Start-Up - Furnaces (all units)

important

For the unit to function properly, all stage or modulation valves must be set for high and low fire.

Note

There are five furnace control options available. Be sure to refer to the specific instructions for your control type.

important

Multi furnace units may use a combination of the available control options. Each furnace must be set- up per the specific instructions for its control type.

important

Multi furnace units will use one stage or electronic modulation controller per unit and one or two ignition controller(s) per furnace. Each furnace will have its own gas valve(s). Each valve must be set for high and low fire.

Note

To force the unit to light for set-up purposes, the heat switch must be closed or jumpered out. See the Ladder Diagram on the inside of the control center door for proper terminals to jumper out.

Note

If the unit is equipped with an independent inlet air sensor (not incorporated into the stage or modulation controller), the unit will not light unless the outside air temperature is less than the inlet air sensor setting. If the outside air is greater than the inlet air sensor setting, turn the setting to its maximum position. When set-up is complete, reset the inlet air sensor to the proper temperature. If the unit is equipped with a stage or electronic modulation controller that includes an inlet air sensor function, the inlet air sensor will be overridden when the unit is forced to high fire.

®

Available Control Options

Single Furnace Units

1:1 Staged

one 1-stage furnace

2:1 Staged

one 2-stage furnace

 

 

8:1 Staged

one 8-stage furnace

 

 

2:1 Electronic

one 2:1 modulating furnace

Modulation

 

4:1 Electronic

one 4:1 modulating furnace

Modulation

 

Two Furnace Units

 

 

1:1 Staged

two independent 1-stage furnaces

2:1 Staged

two independent 1-stage furnaces

4:1 Staged

two independent 2-stage furnaces

 

 

16:1 Staged

one 8-stage and

one 1-stage furnace

 

8:1 Electronic

one 4:1 modulating and

Modulation

one 2-stage furnace

Three Furnace Units

 

 

1:1 Staged

three independent 1-stage furnaces

3:1 Staged

three independent 1-stage furnaces

6:1 Staged

three independent 2-stage furnaces

 

 

24:1 Staged

one 8-stage and

two 1-stage furnaces

 

12:1 Electronic

one 4:1 modulating,

one 2-stage and

Modulation

one 1-stage furnace

 

Start-Up - Single Stage Control

1. Send Unit to High Fire

Send the unit to high fire by setting the temperature selector to

its maximum setting.Temperature

Selector

2.Check the High Fire Manifold Pressure

Using a manometer, measure the burner manifold pressure at the manifold pressure test port. Refer to the Gas Train Layout in the Reference section for the test port location.

The pressure on high fire

 

 

Single Stage Manifold

should be 3-1/2 in. wg for

Pressure (in. wg)

natural gas and

 

 

 

 

 

Natural Gas

LP

10 in. wg for

 

 

 

 

 

 

 

High Fire

3-1/2

10

LP gas.

 

If needed, use the

 

 

 

high fire adjustment

 

 

High Fire

screw on the staged gas

 

 

Adjustment

valve to adjust the high

 

 

fire manifold pressure.

 

 

 

Counterclockwise rotation

 

 

will decrease the gas

 

 

 

pressure and clockwise

 

 

rotation will increase the

 

 

gas pressure.

 

 

 

3. Reset the Temperature Setting

Reset the temperature setting on the temperature selector to the desired setting.

Model IG / IGX Make-Up Air 25

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Greenheck Fan 470656 manual Start-Up Furnaces all units, Start-Up Single Stage Control, Send Unit to High Fire