Modulation - Greenheck IG Installation, Operation And Maintenance Manual

Start-Up - 4:1 Electronic Modulation
1. Send the Unit to High Fire
To send the unit to high fire, press and hold the Up,
Down and Enter keys. The unit will remain at high fire
until the Function key is pressed.
Function
Enter
WARNING
If the unit is forced to high fire, it will remain at high
fire until the Function key is pressed.
After modifying a setting, the Enter key must be
pressed to save the change. If the Enter key is not
pressed the display will return to the Program Menu
without saving the change.
Forcing the unit to high fire in mild weather
conditions may cause the high limit switch to trip. If
the switch trips, it will reset once the discharge air
temperature is at a safe level.
2. Check the High Fire Manifold
Pressure
Before setting high fire on the EXA valve, turn the
regulator screw on the combination valve all the way
in (increase pressure).
Using a manometer, measure the high fire manifold
pressure at the pressure test port. Refer to the Gas
Train Layout in the Reference section for the test port
location.
The recommended high fire manifold pressure is
3-1/2 in. wg for natural gas and 10 in. wg for LP gas.
If needed, adjust the high
fire screw on the shut-
off valve to set the high
fire manifold pressure.
Counterclockwise rotation
will decrease the gas
pressure and clockwise
rotation will increase the
gas pressure.
30
Model IG / IGX Make-Up Air
Up
Down
NOTE
NOTE
High Fire
Adjustment
To enter the high fire
setting mode, press
and hold button #1
until the LED lights
solid red. Release.
The valve is now in
the high fire setting
mode.
Press or hold button
#2 to decrease gas
flow. Each button press equates to the minimum
available step size and will decrease flow slowly.
Holding the button down auto-steps and eliminates
the need to continuously press the button. Use this
feature to rapidly decrease the flow.
Press or hold button #1 to increase gas flow. Each
button press equates to the minimum available
step size and will increase flow slowly. Holding the
button down auto-steps and eliminates the need to
continuously press the button. Use this feature to
rapidly decrease the flow.
High fire setting should be 3.5 in. wg for natural gas
and 10.0 in. wg for LP gas.
To save high fire setting, simultaneously hold button
#1 and #2 until the LED turns off.
Controls left in the high fire setting mode will default
to the current setting after 5 minutes of inactivity.
3. Exit High Fire Mode
Press the Function key to exit high fire mode.
4. Send Unit to Low Fire
Remove the cover on the modulating gas valve. Press
and hold button #2 until the LED light blinks red;
release. The unit is now in low fire.
5. Check the Low Fire Manifold
Pressures
With the unit at low fire, use a manometer to check the
manifold pressure. Refer to the Gas Train Layout in the
Reference section for the test port location.
The recommended low
fire manifold pressure
is 1/3 in. wg for natural
gas and 1.0 in.
Low Fire
wg for LP gas.
High Fire
To adjust the
low fire gas pressure, use button #1 and #2 on the
gas valve. Button #1 will increase the gas pressure,
while button #2 will decrease the gas pressure. Each
time the button is pressed, it corresponds to the
minimum available step size and will slowly change
the gas pressure. Holding the button down will rapidly
change the gas pressure. To save the low fire setting,
simultaneously hold buttons 1 and 2 until the LED
turns off.
#1 #2
LED
Light
NOTE
4:1 Modulation Manifold
Pressure (in. wg)
Natural Gas LP
1/3 1
3-1/2 10
®