AAON RSMD Quick start guide

RSMD
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: G039810, Rev. F
Copyright March 2021 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.
RSMD REVISION LOG
REVISION & DATE CHANGE
Rev. F, March 15, 2021 Incorporated RSMD2R di󰀨erentiation information
www.aaon.com
RSMD PARTS REFERENCE
PART DESCRIPTION PART NUMBER
Refrigerant System Module for Digital Compressors ( RSMD) ASM02201
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.

3
RSMD Technical Guide
TABLE OF CONTENTS
OVERVIEW....................................................................................................................... 5
RSMD Overview .................................................................................................................................................... 5
RSMD Dimensions................................................................................................................................................. 6
INSTALLATION AND WIRING......................................................................................... 7
Electrical and Environmental Requirements .......................................................................................................... 7
WIRING ............................................................................................................................ 8
RSMD Inputs Wiring .............................................................................................................................................. 8
RSMD Outputs Wiring............................................................................................................................................ 9
INPUTS AND OUTPUTS................................................................................................ 10
RSMD Module Inputs/Outputs Map ..................................................................................................................... 10
RSMD Inputs and Outputs ....................................................................................................................................11
SEQUENCE OF OPERATIONS....................................................................................... 12
Cooling Mode, Dehumidication, and Head Pressure Control.............................................................................. 12
LCD SCREENS ............................................................................................................... 13
LCD Display Screen and Navigation Keys............................................................................................................ 13
Main Screens Map and RSMD Module Screens .................................................................................................. 14
System Status Screens......................................................................................................................................... 15
Sensor Status Screens ......................................................................................................................................... 16
Setpoint Status Screens ....................................................................................................................................... 17
Alarms Screens..................................................................................................................................................... 18
Alarm History and Protected Screens................................................................................................................... 20
Conguration and Diagnostic Screens.................................................................................................................. 21
Diagnostic Screens ............................................................................................................................................... 22
Alarm Counts and Address Screen....................................................................................................................... 23
TROUBLESHOOTING .................................................................................................... 24
LED Diagnostics ................................................................................................................................................... 24
Suction Pressure Transducer Testing ................................................................................................................... 25
Copeland®Discharge Thermistor Temperature Sensor Testing............................................................................ 26
Temperature Sensor Testing ................................................................................................................................. 27
Head Pressure Transducer ................................................................................................................................... 28
APPENDIX A: CONDENSER OPTIONS ......................................................................... 29
Default: Two Condenser Operation....................................................................................................................... 29
Single Condenser Per Module .............................................................................................................................. 31
Single Condenser Per Two Modules..................................................................................................................... 33
Single Condenser for Three Modules ................................................................................................................... 35
Two Condensers Per Two Modules ...................................................................................................................... 37
ON/OFF Condenser Options ................................................................................................................................ 40

