RM454-V Controller Module
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Product Information
Specifications
- Model: RM454-V Module
- Part Number: ASM07718
- Compatibility: VCCX-454 Series
- Software: SS1195
- Revision: Rev. A, January 17, 2025
Product Usage Instructions
Overview
The RM454-V Module is designed to monitor and control
refrigeration circuits of the AAON unit. It is compatible with the
VCCX-454 controller and is specifically intended for units
operating with R-454B refrigerant.
Features
- Automatically configures condensers, EXVs, and compressors
based on unit selection. - Connects to a superheat controller.
- Utilizes an E-BUS cable to connect to the VCCX-454 Controller
with support for up to four RM454-V Modules. - Configured using Prism 2 software.
- Provides five analog inputs, four binary inputs, four relays,
and one analog output.
Installation
Electrical and Environmental Requirements
Correct wiring of the AAON unit controller and its modules is
crucial for successful installation. Ensure that the AAON unit
controller and modules are properly installed and wired.
Familiarize yourself with the system wiring in case troubleshooting
is needed.
FAQ
Q: How many RM454-V Modules can be connected to the VCCX-454
Controller?
A: Up to four RM454-V Modules can be connected.
Q: What software is used to configure the RM454-V Module?
A: The RM454-V Module is configured using Prism 2 software.
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Compatible with
VCCX-454 Series
RM454-V Module Technical Guide
ASM07718
Software SS1195
REVISION AND DATE Rev. A, January 17, 2025
RM454-V REVISION LOG
Initial Release
CHANGE
RM454-V PARTS REFERENCE
PART DESCRIPTION
PART NUMBER
RM454-V Module VCCX-454 Controller RM454-SC (Subcool Monitor) Reheat Expansion Module 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 ft. Spool E-BUS Adapter Hub with 1.5 ft.. E-BUS Cable E-BUS Adapter Board
ASM07718 ASM07503 ASM07719 ASM01687 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) ASM01635 ASM01878
www.aaon.com
All manuals are also available for download from www.aaon.com
AAON, Inc. 2425 South Yukon Ave. Tulsa, OK 74107-2728 Factory Technical Support Phone: 918-382-6450 Controls Support Phone: 866-918-1100 All rights reserved. © January 2025 AAON, Inc.
RM454-V Technical Guide
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, specifications, and/or design of its product without notice, obligation, or liability.
Rev. A AAON® is a registered trademark of AAON, Inc., Tulsa, OK. BACnet® is a registered trademark of ASHRAE Inc., Atlanta, GA. BITZER® is a registered trademark of BITZER Kühlmaschinenbau GmbH. Danfoss VFD® is a registered trademark of Danfoss Commercial Compressors, S.A., Tallahassee, FL
2
TABLE OF CONTENTS
OVERVIEW ………………………………………………………………………………………………………………………………. 5 RM454-V Overview………………………………………………………………………………………………………………………………. 5
INSTALLATION ………………………………………………………………………………………………………………………… 6 Electrical and Environmental Requirements …………………………………………………………………………………………….. 6 Dimensions …………………………………………………………………………………………………………………………………………. 7 Wiring…………………………………………………………………………………………………………………………………………………. 8 Inputs and Outputs……………………………………………………………………………………………………………………………… 10
SEQUENCE OF OPERATIONS ……………………………………………………………………………………………….. 12 Modes of Operation ……………………………………………………………………………………………………………………………. 12 Staging……………………………………………………………………………………………………………………………………………… 13 Envelope Protection……………………………………………………………………………………………………………………………. 14 Component Operation…………………………………………………………………………………………………………………………. 15
LCD SCREENS ………………………………………………………………………………………………………………………. 16 LCD Display Screen and Navigation Keys……………………………………………………………………………………………… 16 Main Screens Map ……………………………………………………………………………………………………………………………… 17 Screen Descriptions……………………………………………………………………………………………………………………………. 18
TROUBLESHOOTING …………………………………………………………………………………………………………….. 26 LED Diagnostics ………………………………………………………………………………………………………………………………… 26 Sensor Testing …………………………………………………………………………………………………………………………………… 27 Transducer Testing……………………………………………………………………………………………………………………………… 29
RM454-V Technical Guide
3
FIGURES AND TABLES
Figure 1: Figure 2: Figure 3: Figure 4: Figure 5: Figure 6:
FIGURES
RM454-V Dimensions ……………………………………………………………………………………………………………………………………. 7 RM454-V Inputs Wiring…………………………………………………………………………………………………………………………………… 8 RM454-V Outputs Wiring ……………………………………………………………………………………………………………………………….. 9 Example – Prism 2 Envelope Protection Graph …………………………………………………………………………………………….. 14 LCD Display and Navigation Keys ………………………………………………………………………………………………………………… 16 RM454-V LED Locations ………………………………………………………………………………………………………………………………. 26
Table 1: Table 2: Table 3: Table 4: Table 5: Table 6: Table 7: Table 8: Table 9: Table 10: Table 11: Table 12: Table 13: Table 14: Table 15: Table 16: Table 17: Table 18: Table 19: Table 20: Table 21: Table 22:
TABLES
RM454-V Electrical and Environmental Requirements ……………………………………………………………………………6 RM454-V Inputs and Outputs ………………………………………………………………………………………………………………..10 Staging – 2 RM454-V 2 Circuit: VFD, 2-Step Cooling States …………………………………………………………………13 Staging – 2 RM454-V 2 Circuit: VFD, 2-Step Secondary (Second Circuit) Reheat States ……………………..13 Staging – 4 RM454-V 2 Circuit: VFD, 2-Step, VFD, 2-Step Cooling States ……………………………………………13 Staging – 4 RM454-V 2 Circuit: VFD, 2-Step, VFD, 2-Step Secondary (Second Circuit) Reheat States..13 Navigation Key Functions………………………………………………………………………………………………………………………16 Main Screens ………………………………………………………………………………………………………………………………………..18 Module Screens …………………………………………………………………………………………………………………………………….18 System Status Screens …………………………………………………………………………………………………………………………19 Sensor Status Screens ………………………………………………………………………………………………………………………….19 Alarms Screens……………………………………………………………………………………………………………………………………..20 Alarm History Screens …………………………………………………………………………………………………………………………..21 Setpoint Status Screens ………………………………………………………………………………………………………………………..22 Copeland EVM Status Screens……………………………………………………………………………………………………………..23 Danfoss VFD Screens …………………………………………………………………………………………………………………………..24 Sanhua EXV Screens ……………………………………………………………………………………………………………………………25 Sporlan EXV Screens ……………………………………………………………………………………………………………………………25 0-5V Temperature Sensor – Voltage and Resistance for Type III Sensors ……………………………………………..27 Discharge Thermistor Temperature and Resistance………………………………………………………………………………28 Suction Pressure Transducer Chart for R454-B Refrigerant (Vapor) ……………………………………………………..29 Head Pressure Transducer Chart ………………………………………………………………………………………………………….30
RM454-V Technical Guide
4
OVERVIEW RM454-V Overview
CAUTION: This module is intended to only function with units operating with R-454B refrigerant.
Features
The ASM07718 Refrigerant System Module for VFD Compressors with Independent Electronic Expansion Valve (EXV) Control (RM454-V) monitors and controls the refrigeration circuits of the AAON unit. It connects to a superheat controller and is used with the VCCX-454 controller.
