Orion MHGRV II User Manual

MHGRV II Controller

Technical Guide

Table Of Contents
Controller Overview.........................................................................................................................................	3
General.........................................................................................................................................................................................	3
Features .......................................................................................................................................................................................	3
Operation......................................................................................................................................................................................	3
Controller Inputs and Outputs.........................................................................................................................	4
General.........................................................................................................................................................................................	4
Analog Inputs ...............................................................................................................................................................................	4
24 VAC Contact Closure Inputs:...................................................................................................................................................	4
Controller Installation & Wiring ......................................................................................................................	4
Controller Mounting......................................................................................................................................................................	4
Relay Outputs...............................................................................................................................................................................	4
Modulating HGR Valve Outputs ...................................................................................................................................................	4
Important Wiring Considerations..................................................................................................................................................	4
DIP Switch Settings.........................................................................................................................................	7
Supply Air Temperature ................................................................................................................................................................	7
Supply Air Temperature Reset Limit ............................................................................................................................................	7
Start-up & Commissioning...............................................................................................................................	8
General.........................................................................................................................................................................................	8
Power Wiring ...............................................................................................................................................................................	8
Power Up And Operation..............................................................................................................................................................	8
Programming The Controller ........................................................................................................................................................	8
Sequence Of Operation ...................................................................................................................................	9
Initialization...................................................................................................................................................................................	9
Modulating Hot Gas Valves ..........................................................................................................................................................	9
Modes Of Operation.....................................................................................................................................................................	9
Additional Features ......................................................................................................................................................................	9
Troubleshooting.............................................................................................................................................	10
Using LED’s To Verify Operation ................................................................................................................................................	10
Other Checks .............................................................................................................................................................................	10

WattMaster Controls Inc.

8500 NW River Park Drive · Parkville , MO 64152 Toll Free Phone: [phone]

PH: [phone] · FAX: [phone] · E-mail: [e-mail] Visit our web site at www.orioncontrols.com

AAON® Part No.: R12200

WattMaster Form: AA-MHGRVII-TGD-01E Copyright September 2011 WattMaster Controls, Inc.

AAON is a registered trademark of AAON, Inc., Tulsa, OK.

WattMaster Controls, Inc. assumes no responsibility for errors, or omissions. This document is subject to change without notice.

Technical Guide

Controller Overview

General

The MHGRV II Controller is designed to control a Modulating Hot Gas Reheat Valve to maintain a desired Supply Air Temperature and Humidification setpoint . The controller can be used as a stand-alone controller or it can be connected to and used in conjunction with the AAON Factory Packaged HVAC unit controller. The MHGRV II controller is connected to the HVAC unit controller via a modular expansion cable and corresponding connectors on the controllers.

Features

The MHGRV II provides the following features.

Can Be Operated as a Stand-Alone Controller or Integrated with the HVAC Unit Controller

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 Flushing for Positive Refrigerant Oil Return

Operation

When used in a stand-alone application (not connected to an HVAC unit controller board) the MHGRV II controller will control the Modulating Hot Gas Valve to maintain the Supply Air Setpoint based on the Supply Air Temperature Sensor connected to the MHGRV II controller. The MHGRV II controller is activated by a 24 VAC wet contact closure

signal connected to the H1 (RHT EN) input terminal on the controller. Heating Override and Cooling Override are also controlled by 24 VAC wet contact closure signals connected to the HTG OVR and CLG OVR input terminals on the controller. The Supply Air Setpoint is set by configuring a DIP switch on the MHGRV II controller board. Supply Air Temperature Reset is also available and is set by configuring a DIP switch on the controller board. When Supply Air Temperature Reset is used it is reset by a 0-10 VDC signal supplied to the RST IN terminal on the MHGRV II controller.

When the MHGRV II controller is connected to an HVAC unit controller board via its modular cable it will operate exactly as the stand-alone controller except the following information will be passed between the MHGRV II controller and the HVAC unit controller.

Reheat Enable command

Supply Air Temperature Setpoint. This replaces the setpoint that is set with the Supply Air Temperature DIP switch on the MHGRV II controller.

The Reset Supply Air Temperature Setpoint. This replaces the setpoint that is set with the Supply Air Temperature Reset DIP switch on the MHGRV II controller. The Supply

Air Temperature Reset Signal is also supplied from the HVAC unit controller.

If the communication is interrupted between the MHGRV II controller and the HVAC unit controller, the

MHGRV II controller will revert to stand-alone operation.