4RSMD Technical Guide
FIGURES AND TABLES
TABLES
Table 1: RSMD Controller Electrical and Environmental Requirements..........................................................................7
Table 2: RSMD Inputs and Outputs ....................................................................................................................................10
Table 3: Navigation Key Functions.......................................................................................................................................13
Table 4: Coil Pressure/Voltage/Temp for Suction Pressure Transducers - R410-A Refrigerant ................................25
Table 5: Discharge Thermistor Temperature/Resistance .................................................................................................26
Table 6: 0-5V Temperature Sensor - Voltage & Resistance for Type III Sensors.........................................................27
Table 7: Head Pressure Transducer Chart .........................................................................................................................28
FIGURES
Figure 1: RSMD Dimensions ...................................................................................................................................................6
Figure 2: RSMD Inputs Wiring..................................................................................................................................................8
Figure 3: RSMD Outputs Wiring...............................................................................................................................................9
Figure 4: LCD Display and Navigation Keys........................................................................................................................13
Figure 5: RSMD LED Locations .............................................................................................................................................24
Figure 6: Default: Two Condenser RSMD Module Wiring..................................................................................................29
Figure 7: Prism 2 Condenser Conguration: Default Two Condenser Operations ........................................................30
Figure 8: Single Condenser Per RSMD Module Wiring .....................................................................................................31
Figure 9: Prism 2 Condenser Conguration: Single Condenser Per Module .................................................................32
Figure 10: Single Condenser Per Two RSMD Modules Wiring...........................................................................................33
Figure 11: Prism 2 Condenser Conguration: Single Condenser Per Two Modules.......................................................34
Figure 12: Single Condenser for Three RSMD Modules Wiring .........................................................................................35
Figure 13: Prism 2 Condenser Conguration: Single Condenser for Three Modules .....................................................36
Figure 14: A1/B1 Wiring.............................................................................................................................................................37
Figure 15: A2/B2 Wiring.............................................................................................................................................................38
Figure 16: Prism 2 Condenser Conguration: A1/B1 and A2/B2 Condenser Conguration...........................................39
Figure 17: Prism 2 Condenser Conguration: ON/OFF Condenser Options....................................................................40

5
RSMD Technical Guide
OVERVIEW
RSMD Overview
Features & Applications
The Refrigerant System Module for Digital Compressors
(RSMD) can monitor and control up to two compressors and
condensers. The compressors can be in either a tandem or
non-tandem conguration. The module is designed for R410-A
refrigerant.
NOTE: The RSMD is for units that match all of the
following criteria:
1. One or two circuits.
2. Compressors may be any mix of xed, two-step,
and digital.
3. Reheat is present on the rst circuit.
The RSMD is connected to the VCCX2 Controller. Up to four
RSMD’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 RSMD provides three analog inputs, four binary inputs,
ve relays, and two analog outputs. See Figures 2 & 3, pages
8 & 9 for wiring.
The RSMD 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 RSMD 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.

6RSMD Technical Guide
OVERVIEW
RSMD Dimensions
Figure 1: RSMD 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: ASM02201
+24 VAC
GND
RELAY CONTACT
MAX @ 24 VAC
RATING IS 1 AMP
CONDENSER 1
COMP 1
COMP 2
ANALOG OUT
REVERSING VALV E
COMMON
RELAY OUTPUT
TERMINALS
LABEL P/N:
G041660
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
RSM FOR DIGITAL COMPRESSORS
www.aaon.com
SUCTION PRES 1

7
RSMD Technical Guide
INSTALLATION AND WIRING
Electrical and 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 -22ºF
(-30ºC), 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, RSMD, and
any associated module.
Please carefully read and apply the following information when
wiring the unit controller, RSMD, 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,
RSMDs, 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)
RSMD
Controller
18-30VAC 18 -22°F to 158°F
-30ºC 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: RSMD Controller Electrical and
Environmental Requirements

8RSMD Technical Guide
WIRING
RSMD Inputs Wiring
RSMD Wiring
The RSMD monitors and controls one refrigeration circuit of
the HVAC unit. The module is designed for R410-A refrigerant.
The RSMD is connected to the VCCX2 Controller. Up to four
RSMD’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 RSMD 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 Dehumidification 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: RSMD 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: ASM02201
+24 VAC
GND
RELAY CONTACT
MAX @ 24 VAC
RATING IS 1 AMP
CONDENSER 1
COMP 1
COMP 2
ANALOG OUT
REVERSING VALVE
COMMON
RELAY OUTPUT
TERMINALS
LABELP/N:
G041660
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
RSM FOR DIGITAL COMPRESSORS
www.aaon.com
SUCTION PRES 1