The RM454-V is for units with the following configurations: · Must have at least one VFD compressor on the first circuit of the first module connected using Modbus. The second module, if used, can use a non-VFD compressor. · Must have at least one EXV. · One or two circuits with no reheat, or reheat on the second circuit.
This module automatically configures condensers, EXVs, and compressors based on unit selection.
The RM454-V provides the following:
· Modulates the compressors or controls staging to satisfy the Suction Coil (Saturated) Temperature during Cooling Mode. During Dehumidification Mode, it controls the compressors to the Suction (Saturation) Temperature Setpoint.
· Modulates the condenser fan(s) to maintain the Head Pressure Setpoint.
· Monitors the performance of the superheat controller to maintain the Superheat Setpoint of each evaporator coil.
· Provides alarms and safeties for the compressor and condenser operation.
· Provides a 2 x 8 LCD character display and four buttons that allow for status of system operation, system setpoints, system configurations, sensors, and alarms.
The RM454-V uses an E-BUS cable to connect to the VCCX-454 Controller. Up to four RM454-V Modules can be connected. There are two E-BUS expansion ports which allow connection to the
VCCX-454 Controller, communicating sensors, and other E-BUS
modules.
The RM454-V is configured using Prism 2 software.
The RM454-V provides five analog inputs, four binary inputs, four relays, and one analog output. See Figures 3 and 4, pages 9 and 10, for wiring.
RM454-V Technical Guide
5
INSTALLATION Electrical and Environmental Requirements
General
Correct wiring of the AAON unit controller and its modules is the most important factor in the overall success of the installation process. The AAON unit controller and modules are installed and wired at the AAON factory. Some of the following information may not apply if the unit 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.
Control Device Voltage VA Load Operating Temperature Humidity (NonCondensing)
RM454-V
18-30 VAC
18
-22ºF to 158ºF -30ºC to 70ºC
0-95% RH
Inputs
Resistive Inputs require 10K Type III Thermistor
24 VAC Inputs provide 4.7K Load
Outputs
Relay Outputs: 1 amp maximum per output.
Table 1: RM454-V Electrical and Environmental Requirements
Please carefully read and apply the following information when wiring the unit controller, RM454-V, and any associated module.
1. All wiring is to be in accordance with local and national electrical codes and specifications.
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 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 used to interconnect AAON unit controllers together or to connect to other communication devices, all wiring must be plenumrated, minimum 18-gauge, two-conductor, twisted pair with shield. AAON can supply communication wire that meets this specification 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 AAON unit controller, RM454-V Modules, and any associated modules, be sure to recheck all wiring connections and terminations thoroughly.
Powering Up
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 AAON unit controller, RM454-V, and any associated module.
When the controller and modules are first powered up, the POWER LED should light up and stay on continuously. If it does not light up, check to be sure the 24 VAC is connected to the controller, that the wiring connections are tight, and they are wired for the correct polarity. The 24 VAC power must be connected so 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.
Support is available Monday through Friday 7:00 A.M. to 5:00 P.M., Central Time. 1-866-918-1100 | 1-918-382-6450 controls.support@aaon.com
RM454-V Technical Guide
6
INSTALLATION Dimensions
5.61
4.98
Figure 1: RM454-V Dimensions
6.10
2.05
2.05
ALAR M
MENU
UP ENTER
DOWN
www.aaon.com
RM454-V
+5 V SP GND
+5 V HP GND
SUCTION PRESSURE
HEAD PRESSURE
AAON P/N: ASM07718
RELAY CONTACT RATING IS RELAY OUTPUTS 1 AMP MAX @ 24 VAC
COMP 1 ENABLE COMP 2 / HI SPEED
DISCHARGE TEMP 1 DISCHARGE TEMP 2
CONDENSER REVERSING VALVE
TXV COIL TEMP
COMMON
NOT USED
NOT USED NOT USED GND
EACH EXP VALVE IS INDIVIDUALLY ELECTRICALLY ISOLATED
GND
BINARY INPUTS
COMP STAT 1 COMP STAT 2 DEFROST SW EMER SHDN GND
45
EXP VALVE 1
R+ SHD
T-
EXP VALVE 2
R+ SHD
T-
EXP VALVE 3 EXP VALVE 4
ANALOG OUTPUTS
NOT USED COND FAN GND
4
NOT INSTALLED
NOT INSTALLED
24 VAC POWER ONLY WARNING! POLARITY
MODBUS
LABEL P/N: G162440
DUAL E-BUS
MUST BE OBSERVED OR THE CONTROLLER
WILL BE DAMAGED
R+ SH T-
GND +24 VAC
4.10 Note: All dimensions are in inches.
RM454-V Technical Guide
7
INSTALLATION Wiring
Inputs Wiring
The RM454-V uses an E-BUS cable to connect to the VCCX454 Controller. Up to four RM454-V Modules can be connected. Two E-BUS expansion ports allow connection to the VCCX-454 Controller, communicating sensors, and other E-BUS modules.
The RM454-V uses five analog inputs, four binary inputs, four relays, and one analog output. See Figure 2, this page, for inputs wiring and Figure 3, page 9, for outputs wiring.
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 so 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.
RD
Suction Pressure
WH
Transducer
BK
Discharge Line Temp 1 Discharge Line Temp 2
TXV Coil Temp
Comp 1 Stat Comp 2 Stat Coil Temp Switch Emer Shutdown (Optional)
