AAON RSMD2R Quick start guide

RSMD2R
Technical Guide

2RSMD2R Technical Guide
AAON
2425 South Yukon Ave.
Tulsa, OK 74107-2728
www.aaon.com
Factory Technical Support Phone: [phone]
AAON®Controls Support: 866-918-1100
It is the intent of AAON®to provide accurate and current
product information. However, in the interest of product
improvement, AAON®reserves the right to change pricing,
specications, and/or design of its product without notice,
obligation, or liability.
AAON Part Number: G088350, Rev. D
Copyright February 2024 AAON, Inc.
AAON®is a registered trademark of AAON, Inc., Tulsa, OK.
AAON®assumes no responsibility for errors or omissions in
this document.
This document is subject to change without notice.
RSMD2R REVISION LOG
REVISION & DATE CHANGE
Rev. A, March 15, 2021 Original
Rev. B, December 18, 2023 Added Condenser Fan Cleaning to Sequence, cosmetic updates
Rev. C, January 19, 2024 Updated Dehumidication Sequence
Rev. D, February 2, 2024 Added WSHP Valve Control to Sequence
www.aaon.com
RSMD2R PARTS REFERENCE
PART DESCRIPTION PART NUMBER
Refrigerant System Module for Digital Compressors ( RSMD2R) ASM02869
VCCX-IP Controller ASM07424
VCCX2 Controller ASM01698
Prism 2 ASM02533
IP Module Kit ASM01902
CommLink 5 ASM01874
EBC E-BUS Cable Assembly E-BUS Power & Comm
1.5 Ft, 3 Ft, 10 Ft, 25 Ft, 50 Ft, 75 Ft,
100 Ft, 150 Ft, 250 Ft, and 1000 Foot Spool
G029440 (1.5 Ft), G012870 (3 Ft), G029460 (10 Ft), G045270 (25
Ft), G029510 (50 Ft), G029530 (75 Ft), G029450 (100 Ft), G029470
(150 Ft), V36590 (250 Ft), G018870 (SPOOL)
Modular Service Tool SD - Operator Interface ASM01895
All manuals are also available for download from
www.aaon.com/controlsmanuals.

3RSMD2R Technical Guide
TABLE OF CONTENTS
OVERVIEW ................................................................................................................................................. 5
RSMD2R Overview................................................................................................................................................. 5
Dimensions ............................................................................................................................................................. 6
INSTALLATION AND WIRING.................................................................................................................. 7
Electrical Environmental Requirements .................................................................................................................. 7
WIRING ....................................................................................................................................................... 8
Inputs ...................................................................................................................................................................... 8
Outputs ................................................................................................................................................................... 9
INPUTS AND OUTPUTS ......................................................................................................................... 10
Inputs/Outputs Map............................................................................................................................................... 10
Input and Output Descriptions ...............................................................................................................................11
SEQUENCE OF OPERATIONS .............................................................................................................. 12
Cooling Mode, Dehumidication, and Head Pressure Control.............................................................................. 12
LCD SCREENS ........................................................................................................................................ 13
LCD Display Screen and Navigation Keys............................................................................................................ 13
Screen Map........................................................................................................................................................... 14
Screen Descriptions.............................................................................................................................................. 15
Protected Screen Map .......................................................................................................................................... 19
Protected Screen Descriptions ............................................................................................................................. 20
TROUBLESHOOTING ............................................................................................................................. 23
LED Diagnostics ................................................................................................................................................... 23
Suction Pressure Transducer Testing ................................................................................................................... 24
Copeland®Discharge Thermistor Temperature Sensor Testing............................................................................ 25
Temperature Sensor Testing ................................................................................................................................. 26
Head Pressure Transducer ................................................................................................................................... 27
APPENDIX A: CONDENSER OPTIONS ................................................................................................ 28
Default: Two Condenser Operation....................................................................................................................... 28
Single Condenser Per Module .............................................................................................................................. 30
Single Condenser Per Two Modules..................................................................................................................... 32
Single Condenser for Three Modules ................................................................................................................... 34
Two Condensers Per Two Modules ...................................................................................................................... 36
ON/OFF Condenser Options ................................................................................................................................ 39

4RSMD2R Technical Guide
FIGURES AND TABLES
TABLES
Table 1: RSMD2R Controller Electrical and Environmental Requirements .....................................................................7
Table 2: RSMD2R Inputs and Outputs ..............................................................................................................................10
Table 3: Navigation Key Functions.......................................................................................................................................13
Table 4: Main Screens............................................................................................................................................................15
Table 5: Module Screens .......................................................................................................................................................15
Table 6: System Status Screens...........................................................................................................................................16
Table 7: Sensor Status Screens ...........................................................................................................................................16
Table 8: Alarms Screens ........................................................................................................................................................17
Table 9: Alarm History Screens.............................................................................................................................................18
Table 10: Setpoint Status Screens .........................................................................................................................................18
Table 11: Conguration Screens.............................................................................................................................................20
Table 12: Diagnostic Screens..................................................................................................................................................21
Table 13: Coil Pressure/Voltage/Temp for Suction Pressure Transducers - R410-A Refrigerant.................................24
Table 14: Discharge Thermistor Temperature/Resistance..................................................................................................25
Table 15: 0-5V Temperature Sensor - Voltage & Resistance for Type III Sensors .........................................................26
Table 16: Head Pressure Transducer Chart..........................................................................................................................27
FIGURES
Figure 1: RSMD2R Dimensions ..............................................................................................................................................6
Figure 2: RSMD2R Inputs Wiring.............................................................................................................................................8
Figure 3: RSMD2R Outputs Wiring .........................................................................................................................................9
Figure 4: LCD Display and Navigation Keys........................................................................................................................13
Figure 5: RSMD2R LED Locations........................................................................................................................................23
Figure 6: Default: Two Condenser RSMD2R Module Wiring ............................................................................................28
Figure 7: Prism 2 Condenser Conguration: Default Two Condenser Operations ........................................................29
Figure 8: Single Condenser Per RSMD2R Module Wiring ................................................................................................30
Figure 9: Prism 2 Condenser Conguration: Single Condenser Per Module .................................................................31
Figure 10: Single Condenser Per Two RSMD2R Modules Wiring......................................................................................32
Figure 11: Prism 2 Condenser Conguration: Single Condenser Per Two Modules.......................................................33
Figure 12: Single Condenser for Three RSMD2R Modules Wiring ....................................................................................34
Figure 13: Prism 2 Condenser Conguration: Single Condenser for Three Modules .....................................................35
Figure 14: A1/B1 Wiring.............................................................................................................................................................36
Figure 15: A2/B2 Wiring.............................................................................................................................................................37
Figure 16: Prism 2 Condenser Conguration: A1/B1 and A2/B2 Condenser Conguration...........................................38
Figure 17: Prism 2 Condenser Conguration: ON/OFF Condenser Options....................................................................39

