MHGRVX-A2 Module
Field Technical Guide
Designed to work exclusively with Sanhua EBV05H reheat valves
Страница 1: ...MHGRVX A2 Module Field Technical Guide Designed to work exclusively with Sanhua EBV05H reheat valves ...
Страница 2: ...AAON assumes no responsibility for errors or omissions in this document This document is subject to change without notice www aaon com MHGRVX A2 PARTS REFERENCE PART DESCRIPTION PART NUMBER MHGRV X ASM01670 MHGRVX A1 MHGRVX B1 Module no I2 C ASM07265 ASM06910 MHGRVX A2 MHGRVX B2 Module no I2 C Sanhua EBV05H valve only ASM06926 ASM06927 MODGAS X Controller ASM01668 VCCX2 Controller ASM01698 AAON Un...
Страница 3: ...HG REHEAT Screens 15 Status and Alarm Screens 16 Setpoint and Force Valves Screens 17 Protected Screens 18 TROUBLESHOOTING 21 LED Diagnostics 21 Alarms 22 Other Checks 23 APPENDIX A SAT SENSOR 25 Supply Air Temperature Sensor Installation 25 SAT Sensor Wiring Guide and Jumper Settings 26 APPENDIX B COMPATIBILITY 27 MHGRVX Series Drop In Replacement 27 APPENDIX C REHEAT EXPANSION MODULE 28 Features...
Страница 4: ...or Voltage and Resistance for Type III Sensors 24 Table 8 SAT Wiring Conditions 26 Table 9 Reheat Expansion Module ALARM LED Blink Codes 31 FIGURES Figure 1 MHGRVX A2 Dimensions 5 Figure 2 MHGRVX A2 to AAON Unit Controller Wiring 7 Figure 3 MHGRVX A2 Stand Alone Wiring 8 Figure 4 LCD Display and Navigation Keys 14 Figure 5 MHGRVX A2 LED Locations and Descriptions 22 Figure 6 Supply Air Temperature...
Страница 5: ...capability when using two hot gas reheat valves Control of the reheat solenoid valve to provide coil flushing for positive refrigerant oil return Can provide further reheat control using up to seven Reheat Expansion Modules Contains a 2 x 8 LCD character display and four buttons that allow for status display setpoint changes and configuration changes 5 73 2 62 2 04 4 09 0 57 0 21 5 04 5 63 5 24 D8...
Страница 6: ...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 ...
Страница 7: ...ture Sensor Supply Air Temperature Sensor connects to AI3 and GND on the VCCX2 Controller Set jumper to NORMAL E BUS cable connects to the VCCX2 expansion port E BUS cable connects to the Reheat Expansion Module Line Voltage 40 VA transformer minimum 18 30 VAC Fan Alternate configuration for three way valve D8 R2 J3 MODGASx MODGAS NORMAL R1 SAT OPTIONS SAT GND COOL OVRD HEAT OVRD REHEAT EN RESET I...
Страница 8: ...used per application 0 10 VDC External Reset Signal H1 Dehumidification Heating Override Cooling Override Mount in Supply Air Duct Supply Air Temperature Sensor D8 R2 J3 MODGASx MODGAS NORMAL R1 SAT OPTIONS SAT GND COOL OVRD HEAT OVRD REHEAT EN RESET IN AUX IN GND TB2 LC FAN COMP VALVE AUX COMMON TB1 STATUS ALARM COMM POWER CONDENSOR DRIVE BLACK WHITE RED GREEN OPENING TB3 REHEAT DRIVE BLACK WHITE ...
Страница 9: ...rature AUX IN Auxiliary Reheat Valve Input Used when AUX mode is configured as enabled This input looks at a 0 10 VDC signal to control the valve position 0VDC 0 Reheat Valve position 5VDC 50 Reheat Valve position 10VDC 100 Reheat Valve position Binary Inputs REHEAT EN Reheat Enable Contact Used only in Stand Alone Mode When a call for dehumidification is initiated by another controller this inter...
Страница 10: ... Air Temperature is 5 F below setpoint for one minute After being off for 10 minutes it can come back on if the Supply Air Temperature is 5 F above setpoint and the valve is at 0 AUX Two Position HGR Valve Reversing Valve If configured as standard this relay will be used to control a two position HGR valve Used on larger capacity systems that have an optional two position HGR Valve in addition to ...
