Orion MODGAS II User Manual

Name: Orion MODGAS II
Brand: Orion
SKU: 1627251
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FACTORY CONTROLS SYSTEM

MODGAS II Controller

Installation &

Operations Manual

FACTORY CONTROLS SYSTEM

MODGAS II Controller

For Modulating Gas Heating Applications

Installation &

Operations Manual

This document is subject to change without notice. WattMaster Controls, Inc. or AAON Inc. do not assume responsibility for errors or omissions herein.

AAON MODGAS Controller

Installation & Operations Manual - Form WM-MG2-IOM-01C

AAON is a registered trademark of AAON, Inc.

Section 1

Table of Contents
Component Overview.......................................................	1
MODGAS II Controller...............................................................................................................	1
Blink Codes for Status LED ........................................................................................................	2
Supply Air Temperature Sensor ..................................................................................................	4
Component Wiring............................................................	5
MODGAS II Controller...............................................................................................................	5
Board Inputs & Outputs ...................................................	7
Analog Inputs ..............................................................................................................................	7
Relay Outputs ..............................................................................................................................	7
Setting DIP Switches .......................................................	8
Discharge Air Temperature .........................................................................................................	8
Discharge Air Temperature Reset Limit......................................................................................	8

Table of Figures
Figure 1-1: MODGAS II Controller Component Locations....................................................	2
Table 1-1: Diagnostic LED Blink Codes.................................................................................	2
Figure 1-2: MODGAS II Controller Dimensions....................................................................	3
Figure 1-3: Supply Air Sensor Installation..............................................................................	4
Figure 1-4: MODGAS II Controller Wiring............................................................................	5
Figure 1-5: MODGAS II Controller DIP Switch Settings...................................................	9

Overview & Wiring

MODGAS II Controller	Section 1

Component Overview

MODGAS II Controller

The MODGAS II Controller is designed to modulate a gas valve to maintain a desired Discharge Air Temperature. It also controls the speed of the induced draft fan to maintain proper combustion in the heat exchanger. The controller can be used as a stand-alone unit or be connected to the AAON HVAC unit controller as an expansion board.

The MODGAS II Controller has the following inputs and outputs:

4 Inputs:

•	Supply Air Temperature Sensor	•	HEAT EN Input (24VAC)
•	Discharge Air Temperature Reset Signal from a	•	AUX Input (not used)
	control automation system (0-10VDC)

4 Outputs:

•	Fan Enable (relay)	•	LO SPEED fan control (relay)
•	AUX Output (relay / not used*)	•	Gas Valve Analog Output (0-20VDC)

* If using EPROM SS0056 V 2.20 or higher, the AUX Output Relay is functional. Once the MODGAS II Controller brings on heat, if the Supply Air Temperature rises 5˚F and the valve output has reached 90%, then the AUX Relay will activate to bring on a 2nd stage of fixed heat. The modulating valve is then able to modulate as needed to maintain the Heating Supply Air Setpoint. If the modulating valve falls below 30%, the AUX Relay will disable.

When used in a stand-alone application (not connected to an AAON HVAC unit controller board), the MODGAS II Controller will modulate the gas valve to maintain the DISCHARGE setpoint set by the DIP switch on the board. The MODGAS II Controller is activated by a 24VAC signal to the HEAT EN input.

When the MODGAS II Controller is connected to an AAON HVAC unit controller via the modular cable, the following information will be passed between the MODGAS II and the AAON HVAC unit controller.

•Heat activation command

•Heating Discharge Setpoint. This replaces the setpoint that is set with the Discharge Air Temperature DIP switch on the MODGAS II Controller.

•The offset for the Supply Air Temperature Sensor.

•Hi Limit Temperature Setpoint.

•If the communication is interrupted between the MODGAS II Controller and the AAON HVAC unit controller, the MODGAS II Controller will revert to stand-alone operation.

Overview and Wiring

1-1

Section 1	MODGAS II Controller

Status LED

Discharge Setpoint

Relay Output

DIP Switch

LEDs

Modulating Gas

Reset Limit

DIP Switch

Controller Board

Relay Output

Analog Input

Terminals

Heat Sink

Must Be Fastened

YS101826PREV 1

STATUS

RESET

DISCHARGE

With Sheet Metal

MODULATING

LIMIT

SETPOINT

GAS BOARD

TB1

Screws

O F F

RV1

+VDC

SAT

IN RST

IN AUX EN HEAT

GND

FAN

LOSPDLOSPD

AUX

COM

To A Sheet Metal

PJ1

J01

Surface

IN I2C

VR1

128

FAN

AUX

ADD

These Terminals

TB2

D1 R7

R15

Not Used For

WDOG

SHLD

CX2

This Application

POWER

CX6

RAM

EPROM

CX1

R26

R25

PHILIPS

24 VAC Power

Input Terminals

SER. #:

CX5

(See Note 1 & 2)

24VAC

CX4

YS101818

CX3

GAS

GND

552 PROCESSOR

VALVE

Max. Power

POWER

BOARD

GND

V5 VOUT

TB3

Consumption

C13

1 Gas Valve =15VA

TB4

2 Gas Valves = 30VA

552 Processor Board

Notes:

1.)24 VAC Must Be Connected So That All Ground

Wires Remain Common.

2.)All Wiring To Be In Accordance With Local And National Electrical Codes And Specifications.

PAL Chip	EPROM Chip
Pin 1	Pin 1	Gas Valve
	RAM Chip	Output
	Pin 1	Terminals

Figure 1-1: MODGAS II Controller Component Locations

Blink Codes for Status LED

The MODGAS II Controller uses an on-board LED to indicate various diagnostic conditions during power-up and operation. The LED is labeled “STATUS”. Starting with power up, the LED blink codes are as follows:

•One Blink

•Off for five seconds

•Blinks 30 times

•Blinks 3 times rapidly

•Status code repeatedly blinks every ten seconds to indicate controller status:

Priority	No. of Blinks	Status
Lowest	1	Normal Operation
-	2	SAT Over High Limit
Highest	3	Bad SAT Sensor

Table 1-1: Diagnostic LED Blink Codes

Only the highest priority failure code will be shown. You must correct the highest priority alarm before other problems will be indicated.

1-2	Overview and Wiring

MODGAS II Controller

Section 1

Figure 1-2: MODGAS II Controller Dimensions

Overview and Wiring

1-3

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