Settings”.
POWER UP
1. Double check wiring, be sure that there are no stray wires or wire strands at the
connections.
2. Connect power to the transformer and system. The display will show the current
temperature reading.
3. Press [FAN]. The fan icon should display in the lower left-hand corner of the
display and the system fan should come on. NOTE: If “Fan Stages” have been
set to more than 1, a second icon depicting a staircase, with the first step
displayed in black will appear. Press [FAN] again to continue to Stage 2 and
Stage 3 (based on Fan Stages set in HVAC Settings).
Figure 9
Connections for two speed heat pump thermostat
Two Speed Heat Pump (3 Stage Heat / 2 Stage Cool)
12345678
(RC)
(Y2)
(AUX)
(G)
(Y1)
(O/B)
(C)
HVAC SYSTEMS
24VAC “HOT”
THERMOSTAT
24VAC Common
24VAC
CONTROL
TRANSFORMER
Reversing Valve
Compressor Stage 1
Fan
Auxiliary Heat
Compressor Stage 2
13

14
Two Speed Heat Pump (3 Stage Heat / 2 Stage Cool) - Continued
4. Press [FAN] again. The thermostat will turn off, as evidenced by a power icon
appearing in the lower left-hand corner, no temperature displayed, and the fan
stopping.
5. Press [FAN] one more time. The thermostat will turn on, restoring the temperature
display and setting the fan to automatic mode (engage as necessary when an
appropriate heating or cooling call is made).
6. Test the “Heat” mode by performing the following steps:
a. Tap the “-“ or “+” button one time – this will bring up the raise/lower setpoint,
as well as a “ flame” or “snowflake” icon below the setpoint.
b. Tap the Fan button as necessary, to change the icon below the setpoint to ”
flame” (Heat mode).
c. Use the “+” button to raise the desired heat setpoint 1 degree above the
current temperature - the heating unit should come on. NOTE: Ensure that
the heating system is actually heating.
d. After approximately 2-3 minutes, raise the heat setpoint to 3 degrees above
the current temperature – the second stage of heat will engage.
e. Use the “-“ button to lower the heat setpoint back below the current
temperature. Ensure that the heating unit goes off.
7. Test the “Cool” mode by performing the following steps:
a. Tap the “-“ or “+” button one time – this will bring up the raise/lower setpoint,
as well as a “ flame” or “snowflake” icon below the setpoint.
b. Tap the Fan button as necessary, to change the icon below the setpoint to
”snowflake”
(Cool mode).
c. Use the “-” button to lower the desired cool setpoint 1 degree below the
current temperature - the cooling unit should come on.
d. After approximately 2-3 minutes, lower the cool setpoint to 3 degrees below
the current temperature – the second stage of cool will engage.
e. Use the “+“ button to raise the cool setpoint back above the current
temperature. Ensure that the cooling unit goes off.

CONFIGURATION
• The “System Type” must be set to “2-Pipe” under “HVAC Settings”.
POWER UP
1. Double check wiring, be sure that there are no stray wires or wire strands at the
connections.
2. Connect power to the transformer and system.
3. Attach the thermostat to the base, the display will show the current temperature
reading.
Figure 10
Connections for 2-Pipe thermostat
About 2-Pipe Systems
2-Pipe
1) 2-Pipe systems require an external pipe temperature sensor to determine if the
thermostat will be calling for cooling or heating.
2) The external pipe temperature sensor connects to the two-position header
terminal marked J4 on the back of the thermostat printed circuit board (Refer to
Figure 12).
12345678
(RC)
(G)
(Y1)
(C)
(G2)
(G3)
HVAC SYSTEMS
24VAC “HOT”
THERMOSTAT
24VAC Common
24VAC
CONTROL
TRANSFORMER
Fan
Fan Stage 2
Fan Stage 3
Cool/Heat Valve
15