9
RSMD Technical Guide
WIRING
RSMD Outputs Wiring
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: RSMD 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
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
Signal 1
Condenser
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
ALARM
UP
DOWN
ENTERMENU
AAON P/N: ASM02201
+24 VAC
GND
RELAY CONTACT
MAX @ 24 VAC
RATING IS 1 AMP
CONDENSER 1
COMP 1
COMP 2
ANALOG OUT
REVERSING VALVE
COMMON
RELAY OUTPUT
TERMINALS
LABEL P/N:
G041660
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
RSM FOR DIGITAL COMPRESSORS
www.aaon.com
SUCTION PRES 1

10 RSMD Technical Guide
INPUTS AND OUTPUTS
RSMD Module Inputs/Outputs Map
Inputs/Outputs Map
See Table 2, this page for the RSMD inputs and outputs.
Table 2: RSMD 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)

11
RSMD Technical Guide
INPUTS AND OUTPUTS
RSMD Inputs and Outputs
RSMD - 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 Dehumidification 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.

12 RSMD 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 ( RSMD). Multiple
RSMDs 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 RSMD 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.
For Copeland Digital Scroll™ Compressor units, the RSMD 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 1st 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 RSMD has two Digital Compressors, the 1st Compressor
will be locked at 100% and the 2nd Compressor will modulate.
Head Pressure Control
The Refrigeration System Module for Digital Compressors (
RSMD) can monitor a Head Pressure Transducer and control a
Condenser Fan to maintain a Head Pressure Setpoint. The RSMD
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%.

13
RSMD 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

14 RSMD Technical Guide
LCD SCREENS
Main Screens Map and RSMD Module Screens
RSMD Main Screens Map
Refer to the following map when navigating through the LCD
Main Screens. To scroll through the screens, press the <MENU>
button.
RSMD Module Screens
Refer to the following map when navigating through the RSMD
Screens. From the RSMD Screen, press <ENTER> to scroll
through the screens.
SENSOR
STATUS
Press to scroll through REFRIG MODULE screens.
Press to go to SYSTEM STATUS screens.
SYSTEM
STATUS
Press to scroll through SYSTEM STATUS screens.
Press to go to SENSOR STATUS screens.
SENSOR
STATUS
Press to scroll through SENSOR STATUS screens.
Press to go to ALARMS screens.
ALARMS
Press to scroll through ALARMS screens.
Press to go to ALARM HISTORY screens.
ALARM
HISTORY
Press to scroll through ALARM HISTORY screens.
Press to go to SETPOINT STATUS screens.
SETPOINT
STATUS
Press to scroll through SETPOINT STATUS screens.
RSMD
1067vxxx
EBUS COMM
PACKETS
E-BUS COMMUNICATION DIAGNOSTICS
Number of COMM packets received.
SOFTWARE
1067vXXX
CURRENT SOFTWARE VERSION
You can access the protected screens from this screen by holding
the <UP> button for 5 seconds.
BOARD/EBUS
ADDRESS
CURRENT BOARD ADDRESS
#COMP
CONFIGURED
# OF COMPRESSORS CONFIGURED
#COND
CONFIGURED
# OF CONDENSERS CONFIGURED

15
RSMD Technical Guide
LCD SCREENS
System Status Screens
COMP A1-B1
FIXED OR DIG
COMPRESSOR A1 or B1 - FIXED or DIGITAL
COMP A2-B2
FIXED OR DIG
COMPRESSOR A2 or B2 - FIXED or DIGITAL
System Status Screens
Refer to the following map when navigating through the System
Status Screens. From the SYSTEM STATUS Screen, press
<ENTER> to scroll through the screens.
SYSTEM
STATUS
MODE OF
OPERATION
SYSTEM MODE OF OPERATION
Possible Choices are:
OFF, COOL, HEAT, DEHUMID, FORCE
COMP A1-B1
OFF/
MODULATING %
COMPRESSOR A1, B1
(based on board address)
OFF / MOD POSITION
OFF: Compressor is o󰀨.
MODULATING PERCENTAGE: 0-100%
COMP A2-B2
ON/OFF
COMPRESSOR A2, B2
(based on board address)
ON, OFF, FORCED
OFF: Compressor is o󰀨.
ON: Compressor is on.
COND 1 FAN
OFF/
MODULATING %
CONDENSER FAN 1
OFF / MOD POSITION
OFF: Compressor is o󰀨.
MODULATING PERCENTAGE: 0-100%
COND 2 FAN
OFF/
MODULATING %
CONDENSER FAN 2
OFF / MOD POSITION
OFF: Compressor is o󰀨.
MODULATING PERCENTAGE: 0-100%
BYPS VLV
CLOSED OR
% VALVE
WATERSIDE ECONOMIZER BYPASS VALVE
CLOSED or MOD POSITION
CLOSED: Valve is closed.
MODULATING PERCENTAGE: 0-100%