5RSMD2R Technical Guide
OVERVIEW
RSMD2R Overview
Features & Applications
The Refrigerant System Module for Digital Compressors (RSMD2R)
can monitor and control up to two compressors and condensers. The
compressors can only be in a non-tandem conguration. The module
is designed for R410-A refrigerant.
NOTE: The RSMD2R is for units that match
all of the following criteria:
1. Two circuits, single compressor per circuit.
2. Compressors may be any mix of xed, two-step,
and digital.
3. Reheat is present on the second circuit only.
The RSMD2R is connected to the VCCX2 Controller. Up to four
RSMD2R’s can be connected, depending on the size of the system.
There are two E-BUS Expansion Ports which allow the use of
communicating sensors and the E-BUS Modules.
The RSMD2R provides three analog inputs, four binary inputs,
ve relays, and two analog outputs. See Figures 2 & 3, pages 8
& 9 for wiring.
The RSMD2R Module provides the following:
• Modulates the Compressors to satisfy the Suction Coil
(Saturated) Temperature. The Suction Coil (Saturated)
Temperature Setpoint is reset by the VCCX2 Controller
to maintain the Supply Air Temperature during Cooling
mode. During Dehumidication mode, it controls the
Compressors to the Suction (Saturation) Temperature
Setpoint.
• In Heat Pump Heating mode, the RSMD2R modulates
and stages the compressors to maintain a given Supply
Air Temperature Setpoint.
• Modulates the Condenser Fan or Valve to maintain the
Head Pressure Setpoint.
• Provides alarms and safeties for the Compressor and
Condenser operation.
• Allows connection of the Modular Service Tool SD to the
module when required communication wire is run to the
VCCX2 Controller.
• Provides a 2 x 8 LCD character display and four buttons
that allow for status of system operation, system setpoints,
system congurations, sensors, and alarms, and to change
the module’s address, if necessary.

6RSMD2R Technical Guide
OVERVIEW
Dimensions
Figure 1: RSMD2R Dimensions
10A250VAC ~
5A30VDC
SA
VDE
G5Q-1A4
OMRON
DC12V
CHINA
1.33 1.50
1.50
0.45
6.15
3.09
3.07
4.96
5.26
5.55
0.75 4.10 0.74
5.05
1.50
0.52
1.33
1.50
ALARM
UP
DOWN
ENTERMENU
AAON P/N: ASM02869
+24 VAC
GND
RELAY CONTACT
RATING IS 1 AMP
MAX @ 24 VAC
CONDENSER 1
COMP 1
COMP 2
ANALOG OUT
REVERSING VALV E
COMMON
RELAYOUTPUT
TERMINALS
LABEL P/N:
G088060
COND 1
COND 2
GND
24 VAC
POWER ONLY
WARNING!
POLARITY
MUST BE
OBSERVED
OR THE
CONTROLLER
WILL BE
DAMAGED
CONDENSER 2
HEAD PRES 1
+5 V
+5 V
COMP DIS 1
COMP 1
SP-1
HP-1
COMP DIS 2
COMP 2
GND
GND
OA COIL / POWF
EMER SHDN
GND
LEAVING H20
GND
SUCTION PRES 2
HEAD PRES 2
+5 V
+5 V
SP-2
HP-2
GND
GND
R+
SHD
T-
E-BUS
R+ SHD T-
DUAL E-BUS
EXPANSION
RSMD2R
www.aaon.com
SUCTION PRES 1

