AAON M2-036 - Manual (Page 60)

60
Input
The correct heat capacity of the furnace is
controlled by the burner orifices and the gas
manifold pressure. The manifold pressure is
factory set, but should be checked at the
time of start-up.
Operating and Safety Instructions
1. This duct furnace does not have a pilot. It
is equipped with a direct spark ignition
device that automatically lights the gas
burner. DO NOT try to light burners by
hand.
2. BEFORE OPERATING, leak test all gas
piping up to heater gas valve. Smell around
the unit area for gas. DO NOT attempt to
place heater in operation until source of gas
leak is identified and corrected.
3. Use only hand force to push and turn the
gas control knob to the “ON” position.
NEVER use tools. If knob does not operate
by hand, replace gas valve prior to staring
the unit. Forcing or attempting to repair the
gas valve may result in fire or explosion.
4. Do not attempt to operate unit, if there is
indication that any part or control has been
under water. Any control or component that
has been under water must be replaced prior
to trying to start the unit.
Startup
1. Turn thermostat or temperature controller
to its lowest setting.
2. Turn off gas supply at the manual shut-off
valve (supplied by others).
3. Turn off power to the unit at the
disconnect switch.
4. Open door to unit module housing the gas
heater.
5. Move gas control knob to “Off” position.
6. Install a tapped fitting for attachment to a
manometer, or other gauge suitable for 14.0”
w.c., in the inlet pressure tap, and for 10.0”
w.c., in the manifold pressure tap.
7. Wait 5 minutes for any gas to clear out. If
you smell gas, turn off gas supply at the
manual shut-off valve (field installed). If
you don’t smell gas or have corrected any
leaks, go to the next step.
8. Turn gas control knob to “On” position.
9. Open all manual gas valves (supplied by
others).
10. Turn power on at disconnect switch.
11. Set thermostat or controller to its highest
position to initiate call for heat and maintain
operation of unit.
12. Draft inducer will run for a 15 to 30
second pre-purge period.
13. At the end of the pre-purge the direct
spark will be energized and gas valve will
open.
Check and Adjust Manifold Pressure
For 2 stage (TS) and modulating control
(MD) systems manifold pressure should be
1.2” w.c. Adjust Lo Regulator on 2 stage gas
valve, if necessary. The controls are design
to hold operation at this pressure for 2
minutes. After that time manifold pressure
should increase to 3.5” w.c. within 30 to 45
seconds.
Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other appliance.
WARNING