Reference - Model IGX (2:1 Modulation)
Reference - Model IGX (4:1 Modulation)
5 | 1 |
| |
6 |
|
4 | 2 |
3 |
|
7 |
|
9 | 8 |
Manifold
Gas Pressure
Test Port
Modulating | Staged |
Gas Valve | Gas Valve |
3/4 inch Gas Supply 
Connection
6 10 | 9 | 3 |
1 | 2 |
|
7 |
| 4 |
| 5 |
|
| 8 |
|
|
| 11 |
|
| 11 |
Manifold
Gas Pressure
Test Port
Modulating | Staged |
Gas Valve | Gas Valve |
3/4 inch Gas Supply 
Connection
note
This is a typical furnace control center, the control center in your unit may be different. Reference the ladder diagram on the inside of the control center door for a unit specific wiring diagram.
1.Low Voltage Transformer - Provides low voltage to the ignition controller and amplifier.
2.Control Terminal Block - Provides wiring access to heat controls.
3.Control Terminal Block - Provides wiring access to heat controls.
4.Ignition Controller - Controls the ignition of the furnace. Maintains safe operation of the furnace.
5.Amplifier - Controls the modulating valve based on the input from the temperature selector and the discharge air sensor.
6.Temperature Selector - Allows the user to adjust discharge air temperature.
7.Combustion Blower Contact - Passes power to the combustion blower.
8.Airflow Switch - Monitors the airflow inside the heat exchanger to ensure proper combustion airflow.
9.High Fire Relay - Allows furnace to ignite on high fire.
®
note
This is a typical furnace control center, the control center in your unit may be different. Reference the ladder diagram on the inside of the control center door for a unit specific wiring diagram.
1.Low Voltage Transformer - Provides low voltage to the ignition controller.
2.Low Voltage Transformer - Provides low voltage to the 4:1 electronic modulation controller.
3.Low Voltage Transformer - Provides low voltage to the amplifier.
4.Control Terminal Block - Provides wiring access to controls.
5.Control Terminal Block - Provides wiring access to controls.
6.Input Converter - Receives and converts signal from Building Management System (BMS).
7.Ignition Controllers - Controls the ignition of the furnace. Maintains safe operation of the furnace.
8.Modulation Controller - Provides 4:1 modulation turndown control of furnace based on the discharge air temperature.
9.Amplifier - Controls the modulating valve based on the input from the modulation controller settings and discharge air temperature sensor reading.
10.Combustion Blower Relay - Passes power to the variable speed combustion blower.
11.Airflow Switches - Monitors the airflow inside the heat exchanger to ensure proper combustion airflow.
Model IG / IGX