7RSMD2R Technical Guide
INSTALLATION AND WIRING
Electrical Environmental Requirements
General
Correct wiring of the main unit controller and its modules is the most
important factor in the overall success of the controller installation
process. The main unit controller and modules are factory installed
and wired at the AAON factory. Some of the following information
may not apply to your installation if it was pre-wired at the factory.
However, if troubleshooting of the controller or modules is required,
it is a good idea to be familiar with the system wiring.
Wiring
The modules must be connected to an 18-30 VAC power source
of the proper size for the calculated VA load requirements. All
transformer sizing should be based on the VA ratings listed in Table
1, this page.
NOTE: If the temperature at the controller is below -4ºF
(-20ºC), the display refresh rate could be less
responsive.
WARNING: When using a single transformer to power
more than one controller or expansion module,
the correct polarity must always be maintained
between the boards. Failure to observe
correct polarity will result in damage to the
unit controller, RSMD2R, and any associated
module.
Please carefully read and apply the following information when
wiring the unit controller, RSMD2R, and any associated module.
1. All wiring is to be in accordance with local and national
electrical codes and specications.
2. All 24 VAC wiring must be connected so that all ground
wires remain common. Failure to follow this procedure
can result in damage to the controller and connected
devices.
3. Minimum wire size for 24 VAC wiring should be
18-gauge.
4. Minimum wire size for all sensors should be 24-gauge.
Some sensors require two-conductor wire and some
require three-or four-conductor wire.
5. Minimum wire size for 24 VAC thermostat wiring should
be 22-gauge.
6. Be sure that all wiring connections are properly inserted
and tightened into the terminal blocks. Do not allow wire
strands to stick out and touch adjoining terminals which
could potentially cause a short circuit.
7. When communication wiring is to be used to interconnect
HVAC Unit Controllers together or to connect to other
communication devices, all wiring must be plenum-rated,
minimum 18-gauge, two-conductor, twisted pair with
shield. AAON can supply communication wire that meets
this specication and is color coded for the network or
local loop. Please consult your AAON distributor for
information. If desired, Belden #82760 or equivalent
wire may also be used.
8. Before applying power to the HVAC Unit Controller,
RSMD2Rs, and any associated modules, be sure
to recheck all wiring connections and terminations
thoroughly.
Powering Up
When the controller and modules are rst powered up, the POWER
LED should light up and stay on continuously. If it does not light up,
check to be sure that you have 24 VAC connected to the controller,
that the wiring connections are tight, and that they are wired for the
correct polarity. The 24 VAC power must be connected so that all
ground wires remain common. If after making all these checks, the
POWER LED does not light up, please contact AAON Controls
Support for assistance.
Control
Device
Voltage
VA Load
Operating
Temperature
Humidity
(Non-
Condensing)
RSMD2R
Controller
18-30VAC 18 -4°F to 158°F
-20ºC to 70ºC 0-95% RH
Inputs
Resistive Inputs require 10KΩ
Type 3 Thermistor
24VAC Inputs provide 4.7kΩ Load
Outputs Relay Outputs: 1 Amp
maximum per output.
Table 1: RSMD2R Controller Electrical and
Environmental Requirements

8RSMD2R Technical Guide
WIRING
Inputs
RSMD2R Wiring
The RSMD2R monitors and controls one refrigeration circuit of
the HVAC unit. The module is designed for R410-A refrigerant.
The RSMD2R is connected to the VCCX2 Controller. Up to four
RSMD2R’s can be connected, depending on the size of the system.
There are two E-BUS Expansion Ports which allow the use of
communicating sensors and the E-BUS Modules.
The RSMD2R provides three analog inputs, four binary inputs, ve
relays, and two analog outputs. See Figure 2, this page for inputs
wiring and Figure 3, page 9 for outputs wiring.
Suction Pressure Sensor Wiring
The Suction Pressure Transducers must be wired as shown in Figure
2, this page. It is typically required for all VCCX2 applications.
The Suction Pressure Sensors are used to measure suction pressure
at the HVAC unit’s DX evaporator coil suction line. This suction
line pressure is converted to saturated refrigerant temperature.
The saturated refrigerant temperature is used to properly control
the compressors to maintain a given Suction Coil (Saturated)
Temperature Setpoint. In Cooling mode, the VCCX2 resets the
Suction Coil (Saturated) Temperature Setpoint to maintain a given
Supply Air Temperature Setpoint. In Dehumidication Mode, the
Suction Coil (Saturated) Temperature Setpoint is a user congurable
setpoint that can be reset based on indoor humidity levels.
WARNING: Observe Polarity! All boards must be wired
with GND-to-GND and 24-VAC-to-24
VAC. Failure to observe polarity will result
in damage to one or more of the boards.
Expansion modules must be wired in such
a way that the expansion modules and the
controller are always powered together. Loss
of power to the expansion module will cause
the controller to become inoperative until
power is restored to the expansion module.
Figure 2: RSMD2R Inputs Wiring
GND18-30
VAC
Head Pressure 2 Sensor
(by others)
Comp. Discharge
Temp 1 Sensor
Comp. Discharge
Temp 2 Sensor
Leaving Water
Temp Sensor
Comp Status 1
Comp Status 2
Outside Coil Temp/POWF
Emergency Shutdown
TEMP1
TEMP2
TEMP3
GND
GND
BIN4
BIN3
BIN2
BIN1
HP
+V
Suction Pressure 1
Sensor GND
+V
SP
RD
WT
BL
Head Pressure 1 Sensor
(by others) GND
HP
+V
RD
WT
BL
Suction Pressure 2
Sensor GND
+V
SP
RD
WT
BL
RD
WT
BL
Line Voltage
Size transformer for
correct total load.
RSMD2R = 18 VA
GND
10A250VAC ~
5A30VDC
SA
VDE
G5Q-1A4
OMRON
DC12V
CHINA
ALARM
UP
DOWN
ENTERMENU
AAON P/N: ASM02869
+24 VAC
GND
RELAYCONTACT
RATING IS 1 AMP
MAX @ 24 VAC
CONDENSER 1
COMP 1
COMP2
ANALOG OUT
REVERSING VALVE
COMMON
RELAY OUTPUT
TERMINALS
LABEL P/N:
G088060
COND 1
COND 2
GND
24 VAC
POWER ONLY
WARNING!
POLARITY
MUST BE
OBSERVED
OR THE
CONTROLLER
WILL BE
DAMAGED
CONDENSER 2
HEAD PRES 1
+5 V
+5 V
COMP DIS 1
COMP1
SP-1
HP-1
COMP DIS 2
COMP2
GND
GND
OA COIL / POWF
EMER SHDN
GND
LEAVING H20
GND
SUCTION PRES 2
HEAD PRES 2
+5 V
+5 V
SP-2
HP-2
GND
GND
R+
SHD
T-
E-BUS
R+ SHD T-
DUAL E-BUS
EXPANSION
RSMD2R
www.aaon.com
SUCTION PRES 1