16 RSMD Technical Guide
LCD SCREENS
Sensor Status Screens
DEFROST
# MINUTES
DEFROST INTERVAL TIMER
# of MINUTES
OR
If congured for Water Source Heat Pump
H2O FLOW
YES/NO
WATER FLOW
YES/NO
Sensor Status Screens
Refer to the following map when navigating through the Sensor
Status Screens. From the SENSOR STATUS Screen, press
<ENTER> to scroll through the screens.
SENSOR
STATUS
SUCTION 1
XXX PSI
SUCTION PRESSURE 1 READING FROM INPUT
HEAD PR1
XXX PSI
HEAD PRESSURE 1 READING FROM INPUT
SUCTION 2
XXX PSI
SUCTION PRESSURE 2 READING FROM INPUT
HEAD PR2
XXX PSI
HEAD PRESSURE 2 READING FROM INPUT
CALC CT1
XX DEG
CALCULATED COIL TEMPERATURE 1 FROM SUCTION
PRESSURE 1 INPUT
CALC CT2
XX DEG
CALCULATED COIL TEMPERATURE 2 FROM SUCTION
PRESSURE 2 INPUT
COMPTMP1
XX DEG
COMPRESSOR TEMPERATURE 1 READING FROM HEAD
PRESSURE 1 INPUT
COMPTMP2
XX DEG
COMPRESSOR TEMPERATURE 2 READING FROM HEAD
PRESSURE 2 INPUT
OR
If congured for Water Source Heat Pump
H2O TEMP
XX DEG
WATER TEMPERATURE READING FROM LEAVING WATER
TEMPERATURE SENSOR

17
RSMD Technical Guide
LCD SCREENS
Setpoint Status Screens
Setpoint Status Screens
Refer to the following map when navigating through the Setpoint
Status Screens. From the SETPOINT STATUS Screen, press
<ENTER> to scroll through the screens.
SETPOINT
STATUS
COILT SP
35 DEG
COIL TEMPERATURE SETPOINT STATUS
Valid range is 35 to 70 degrees. Default is 35 degrees.
IF CONFIGURED FOR MODULATING CONDENSER,
THE FOLLOWING SCREEN WILL DISPLAY
HEADPRSP
340 PSI
HEAD PRESSURE SETPOINT STATUS
Valid range is 275 to 475 PSI. Default is 340 PSI.
IF CONFIGURED FOR FAN CYCLE, THE
FOLLOWING TWO SCREENS WILL DISPLAY
FAN ON
XX PSI
HEAD PRESSURE HEADING WHEN FAN CYCLE IS ON
FAN OFF
XX PSI
HEAD PRESSURE READING WHEN FAN CYCLE IS OFF
IF CONFIGURED WATER SOURCE HEAT PUMP,
THE FOLLOWING THREE SCREENS WILL DISPLAY
GLYCOL %
%
GLYCOL PERCENTAGE STATUS
LOW SUCT
95 PSI
LOW SUCTION PRESSURE SETPOINT STATUS
Default is 95 PSI.
LOW H2O
37 DEGF
LOW LEAVING WATER TEMPERATURE SETPOINT STATUS
Default is 37ºF.
IF CONFIGURED FOR AIR TO AIR HEAT PUMP,
THE FOLLOWING SCREEN WILL DISPLAY
DEFR INT
30 MIN
DEFROST INTERVAL SETPOINT STATUS
Default is 30 minutes.

