Orion MHGRV-X User Manual
Factory Packaged Controls
MHGRV-X Controller
Field Technical Guide
TABLE OF CONTENTS
CONTROLLER OVERVIEW ............................................................................................................... 3
Features ...................................................................................................................................................................3
INSTALLATION & WIRING ............................................................................................................... 4
Important Wiring Considerations ..............................................................................................................................4
MHGRV-X Controller to AAON Unit Controller Wiring..............................................................................................5
MHGRV-X Stand Alone Wiring .................................................................................................................................6
INPUTS AND OUTPUTS .................................................................................................................. 7
OPERATION OVERVIEW .................................................................................................................. 8
Initialization ..............................................................................................................................................................8
Modulating Hot Gas Valves ......................................................................................................................................8
Modes of Operation .................................................................................................................................................8
Additional Features ..................................................................................................................................................8
LCD DISPLAY SCREENS .................................................................................................................. 9
TROUBLESHOOTING ..................................................................................................................... 13
Using LEDs to Verify Operation .............................................................................................................................13
Temperature Sensor Testing ........................................................................................................................................14
APPENDIX A - Supply Air Temperature Sensor Guide ................................................................. 17
Supply Air Temperature Sensor Installation ........................................................................................................... 17
Supply Air Temperature Sensor Wiring Chart and Jumper Settings ......................................................................18
APPENDIX B .................................................................................................................................. 19
MHGRV-X Replacement of MHGRV II ...................................................................................................................19
APPENDIX C .................................................................................................................................. 20
Reheat Expansion Module .....................................................................................................................................20
PART NUMBER CROSS REFERENCE TABLE
PART DESCRIPTION
MHGRV-X Controller OE377-26-00059 V12100
Reheat Expansion Module OE377-01-00059 V42450
MODGAS-X Controller OE377-26-00058 V12090
Supply Air Temperature Sensor OE231 P87140
EBC E-BUS Cables - Varying Lengths EBC-XXX-F N/A
www.aaon.com
ORION
AAON
TULSA
2
WattMaster Controls Inc.
8500 NW River Park Drive · Parkville, MO 64152
Toll Free Phone: 866-918-1100
PH: (816) 505-1100 · FAX: (816) 505-1101
E-mail: mail@wattmaster.com
Visit our web site at www.orioncontrols.com
WattMaster Form: AA-MHGRVX-FIELD-TGD-01H
Copyright April 2015 WattMaster Controls, Inc.
AAON® Manual Part No.: V16950
®
AAON
is a registered trademark of AAON, Inc., Tulsa, OK.
Neither WattMaster Controls, Inc. nor AAON® assumes any
responsibility for errors or omissions in this document.
This document is subject to change without notice.
MHGRV-X Field Technical Guide
OVERVIEW
MHGRV-X Controller General Information
Overview
The OE377-26-00059 MHGRV-X Controller (AAON Part
No. V12100) is designed to control a Modulating Hot Gas Reheat Valve to maintain a desired Supply Air Temperature setpoint. The controller can be used as a stand-alone controller
or can be used in conjunction with any AAON unit controller.
In addition, up to (7) Reheat Expansion Modules can be connected to
the Controller and to each other for additional Reheat V alve Control.
The MHGRV-X controller connects to an AAON unit controller or
expansion module via a modular cable. Depending on the type of
unit controller, this connection will utilize an I
E-BUS connection.
When using the MHGRV-X Controller to replace an existing
MHGRV II Controller, see Appendix B, page 19 for details.
See Figure 1 for dimensions (in inches).
2
C connection or an
5.73
5.24
Features
The MHGRV-X provides the following:
Can be operated as a stand-alone controller or
communicating with AAON unit controllers.
Provides for Supply Air Temperature Setpoint
reset when required
Second stage reheat capability when using
2 Hot Gas Reheat Valves
Control of reheat solenoid valve to provide coil
fl ushing for positive refrigerant oil return
Can provide further Reheat control using up to (7)
Reheat Expansion Modules
Contains a 2 x 8 LCD character display and 4 buttons
that allow for status display, setpoint changes, and
confi guration changes
5.04
0.21
2.62
0.57
5.63
2.04
Note: iDepth s 1.49 inches.
4.09
Figure 1: OE377-26-00059 MHGRV-X Controller Dimensions
MHGRV-X Field Technical Guide
3
WIRING
Installation & Wiring
Installation & Mounting
The MHGRV-X Controller is housed in a plastic enclosure. It
is designed to be mounted by using the 3 mounting holes in the
enclosure base. It is important to mount the module in a location
that is free from extreme high or low temperatures, moisture, dust,
and dirt. Be careful not to damage the electronic components when
mounting the module.
