Modulating Valve High Fire Setting; Modulating Valve Low Fire Setting - LG GEN2 Series Installation And Operation Manual

Before making furnace adjustments, enter the
Commissioning Menu on the unit or Furnace Controller.
The Commissioning Menu is located under Service >
Overrides > Control Loops. Reference the controller
IOM for more information about navigating through the
controller menus. The Commissioning Menu offers a
step by step guide to setting up the furnace. Follow the
instructions on the screen. The following sections of this
IOM offer detailed information about setting the gas
pressures.
Combination Valve Adjustments
Conduct this step when the Commissioning Menu
reaches the High Fire Setting screen.
Connect a manometer to
the outlet pressure tap on
the Honeywell combination
valve and remove the cover
over the outlet pressure
adjustment screw. Use the
outlet pressure adjustment screw on the combination
valve to adjust the outlet pressure to the value listed in
the table.
Outlet Pressure
Tap
Typical Single Stage Gas Valve
Modulating Valve Adjustments
At start-up, remove the cover from the circuit board
housing by loosening the two Phillips head retaining
screws. Identify Button #1 and Button #2 and also
locate the LED indicator light.
Terminals 1 & 2
(signal)
Button #1
EXA Modulating Gas Valve
(with cover removed)
Combination Valve
Outlet Settings
Natural Gas 5 in. wg
LP Gas 11.5 in. wg
ON / OFF
Gas Control Knob
Outlet Pressure
Adjustment
Terminals 3 & 4
(power)
Button #2
LED Light

Modulating Valve High Fire Setting

Conduct this step with the Commissioning Menu on the
High Fire Setting screen.
1. Connect a manometer
to the test port on the
burner manifold.
2. Press and hold button #1
until the LED lights solid
red. Release the button.
Observe the gas pressure on the manometer.
3. Adjust the modulating valve by pushing button #1 to
increase the pressure or by pushing button #2 to
decrease the pressure.
4. Save the High Fire setting by simultaneously
holding down buttons #1 and #2 until the LED
turns off. If the new setting is not saved within five
minutes, the modulating valve will default back to its
last saved setting.
NOTE
During the adjustment process, each push of either
button will increase or decrease the pressure in steps.
Holding down either button auto-steps and eliminates
the need to repeatedly push the button. Use this
feature to rapidly increase or decrease the gas flow.

Modulating Valve Low Fire Setting

Conduct this step when the Commissioning Menu
reaches the Low Fire Setting screen.
1. With a manometer
installed at the burner
manifold test port, press
and hold down button
#2 until the LED blinks
red. Release the button.
Observe the gas pressure on the manometer.
2. Adjust the Low Fire setting by pushing button #1 to
increase the pressure or by pushing button #2 to
decrease the pressure.
3. Save the Low Fire setting by simultaneously
holding down buttons #1 and #2 until the LED
turns off. If the new setting is not saved within five
minutes, the Modulating Valve will default back to its
last saved setting.
Continue through the Commissioning Menu to verify
proper furnace operation. If additional furnaces are
present, the Commissioning Menu will step through
setting up those furnaces as well. Reference the
appropriate section in this IOM for detailed information
about each furnace.
Reinstall the cover on the modulating valve, remove the
manometer and reinstall the plug in the manifold test
port.
Modulating Valve
High Fire Settings
Natural Gas 3.5 in. wg
LP Gas 10.0 in. wg
Modulating Valve
Low Fire Settings
Natural Gas 0.3 in. wg
LP Gas 1.0 in. wg