Страница 11: ...CMP output starting the HVAC unit compressor At this time the MHGRVX A2 will start to modulate the Modulating Hot Gas Reheat Valve The module will modulate the MHGR valve to maintain the Supply Air Temperature Setpoint by activating the stepper motor outputs on the MHGR Valve The Supply Air Setpoint is configured with the Setpoint Screen in the LCD display If Supply Air Temperature Reset is used i...
Страница 12: ...r motor outputs on the MHGR valve The Supply Air Setpoint is set by programming the HVAC unit controller If Supply Air Temperature Reset is used it will initiate when the HVAC unit controller ends a request to reset the Supply Air Temperature The Supply Air Temperature will be reset towards the Supply Air Reset Temperature Setpoint stored in the HVAC unit controller It will send a request to move ...
Страница 13: ...0 the timer is reset The flush reheat interval timer is a setpoint that is configurable using the keypad and display 0 to 120 minutes in 10 minute increments Condenser Coil Flush If Condenser Coil Flush is configured and the unit is in Dehumidification Mode and the reheat valve is above 70 for the flush reheat interval timer value a condenser flush will occur This shares the timer with the reheat ...
Страница 14: ...riptions 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 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 th...
Страница 15: ...eens Press to go to FORCE VALVE Screens FORCE VALVES Press to scroll through FORCE VALVES Screens Main Screens Refer to the following map when navigating through the Main Screens From the main screen press ENTER to scroll through the screens MHGRVX 1176vXXX S A MODE SA MODE LOCKED OR COMM MODE In Stand Alone Mode the screen will display S A MODE or S A MODE LOCKED In Communications Mode the screen...
Страница 16: ...R 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 40ºF to 150ºF or 5ºC to 65ºC If no sensor is detected screen will display NO SENSR Alarm Screens Refer to the following map when viewing Alarm Screens These screens will display automatically when alarms are present For more information see pages 21 and 22 ACTIV...
Страница 17: ...REHEAT SUPPLY 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 and is set by the AAON unit controller in communicating mode Force Valves Screens Refer to the following map when navigating through the Force Screens From the FORCE VALVES screen press EN...
Страница 18: ...ugh the LCD Protected Screens From the main screen press the ENTER twice until you get to the SOFTWARE Screen Then hold the UP button for five seconds To scroll through the rest of the screens press the MENU button MHGRVX 1176vXXX S A MODE SA MODE LOCKED OR COMM MODE SOFTWARE 1176vXXX Hold for five seconds CONFIG DIAGNSTC ENTER TO EXIT ...
Страница 19: ...EPS 2800 VALVE STEPS This value cannot be modified TMPSCALE FAHRENHT TEMPERATURE SCALE Fahrenheit default or Celsius This setting is only used in Stand Alone Mode S A MODE AUTODETECT S A MODE FORCED S A Mode Autodetect default or Locked Forces the module to be Stand Alone Mode only EXP VLVS DISABLED REHEAT EXPANSION MODULE VALVES Expansion Valves Disabled default or Enabled If Expansion Valves are...
Страница 20: ...ondenser flushes Diagnostic Screens Refer to the following map when navigating through the Diagnostic Screens From the DIAGNSTC Screen press ENTER to scroll through the screens DIAGNSTC WDOG CNT WATCH DOG TIMER Displays the number of times the board has been reset due to watchdog timer overflow PWER CNT POWER LOSS COUNT Displays the number of times the board has been reset due to power loss STEP C...
Страница 21: ...alarm will display on the LCD display See Table 5 this page ALARM above LCD display The LED blinks when an alarm is active Communication LED COMM This yellow LED will light up and blink when communications are detected Relay LEDs FAN This green LED will light up to indicate that the relay for the FAN output is energized and its Normally Open Contact is closed COMP This green LED will light up to i...
Страница 22: ...VX A2 status screen displays Position and that main screens show COMM MODE ALARM LED REHEAT ENABLE LED HEAT OVERRIDE LED COOL OVERRIDE LED FAN RELAY LED COMPRESSOR RELAY LED VALVE RELAY LED AUX RELAY LED STATUS LED ALARM LED COMM LED POWER LED CONDENSER DRIVE LED REHEAT VALVE DRIVE THREE WAY VALVE LED D8 R2 J3 MODGASx MODGAS NORMAL R1 SAT OPTIONS SAT GND COOL OVRD HEAT OVRD REHEAT EN RESET IN AUX ...
Страница 23: ...ad 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 Table 6 this page and Table 7 page 24 Temp F Temp C Resistance Ohms Voltage Input VDC 10 23 3 93333 2 98 5 20 6 80531 2 94 0 17 8 69822 2 89 5 15 60552 2 83 10 12 2 52500 2 77 15 9 4 45902 2 71 20...