9RSMD2R Technical Guide
WIRING
Outputs
Head Pressure Control
The Head Pressure Transducers are used to measure Head Pressure at
the discharge line. This Head Pressure is used to drive the Condenser
Fans with a 0-10 VDC output signal or valve with a 2-10 VDC output
signal to maintain a given Head Pressure Setpoint.
Compressor Discharge Sensors
The Digital Compressor Discharge Temperature Sensor monitors
the discharge temperature from the Digital Compressor to protect
against overheating.
Leaving Water Temperature Sensor
The Leaving Water Temperature Sensor is used to measure the
Leaving Water Temperature when used on a WSHP unit.
CAUTION: The Shraeder port used for installation of the
suction pressure transducer should be located in
a vertical position of the suction line to prevent
refrigerant oil from accumulating in the sensor.
NOTE: If there are two compressors on a single circuit (a
tandem circuit), Suction Pressure 2, Head Pressure
2, and Condenser Signal 2 would not be used.
Figure 3: RSMD2R Outputs Wiring
GND18-30
VAC
Line Voltage
Size transformer for
correct total load.
RSMD2R = 18 VA
10A250VAC ~
5A30VDC
SA
VDE
G5Q-1A4
OMRON
DC12V
CHINA
ALARM
UP
DOWN
ENTERMENU
AAON P/N: ASM02869
+24 VAC
GND
RELAY CONTACT
RATING IS 1 AMP
MAX @ 24 VAC
CONDENSER 1
COMP 1
COMP 2
ANALOG OUT
REVERSING VALVE
COMMON
RELAY OUTPUT
TERMINALS
LABEL P/N:
G088060
COND 1
COND 2
GND
24 VAC
POWER ONLY
WARNING!
POLARITY
MUST BE
OBSERVED
OR THE
CONTROLLER
WILL BE
DAMAGED
CONDENSER 2
HEAD PRES 1
+5 V
+5 V
COMP DIS 1
COMP 1
SP-1
HP-1
COMP DIS 2
COMP 2
GND
GND
OA COIL / POWF
EMER SHDN
GND
LEAVING H20
GND
SUCTION PRES 2
HEAD PRES 2
+5 V
+5 V
SP-2
HP-2
GND
GND
R+
SHD
T-
E-BUS
R+ SHD T-
DUAL E-BUS
EXPANSION
RSMD2R
www.aaon.com
SUCTION PRES 1
Belimo actuator wiring
shown. Consult factory for
other manufacturer wiring
instructions.
Note:
All relay outputs are normally open
and rated for 24 VAC power only.
1 Amp maximum load.
24 VAC ONLY
COMPRESSOR 1 ENABLE
COMPRESSOR 2 ENABLE
CONDENSER 1 ENABLE
CONDENSER 2 ENABLE
REVERSING VALVE
Digital Compressor 1
Digital Compressor 2
Condenser
Signal 1
Condenser
Signal 2
WSE Bypass
Valve Actuator
RLY2
RLY1
RLY4
RLY3
RLY5
COMM
UNLOAD
24 VAC
UNLOAD
AOUT1
GND
AOUT2
Connects to VCCX2
Loop Communications
connector when used on
a split system.
GND
+
GND
+
COM
+
COM
+
1 COM
2 +
3Y1

10RSMD2R Technical Guide
INPUTS AND OUTPUTS
Inputs/Outputs Map
Table 2: RSMD2R Inputs and Outputs
REFRIGERATION SYSTEM MODULE
FOR DIGITAL COMPRESSORS
Analog Inputs
1Suction Pressure 1 Sensor (SP-1)
2Head Pressure 1 Sensor (HP-1)
3Suction Pressure 2 Sensor (SP-2)
4Head Pressure 2 Sensor (HP-2)
5Compressor Discharge Temperature Sensor 1 (TEMP1)
6Compressor Discharge Temperature Sensor 2 (TEMP2)
7Leaving Water Temperature Sensor (TEMP3)
Binary Inputs
1Compressor Status 1 (BIN1)
2Compressor Status 2 (BIN2)
3Outside Coil Temperature / Proof of Water Flow (BIN3)
4Emergency Shutdown (BIN4)
Analog Outputs (0-10 VDC)
1Condenser 1 Fan Signal (AOUT1)
2Condenser 2 Fan Signal (0-10 VDC) or WSE Bypass Actuator
(2-10 VDC) (AOUT2)
Relay Outputs (24 VAC)
1Compressor 1 Enable Relay (RLY1)
2Compressor 2 Enable Relay (RLY2)
3Condenser 1 Enable Relay (RLY3)
4Condenser 1 Enable Relay (RLY4)
5Reversing Valve Relay (RLY5)