NOTE: The MHGRV-X Controller contains no user-serviceable
parts. Contact qualifi ed technical personnel if your Con-
troller or Module is not operating correctly.
General Wiring Information
Depending on if the MHGRV-X Controller is to be connected to
the HVAC controller or is to be used as a stand-alone controller
determines how the MHGRV-X should be wired. For the wiring
diagram to use when the MHGRV-X Controller is connected to an
AAON Unit Controller, see Figure 2, page 5. For the stand-alone
wiring diagram, see Figure 3, page 6.
For Reheat Expansion Module wiring, see Figure 9, page 22.
Please carefully read and apply the following information when
wiring the MHGRV-X controller and its expansion board(s):
1. 18 gauge minimum wire unless otherwise noted.
24 VAC power connection with an appropriate VA rating.
2.
3. Supply Air Temperature Sensor and Heat Enable must have
24 gauge minimum wire.
4. 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 module and connected devices.
5. All wiring is to be in accordance with local and
national electrical codes and specifi cations.
6. Check all wiring leads at the terminal block for tightness.
Be sure that wire strands do not stick out and touch
adjacent terminals. Confi rm that all transducers required for
your system are mounted in the appropriate location and
wired into the correct terminals.
4
MHGRV-X Field Technical Guide
WIRING
MHGRV-X to AAON Unit Controller Wiring
Communications Wiring
For connection to a VCB-X Controller, VCB-X Expansion Module,
and Reheat Expansion Module, use an E-BUS Cable to connect to
the appropriate E-BUS port on those modules and/or controller.
For all other controllers, including the VAV/CAV, MUA,VCM,
VCM-X, SA, and RNE Controllers, use an I
the appropriate I
2
C ports on those controllers.
Connect
Supply Air Temperature
o AI2 & GND
Sensor T
On Main Controller
(This Does Not Apply To
CAV/VAV Or MUAApplications)
Supply
Air Temperature
Sensor
Mount In Supply
Air Duct
2
C Cable connecting to
MHGRV-X CONTROLLER
(OE377-26-00059)
When connected to an AAON Unit Controller, the Supply Air
Temperature Sensor is attached to the Main Controller. See Figure
2 below.
See the SAT Wiring Conditions Table and SAT OPTIONS jumper
settings in Tables 7 & 9, page 18.
Fan
C1
Compressor
C2
HGR Solenoid Valve
2 Position HGR Valve (Optional)
COMM
See
Table 9 On Page 18
For
SAT OPTIONS
Settings.
Jumper
Only One Supply Air
Temperature Sensor Can Be
Used Per Application.
Any Non VCB-X Controller Or
2
I C Cable
Connects To
2
Port On
IC
Expansion Module
EBC E-BUS Cable
Connects To
VCB-X Expansion
Port When Used
With VCB-X
Controller
EBC
E-BUS
Cable
Connects
To Reheat
Expansion
Module
GND
24VAC
Transformer
Minimum
Line
Condenser Valve #1
BLK
WHT
RED
GRN
BLK
WHT
GRN
RED
HGR Valve #1
40 VA
Figure 2: MHGRV-X Controller to AAON Unit Controller Wiring
MHGRV-X Field Technical Guide
5
WIRING
MHGRV-X Stand-Alone Wiring
Stand-Alone Wiring
In Stand-Alone mode, the MHGRV-X connects to the E-BUS port
of the Reheat Expansion Module with an EBC E-BUS cable.
See the SAT Wiring Conditions Table and SAT OPTIONS jumper
settings in Tables 7 & 8, page 18.
See Figure 3 below.
MHGRV-X CONTROLLER
(OE377-26-00059)
0-10VDC
External Reset
Signal
H1 (Dehumidification)
Heating Override
Cooling Override
Mount In Supply
Air Duct
Supply
Air Temperature
Sensor
See
For SAT OPTIONS Jumper Settings.
Sensor Can Be Used Per Application.
