Orion MODGAS II User Manual

r

FACTORY CONTROLS SYSTEM

MODGAS II Controlle

Installation &

Operations Manual

r

FACTORY CONTROLS SYSTEM

MODGAS II Controlle

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.

Copyright 2010 WattMaster Controls, Inc.

All rights reserved.

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

control automation system (0-10VDC)

• AUX Input (not used)

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 2
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.

nd

stage of fixed heat. The modulating valve is then able to

• Heat activation command • The offset for the Supply Air

Temperature Sensor.

• Hi Limit Temperature Setpoint. • Heating Discharge Setpoint. This replaces the

setpoint that is set with the Discharge Air
Temperature DIP switch on the MODGAS II
Controller.

• 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

Modulating Gas

Controller Board

These Terminals

Not Used For

This Application

24 VAC Power
Input Terminals
(See Note 1 & 2)

Max. Power
Consumption
1 Gas Valve =15VA
2 Gas Valves = 30VA

C6

I2C IN

POWER

TB3

TB2

R26

R26

R25

Analog Input

Terminals

YS101826PREV 1
MODULATING
GAS BOARD

PJ1

R15

R

SHLD

POWER

T

C7

U5

D8

V4

24VAC

GND

P1

RV1

+VDC

VR1

R7

D1

P

WDOG

CX6

U6

U1

C4

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.

Discharge Setpoint

Reset Limit
DIP Switch

RST IN

SAT

AUX IN

GND

HEAT EN

C1

C2

R8

D2

R9

R2

CX1

PHILIPS

PHILIPS

C2

YS101818

P1

552 PROCESSOR
BOARD

DIP Switch

STATUS

RESET
LIMIT

F

F

J01

ADD

R1R3R1

P

U2

C3

R1

1

CX5

C1

PAL Chip
Pin 1

Relay Output

LEDs

Relay Output

Terminals

DISCHARGE
SETPOINT

TB1

O

O

F

F

1

1
2
4
8
16
32
64
128

R4

CX2

U5

2
4
8
16
32
64
128

ADD

RAM

CX4

RAM Chip
Pin 1

LO SPD

FAN

LOSPD

FAN

U4

CX3

V1 V3K3V2

K1

AUX

COM

AUX

EPROM

U3

C13

EPROM Chip
Pin 1

K2

FT

SER.#:

GAS

VALVE

GND

TB4

VOUT

V5

Gas Valve
Output
Terminals

Heat Sink

Must Be Fastened

With Sheet Metal

Screws

To A Sheet Metal

Surface

D9

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