Condenser Fan
+ COM
Figure 2: RM454-V Inputs Wiring
RM454-V Technical Guide
ALARM
MENU
UP ENTER
DOWN
www.aaon.com
RM454-V
+5 V SP GND
+5 V HP GND
SUCTION PRESSURE
HEAD PRESSURE
AAON P/N: ASM07718
RELAY CONTACT RATING IS RELAY OUTPUTS 1 AMP MAX @ 24 VAC
COMP 1 ENABLE COMP 2 / HI SPEED
DISCHARGE TEMP 1 DISCHARGE TEMP 2
CONDENSER REVERSING VALVE
TXV COIL TEMP
COMMON
NOT USED
NOT USED NOT USED GND
EACH EXP VALVE IS INDIVIDUALLY ELECTRICALLY ISOLATED
GND
BINARY INPUTS
COMP STAT 1 COMP STAT 2 DEFROST SW EMER SHDN GND
45
EXP VALVE 1
R+ SHD
T-
EXP VALVE 2
R+ SHD
T-
EXP VALVE 3 EXP VALVE 4
ANALOG OUTPUTS
NOT USED COND FAN GND
4
NOT INSTALLED
NOT INSTALLED
24 VAC POWER ONLY WARNING! POLARITY
MODBUS
LABEL P/N: G162440
DUAL E-BUS
MUST BE OBSERVED OR THE CONTROLLER
WILL BE DAMAGED
R+ SH T-
GND +24 VAC
GND
18-30 VAC
Line Voltage Size transformer for correct total load:18VA
8
INSTALLATION Wiring
Outputs Wiring
ALARM
MENU
UP ENTER
DOWN
www.aaon.com
RM454-V
+5 V SP GND
+5 V HP GND
SUCTION PRESSURE
HEAD PRESSURE
AAON P/N: ASM07718
RELAY CONTACT RATING IS RELAY OUTPUTS 1 AMP MAX @ 24 VAC
COMP 1 ENABLE COMP 2 / HI SPEED
DISCHARGE TEMP 1 DISCHARGE TEMP 2
CONDENSER REVERSING VALVE
TXV COIL TEMP
COMMON
NOT USED
NOT USED NOT USED GND
EACH EXP VALVE IS INDIVIDUALLY ELECTRICALLY ISOLATED
GND
BINARY INPUTS
COMP STAT 1 COMP STAT 2 DEFROST SW EMER SHDN GND
45
EXP VALVE 1
R+ SHD
T-
EXP VALVE 2
R+ SHD
T-
EXP VALVE 3 EXP VALVE 4
ANALOG OUTPUTS
NOT USED COND FAN GND
4
NOT INSTALLED
NOT INSTALLED
24 VAC POWER ONLY WARNING! POLARITY
GND +24 VAC
MODBUS
T-
LABEL P/N: G162440
DUAL E-BUS
MUST BE OBSERVED OR THE CONTROLLER
WILL BE DAMAGED
RED GRN BLK
RED GRN BLK
24 VAC ONLY All relay outputs are normally open and rated for 24 VAC power only, 1 amp maximum load.
Compressor 1 Enable Compressor 2 Enable or Comp 1 Hi Speed Condenser 1 Enable Reversing Valve
Superheat Controller’s Modbus Terminal
Superheat Controller’s Modbus Terminal
R+ SH
T- to Term 69
SH to Term 61
R+ to Term 68
GND 18-30 VAC
1 2693 4 5686 7 861 RS-485 Interface
Danfoss VFD
Connect to VCCX-454 Controller
Connect shield to GND, but only on one end.
Line Voltage Size transformer for correct total load:18VA
NOTE: Switch 1 of SW2 needs to be set to ON.
R+ to Drive 6 SH to Drive 5 T- to Drive 7
Connect shield to GND, but only on one end.
Copeland EVM
Drive
1 DIN1
SW2
2 DIN2 OFF ON
3 DIN3
1
4 DIN4
2
5 CM
3
6 A+
7 B-
Figure 3: RM454-V Outputs Wiring
RM454-V Technical Guide
9
INSTALLATION Inputs and Outputs
Inputs/Outputs Map
See Table 2, this page, for the RM454-V inputs and outputs.
RM454-V INPUTS AND OUTPUTS
Analog Inputs
SP
Suction Pressure Transducer
HP
Head Pressure Transducer
TEMP1
Discharge Line Temperature 1
TEMP2
Discharge Line Temperature 2
TEMP3
TXV Coil Temperature
TEMP4
Not used
TEMP5
Not used
TEMP6
Not used
Binary Inputs
BIN1
Compressor 1 status
BIN
Compressor 2 status
BIN3
Coil Temperature Switch
BIN4
Emergency shutdown (optional)
Analog Outputs (0-10 VDC)
AOUT1
Not used
AOUT2
Condenser Fan 1
EXV COMM Ports
EXV-1
EXV Controller 1
EXV-2
EXV Controller 2
EXV-3
Not used
EXV-4
Not used
Binary Outputs (24 VAC)
RLY1
Compressor 1 enable
RLY2
Compressor 2 enable or Compressor 1 high speed enable
RLY3
Condenser 1 enable
RLY4
Reversing Valve
Communication Terminals
DUAL E-BUS E-BUS communication loop ports
MODBUS VFD compressor
Table 2: RM454-V Inputs and Outputs
RM454-V Technical Guide
10
INSTALLATION Inputs and Outputs
Descriptions
+5 – VDC Power This output is a 5 VDC output that supplies power to the Suction or Head Pressure Transducer.
SP – Suction Pressure Transducer The Suction Pressure Transducer is used on modules that do not have VFD compressors wired to them. Units have two options to obtain suction pressure/saturation temperature/superheat.
1. Through MODBUS communications to superheat controller.
2. From onboard sensors; suction pressure, coil temperature sensors
HP – Head Pressure Transducer The Head Pressure Transducer is used to measure head pressure at the discharge line. This head pressure is used to drive condenser fan to maintain a given head pressure setpoint.
BIN2 – Compressor 2 Status A wet contact closure (24 VAC) on this input indicates Compressor 2 is running. Typically, the source for this is a relay output from the auxiliary contact on the compressor contactor. If BIN2 opens, Compressor 2 Enable Relay de-energizes and a compressor alarm is generated.
NOTE: The binary inputs require wet contacts (24 VAC only) to recognize an active input. Contact closure will not be recognized if dry contacts are used.
BIN3 – Coil Temperature Switch A wet contact closure (24 VAC) on this input indicates the condenser coil is frozen or has frost build-up and a defrost is needed.
BIN4 – Emergency Shutdown Contact If configured, when this wet contact input is open, the RSM operation is disabled.
TEMP1 – Discharge Line Temperature 1 This sensor is the Discharge Line Temperature Sensor for Circuit 1. It is strapped to the discharge line immediately after the VFD compressor and is used as a safety against high compressor temperatures.
TEMP2 – Discharge Line Temperature 2 This sensor is the Discharge Line Temperature Sensor for Circuit 2. It is required on all ASHP and WSHP with a second compressor on module.
TEMP3 – TXV Coil Temperature If the unit does not have a communicating EXV/superheat controller, then the coil temperature sensor is wired to this input to calculate superheat.
BIN1 – Compressor 1 Status A wet contact closure (24 VAC) on this input indicates Compressor 1 is running. Typically, the source for this is a relay output from the auxiliary contact on the compressor contactor. If BIN1 opens, Compressor 1 Enable Relay de-energizes and a compressor alarm is generated.
If Compressor 1 on module is a VFD, then compressor status is validated through VFD communications and wiring to this input is not necessary.
AOUT2 – Condenser Fan VFD Signal This is a direct acting output signal that is used to modulate the Condenser Fan VFD (0-10 VDC signal) on an air cooled unit.
EXV-1 – EXV Controller 1 The EXV-1 is the MODBUS port for EXV Controller 1’s setpoints and status communications.
EXV-2 – EXV Controller2 The EXV-2 is the MODBUS port for EXV Controller 2’s setpoints and status communications.
RLY1 – Compressor 1 Enable This relay turns on Compressor 1.
RLY2 – Compressor 2 Enable / Compressor 1 High Speed Enable This enables Compressor 2 when there are tandem compressors. If Compressor 1 is a two-step compressor, this relay enables high speed.
RLY3 – Condenser 1 Enable This relay enables Condenser Fan 1.
RLY4 – Reversing Valve Enable This relay enables the reversing valve.
RM454-V Technical Guide
11
SEQUENCE OF OPERATIONS
Modes of Operation
Cooling and Heating Modes
Staging of the compressors is determined by the Supply Air Temperature setpoint not being satisfied. Staging is met by turning the VFD compressors and on/off compressor on or off, or the twostep compressor to low speed (two-thirds, 67%, capacity) or to high speed (full, 100%, capacity).
During Cooling Mode, the VFD compressor modulation is determined from Saturation Temperature. During Heating Mode, the VFD compressor modulation is determined from Supply Air Temperature.
Compressor envelope and/or electrical current protections also affect the VFD compressor modulation by limiting minimum and maximum RPM speed.