18 RSMD Technical Guide
LCD SCREENS
Alarms Screens
Alarms Screen
If an alarm is present, the ALARM LED above the LCD display
will light up red and blink. The Alarms will display and scroll
automatically from the ALARMS screen when alarms are present.
The alarms are as follows:
NO ALARMS: This will be shown if there are no current alarms.
EBUS SLAVE (SLV) TIMEOUT: This alarm indicates that
communication has been lost between the RSMD and the Main
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 SUCTION PRESSURE SENSOR 1 (SUCT1) DETECTED:
This alarm indicates the Suction Pressure Sensor 1 is not detected
by the system. There is no compressor failure from this alarm.
The failure will be unsafe suction pressure.
NO SUCTION PRESSURE SENSOR 2 (SUCT2) DETECTED:
This alarm indicates the Suction Pressure Sensor 2 is not detected
by the system. There is no compressor failure from this alarm.
The failure will be unsafe suction pressure.
NO HEAD PRESSURE SENSOR 1 (HEAD1) DETECTED: This
alarm indicates the Head Pressure Sensor 1 is not detected by the
system. This will cause the condenser fan/valve to go to 100%.
NO HEAD PRESSURE SENSOR 2 (HEAD2) DETECTED: This
alarm indicates the Head Pressure Sensor 2 is not detected by the
system. This will cause the condenser fan/valve to go to 100%.
HIGH HEAD PRESSURE 1 (HP1) DETECTED: This indicates
a High Head Pressure Alarm condition which is activated when
the Head Pressure 1 rises above 550 PSIG. This will cause the
condenser to go to 100%.
HIGH HEAD PRESSURE 2 (HP2) DETECTED: This indicates
a High Head Pressure Alarm condition which is activated when
the Head Pressure 2 rises above 550 PSIG. This will cause the
condenser to go to 100%.
LOW SUCTION PRESSURE 1 (SP1) FAILURE: This alarm will
occur if Suction Pressure 1 stays below the low suction pressure
setpoint for one minute or falls below 40 psi for ve seconds.
This alarm will shut down the system. Power must be cycled to
clear the alarm.
LOW SUCTION PRESSURE 2 (SP2) FAILURE: This alarm will
occur if Suction Pressure 2 stays below the low suction pressure
setpoint for one minute or falls below 40 psi for ve seconds.
This alarm will shut down the system. Power must be cycled to
clear the alarm.
LOW SUCTION PRESSURE 1 (SP1) DETECTED: This alarm
will occur if Suction Pressure 1 falls below the low suction
pressure setpoint for 20 seconds. The system will try to protect
by lowering compressor modulation percentage.
LOW SUCTION PRESSURE 2 (SP2) DETECTED: This alarm
will occur if Suction Pressure 2 falls below the low suction
pressure setpoint for 20 seconds. The system will try to protect
by lowering compressor modulation percentage.
COMPRESSOR (COMP1) 1 FAULT: This alarm will occur if the
compressor fails to run 45 seconds after the relay is activated
or if the signal is lost after activation. This will cause an alarm
and will shut down the compressor (relay). The system will retry
after ve minutes.
COMPRESSOR (COMP) 2 FAULT: This alarm will occur if the
compressor fails to run 45 seconds after the relay is activated
or if the signal is lost after activation. This will cause an alarm
and will shut down the compressor (relay). The system will retry
after ve minutes.
COMPRESSOR (COMP1) 1 BAD TEMPERATURE: This alarm
will occur if the Discharge Temp Sensor 1 measures less than
-40ºF or more than 356ºF. This will cause an alarm and will
shut down the compressor (relay). The system will retry after
ve minutes.
COMPRESSOR (COMP2) 2 BAD TEMPERATURE: This alarm
will occur if the Discharge Temp Sensor 2 measures less than
-40ºF or more than 356ºF. This will cause an alarm and will
shut down the compressor (relay). The system will retry after
ve minutes.
COMPRESSOR (COMP) 1 CUTOFF: This alarm will occur if
the Discharge Temp Sensor 1 measures more than 265ºF. This
will cause an alarm and will shut down the compressor (relay).
The system will can be restarted after 30 minutes.
COMPRESSOR (COMP) 2 CUTOFF: This alarm will occur if
the Discharge Temp Sensor 2 measures more than 265ºF. This
will cause an alarm and will shut down the compressor (relay).
The system will can be restarted after 30 minutes.
ALARMS