Table 8 On Page 18
Only One Supply Air Temperature
+
EBC E-BUS
Cable Connects
To Reheat
Expansion
Module
GND
24VAC
Transformer
Minimum
Line
Fan
C1
Compressor
C2
HGR Solenoid Valve
2 Position HGR Valve (Optional)
COMM
Condenser Valve #1
BLK
WHT
RED
GRN
BLK
WHT
GRN
RED
HGR Valve #1
40 VA
Figure 3: MHGRV-X Controller Stand-Alone Wiring
6
MHGRV-X Field Technical Guide
INPUTS & OUTPUTS
Inputs and Outputs
I/O Map
The following inputs and outputs are available on the MHGRV-X
Controller. See Table 1 below to reference the Input/Output Map.
Analog Inputs
1 Supply Temperature
2 Reset Signal
3 AUX Input - Future Application
Binary Inputs
1 Reheat Enable
2 Heating Override
3 Cooling Override
Relays
1 Fan
2 Compressor
3 Reheat Valve
4 Auxiliary
Table 1: MHGRV-X Controller Inputs & Outputs
Binary Inputs
REHEAT EN: Reheat Enable Contact
Used only in stand-alone operation. When a call for dehumidifi cation
is initiated by another controller, this interlocked 24 VAC wet contact
closure is used to enable the MHGRV-X controller.
HEAT OVR: Heating Override
Used only in stand-alone operation. When a call for heating is initiated by the HVAC unit, this interlocked 24 V AC wet contact closure
is used to override the MHGR V -X controller dehumidifi cation mode.
COOL OVR: Cooling Override
Used only in stand-alone operation. When a call for cooling is initiated by the HVAC unit, this interlocked 24 V AC wet contact closure
is used to override the MHGR V -X controller dehumidifi cation mode.
Relay Outputs
FAN: Fan Enable
When a call for Dehumidifi cation, Cooling Override, or Heating
Override is received, this relay output will be closed to energize the
HVAC unit Supply Fan.
NOTE: All analog and 24 VAC contact closure inputs are used
only in Stand Alone operation.
Analog Inputs
SAT: Supply Air Temperature Sensor
Used in stand-alone operation and when MODGAS is connected
to a CAV/VAV or MUA Controller. The Supply Air Temperature
Sensor is the main control input. This sensor has to be installed for
the unit to operate. The Supply Air Temperature Sensor is located
in the discharge air stream and monitors the HVAC unit’s Supply
Air Temperature to maintain the Supply Air Temperature Setpoint.
RST IN: Reset Signal
Used only in stand-alone operation. The Discharge Temperature
Setpoint can be reset by supplying a 0-10 VDC signal to the RESET
IN low voltage terminal block. This reset signal is optional and need
only be used if you require resetting of the discharge air temperature.
CMP: Compressor Enable
When a call for Dehumidifi cation or Cooling Override is received,
this relay output will be closed to energize the Compressor(s).
VALVE: Reheat Solenoid Valve
When a call for Dehumidifi cation is active for 30 seconds, this
relay output will be closed to energize the Hot Gas Solenoid Valve.
AUX: 2 Position HGR Valve
Used on larger capacity systems that have an optional 2 Position
HGR Valve in addition to the Modulating HGR Valve. When a call
for Dehumidifi cation is received if the modulating HGR valve is at
100% and the Supply Air Temperature is at least 5 degrees below
setpoint, this relay output will energize to enable the 2 Position HGR
Valve. The relay will de-energize when the modulating HGR valve
closes to 0% and the Supply Air Temperature is at least 5 degrees
above setpoint. The modulating valve is then enabled to modulate
to maintain the Supply Air Setpoint.
COM: Relay Common
Requires 24 VAC from transformer.
MHGRV-X Field Technical Guide
7
OPERATION MODES
Operation Modes
Initialization
The MHGR V-X Controller uses on-board LEDs to indicate various
diagnostic conditions during power-up and operation. It also uses the
LCD Display to show initialization. Please review this information
for a complete description of the controller initialization sequence.
Modulating Hot Gas Valves
The MHGR V -X Controller utilizes two modulating valves to control
the fl ow of Hot Gas through the Hot Gas Reheat Coil. One of these
valves is the Condenser Hot Gas Valve and the other is the Reheat
Hot Gas Valve. The valves are wired to the MHGRV-X Controller
Modulating Hot Gas V alve Output terminals on the controller . These
valves work in concert with each other to create a “three-way valve”
confi guration. As one closes, the other opens, etc. All modes of opera-
tion that follow referring to the Hot Gas Reheat Valve are actually
a combination of these two valves working together to achieve the
specifi ed sequence of operation.