11RSMD2R Technical Guide
INPUTS AND OUTPUTS
Input and Output Descriptions
RSMD2R - Inputs & Outputs
+5V VDC Power
This output is a 5 VDC output that supplies power to the Suction
Pressure Transducers.
SP-1 & SP-2 - Suction Pressure Transducers
The Suction Pressure Sensors are used to measure suction pressure
at the HVAC unit’s DX evaporator coil suction line. This suction
line pressure is converted to saturated refrigerant temperature.
The saturated refrigerant temperature is used to properly control
the compressors to maintain a given Suction Coil (Saturated)
Temperature Setpoint. In Cooling mode, the VCCX2 resets the
Suction Coil (Saturated) Temperature Setpoint to maintain a given
supply air temperature setpoint. In Dehumidication mode, the
Suction Coil (Saturated) Temperature Setpoint is a user congurable
setpoint that can be reset based on indoor humidity levels.
+5V VDC Power
This output is a 5 VDC output that supplies power to the Head
Pressure Transducer.
HP-1 & HP-2 - Head Pressure Transducers
The Head Pressure Transducers are used to measure Head Pressure at
the discharge line. This Head Pressure is used to drive the Condenser
Fans to maintain a given Head Pressure Setpoint.
TEMP1 & TEMP2 - Compressor Discharge Temperature
Sensor 1 & Sensor 2 Input
The Digital Compressor Discharge Temperature Sensors monitor
the discharge temperature from the Digital Compressor to protect
against overheating.
TEMP3 - Leaving Water Temperature Sensor Input
This input monitors the Condenser Leaving Water Temperature
and determines if the water source condenser is operating in a safe
water temperature range.
BIN1 - Compressor Status 1
When this wet contact input closes, a 24 volt signal to Binary Input
#1 indicates that Compressor 1 is running. Typically, the source for
this is relay output 1. If Binary Input 1 opens, Compressor 1 Enable
Relay will de-energize and a Compressor Alarm will be generated.
BIN2 - Compressor Status 2
When this wet contact input closes, a 24 volt signal to Binary Input
#2 indicates that Compressor 2 is running. Typically, the source for
this is relay output 2. If Binary Input 2 opens, Compressor 2 Enable
Relay will de-energize and a Compressor Alarm will be generated.
BIN3 - Outside Coil Temperature / Proof of Water Flow
Status
This input can be used for the following two options:
Air to Air Heat Pump
This wet contact input monitors a Defrost Coil Temperature Switch
on air to air heat pump units. If the compressors are operating in the
Heating Mode and this switch closes, it will initiate a Defrost Mode.
Water Source Heat Pump
This wet contact input is for the Water Proof of Flow Switch. If the
Water Proof of Flow Switch contact opens while the Condenser
Valve is operating, the controller will react to protect the system
depending on the current mode of operation.
BIN4 - Emergency Shutdown
This wet contact input is used to initiate shutdown of the HVAC
unit when a N.C. Smoke Detector (by others), Firestat (by others),
or other shutdown condition (by others) contact is opened. The
controller remains active and can initiate alarm relays.
NOTE: The Binary Inputs require wet contacts (24 VAC
only) to recognize an active input. If you provide dry
contacts, the contact closure will not be recognized.
AOUT1 - Condenser Fan 1 Signal
This 0-10 VDC output is used to control/modulate the Condenser
1 Fan /Valve to maintain the Head Pressure Setpoint.
AOUT2 - Condenser Fan 2 Signal or Waterside
Economizer Bypass Actuator Valve
This 0-10 VDC output is used to control/modulate the Condenser
2 Fan /Valve to maintain the Head Pressure Setpoint or this output
signal is a Direct Acting 2-10 VDC output signal that is used to
modulate the Water Side Economizer Bypass Actuator.
RLY1 - Compressor 1 Enable
This relay enables the Compressor 1.
RLY2 - Compressor 2 Enable
This relay enables the Compressor 2.
RLY3 - Condenser 1 Enable
This relay enables the Condenser 1 Fan / Water Valve.
RLY4 - Condenser 2 Enable
This relay enables the Condenser 2 Fan / Water Valve.
RLY5 - Reversing Valve Enable
This relay enables the Reversing Valve.

12RSMD2R Technical Guide
SEQUENCE OF OPERATIONS
Cooling Mode, Dehumidication, and Head Pressure Control
Cooling Mode Operation
In the Cooling Mode, as the Supply Air Temperature (SAT) rises
above the Active SAT Cooling Setpoint, the compressors will stage
on and modulate to maintain the Active Evaporator Coil Suction
(Saturated) Temperature Setpoint. Two compressors are controlled
per Refrigerant System Module ( RSMD2R). Multiple RSMD2Rs
are needed when there are more than two compressors.
In units with one digital and one xed compressors, if the digital
compressor modulates to 100% and the SAT is still above the SAT
Cooling Setpoint for the Cooling Stage Up Delay, then the xed
compressor will stage on. The digital compressor will then be
allowed to modulate as necessary to maintain the Active Evaporator
Coil Suction (Saturated) Temperature Setpoint. Minimum o times
must also be met before compressors can stage on.
In units with multiple digital compressors, if the 1st digital
compressor modulates to 100% and the SAT is still above the SAT
Cooling Setpoint for the Cooling Stage Up Delay, then the 2nd
digital compressors will enable and the two digital Compressors
will then modulate together to maintain the Active Evaporator Coil
Suction (Saturated) Temperature Setpoint.
To stage down compressors, if the digital compressor(s) have
modulated down to 30% for the Stage Down Delay period and the
SAT has fallen below the SAT Cooling Setpoint minus the Stage
Control Window, then the last compressor to have staged on (digital
or Fixed) will stage o – assuming its Minimum Run Time has
been met. Any remaining digital compressors are then allowed to
modulate as needed. If the last remaining digital compressor reaches
0% for the Stage Down Delay, it will stage o.
Dehumidication Operation
The RSMD2R activates the Cooling Stages based on the actual
Evaporator Coil Temperature compared to the Evaporator Coil
Suction (Saturation) Temperature Setpoint. The Evaporator Coil
Suction (Saturation) Temperature is calculated by using the Suction
Pressure Sensor and converting the pressure to temperature.
The RSMD2R will always turn its second compressor on rst for
dehumidication mode and not shut it o.
For Copeland Digital Scroll™ Compressor units, the RSMD2R will
modulate the Copeland Digital Scroll™ Compressor to maintain
the Evaporator Coil Suction (Saturation) Temperature Setpoint and
activate the Compressors as necessary.
On units that have one Digital and one Fixed Capacity Compressor,
if the Fixed Capacity Compressor is activated, the Copeland Digital
Scroll™ Compressor will only be allowed to modulate within the
range of 70% - 100% in order to prevent the loss of reheat capacity
during low load conditions.
If, with both compressors on, the rst digital compressor has
modulated down to its 70% minimum and the Coil Suction
Temperature falls below the Coil Temperature Setpoint minus the
Cooling Stage Control Window, then the second compressor will
stage o once its Compressor Minimum Run Time and the Stage
Down Delay Timers have been met. At that point, the Copeland
Digital Scroll™ Compressor can modulate down as needed to
maintain the Coil Temperature Setpoint.
If the RSMD2R has two Digital Compressors, the rst compressor
modulates and can shut o. The second compressor will modulate
between 70% and 100%.
Head Pressure Control
The RSMD2R can monitor a Head Pressure Transducer and control a
Condenser Fan to maintain a Head Pressure Setpoint. The RSMD2R
must be congured for an Air Cooled Condenser.
A Condenser Relay is commanded on when the rst compressor is
enabled (except if the unit is in Heat Pump Defrost Mode). On an
Air Cooled Unit, the Condenser Fan will be controlled with 0-10
VDC output signal. When the Condenser Signal rst activates, it
maintains at 100% for 10 seconds.
In the Cooling Mode, the Condenser Signal will modulate to
maintain the Cooling Head Pressure Setpoint. The signal can
modulate between 15% and 100%. If the Head Pressure exceeds 550
PSIG, the condenser control signal will immediately go to 100%
and a High Head Pressure Alarm will be generated. The alarm will
be deactivated when the Head Pressure drops below 540 PSIG.
In the Dehumidication Mode, the Condenser Output Signal controls
to the Reheat Head Pressure Setpoint. High Head Pressure conditions
produce the same eects as in the Cooling Mode.
If no Head Pressure Sensor is detected, the Condenser Output Signal
will be maintained at 100%.
WSHP Valve Control
When the initial call for a compressor is received by the RSM the
water valve will open 100% and stay there for 3 minutes. If water
ow is proved after that initial time period the compressor will
enable. In Cooling Mode the water valve will modulate to maintain
the head pressure setpoint. In Heat Mode the water valve will stay at
100% unless the compressor is running out of its operating envelope.
In O Mode the water valve will close unless mechanical stops are
being used to prevent it from fully closing.
Condenser Fan Cleaning
If the RSMD2R is congured for Fan Cleaning and the ambient
temperature is below 35 degrees, the condenser fan will cycle on
once an hour for the Fan Cleaning Duration time period. This feature
is meant for cleaning snow o the fan blades on heat pump units.