Dehumidification Operation
Dehumidification Mode control staging and VFD modulation is determined using the Saturation Temperature from each circuit. Circuit 1 uses Superheat Controller Saturation Temperature and Circuit 2 uses the Saturation Coil Temperature Sensor (TEMP3 input) mounted after the TXV.
NOTE: Compressor 2 cannot be turned off in Dehumidification Mode unless it shuts down because of an alarm fault.
RM454-V Technical Guide
12
SEQUENCE OF OPERATIONS Staging
NOTE: Slight changes may occur based off of minimum run times and minimum off times.
NOTE: The RM454-V will transition to the most appropriate state depending on configuration and environmental conditions.
CAUTION:
If compressors are operating in a configuration not shown, it could be due to environmental conditions, compressor availability, or alarm conditions.
CAUTION: Initial transitions between states may lower capacity during transition.
Circuit 1 2
2 RM454-V 2 CIRCUIT: VFD, 2-STEP COOLING
Compressor Type
Stage 0
Stage 1
Stage 2
VFD
OFF
ON (Modulating)
OFF
Two Step
OFF
OFF
LOW
Stage 3 ON (Modulating) HIGH
Table 3: Staging – 2 RM454-V 2 Circuit: VFD, 2-Step Cooling States
Circuit 1 2
2 RM454-V 2 CIRCUIT: VFD, 2-STEP SECONDARY (SECOND CIRCUIT) REHEAT
Compressor Type
Stage 0
Stage 1
Stage 2
VFD
OFF
OFF
OFF
Two Step
OFF
LOW
HIGH
Stage 3 ON (Modulating) HIGH
Table 4: Staging – 2 RM454-V 2 Circuit: VFD, 2-Step Secondary (Second Circuit) Reheat States
Circuit 1 2 3 4
4 RM454-V 4 CIRCUIT: VFD, 2-STEP, VFD, 2-STEP COOLING
Compressor Type
Stage 0
Stage 1
Stage 2
VFD
OFF
ON (Modulating)
ON (Modulating)
VFD
OFF
ON (Modulating)
ON (Modulating)
Two Step
OFF
OFF
LOW
Two Step
OFF
OFF
LOW
Table 5: Staging – 4 RM454-V 2 Circuit: VFD, 2-Step, VFD, 2-Step Cooling States
Stage 3 ON (Modulating) ON (Modulating) HIGH HIGH
Circuit 1 2 3 4
4 RM454-V 4 CIRCUIT: VFD, 2-STEP, VFD, 2-STEP SECONDARY (SECOND CIRCUIT) REHEAT
Compressor Type VFD
Stage 0 OFF
Stage 1 OFF
Stage 2 OFF
VFD
OFF
OFF
OFF
Two Step
OFF
LOW
HIGH
Two Step
OFF
LOW
HIGH
Stage 3 ON (Modulating) ON (Modulating) HIGH HIGH
Table 6: Staging – 4 RM454-V 2 Circuit: VFD, 2-Step, VFD, 2-Step Secondary (Second Circuit) Reheat States
RM454-V Technical Guide
13
SEQUENCE OF OPERATIONS Envelope Protection
Envelope Protection
Compressor manufacturer specifications require the compressor to operate within its given operating envelope to maintain the life and longevity of the compressor. Some envelopes also have areas within that limit the minimum/maximum operating speeds. Min/ max speeds may also be limited based on the requirements of the unit’s total capacity. Prism 2 interface allows the ability to see real time envelope plotting while the compressor is running.
The minimum operating speed reference is read from the VFD and can change depending on where the compressor is operating within its envelope.
The VFD compressor is set to 67% at any stage event. Therefore, whenever a staging event occurs, the VFD compressor position is reset to the middle point of the modulation range. This allows the compressor enough modulation time before making another staging event to try to avoid cycling between staging events.
Figure 4, this page, for an example of a compressor envelope.
Figure 4: Example – Prism 2 Envelope Protection Graph
RM454-V Technical Guide
14
SEQUENCE OF OPERATIONS
Component Operation
Electronic Expansion Valve Operation
EXV operation is fully integrated into the superheat controller. The superheat controller measures suction pressure and temperature to determine superheat and automatically modulates the EXV to maintain the configured superheat. The RM454-V communicates with the superheat controller to set the desired Superheat Setpoint and to retrieve operational data for display and trending purposes.
Head Pressure Control
The RM454-V can monitor a head pressure transducer and control a condenser fan to maintain a Head Pressure Setpoint.
The condenser fan starting speed varies based on outside air temperatures. At 40°F or colder the fan starts at 10%; at 70°F or warmer the fan starts at 100%. Starting speed adjusts linearly between 40º F and 70º F.
In Cooling Mode, the condenser fan modulates speeds to target the discharge pressure setpoint based on the highest running circuit it is controlling. This is also true for Dehumidification Mode and has a separate discharge pressure setpoint adjustable in Prism 2.
In Heat Pump Heating, the outside fan modulates speeds to target the outside approach temperature setpoint which is outside temperature minus the lowest saturation temperature of the running circuit it is controlling.
If the pressure exceeds 575 psig, the circuit shuts down in an attempt to fail before the mechanical high pressure switch opens. The circuit is allowed to restart after five minutes.
If no head pressure is detected on a circuit, the compressor is disabled and not allowed to run. If the head pressure reading is lost while circuit is on, the condenser signal goes to 100% until the compressor shuts down.
RM454-V Technical Guide
15
LCD SCREENS LCD Display Screen and Navigation Keys
The LCD display screens and buttons allow you to view status and alarms, and enable force modes. See Figure 5, this page, and refer to Table 7 and Table 8, this page, for key functions.
ALARM
MENU
UP ENTER
DOWN
Figure 5: LCD Display and Navigation Keys
Navigation Key
MENU
Key Function
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
configurations.
DOWN
Use this key to adjust setpoints and change configurations.
ENTER
Use the <ENTER> key to navigate through the Main Menu Screen categories.
Table 7: Navigation Key Functions
RM454-V Technical Guide
16
LCD SCREENS Main Screens Map
RM454-V
SYSTEM
SENSOR
NO
NO ALARM
SETPOINT
VFD
EXV TYPE
1195vXXX
STATUS
STATUS
ALARMS
HISTORY
STATUS
EBUS +XXX
MODE COOLING
SUCTION XXX PSIG
SOFTWARE 1195vXXX
COMP Z1 XXXXXXXX
HEAD XXX PSIG
ADDRESS X(XXX)A
COND FAN XXX%
SUPRHT X XX.X°F
HEADPRSP XXX PSIG
SPRHT SP XX.X°F
LOW SUCT XX PSIG
YASKAWA VFD
OR
DANFOSS COMP
OR
YAV0302E COMP
EXV TYPE SANHUA
EXV TYPE SPORLAN
SYS TYPE COOLONLY
EXV ZX XXX%
COIL X XX.X°F
#OF COMP X
SATURATN XX.X°F
#OF EXVs ISO XXX
DLT X XXX.X°F
COMP Z1= XXXXXXXX
#OF COND X
COILT SP XX.X°F
The VFD Menu screen displayed depends on which compressor is installed on the unit. The options are Yaskawa VFD and Danfoss VFD. The EXV Type screen displayed depends on which EXV is installed on the unit. The current available option is Sanhua.