Modes of Operation
The MHGR V -X Controller 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 dehumidifi cation
process. The following is a description of these modes:
Stand-Alone Operation
As the name implies, in this mode the controller behaves as an independent unit. The controller begins the dehumidifi cation process
when the Dehumidifi cation Input “H1” receives a 24 VAC signal
from an outside source. When the signal is received, the controller
will activate the “F AN” output to energize the HVAC unit fan. At the
same time, the controller will initiate Cooling Mode by energizing
the “CMP” output starting the HVAC unit compressor. In addition,
the controller will open the Hot Gas Reheat Coil by activating the
“VALVE” output. At this time, the MHGRV-X Controller will start
to modulate the Modulating Hot Gas Reheat valve. The controller 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 confi gured with the
Setpoint Screen in the LCD Display. If Supply Air Temperature
Reset is used, it will initiate when a 0-10 VDC signal is supplied to
the “RESET IN” input. As the voltage increases from 0 to 10 Volts
at the “RESET IN” input, the Supply Air Temperature will be reset
towards the Supply Air Reset Temperature Setpoint. This setpoint
is confi gured with the Setpoint Screen in the LCD Display. When
a 10 Volt input signal is received at the “RESET IN” input, it will
be controlling at the Supply Air Temperature Reset Setpoint. The
controller will conclude the Dehumidifi cation process when input
“H1” is deactivated, the input “Cool Override” is activated, or the
input “Heat Override” is activated.
Operation in Communicating Mode
In this mode, the MHGRV-X Controller behaves as an expansion
board for an AAON Unit controller . The controller begins the dehumidifi cation process when the AAON Unit controller makes a request
to the MHGR V-X Controller for dehumidifi cation. At that time, the
controller will activate the “F AN” output to energize the HVAC unit
fan. At the same time, the controller will initiate Cooling Mode by
energizing the “CMP” output starting the HVAC unit compressor.
In addition, the controller will open the Hot Gas Reheat Coil by
activating the “VALVE” output which opens the Reheat Solenoid
V alve. At this time, the MHGR V-X Controller will start to modulate
the Modulating Hot Gas Reheat valve. The controller 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 set by programming the HVAC unit controller. If Supply Air Temperature Reset is used, it will initiate when
the HVAC sends a request to reset the Supply Air T emperature. The
Supply Air Temperature will be reset towards the Supply Air Reset
Temperature Setpoint stored in the HVAC controller. It will send a
request to move towards the Supply Air T emperature Reset Setpoint
based on its setpoints and confi guration. The controller will conclude
the Dehumidifi cation process when the HVAC control sends a request
to terminate Dehumidifi cation 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 Controller will be ignored.
Additional Features
Reheat Coil Flush
To assure positive oil return to the compressor, the Hot Gas Reheat
Coil will be fl ushed of liquid refrigerant by moving the Modulat-
ing Gas Reheat Valve to its maximum position for a short interval.
Cooling Flush: If the unit is in cooling mode, a fl ush will occur
when the unit’s fl ush cooling interval timer has elapsed. The time
is accumulated whenever it is in cooling mode and resets after each
fl ush cycle. The fl ush cooling interval timer is a setpoint that is
confi gurable using the keypad and display (0 to 120 minutes in 10
minute increments).
Reheat Mode Flush: If the unit is in dehumidifi cation mode and
the valve is below 70% for the fl ush reheat interval timer value, a
fl ush will occur. If the valve goes above 70%, the timer is reset. The
fl ush reheat interval timer is a setpoint that is confi gurable using the
keypad and display (0 to 120 minutes in 10 minute increments).
Optional Second Stage Reheat
On larger systems, where more hot gas reheat capacity may be required, a 2 Position Hot Gas Reheat valve can be connected to the
MHGR V -X Controller to be used in conjunction with the Modulating
Hot Gas Reheat valve. Any time the reheat demand moves above
the Modulating Hot Gas Reheat valve capacity, this 2 position
valve would be energized to supply additional hot gas to the Hot
Gas Reheat coil. As the reheat demand is satisfi ed, the MHGRV-X
Controller will de-energize the 2 position valve and control reheat
with the Modulating Hot Gas Reheat valve.
Reheat Solenoid Valve Control
The Hot Gas Reheat Solenoid valve for the Reheat Coil is activated
when there is a call for Dehumidifi cation. In this mode, the Hot Gas
Reheat Solenoid will be deactivated 2 minutes after the reheat demand ceases. The Hot Gas Reheat Solenoid valve will be reactivated
when a request for reheat is received by the MHGR V-X Controller.
8
MHGRV-X Field Technical Guide
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