13RSMD2R Technical Guide
LCD SCREENS
LCD Display Screen and Navigation Keys
LCD Display Screen & Navigation Keys
The LCD display screens and buttons allow you to view status and
alarms, and enable force modes. See Figure 4, this page and refer
to Table 3, this page for descriptions.
Navigation
Key Key Function
MENU Use the MENU key to move through screens within
Main Menu categories and return to the Main Menu
while at other screens.
UP Use this key to adjust setpoints and change
congurations.
DOWN Use this key to adjust setpoints and change
congurations.
ENTER Use the ENTER key to navigate through the Main
Menu Screen categories.
ALARM
UP
DOWN
ENTERMENU
Figure 4: LCD Display and Navigation Keys
Table 3: Navigation Key Functions

14RSMD2R Technical Guide
LCD SCREENS
Screen Map
RSMD2R
1134VXXX
SYSTEM
STATUS
SENSOR
STATUS
ALARMS ALARM
HISTORY
SETPOINT
STATUS
EBUS COMM
PACKETS
SOFTWARE
1134VXXX
BOARD/EBUS
ADDRESS
#COMP
CONFIGURED
#COND
CONFIGURED
COMP A1
DIGITAL
COMP B2
FIXED
MODE
OFF
COMP A1
ON
COMP B2
OFF
COND 1 FAN
20%
SUCTION 1
XXX PSI
HEAD PR1
XXX PSI
SUCTION 2
XXX PSI
HEAD PR2
XXX PSI
HEADPRSP
340 PSI
FAN ON
XX PSI
COILT SP
35 F
COND 2 FAN
OFF
BYPS VLV
CLOSED
DEFROST
10 MINS
H2O FLOW
YES
CALC CT1
XX F
CALC CT2
XX F
COMPTMP1
XX F
COMPTMP2
XX F
H2O TEMP
XX F
FAN OFF
XX PSI
GLYCOL %
XX %
LOW SUCT
95 PSI
LOW H2O
37 F
DEFR INT
30 MIN
or if congured
for water source
heat pump
or if congured
for water source
heat pump
If congured
for modulating
condenser, the
following screen
displays
If congured for fan
cycle, the following
two screens display
If congured for
water source heat
pump, the following
three screens
display
If congured for air
to air heat pump,
the following screen
displays

15RSMD2R Technical Guide
LCD SCREENS
Screen Descriptions
Main Screens
Refer to Table 4, this page, when navigating through the LCD
Main Screens.
Press the <MENU> button to navigate between the top level screens.
Press the <ENTER> button to scroll through the next level screens,
MAIN SCREENS
Screen Text Description
RSMD2R
1134vxxx
Refrigeration module screens.
SYSTEM
STATUS
System status screens.
SENSOR
STATUS
Sensor status screens.
ALARMS Alarms screens. Screen shows NO
ALARMS if no alarms are active.
ALARM
HISTORY
Alarm history screens.
SETPOINT
STATUS
Setpoint status screens.
Table 4: Main Screens
Module Screens
Refer to Table 5, this page, when navigating through the RSMD2R
Screens. From the RSMD2R Screen, press <ENTER> to scroll
through the screens.
MODULE SCREENS
Screen Text Description
RSMD2R
1134vxxx
Refrigeration module screens
EBUS
+X
E-BUS communication diagnostics with
X being the number of COMM packets
received. The number increases as
packets are received.
SOFTWARE
1134vxxx
Current software version. Access the
protected screens from this screen by
holding the <UP> button for ve seconds.
ADDRESS
1(152)A
Current board address.
BoardAddress(EBUS Address)CircuitLetter
The rst number is the board address.
The second number is the EBUS address.
The third number is the circuit letter.
#OF COMP
1
Number of compressors congured.
#OF COND
1
Number of condensers congured.
COMP A1
DIGITAL
Compressor A1 or B1 type, xed or digital
COMP B2
FIXED
Compressor A2 or B2 type, xed or digital
(if second compressor installed).
Table 5: Module Screens