WARNING: Contact Controls Tech Support before making any changes to the configuration of this module.
NOTE: See the following pages for detailed descriptions of the options for each menu.
UNIT # XXX
STAGE ID XXX XX
RM454-V Technical Guide
17
LCD SCREENS Screen Descriptions
Main Screens
Module Screens
Refer to the following table 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,
Screen Text RM454-V 1195vXXX SYSTEM STATUS SENSOR STATUS NO ALARMS
NO ALARM HISTORY SETPOINT STATUS VFD MENU
EXV TYPE
MAIN SCREENS
Description Refrigeration module screens. The second line shows the software number and its version. System status screens
Sensor status screens
Alarm status screens. Screen shows NO ALARMS if no alarms are active. Alarm history screens. Screen shows NO ALARM HISTORY if no alarms have been activated. Setpoint status screens
VFD menu screens. There are two VFD menus possible. The one that appears depends on the unit’s configuration. The options are:
· COPELAND · DANFOSS · YASKAWA Expansion valve type screens. There are two EXV TYPE menus possible. The one that appears depends on the unit’s configuration. The current available option is: · SPORLAN · SANHUA
Table 8: Main Screens
Refer to the following table when navigating through the module screens. From the RM454-V screen, press <ENTER> to scroll through the screens.
Screen Text RM454-V 1195vXXX EBUS +XXX
SOFTWARE 1195vXXX
ADDRESS X(XXX)Z
SYS TYPE COOLONLY
#OF COMP X
#OF EXVs ISO XXX COMP Z1 XXXXXXXX
#OF COND X
UNIT # XXX
STAGE ID X X
MODULE SCREENS
Description
Refrigeration module screens. The second line shows the software number and its version.
E-BUS communication. XXX equals the number of COMM packets received. The number increases as packets are received.
Current software version. The second line shows the software number and its version. Access the protected screens from this screen by holding the <UP> button for five seconds.
Current board address Board Address(E-BUS Address)Circuit Letter X equals the board address; (XXX) equals the E-BUS address; Z equals the circuit letter.
Current system type. Possible options for the second line are:
· COOLONLY · AIR HP
The number of compressors configured. The X equals only 1 or 2, depnding on how many compressors the system is configured for.
Number of expansion valves found. XXX equals 1 or 1&2
Configured compressor screens. The number of compressor menus depends on the unit’s configuration. Z equals the circuit and can be A, B, C, or D. The seond line shows the type of VFD or type of compressor if not a VFD. Possible options for the second line are:
· COPE EVM · YASK VFD (for a Yaskawa VFD) · DFOS 303 (Danfoss 303 VFD) · DFOS 803 (Danfoss 803 VFD) · FIXED · 2 STAGE · ERROR! (possible if the VCCX-454 is
not communicating to RSM)
Number of condensers controlled by this module.
Units numbered 1 through XXX. Shows which unit has been selected. Matches the unit # shown in Prism 2.
Stage type and current stage number. The first number is the stage type number being used (1-6). The second number is the current stage that is active (0-7).
Table 9: Module Screens
RM454-V Technical Guide
18
LCD SCREENS Screen Descriptions
System Status Screens
Sensor Status Screens
Refer to the following map when navigating through the System Refer to the following map when navigating through the Sensor
Status Screens. From the SYSTEM STATUS Screen, press Status Screens. From the SENSOR STATUS Screen, press
<ENTER> to scroll through the screens.
<ENTER> to scroll through the screens.
SYSTEM STATUS SCREENS
Screen Text
Description
SYSTEM STATUS
System status screens
MODE OFF
System mode. Options are: · MIN RUN · OFF · COOLING · HEATING · DEHUM · FORCED
COMP Z1 XXXXXXXX
Compressor operation status. Z equals the circuit and can be A, B, C, or D. The second line shows the status of the compressor on the circuit.
· For a VFD compressor (YASK, DFOS, or COPE), it shows the RPM the compressor is running at. It will show OFF if the compressor is not running.
· If FIXED, it will show ON or OFF · If 2 STAGE, it will show LOW SPD or
HIGH SPD · Can also show FAIL if RSM determines
the compressor is off due to an alarm.
COND FAN XXX%
Condenser fan operation status. Options are: · 0-100% · NOT USED – Condenser fan not in use · OFF – Condenser is off
EXV ZX XXX%
Expansion valve operation status 0-100%
Table 10: System Status Screens
SENSOR STATUS SCREENS
Screen Text
Description
SENSOR STATUS
Sensor status screens
SUCTION XXX PSIG
Suction pressure reading from input. Measured in PSIG.
HEAD XXX PSIG
Head pressure reading from input. Measured in PSIG.
SUPRHT X XX.X°F
Current superheat calculation. The number of screens depends on the unit’s configuration.Measured in degrees Fahrenheit.
COIL X XX.X°F
Coil temperature. Measured in degrees Fahrenheit.
SATURTN XXX.X°F
Calculated saturation coil temperature from suction pressure input. Measured in degrees Fahrenheit.
DLT X XXX.X°F
Discharge line temperature from TEMP1 input. Measured in degrees Fahrenheit.
Table 11: Sensor Status Screens
RM454-V Technical Guide
19
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. The alarms are as follows:
Screen Text ALARMS
EMERGENCY SHUTDOWN
ALARMS SCREENS
Description
Screen Text
Alarms Status screens
NO ALARMS
If RSM is configured to use Binary Input 4 (BI4) as a fault indicator, this fault will show up if the input is open.
COIL X TEMPFAIL
COMP X FAULT
EXV NOT DETECTED
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 five minutes.
This will be shown if no communication exists between the RSM and installed EXV.
COMP VFD FAULT
EBUS COM TIMEOUT
EMERGNCY SHUTDOWN
HIGH DIS LINETEMP
SUPRHEAT LOCKOUT
If Binary Input 4 (BI4) on the RSM is configured as an Emergency Shutdown input, the circuit will be disabled if the input is open.
If discharge line temperature is above 220ºF, the compressor will back off. If the temperature doesn’t drop below 220ºF after one minute, the compressor will turn off. Discharge line temperature needs to drop below 150ºF for the compressor to come back after it has been off for 13 minutes. If this occurs three times in two hours, the compressor will be locked out until the module is reset.
If the module fails on High Superheat twice in two hours, it will lock out the compressors.
ENVELOPE FAULT
HIGH HP DETECTED
LOW SHX DETECTED
LOW SP DETECTED
LOW SP FAILURE
NO HEAD DETECTED
This alarm will occur if suction pressure falls below the Low Suction Pressure Setpoint for 20 seconds. The system will try to protect by lowering compressor modulation percentage.
This alarm will occur if suction pressure stays below the Low Suction Pressure Setpoint for one minute or falls below 40 psig for five seconds. This alarm will shut down the system. The system will retry after five minutes.
This alarm indicates the Head Pressure Transducer is not detected by the system. This will cause the condenser to go to 100%.
NO WATER FLOW
Proof of Water Flow
MODBUS TIMEOUT
NO SUCT DETECTED
HI SHX FAILURE
Description This is shown if there are no current alarms.