19
RSMD Technical Guide
LCD SCREENS
Alarms Screens
COMPRESSOR (COMP) 1 or 2 LOCKOUT: If active cuto
occurs ve times within a four-hour period, the compressor will
be locked out. Must cycle power to RSMD to clear the alarm.
• If a circuit’s Suction Pressure falls below the Low
Suction Pressure Setpoint for longer than one minute
twice within a two hour window, 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 locked out. Power will need to be cycled to restart
the unit.
• If the Leaving Water Temperature falls below setpoint,
the last compressor will be locked out until the Leaving
Water Temperature rises 6ºF above setpoint.
• The Leaving Water Temperature remains below setpoint
for one minute or falls 3ºF below setpoint. This alarm
will disable when the leaving water temperature rises
12ºF above the setpoint.
NO PROOF OF H2O FLOW: There is a call for a compressor
and there is no Proof of Flow Input Enable for more than three
minutes or if during Heat Pump heating, the Proof of Flow Enable
is open for more than two seconds. This alarm will disable when
Proof of Flow is enabled.
LOW H2O TEMPERATURE: If both compressors are on and
water temp goes below setpoint, Compressor 2 will fail. If both
compressors are on and water temp goes 3ºF below setpoint, both
compressors will fail. If Compressor 2 is o or failed and water
temp is still low for one minute, the Compressor 1 will also fail.
This alarm will disable when the leaving water temperature rises
6ºF above the setpoint.
EMERGENCY SHUTDOWN: If the Emergency Shutdown binary
input is not activated, the compressors will shut o.
COMPRESSOR 1 FALSE ACTIVE INPUT: If the compressor
relay is o but the compressor binary active input is activated
for 60 seconds, it will cause an alarm.
COMPRESSOR 1 FALSE ACTIVE INPUT: If the compressor
relay is o but the compressor binary active input is activated
for 60 seconds, it will cause an alarm.
WSHP HEATING OUT OF ENVELOPE FAULT: If the circuit
is running below the envelope consecutively for one minute,
the compressor(s) on the circuit will fail and an alarm will be
generated. The system will retry after ve minutes.

20 RSMD Technical Guide
LCD SCREENS
Alarm History and Protected Screens
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 Alarm will appear on the rst line and the second line will
display how long ago each alarm last occurred. As a result, the
alarms listed on the ALARMS screen will be abbreviated as
follows in order of the way they are listed in the prior ALARMS
screen section.
NOTE: The screen will display minutes for the rst 60
minutes of alarm occurrence, hours for the next
72 hours of alarm occurrence, and days for the
next 30 days of alarm occurrence. After 30 days,
the alarm will clear. Alarm history is not stored in
memory. So, if power is lost, the alarms will clear.
Protected Screens Map
Refer to the following map when navigating through the LCD
Protected Screens. From the RSMD 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.
ALARM
HISTORY
RSMD
1067vxxx
E-BUS
+0
SOFTWARE
1067vxxx
Hold for ve seconds.
CONFIG
DIAGNSTC
ALARM
COUNTS
ADDRESS
1(152)
ENTER TO
EXIT