16
About 2-Pipe Systems - Continued
4. Press [FAN]. The fan icon should display in the lower left-hand corner of the
display and the system fan should come on. NOTE: If “Fan Stages” have been
set to more than 1, a second icon depicting a staircase, with the first step
displayed in black will appear. Press [FAN] again to continue to Stage 2 and
Stage 3 (based on Fan Stages set in HVAC Settings).
5. Press [FAN] again. The thermostat will turn off, as evidenced by a power icon
appearing in the lower left-hand corner, no temperature displayed, and the fan
stopping.
6. Press [FAN] a third time. The thermostat will turn on, restoring the temperature
display and setting the fan to automatic mode (engage when an appropriate
heating or cooling call is made).
****IMPORTANT****
Unlike conventional and heat pump HVAC systems, changing the mode between heat and cool
is not a task that can be achieved readily for testing actual operation of both heat and cool
modes at the time of the thermostat installation. In a 2-Pipe application, take the following
steps to test operation:
• Press either the “-“ or “+” to view the setpoint and observe the icon below the
setpoint. It should match the mode the 2-Pipe system is currently in.
• If the system is currently in Heat mode, raise the heat setting above the current
temperature and ensure that the heating unit comes on. Lower the setpoint below
the current temperature and ensure that the heating stops.
• If the system is currently in Cool mode, lower the cool setpoint below the current
temperature and ensure that the cooling unit comes on. Raise the setpoint above
the current temperature and ensure that the cooling unit goes off.

CONFIGURATION
• The “System Type” must be set to “4-Pipe” under “HVAC Settings”.
POWER UP
1. Double check wiring, be sure that there are no stray wires or wire strands at the
connections.
2. Connect power to the transformer and system.
3. Attach the thermostat to the base, the display will show the current temperature reading.
4. Press [FAN]. The fan icon should display in the lower left-hand corner of the display
and the system fan should come on. NOTE: If “Fan Stages” have been set to more
than 1, a second icon depicting a staircase, with the first step displayed in black
will appear. Press [FAN] again to continue to Stage 2 and Stage 3 (based on Fan
Stages set in HVAC Settings).
5. Press [FAN] again. The thermostat will turn off, as evidenced by a power icon appearing
in the lower left-hand corner, no temperature displayed, and the fan stopping.
6. Press [FAN] a third time. The thermostat will turn on, restoring the temperature display
and setting the fan to automatic mode (engage when an appropriate heating or cooling
call is made).
Figure 11
Connections for 4-Pipe thermostat
4-Pipe
12345678
(RC)
(G)
(W1)
(Y1)
(C)
(G2)
(G3)
HVAC SYSTEMS
24VAC “HOT”
THERMOSTAT
24VAC Common
24VAC
CONTROL
TRANSFORMER
Fan
Fan Stage 2
Fan Stage 3
Heat Valve
Cool Valve
17

18
7. Test the “Heat” mode by performing the following steps:
a. Tap the “-“ or “+” button one time – this will bring up the raise/lower setpoint, as
well as a “ flame” or “snowflake” icon below the setpoint.
b. Tap the Fan button as necessary, to change the icon below the setpoint to ” flame”
(Heat mode).
c. Use the “+” button to raise the desired heat setpoint above the current temperature
(recommend 2 degree raise). Ensure that the heating unit comes on.
d. Use the “-“ button to lower the heat setpoint back below the current temperature.
Ensure that the heating unit goes off.
8. Test the “Cool” mode by performing the following steps:
a. Tap the “-“ or “+” button one time – this will bring up the raise/lower setpoint, as
well as a “ flame” or “snowflake” icon below the setpoint.
b. Tap the Fan button as necessary, to change the icon below the setpoint to
”snowflake” (Cool mode).
c. Use the “-” button to lower the desired cool setpoint below the current temperature
(recommend 2 degree decrease). Ensure that the cooling unit comes on.
d. Use the “+“ button to raise the cool setpoint back above the current temperature.
Ensure that the cooling unit goes off.
Pipe Temperature Sensor
An external pipe temperature sensor can be installed to monitor the temperature of the
pipe in a 2-pipe system. The thermostat uses the temperature from the external pipe
temperature sensor to determine if the thermostat will be calling for cooling or heating.
The temperature sensor should be a point-matched 10,000 ohms @ 25°C thermistor,
R/T Curve A, ±5% @ 25°C.
Run a twisted pair, shielded cable from the RC500-2EW to the pipe where the external
pipe temperature will be installed. For distances up to 100 feet, typical twisted pair,
PVC-insulated, shielded cable may be used. For distances from 100-150 feet, twisted
pair with polypropylene insulated conductors, shielded must be used. For distances
from 150-250 feet, twisted pair with foam-polyethylene insulated conductors, shielded
must be used. Wire runs must not exceed 250 feet.
Crimp each wire of the cable to crimp terminals (Harwin Inc. P/N: M20-1180046, or
equivalent) and insert the terminals into a two-pin SIL connector (Harwin Inc. P/N
M20-1060200, or equivalent). Insert the assembled two-pin SIL connector into the
two-position header terminal labeled J4 on the back of the thermostat printed circuit
board - See Figure 12.
4-Pipe - Continued