This alarm will occur if the coil temperature is not within operable range (below -32ºF or above 310ºF). This could be the result of a bad sensor or faulty wiring. This alarm will shut down the system. The system will reset after five minutes if the sensor is detected. This alarm will occur if the compressor’s VFD communicates through E-BUS it has shut down due to a fault condition. The compressor module will attempt to reset the fault after five minutes if the compressor sends the signal that it is okay to reset the fault. This alarm indicates that communication has been lost between the RM454-V and the AAON controller. This can be the result of a bad cable, a missing cable, or the module not being configured properly. If the compressor was running out of its operating envelope for too long, this fault will occur and the compressor will be turned off. This indicates a High Head Pressure Alarm condition which is activated when the Head Pressure rises above 475 psig or 135ºF. This will cause the condenser to go to 100%.
This alarm will be activated when the superheat is less than 4ºF for two minutes during normal operation or four minutes during the first 10 minutes. The system will shut down and will retry after five minutes. Indicates there is no communication between the RM454-V and compressor VFD.
This alarm indicates the Suction Pressure Transducer is not detected by the system. The system will shut down due to unsafe suction safety and will retry after five minutes.
If Superheat is above 30ºF for ten minutes, it will turn off the compressors. It will retry after five minutes. If it fails twice in two hours, it will lock out the compressors.
Table 12: Alarms Screens
RM454-V Technical Guide
20
LCD SCREENS Screen Descriptions
Alarm History Screens
The first line is the ALARM NAME.
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 HISTORY screens follow the same sequence as the ALARMS screens but are abbreviated differently to allow space to show the time since last occurence.
The second line shows how long ago each alarm last occurred. The screen displays:
· Minutes for the first 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. Alarm history is not stored in memory. If power is lost, the alarms will clear.
Screen Text NO ALARM HISTORY CL TMP X LOH2OTMP COMP X FL HPX SENSE HIGH HP LOW SP LOW SHX
No alarm history.
ALARM HISTORY SCREENS
Description
Screen Text
Description
COMM T/O E-BUS Slave Timeout
Coil Temp Failure Low Leaving Water Temp Compressor Not Running No Head Pressure Sensor Detected High Head Pressure Detected Low Suction Pressure Detected Low Superheat Detected
SP SENSE UNSAFESP NOH2OFLO
HI SHX BIN4 ALM MODBUS HDLT ALM
No Suction Pressure Sensor Detected Unsafe Suction Pressure Detected Proof of Water Flow High Superheat Failure BI4 is open, if configured. MODBUS Not Detected High Discharge Temperature Detected
Table 13: Alarm History Screens
RM454-V Technical Guide
21
LCD SCREENS Screen Descriptions
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 SCREENS
Screen Text
Description
SETPOINT STATUS
Setpoint Status screens
HEADPRSP XXX PSIG
Head Pressure Setpoint. Valid range is 260-475 psig. Default is 340 psig. Measured in PSIG.
SUPRHT SP Superheat Setpoint. Valid range is 1-30ºF. Default
XX.X°F
is 15ºF. Measured in degrees Fahrenheit.
LOW SUCT XX PSIG
Low Suction Pressure Setpoint. Default is 88 psig. Measured in PSIG.
COILT SP XX.XºF
Coil Temperature Setpoint. Valid range is 35-60ºF. Default is 40ºF.Measured in degrees Fahrenheit.
Table 14: Setpoint Status Screens
RM454-V Technical Guide
22
LCD SCREENS Screen Descriptions
VFD Menu Screens
The VFD Menu screen displayed depends on which compressor is installed on the unit. The options are Yaskawa VFD and Danfoss VFD.
Copeland EVM Status Screens Refer to the following map and table when navigating through the Yaskawa VFD Screens. From the COPELAND EVM status screen, press <ENTER> to scroll through the screens.
COPE EVM XXXXXXXX
CONNECT? YES
MAX FREQ 215 Hz
MB RETRY #VALUE
CURRENT 0 AMPS
MB VALID #VALUE
I LIMIT #.## AMPS
COMPSTAT ENABLE
NO ALARMS
SPD CMND 100%
LOH20TMP
COPELAND EVM STATUS SCREENS
Screen Text
Description
COPELAND XXXXXXXX
Comp model #. Options are: · YAV0232E · YAV0302E · YAV0412E · YAV0471E · YAV0661E · YAV066K1E · YAV096K1E · YAV0961E
CONNECT? YES
VFD is connected and communicating. Options are: · YES · NO
MB RETRY #VALUE
Totals if it is missing communication packet information.
MB VALID #VALUE
Totals if it receives good communication packet information.
COMPSTAT ENABLE
· Enable or off
SPD CMND 100%
· 0% – 100%
SPEED FB 222 Hz
Current speed in Hz
SPEED FB 0 RPM
Current speed in RPM
MAX FREQ Value dependent on unit I.D.
CURRENT 0 AMPS
Compressor current in Amps
I LIMIT XXXAMPS
Value dependent on unit I.D., in Amps
NO ALARMS
No current alarms.
LOH2OTMP Low Leaving Water Temp
Table 15: Copeland EVM Status Screens
SPEED FB 222 Hz
SPEED FB 0 RPM
RM454-V Technical Guide
23
LCD SCREENS Screen Descriptions
Danfoss VFD Screens Refer to the following map and table when navigating through the Danfoss VFD screens. From the DANFOSS VFD screen, press <ENTER> to scroll through the screens.
DANFOSS VFD
CONNECT? YES
NO ALARMS
MB RETRY XXXX
I LIMIT XXX.XAMP
MB VALID XXXX
CURRENT XX.X A
VFD STAT
C1 HOURS XXX
COMMAND% XXX%
VFD HRS XXX
MAX REF XXXX RPM
MODEL # XXXXXXXX
MIN REF CONFIRMD
DRIVE# XXXXXXXX
DANFOSS VFD SCREENS
Screen Text
Description
DANFOSS COMP
Danfoss VFD status screens
CONNECT? YES
VFD is connected and communicating. Options are: · YES · NO
MB RETRY XXXX
Totals if it is missing communication packet information.
MB VALID XXXX
Totals if it receives good communication packet information.
VFD STAT
VFD compressor status. Displays a value read from VFD showing status and configuration information. It will display each bit of information separately.
COMMAND% Compressor percentage commanded to VFD. XXX%
MAX REF XXXX RPM
Maximum speed programmed into the VFD in RPM.
MIN REF CONFIRMD
Minimum speed programmed into the VFD. Options are
· CONFIRMD For proper speed command this should always say CONFIRMD, meaning it is set to zero.
NO ALARMS
Alarm codes read from the VFD. Will show NO ALARMS if no alarms have occured or the alarm code
I LIMIT XXX.XAMP
I LIMIT Measured in amps
CURRENT XX.X A
CURRENT Live current read from VFD in amps.
C1 HOURS 14
Compressor running hours read from VFD.
VFD HRS 28
VFD running hours read from VFD.
MODEL # XXXXXXXX
Compressor model number read from VFD. Options are:
· VZH088 · VZH117 · VZH170 · VZH028 · VZH035 · VZH044 · VZH052 · VZH065 · UNKNOWN! If UNKNOWN is shown, check that proper unit is selected in Prism 2.
DRIVE# XXXXXXXX
Drive number. Options are: · CDS803 · CDS303.
Table 16: Danfoss VFD Screens
RM454-V Technical Guide
24
LCD SCREENS Screen Descriptions
EXV Type Screens
The EXV Type screen displayed depends on which compressor is installed on the unit. The current available option is Sanhua.