16RSMD2R Technical Guide
LCD SCREENS
Screen Descriptions
System Status Screens
Refer to Table 6, this page, when navigating through the System
Status Screens. From the SYSTEM STATUS Screen, press
<ENTER> to scroll through the screens.
SYSTEM STATUS SCREENS
Screen Text Description
SYSTEM
STATUS
System status screens
MODE
OFF
System Mode. Options are:
OFF
COOL
HEAT
DEHUMID
FORCED
COMP A1
ON
Compressor A1 or B1 (based on board address)
Options are:
OFF - Compressor is o󰀨.
0-100% - Modulating % position
COMP B2
OFF
Compressor A2 or B2 (based on board address)
Options are:
ON - Compressor is on.
OFF - Compressor is o󰀨.
FORCED
COND 1 FAN
20%
Condenser 1 Fan. Options are:
OFF - Condenser is o󰀨.
0-100% - Modulating % position
COND 2 FAN
OFF
Condenser 2 Fan. Options are:
OFF - Condenser is o󰀨.
0-100% - Modulating % position
BYPS VLV
CLOSED
Waterside Economizer Bypass Valve
CLOSED: Valve is closed
1-100% - Modulating % position
DEFROST
10 MINS
Defrost interval timer in number of minutes
H2O FLOW
YES
Water ow. Options are:
ON
OFF
This screen appears instead of the defrost
interval timer If the system is congured with a
water source heat pump,
Table 6: System Status Screens
Sensor Status Screens
Refer to Table 7, this page, when navigating through the Sensor
Status Screens. From the SENSOR STATUS Screen, press
<ENTER> to scroll through the screens.
SENSOR STATUS SCREENS
Screen Text Description
SENSOR
STATUS
Sensor status screens
SUCTION 1
XXX PSI
Suction Pressure 1 reading from input. Measured
in psi.
HEAD PR1
XXX PSI
Head Pressure 1 reading from input. Measured
in psi.
SUCTION 2
XXX PSI
Suction Pressure 2 reading from input. Measured
in psi.
HEAD PR2
XXX PSI
Head Pressure 2 reading from input. Measured
in psi.
CALC CT1
XX F
Calculated Coil Temperature 1 from Suction
Pressure 1 input. Measured in ºF.
CALC CT2
XX F
Calculated Coil Temperature 2 from Suction
Pressure 2 input. Measured in ºF.
COMPTMP1
XX F
Compressor Temperature 1 reading from Head
Pressure 1 input. Measured in ºF.
COMPTMP2
XX F
Compressor Temperature 2 reading from Head
Pressure 2 input. Measured in ºF.
H2O TEMP
XX F
Water temperature reading from Leaving Water
Temperature Sensor.
This screen appears if the system is congured
with a water source heat pump,
Table 7: Sensor Status Screens

17RSMD2R Technical Guide
LCD SCREENS
Screen Descriptions
Alarms Screens
If an alarm is present, the ALARM LED above the LCD display lights up red and blinks. The alarms display and scroll automatically
from the ALARMS screen when alarms are present. Refer to Table 8, this page, for descriptions.
ALARMS SCREENS
Screen Text Description
ALARMS Alarms status screens
NO
ALARMS
No Alarms. This is shown if there are no current alarms.
EBUS SLV
TIMEOUT
EBUS Slave Timeout. This alarm indicates communication has been lost between the RSMD2R and the controller or other
E-BUS modules that may be connected. This can be the result of a bad cable, a missing cable, or the module not being
congured properly.
NO SUCTx
DETECTED
No Suction Pressure Detected. This alarm indicates the Suction Pressure Transducer is not detected by the system. The module
goes into alarm and shuts down the compressor.
NO HEADx
DETECTED
No Head Pressure Detected. This alarm indicates the Head Pressure Transducer is not detected by the system. This causes the
condenser fan/valve to go to 100%.
HIGH HPx
DETECTED
High Head Pressure Detected. This alarm indicates a high head pressure alarm condition which is activated when the head
pressure rises above 550 psi. This causes the condenser to go to 100%.
LOW SPx
FAILURE
Low Suction Pressure Failure. This alarm occurs if suction pressure stays below the Low Suction Pressure Setpoint for one
minute or falls below 40 psi for ve seconds. This alarm shuts down the system. Power must be cycled to clear the alarm.
LOW SPx
DETECTED
Low Suction Pressure Detected. This alarm occurs if suction pressure falls below the Low Suction Pressure Setpoint for 20
seconds. The system will try to protect itself by lowering compressor modulation percentage.
COMPx
FAULT
Compressor Fault. This alarm occurs if the compressor fails to run 45 seconds after the relay is activated or if the signal is lost
after activation. This causes an alarm and shuts down the compressor enable relay. The system will retry after ve minutes.
COMPx
BADTEMP
Compressor Bad Temperature. This alarm occurs if the Discharge Temperature Sensor measures less than -40ºF or more than
356ºF. This will cause an alarm and will shut down the compressor enable relay. The system will retry after ve minutes.
COMPx
CUTOFF
Compressor Cuto󰀨. This alarm occurs if the Discharge Temperature Sensor measures more than 265ºF. This will cause an alarm
and will shut down the compressor enable relay. The system can be restarted after 30 minutes.
COMP
LOCKOUT
Compressor Lockout. This alarm occurs if an active cuto󰀨 happens ve times within a four-hour period, the compressor will be
locked out. Power must be cycled to clear the alarm.
• If a circuit’s suction pressure falls twice within a two hour window below the Low Suction Pressure Setpoint for longer than
one minute each time, the compressor on that circuit will be locked out. Manual reset or change of mode is required to
return to normal operation.
• If the suction pressure falls below the Unsafe Suction Setpoint for ve seconds, that circuit’s compressor will be locked out.
Power will need to be cycled to restart the unit.
• If the Leaving Water Temperature falls below the setpoint, the last compressor will be locked out until the Leaving Water
Temperature rises 6ºF above the setpoint.
• The Leaving Water Temperature remains below the setpoint for one minute or falls 3ºF below the setpoint. This alarm will
disable when the Leaving Water Temperature rises 12ºF above the setpoint.
NO WATER
FLOW
No Proof of Water Flow. This alarm occurs if there is a call for a compressor and the proof of ow binary input does not see 24
VAC for more than three minutes or if during Heat Pump Heating Mode, the proof of ow binary input is open for more than two
seconds. This alarm will disable when the proof of ow binary input is enabled.
LOW H2O
TEMP
Low Water Temperature. This alarm occurs if both compressors are on and water temperature goes below setpoint, Compressor
2 will fail. If both compressors are on and water temperature goes 3ºF below the setpoint, both compressors will fail. If
Compressor 2 is o󰀨 or failed and water temperature is still low for one minute, Compressor 1 will also fail. This alarm disables
when the Leaving Water Temperature rises 6ºF above the setpoint.
EMERGNCY
SHUTDOWN
Emergency Shutdown. This alarm occurs if the Emergency Shutdown Binary Input is not activated. This alarm shuts o󰀨 the
compressors.
COMPx
FALSE
Compressor False Active Input. This alarm occurs if the compressor enable relay is o󰀨 but the compressor status binary input is
activated for 60 seconds.
ENVELOPE
FAULT
WSHP Heating out of Envelope Fault. This alarm occurs if the circuit is running below the envelope consecutively for one minute.
The compressor(s) on the circuit fails and an alarm is generated. The system will retry after ve minutes.
Table 8: Alarms Screens

