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H. Purge Air From Gas Train
Upon initial start-up, the gas train will be lled with air.
Even if the gas line has been completely purged of air,
it may take several tries for ignition before a ame is
established. If more than 5 tries for ignition are needed,
it will be necessary to press the reset button to restart
the boiler. Once a ame has been established for the
rst time, subsequent calls for burner operation should
result in a ame on the rst try.
I. Check Burner Flame
Inspect the ame visible through the window. On high
re the ame should be stable and mostly blue (Figure
47). No yellow tipping should be present; however,
intermittent ecks of yellow and orange in the ame are
normal.
J. Check Gas Inlet Pressure
Check the inlet pressure and adjust if necessary. Verify
that the inlet pressure is between the upper and lower
limits shown on the rating plate with all gas appliances
on and off.
WARNING
The outlet pressure for the gas valve has been
factory set and requires no eld adjustment. This
setting is satisfactory for both natural gas and
propane. Attempting to adjust the outlet pressure
may result in damage to the gas valve and cause
property damage, personal injury or loss of life.
K. Perform Combustion Test
Perform a combustion test. Boilers equipped with a
concentric vent system have a ue gas sample tap
located in the boiler vent collar (under the screw cap).
Insert the analyzer probe in the ue gas sample tap.
Check CO
2
(or O
2
) and CO at both high and low re.
The boiler may be temporarily locked into high or low
re for 15 minutes as follows:
1. To lock the boiler in high re, simultaneously press
and hold the “Mode” button and “+“ button until the
display ashes “H”, indicating that the boiler has
been driven to high re. After this happens, allow
the boiler to operate for approximately 5 minutes
before taking combustion readings.
2.
To lock the boiler in low re, simultaneously press
and hold the “Mode” button and “-“ button until the
display ashes “L”, indicating that the boiler has
been driven to low re. After this happens, allow the
boiler to operate for approximately 5 minutes before
taking combustion readings.
3.
Normal modulation of the boiler should return 15
minutes after the boiler is locked in high or low re.
T
ypical CO
2
readings are shown in Table 20.
WARNING
Each Alpine Series boiler is tested at the factory
and adjustments to the air fuel mixture are
normally not necessary. Consult a U.S. Boiler
representative before attempting to make any
such adjustments. Improper gas valve or mixture
adjustments could result in property damage,
personal injury, or loss of life.
Boiler
Model
Altitude Range
0 - 7000 Ft.
% CO
2
% O
2
Range CO, PPM
ALP080
8.2 - 8.8 5.5 - 6.5
Less than 75
PPM
ALP105
ALP150
ALP210
ALP285
ALP399
Table 20: Recommended Combustion Settings,
Natural Gas
Figure 47: Burner Flame
L. Test External Limits
Test any external limits or other controls in accordance
with the manufacturer’s instructions.
M. Check Thermostat Operation
Verify that the boiler starts and stops in response to
calls for heat from the heating thermostat and indirect
water heater thermostat. Make sure that the appropriate
circulators also start and stop in response to the
thermostats.