Sanhua Screens Refer to the following map and table when navigating through the Sanhua screens. From the EXV TYPE SANHUA Screen, press <ENTER> to scroll through the screens.
EXV TYPE SANHUA
SPORLAN EXV SCREENS
Screen Text
Description
EXV TYPE SPORLAN
Sporlan EXV status screens
EXV X DETECTED
EXV detected. The number of screens shown depends on unit configuration.
EXVX PSI XXX PSIG
EXV pressure measured in PSIG. The number of screens shown depends on unit configuration.
Table 18: Sporlan EXV Screens
EXV X DETECTED
EXVX PSI XXX PSIG
SANHUA EXV SCREENS
Screen Text
Description
EXV TYPE SANHUA
Sanhua EXV status screens
EXV X DETECTED
EXV detected. The number of screens shown depends on unit configuration.
EXVX PSI XXX PSIG
EXV pressure measured in PSIG. The number of screens shown depends on unit configuration.
Table 17: Sanhua EXV Screens
Sporlan SH Screens
Refer to the following map and table when navigating through the Sporlan SH screens. From the EXV TYPE SPORLAN Screen, press <ENTER> to scroll through the screens.
EXV TYPE SPORLAN
EXV X DETECTED
EXVX PSI XXX PSIG
RM454-V Technical Guide
25
TROUBLESHOOTING LED Diagnostics
Using RM454-V LEDs to Verify Operation
The RM454-V is equipped with LEDs that can be used to verify operation and perform troubleshooting. There are LEDs for communication, operation modes, and diagnostic codes. See Figure 6, this page, for the LED locations. The LEDs associated with these inputs and outputs allow you to see what is active without using a voltmeter. The LEDs and their uses are as follows:
Diagnostic LEDs
STATUS – If the software is running, this LED should blink at a rate of one blink per second.
ALARM (on board) – If the RM454-V Module does not receive communications for more than one minute, this LED lights up, the relays turn off, and the analog outputs go to 0 VDC.
Binary Input LEDs BIN1 – This green LED lights up when Compressor Status 1 input has 24VAC present.
BIN2 – This green LED lights up when Compressor Status 2 input has 24VAC present.
BIN3 – This green LED lights up when the Coil Temperature input has 24VAC present.
BIN4 – This green LED lights up when the Emergency Shutdown input has 24VAC present.
Relay LEDs RLY1 – RLY4 – These green LEDs light up when the relays are enabled and stay lit as long as they are active.
ALARM (above LCD display) – This red LED lights up and stays lit when there is an alarm present. The type of alarm displays on the LCD display. The ALARM LED also blinks when the expansion valve is initializing at startup.
COMM – Every time the RM454-V Module receives a valid E-BUS request from the VCCX-454 Controller, this LED blinks on and then off, signifying that it received a valid request and responded.
POWER – This LED lights up to indicate that 24 VAC power has been applied to the controller.
ALARM
RM454-V Stepper Motor Valve LED
EXV-1 – This yellow LED blinks to indicate communication to the Superheat Controller. If the LED is on solid, that indicates no communication to the Superheat Controller.
EXV-2 – This yellow LED blinks to indicate communication to the Superheat Controller. If the LED is on solid, that indicates no communication to the Superheat Controller.
STATUS ALARM COMM POWER
BINARY INPUT
ALARM
MENU
UP ENTER
DOWN
www.aaon.com AAON P/N: ASM07687
RSM-DEV1
+5 V SP GND
SUCTION PRES
+5 V HP GND
HEAD PRES
DISCHARGE TEMP 1 DISCHARGE TEMP 2 TXV COIL TEMP NOT USED NOT USED NOT USED GND GND
BINARY INPUTS
COMP STAT 1 COMP STAT 2 DEFROST SW EMER SHDN GND
ANALOG OUTPUTS
NOT USED COND FAN GND
MODBUS
LABEL P/N: G149410
RELAY CONTACT RATING IS 1 AMP MAX @ 24 VAC
RELAY OUTPUTS
COMP 1 ENABLE COMP 2 / HI SPEED
CONDENSER REVERSING VALVE
COMMON
EACH EXP VALVE IS INDIVIDUALLY ELECTRICALLY ISOLATED
EXP VALVE 1
R+ SHD
T-
EXP VALVE 2
R+ SHD
T-
EXP VALVE 3 NOT
INSTALLED
EXP VALVE 4 NOT
INSTALLED
DUAL E-BUS
24 VAC POWER ONLY WARNING! POLARITY MUST BE OBSERVED OR THE CONTROLLER WILL BE DAMAGED
RELAY EXV-1 EXV-2
R+ SH T-
GND +24 VAC
Figure 6: RM454-V LED Locations
RM454-V Technical Guide
26
TROUBLESHOOTING Sensor Testing
TXV Coil Temperature Sensor Testing
The Temperature, Resistance, and Voltage for Discharge Sensors, Table 19, this page, is provided to aid in checking sensors that appear to be operating incorrectly. Many system operating problems can be traced to incorrect sensor wiring. Be sure all sensors are wired per the wiring diagrams in this manual.
If the sensors still do not appear to be operating or reading correctly, check voltage and/or resistance to confirm the sensor is operating correctly per the tables.
Thermistor Sensor Testing Instructions
Use the Resistance (kOhms) column to check the thermistor sensor while disconnected from the controllers (not powered).
Use the Voltage @ Input (VDC) column to check sensors while connected to powered controllers. Read voltage with meter set on DC volts. Place the “-” (minus) lead on the GND terminal and the “+” (plus) lead on the sensor input terminal being investigated.
NOTE:
Early releases of units do not have this sensor. If a software update is performed, an alarm will show up for missing sensor. This can be mitigated by contacting support.
TEMPERATURE RESISTANCE VOLTAGE FOR TYPE III 10 K OHM THERMISTOR SENSORS
Temp (ºF)
Temp (ºC)
Resistance (Ohms)
Voltage @ Input (VDC)
Temp (ºF)
Temp (ºC)
Resistance (Ohms)
Voltage @ Input
(VDC)
-10
-23.3
93333
4.51
72
22.2
11136
2.635
-5
-20.6
80531
4.45
73
22.8
10878
2.605
0
-17.8
69822
4.37
74
23.3
10625
2.576
5
-15
60552
4.29
75
23.9
10398
2.549
10
-12.2
52500
4.2
76
24.4
10158
2.52
15
-9.4
45902
4.1
77
25
10000
2.5
20
-6.6
40147
4.002
78
25.6
9711
2.464
25
-3.9
35165
3.891
80
26.7
9302
2.41
30
-1.1
30805
3.773
82
27.8
8893
2.354
35
1.7
27140
3.651
84
28.9
8514
2.3
40
4.4
23874
3.522
86
30
8153
2.246
45
7.2
21094
3.39
88
31.1
7805
2.192
50
10
18655
3.252
90
32.2
7472
2.139
52
11.1
17799
3.199
95
35
6716
2.009
54
12.2
16956
3.143
100
37.8
6047
1.884
56
13.3
16164
3.087
105
40.6
5453
1.765
58
14.4
15385
3.029
110
43.3
4923
1.65
60
15.6
14681
2.972
115
46.1
4449
1.54
62
16.7
14014
2.916
120
48.9
4030
1.436
64
17.8
13382
2.861
125
51.7
3656
1.339
66
18.9
12758
2.802
130
54.4
3317
1.246
68
20
12191
2.746
135
57.2
3015
1.159
69
20.6
11906
2.717
140
60
2743
1.077
70
21.1
11652
2.691
145
62.7
2502
1.001
71
21.7
11379
2.661
150
65.6
2288
0.931
Table 19: 0-5V Temperature Sensor – Voltage and Resistance for Type III Sensors
RM454-V Technical Guide
27
TROUBLESHOOTING Sensor Testing
Discharge Line Thermistor Temperature Sensor Testing
Table 20, this page, is provided to aid in checking sensors that appear to be operating incorrectly. Many system operating problems can be traced to incorrect sensor wiring. Be sure all sensors are wired per the wiring diagrams in this manual.
