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MHGRV-X Field Technical Guide

TABLE OF CONTENTS

OVERVIEW ....................................................................................................................... 5

MHGRV-X General Information............................................................................................................................... 5

WIRING ............................................................................................................................ 6

Installation and Wiring ............................................................................................................................................. 6
MHGRV-X to AAON unit controller Wiring............................................................................................................... 7
MHGRV-X Stand-Alone Wiring ............................................................................................................................... 8

INPUTS AND OUTPUTS .................................................................................................. 9

Inputs and Outputs .................................................................................................................................................. 9

OPERATION MODES ..................................................................................................... 10

Operation Modes .................................................................................................................................................. 10

LCD SCREENS ............................................................................................................... 12

TROUBLESHOOTING .................................................................................................... 16

APPENDIX A: SAT SENSOR .......................................................................................... 20

Supply Air Temperature Sensor Installation .......................................................................................................... 20
SAT Sensor Wiring Guide and Jumper Settings ................................................................................................... 21

APPENDIX B: MHGRV II................................................................................................ 22

MHGRV-X Replacement of MHGRV II .................................................................................................................. 22

APPENDIX C: REHEAT EXPANSION MODULE ............................................................ 23

Summary of Contents for MHGRV-X

Page 1: ...MHGRV X Controller Field Technical Guide...

Page 2: ...21 AAON Inc All rights reserved throughout the world AAON is a registered trademark of AAON Inc Tulsa OK AAON assumes no responsibility for errors or omissions in this document This document is subjec...

Page 3: ...s Map and Main MHG REHEAT Screens 13 Status and Alarm Screens 14 Setpoint and Force Valves Screens 15 TROUBLESHOOTING 16 LED Diagnostics 16 Alarms 17 Other Checks 18 APPENDIX A SAT SENSOR 20 Supply Ai...

Page 4: ...21 Table 9 Stand Alone Mode SAT OPTIONS Jumper Settings 21 Table 10 Communications Mode SAT OPTIONS Jumper Settings 21 Table 11 Reheat Expansion Module ALARM LED Blink Codes 27 FIGURES Figure 1 MHGRV...

Page 5: ...sing the MHGRV X to replace an existing MHGRV II Controller see Appendix B page 22 for details See Figure 1 this page for dimensions Features The MHGRV X provides the following Can be operated as a st...

Page 6: ...ire size for all sensors should be 24 gauge Some sensors require two conductor wire and some require 3 or 4 conductor wire 5 Minimum wire size for 24 VAC thermostat wiring should be 22 gauge 6 Be sure...

Page 7: ...rature Sensor is attached to the AAON unit controller See Figure 2 this page See the SATWiring Conditions Table and SAT OPTIONS jumper settings in Tables 8 and 10 page 21 Figure 2 MHGRV X to AAON Unit...

Page 8: ...Transformer Minimum Mount In Supply Air Duct RED GRN WHT BLK Condenser Valve 1 HGR Valve 1 RED GRN WHT BLK COMM See SAT OPTIONS table for Jumper Settings Only one Supply Air Temperature Sensor can be...

Page 9: ...g Override Used only in Stand Alone operation When a call for heating is initiated by the HVAC unit this interlocked 24 VAC wet contact closure is used to override the MHGRV X Dehumidification Mode CO...

Page 10: ...can be used in two different modes of operation These modes behave in a similar manner the main difference is the way they receive information to control the dehumidification process The following is...

Page 11: ...terminate Dehumidification or a Cooling or Heating Override request is made by the HVAC unit controller Any setpoints or signals at the inputs to the MHGRV X will be ignored Auxiliary Mode Communicat...

Page 12: ...tions Figure 4 LCD Display and Navigation Keys Table 3 Navigation Key Functions NAVIGATION KEY KEY FUNCTION MENU Use the MENU key to move through screens within Main Menu categories and return to the...

