AAON RL-240 - Manual (Page 54)

54
125% of the maximum manifold gas
pressure as shown on the unit nameplate.
7. There is an adjustable manual reset low
gas pressure switch on Main Gas Valve
1. This switch should be set to trip at the
minimum manifold gas pressure as
shown on the unit nameplate.
8. There is an automatic reset valve
proving switch located between the main
shut off valves. This switch should be set
at 50% of the incoming gas pressure.
Initial Start-up Procedure:
1. Bleed air from main gas line.
2. Verify proper incoming gas pressure.
a. Refer to the unit nameplate for
determining the minimum gas supply
pressure for obtaining the maximum
gas capacity for which the heater is
specified.
3. Adjust incoming gas pressure with main
regulator (on blocking valve actuator) to
required gas manifold pressure as shown
on unit nameplate.
4. Activate supply fan for heating call.
5. Verify that all dampers in are the correct
position before and after activating the
heating call.
6. Verify that the supply air, outside air and
return air (if applicable) flow rates are
correct as ordered.
7. Activate a call for heat.
8. With the main burner hand valve closed,
open pilot valve to ignite the pilot. This
may take several attempts in order to
bleed any air from the line.
9. Verify pilot flame size, color and signal.
The pilot should be adjusted during
lighting to a hard, blue flame. Pilot
signal should be between 1.25 VDC and
5 VDC. It is better to be closer to 5
VDC. Adjust pilot pressure as necessary.
10. After the pilot has ignited, open the main
burner hand valve to ignite the burner
11. Measure the gas manifold pressure and
adjust as necessary
12. Verify that the airside differential
pressure across the burner profile plates
meets the unit specifications
13. Verify flame length and color.
Troubleshoot if the flame has yellow
tips. Slight yellow tipping is acceptable
with liquid propane.
First Firing or Restart after Extended
Shut-down:
Before start-up or after an extended period
shut down, the integrity of the system should
be checked by authorized service technician.
Check the condition of the mixing plates,
burner body drillings, as well as the general
mechanical installation of the burner and
piping. Check all bolted connections of the
burner after the first firing and tighten as
necessary.
General Maintenance Instructions:
Makeup heat installations should be
maintained and inspected at a minimum of
once per season. More frequent maintenance
and inspections should be performed in
applications that operate all year. As a
minimum the following procedure should be
followed…
1. Completely shut the system down. Lock
out the power supply to prevent
accidental start-up.
2. Inspect the burners carefully, including
the upstream and downstream sides of
the mixing plates as well as the burner
body face. Any accumulation of scale or
foreign material on either side of the
mixing plates should be removed with a
wire brush. Visually inspect the holes in
the mixing plates to verify that all of the
holes are opened without blockage.
Clean any carbon build-up present and
troubleshoot for cause.
3. Replace or tighten any missing or loose
fasteners. Always use zinc plated or
stainless metric fasteners.