If the sensors still do not appear to be operating or reading correctly, check voltage and/or resistance to confirm that the sensor is operating correctly per the table.
Thermistor Sensor Testing Instructions
Use the resistance column to check the thermistor sensor while disconnected from the controllers (not powered).
Use the voltage column to check sensors while connected to powered controllers. Read voltage with meter set on DC volts. Place the “-” (minus) lead on GND terminal and the “+” (plus) lead on the sensor input terminal being investigated.
DISCHARGE LINE THERMISTOR SENSOR TEMPERATURE AND RESISTANCE
Temp (ºF)
Temp (ºC)
Resistance (kOhms)
Voltage @ Input (VDC)
Temp (ºF)
Temp (ºC)
Resistance (kOhms)
Voltage @ Input (VDC)
-40
-40
2889.60
4.98
167
75
12.73
2.80
-31
-35
2087.22
4.97
176
80
10.79
2.59
-22
-30
1522.20
4.96
185
85
9.20
2.39
-13
-25
1121.44
4.95
194
90
7.87
2.19
-4
-20
834.72
4.94
203
95
6.77
2.01
5
-15
627.28
4.92
212
100
5.85
1.84
14
-10
475.74
4.89
221
105
5.09
1.68
23
-5
363.99
4.86
230
110
4.45
1.53
32
0
280.82
4.82
239
115
3.87
1.39
41
5
218.41
4.77
248
120
3.35
1.25
50
10
171.17
4.72
257
125
2.92
1.12
59
15
135.14
4.65
266
130
2.58
1.02
68
20
107.44
4.57
275
135
2.28
0.92
77
25
86.00
4.47
284
140
2.02
0.83
86
30
69.28
4.36
293
145
1.80
0.76
95
35
56.16
4.24
302
150
1.59
0.68
104
40
45.81
4.10
311
155
1.39
0.61
113
45
37.58
3.94
320
160
1.25
0.55
122
50
30.99
3.77
329
165
1.12
0.50
131
55
25.68
3.59
338
170
1.01
0.45
140
60
21.40
3.40
347
175
0.92
0.42
149
65
17.91
3.20
356
180
0.83
0.38
158
70
15.07
3.00
If the voltage is above 4.98 VDC, then the sensor or wiring is “open.” If the voltage is less than 0.38 VDC, then the sensor or wiring is shorted.
Table 20: Discharge Thermistor Temperature and Resistance
RM454-V Technical Guide
28
TROUBLESHOOTING Transducer Testing
Suction Pressure Transducer Testing for R454-B Refrigerant
The evaporator coil temperature is calculated by converting the suction pressure to temperature. The suction pressure is obtained by using the Suction Pressure Transducer, which is connected to the suction line of the compressor.
Use the voltage column to check the Suction Pressure Transducer while connected to the RM454-V Module. The VCCX-454 and the RM454-V Module must be powered for this test. Read voltage with a meter set on DC volts. Place the positive lead from the meter on the SP1 terminal located on the RM454-V Module terminal block. Place the negative lead from the meter on the ground (GND) terminal located adjacent to the SP1 terminal on the RM454-V Module terminal block. Use a refrigerant gauge set and/or an accurate electronic thermometer to measure the temperature or suction line pressure near where the Suction Pressure Transducer is connected to the suction line. Measure the voltage at the SP1 and GND terminals and compare it to the appropriate chart depending on the refrigerant in use. If the temperature/voltage or pressure/voltage readings do not align closely with the chart, the Suction Pressure Transducer is probably defective and needs to be replaced.
See Table 21, this page. The chart shows a temperature range from 25.88°F to 86.11°F. For troubleshooting purposes, the DC voltage readings are also listed with their corresponding temperatures and pressures.
SUCTION PRESSURE TRANSDUCER CHART FOR R454-B REFRIGERANT (VAPOR)
Temperature (°F)
Temperature (ºC)
Pressure (psi) Signal
DC Volts
25.88
-3.4
80.94
1.8
29.42
-1.4
87.16
1.9
32.81
0.5
93.39
2.0
36.05
2.6
99.62
2.1
39.16
4.0
105.84
2.2
42.15
5.6
112.07
2.3
45.02
7.2
118.29
2.4
47.79
8.8
124.52
2.5
50.47
10.3
130.75
2.6
53.06
11.7
136.97
2.7
55.57
13.1
143.20
2.8
57.99
14.4
149.42
2.9
60.36
15.8
155.65
3.0
62.65
17.0
161.88
3.1
64.88
18.3
168.10
3.2
67.05
19.5
174.32
3.3
69.16
20.6
180.55
3.4
71.23
21.8
186.78
3.5
73.24
22.9
193.00
3.6
75.20
24
199.23
3.7
77.12
25.1
205.46
3.8
79.00
26.1
211.68
3.9
80.83
27.1
217.91
4.0
82.63
28.1
224.14
4.1
84.39
29.1
230.36
4.2
86.11
30.1
236.59
4.3
Table 21: Suction Pressure Transducer Chart for R454-B Refrigerant (Vapor)
RM454-V Technical Guide
29
TROUBLESHOOTING Transducer Testing
If you suspect there is a problem related to the head pressure transducer, measurements can be taken at the HP terminal. See Table 22, this page.
HEAD PRESSURE TRANSDUCER CHART
Voltage
Pressure
Voltage
Pressure
0.5
0
2.6
350
0.6
17
2.7
367
0.7
33
2.8
384
0.8
50
2.9
400
0.9
67
3.0
417
1.0
83
3.1
434
1.1
100
3.2
450
1.2
117
3.3
467
1.3
133
3.4
484
1.4
150
3.5
500
1.5
167
3.6
517
1.6
183
3.7
534
1.7
200
3.8
550
1.8
217
3.9
567
1.9
233
4.0
584
2.0
250
4.1
600
2.1
267
4.2
617
2.2
283
4.3
634
2.3
300
4.4
650
2.4
317
4.5
667
2.5
334
Table 22: Head Pressure Transducer Chart
RM454-V Technical Guide
30
RM454-V Technical Guide Rev. A 250117
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Documents / Resources
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AAON RM454-V Controller Module [pdf] User Guide VCCX-454 Series, RM454-SC, ASM07718, ASM07503, ASM07719, ASM01687, G029440, G012870, G029460, G045270, G029510, G029530, G029450, G029470, V36590, G018870, ASM01635, ASM01878, RM454-V Controller Module, RM454-V, Controller Module, Module |