Page 13: ...ress to go to FORCE VALVE Screens FORCE VALVES Press to scroll through FORCE VALVES Screens Main MHG REHEAT Screens Refer to the following map when navigating through the Main Screens From the MHG REH...

Page 14: ...Valve between 0 100 FORCE The unit is in the Force Mode VLV POS 100 VALVE POSITION 0 to 100 percent SA TEMP XX X SUPPLY AIR TEMPERATURE 40 F to 150 F or 5 C to 65 C If no sensor is detected screen wil...

Page 15: ...LY AIR SETPOINT This is maximum temperature at which the Supply Air Temperature will reset to Will display only in Stand Alone Mode The Reset SAT Setpoint is set by the LCD Display in Stand Alone Mode...

Page 16: ...Normally Open Contact is closed VALVE This green LED will light up to indicate that the relay for the VALVE output is energized and its Normally Open Contact is closed AUX This green LED will light up...

Page 17: ...pen or failed wiring Refer to chart in back of this guide for readings Verify the SAT OPTIONS jumper settings on the MHGRV X for the Supply Air Temperature Sensor Communications Loss Check COMM LED on...

Page 18: ...the resistance set the meter to Ohms Unplug the sensor connector from the board and measure the resistance across the disconnected wires This resistance should match the corresponding temperature from...

Page 19: ...2 607 76 24 4 10158 2 577 78 25 6 9711 2 520 80 26 7 9302 2 465 82 27 8 8893 2 407 84 28 9 8514 2 352 86 30 8153 2 297 88 31 1 7805 2 242 90 32 2 7472 2 187 95 35 6716 2 055 100 37 8 6047 1 927 105 4...

Page 20: ...nt Stand Alone Mode In Stand Alone Mode the SAT Sensor is connected to the MHGRV X If in Stand Alone Mode the MHGRV X is used in conjunction with a Stand Alone MODGAS X the SAT sensor is shared betwee...

Page 21: ...ble Install Supply Air Sensor in AAON unit controller Connect to AAON unit controller using I2 C cable VCM VAV CAV MUA MUA II MUA IID Install Supply Air Sensor in MODGAS X Connect to AAON unit control...

Page 22: ...tep 1 Disconnect power from the MHGRV II Step 2 The Supply Air Temperature Sensor needs to remain installed on whatever controller it is currently on If it is currently installed on the MHGRV II then...

Page 23: ...multiple sets of valves See Figure 8 this page for dimensions Features The Reheat Expansion Module provides the following Up to seven Reheat Expansion Modules can be used Each Reheat Expansion Module...

Page 24: ...ller or Module is not operating correctly General Wiring Information For the wiring diagram to use when the MHGRV X is connected to anAAON unit controller see Figure 2 page 7 For the Stand Alone wirin...

Page 25: ...connectors Up to seven Reheat Expansion Modules can be used Apply power to the first Reheat Expansion Module in a series The last Reheat Expansion Module in a series connects to the MHGRV X using an E...

Page 26: ...il return to the compressor the Hot Gas Reheat Coil will be flushed of liquid refrigerant by moving the Modulating Gas Reheat Valve to its maximum position for a short interval Cooling Flush If the un...

Page 27: ...every second The COMM LED should blink simultaneously on all modules Binary Input LED COMPRESSOR ENABLE This green LED will light up when the Reheat is enabled LED Troubleshooting POWER LED When the R...

Page 28: ...he STATUS LED will blink six times A The valve position displayed on the MHGRV X Status Screen should match the expansion module s valve position The expansion module must have the enable signal activ...

Page 29: ...press the ENTER key once from the main screen It should display S A MODE LOCKED 3 The MHGRV X must be configured for EXP VLVS ENABLED in the MHGRV X Configuration Screens If this is true the COMM LED...

Page 30: ...rved AAON Factory Technical Support 918 382 6450 techsupport aaon com AAON Controls Support 866 918 1100 Monday through Friday 7 00 AM to 5 00 PM Central Standard Time Controls Support website www aao...

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