Страница 24: ...398 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 40 6 5453 1 805 110 43 3 4923 1 687 115 46 1 4449 1 575 120 48 9 4030 1 469 125 51 7 3656 1 369 130 54 4 3317 1 274 135 57 2 3015 1 185 140 60 2743 1 101 145 62 7 2502 1 024 150 65 6 2288 0 952 Temp...
Страница 25: ... Air Temperature Sensor is mounted and wired according to these instructions prior to testing the unit or else the modulating valve will not control properly andmay damage your equipment Stand Alone Mode In Stand Alone Mode the SAT Sensor is connected to the MHGRVX A2 If in Stand Alone Mode the MHGRVX A2 is used in conjunction with a Stand Alone MODGAS X the SAT sensor is shared between the two co...
Страница 26: ...AS X AND MHGRVX A2 Stand Alone Install Supply Air Sensor in MODGAS X Install Supply Air Sensor in MHGRVX A2 Set SAT Options Jumpers to Normal Install Sensor in MODGAS X and daisy chain it to the MHGRVX A2 Set SAT Options Jumpers to MODGAS X VCCX2 VCB X Install Supply Air Sensor in VCCX2 or VCB X Connect to VCCX2 or VCB X using E BUS cable Install Supply Air Sensor in VCCX2 or VCB X Connect to VCCX...
Страница 27: ...nication Valve Dependant Compatibility Other MHGRV X Yes No MHGRV II MHGRVX A1 MHGRVX B1 MHGRVX A1 No No MHGRV X MHGRVX B1 MHGRVX A2 No Sanhua EBV05H only MHGRVX B2 MHGRVX B1 No No MHGRV X MHGRVX A1 Additional AOUT input on board MHGRVX B2 No Sanhua EBV05H only MHGRVX A2 Additional AOUT input on board These modules do no support I2C communication ...
Страница 28: ...ions with slightly different dimensions Both configurations are interchangeable but may require adjustment of the snap tracks 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 controls one set of reheat valves one Reheat and one Condenser Each Reheat Expansion Module has it...
Страница 29: ...le parts Contact qualified technical personnel if your controller or module is not operating correctly General Wiring Information For the wiring diagram to use when the MHGRVX A2 is connected to an AAON unit controller see Figure 2 page 7 For the Stand Alone wiring diagram see Figure 3 page 8 For Reheat Expansion Board wiring see Figure 8 page 30 Please carefully read and apply the following infor...
Страница 30: ...ansion Module in a series connects to the MHGRVX A2 using an E BUS cable See Figure 8 this page for details Figure 8 Reheat Expansion Module s Wiring NOTE Connect the next Reheat Expansion Module to the power connector of the previous Reheat Expansion Module in a series Up to seven expansion modules can be connected together The last Reheat Expansion Module in a series connects to the MHGRVX A2 E ...
Страница 31: ...al Features Reheat Coil Flush To assure positive oil 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 unit is in cooling mode a flush will occur when the unit s flush cooling interval timer has elapsed The time is accumulated whenever it is in cooling mo...
Страница 32: ...nk the same once 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 Reheat Expansion Module is powered up the POWER LED should light up and stay on continuously If it does not light up check to be sure that the power wiring is connected to the board th...
Страница 33: ...onds if the valve is not closed It will blink the position divided by 10 So for example if the position is 68 the STATUS LED will blink six times A The valve position displayed on the MHGRVX A2 Status Screen should match the expansion module s valve position The expansion module must have the enable signal activated for the valve position to mirror the MHGRVX A2 Q The STATUS LED is on solid What d...
Страница 34: ...The VCCX2 or VCB X MHGRVX A2 and Reheat Expansion Module are connected to each other with an E BUS cable and the connections are secure 2 The MHGRVX A2 must be configured as S A AUTODECT in the MHGRVX A2 Configuration Screens To confirm this press the ENTER key once from the main screen It should display COMM MODE 3 The MHGRVX A2 must be configured for EXP VLVS ENABLED in the MHGRVX A2 Configurati...
Страница 35: ...ved AAON Controls Support 866 918 1100 Monday through Friday 7 00 AM to 5 00 PM Central Time Controls Support website www aaon com aaon controls technical support AAON Factory Technical Support 918 382 6450 techsupport aaon com NOTE Before calling Technical Support please have the model and serial number of the unit available PARTS For replacement parts please contact your local AAON Representativ...