8.10"

TB3

FAN

V1

R

SAT D2 R4 PU

GND

OVR CLG

CB/HB U1

CW/HW

CR/HG

CG/HR

K1

#SERIAL

1REVYS101894

R18

PJ1

R3

D5 R3

R1

D6 R11

VR1

R12

R7 D3 R6 R5

R13

R9 R8 D4

R17

AUX

V4

TB5

SHLD

T

OVR HTG

IN RHT

IN RST

IN AUX

GND

GND

+VDC

R2

K2

V2

GAS HOT

COMP

C1

I2 C IN

I2 C OUT

AUX IN

SETUP

D1

COMM

THERM

STEP

VALVE

V3

REHEAT

4-20MA

RV1

0-10V

L1

C3

C2

C4

K3

C8

U2

WDOG

R2

CX2

FAN

4.80"

R19

1

R1

CX5

K4

COM

4.69"

D1

R20

RAM

EPROM

R23

U5

COMP

C12

CX6

U2

VALVE

U6

CX1

C3

D1

U1

AUX

L2

C13

R31

U5

LIMITRESET

128

SW1

1 2

ADD

16 32 64

4 8

V5

D11

SW2

R38

+24VAC

GND

C2

C1

CX5

CX4

U4

POWER

R39

SETPOINT

128

16 32 64

4 8

1 2

ADD

U3

STATUS

X1

CX3

YS101818P552

C4

P1

PROCESSOR

BOARD

TB4

R40

C15

8.01"

Figure 1: MHGRV II Controller Dimensions

VAV/Zone Controller

3

Technical Guide

Controller Inputs and Outputs

General

The following inputs and outputs are available on the MHGRV II controller For component locations of the inputs, outputs and wiring, see

Figure 3 and 4.

COMP: Compressor Enable

When a call for Dehumidification or Cooling Override is received this relay output will be closed to energize the Compressor(s).

Analog Inputs

SAT: Supply Air Temperature Sensor

The SupplyAir 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 units Supply Air Temperature to maintain the Supply Air Temperature Setpoint.

RST IN: Reset Signal

The Discharge Temperature Setpoint can be reset by supplying a 0-10 VDC signal to the RST IN low voltage terminal block. This reset signal is optional and need only be used if you require resetting of the discharge air temperature.

AUX IN: Not Used

VALVE: Reheat Solenoid Valve

When a call for Dehumidification is received and reheat is required this relay output will be closed to energize the Hot Gas Solenoid Valve approximately 30 seconds after the Fan and Compressor have been enabled.

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 Dehumidification is received and additional reheat is required beyond the Modulating HGR valves capacity, this relay output will be closed to energize the 2 Position HGR Valve, while the Reheat Solenoid Valve continues to modulate as required. This AUX (2 Position HGR Valve) Relay will energize when the Modulating HGR Valve stays at 100% for 1 ½ minutes. The AUX Relay will de-energize when the Modulating HGR Valve stays at 0% for 1½ minutes. The AUX Relay is not be energized during the Dehumidification Reheat Coil Flush Cycle.

24 VAC Contact Closure Inputs:

RHT EN: Dehumidification

When a call for dehumidification is initiated by another controller this interlocked 24 VAC wet contact closure is used to enable the MHGRV II controller.

HTG OVR: Heating Override

When a call for heating is initiated by the HVAC unit, this interlocked 24 VAC wet contact closure is used to override the MHGRV II controller dehumidification mode.

CLG OVR: Cooling Override

When a call for cooling is initiated by the HVAC unit, this interlocked 24 VAC wet contact closure is used to override the MHGRV II controller dehumidification mode.

Relay Outputs

FAN: Fan Enable

When a call for Dehumidification, Cooling Override or Heating Override is received, this relay output will be closed to energize the HVAC unit Supply Fan.

Modulating HGR Valve Outputs

CG/HR:

This output is connected to the Condensor HGR Valve Green Wire Termination and to the Reheat HGR Valve Red Wire Termination to control their modulation.

CR/HG:

This output is connected to the Condensor HGR Valve Red Wire Termination and to the Reheat HGR Valve Green Wire Termination to control their modulation.

CW/HW:

This output is connected to the Condensor HGR Valve White Wire Termination and to the Reheat HGR Valve White Wire Termination to control their modulation.

CB/HB:

This output is connected to the Condensor HGR Valve Black Wire Termination and to the Reheat HGR Valve Black Wire Termination to control their modulation.

Controller Installation & Wiring

Controller Mounting Important Wiring Considerations

It is important to mount the controller 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 controller. Remove the controller from its snap track mount. Mark the control enclosure base using the snap track as a template. Drill pilot holes in the enclosure base and secure the snap track to it using sheet metal screws. Do not allow metal shavings to fall onto the circuit board. Reattach the controller to the snap track.

Depending on if the MHGRV II controller is to be connected to the HVAC controller or is to be used as a stand-alone controller determines how the MHGRV II should be wired. For the stand-alone wiring diagram, see Figure 2. For the wiring diagram to use when the MHGRV II controller is connected to an HVAC controller, see Figure 3. Please carefully read and apply the following information when wiring the MHGRV II controller.

4	MHGRVII Controller