18RSMD2R Technical Guide
LCD SCREENS
Screen Descriptions
Alarm History Screens
The ALARM HISTORY screen displays past alarms, if any, and how
long ago the last of each type occurred. From the ALARM HISTORY
screen, press <ENTER> to scroll through the history screens.
The rst line is the ALARM NAME.
The second line shows how long ago each alarm last occurred. The
screen displays:
• Minutes for the rst 60 minutes of alarm occurrence
• Hours for the next 72 hours of alarm occurrence
• Days for the next 30 days of alarm occurrence
Alarms clear after 30 days.
NOTE: Alarm history is not stored in memory. If power is
lost, the alarms will clear.
The ALARM HISTORY screens follow the same sequence as the
ALARMS screens but are abbreviated dierently to allow space to
show the time since last occurrence.
ALARM HISTORY SCREENS
Screen Text Description
NO ALARM
HISTORY
No alarm history.
Table 9: Alarm History Screens
Setpoint Status Screens
Refer to Table 10, this page, when navigating through the Setpoint
Status Screens. From the SETPOINT STATUS Screen, press
<ENTER> to scroll through the screens.
SETPOINT STATUS SCREENS
Screen Text Description
SETPOINT
STATUS
Setpoint Status screens
COILT SP
35 F
Coil Temperature Setpoint Status. Valid range
is 35 to 70 degrees. Default is 35ºF.
HEADPRSP
340 PSI
Head Pressure Setpoint Status. Valid range is
275 to 475 PSI. Default is 340 psi.
Appears if the system is congured for
modulating condenser.
FAN ON
XX PSI
Head Pressure Reading when fan cycle is on.
Appears if the system is congured for fan
cycle.
FAN OFF
XX PSI
Head Pressure Reading when fan cycle is o󰀨.
Appears if the system is congured for fan
cycle.
GLYCOL %
X%
Glycol Percentage Status
Appears if congured for water source heat
pump.
LOW SUCT
95 PSI
Low Suction Pressure Setpoint Status. Default
is 95 psi.
Appears if congured for water source heat
pump.
LOW H2O
37 F
Low Leaving Water Temperature Setpoint
Status. Default is 37ºF.
Appears if congured for water source heat
pump.
DEFR INT
30 MIN
Defrost Interval Setpoint Status. Default is 30
minutes.
Appears if the system is congured for air to air
heat pump.
Table 10: Setpoint Status Screens

19RSMD2R Technical Guide
LCD SCREENS
Protected Screen Map
Protected Screens Map
Refer to the following map when navigating through the LCD Protected Screens. From the RSMD2R Screen, press <ENTER> twice to get
to the SOFTWARE Screen. Then hold the <UP> button for ve seconds. To scroll through the rest of the screens, press the <MENU> button.
RSMD2R
1134VXXX
E-BUS
+0
SOFTWARE
1134VXXX
DIAGNSTC ADDRESS
1(152)
ENTER TO
EXIT
Hold 5 seconds.
CONFIG ALARM
COUNTS

20RSMD2R Technical Guide
LCD SCREENS
Protected Screen Descriptions
Conguration Screens Map
Refer to the following map when navigating through the
Conguration Screens. From the CONFIG Screen, press <ENTER>
to scroll through the screens.
CONFIG
COND FAN
LOCKED
LOCK POS
100%
Conguration Screens
Refer to Table 11, this page, when navigating through the
Conguration Screens. From the CONFIG Screen, press <ENTER>
to scroll through the screens.
DIAGNOSTIC SCREENS
Screen Text Description
CONFIG Diagnostic screens
COND FAN
LOCKED
Condenser Fan. Locked or unlocked
LOCK POS
100%
Condenser fan locked position.
Table 11: Conguration Screens