Gas Flow
Service
To check for proper gas flow to the combustion chamber,
determine the Btu input from the appliance rating plate.
Divide this input rating by the Btu per cubic feet of available
gas. Result is the required number of cubic feet per hour.
Determine the flow of gas through the gas meter for two
minutes and multiply by 30 to get the hourly flow of gas.
Gas Pressure Adjustment
1)
Check gas line pressure with unit firing at maximum
rate. A minimum of 5" (127mm) w.g. for natural gas or
10.4" (264mm) w.g. for LP/propane gas should be
maintained for proper unit operation.
2)
After line pressure has been checked and adjusted,
check regulator pressure. Correct manifold pressure is
shown on the unit rating plate. See figures 9 and 10 for
gas pressure adjustment screw location. A natural gas
to LP/propane gas changeover kit is required to convert
the unit in the field. Refer to installation instructions
provided with changeover kit for conversion procedure.
Limit Control
The limit control switch is factory-set and is not
field−adjustable.
Louver Vane Adjustment
Rotate louver vanes to direct airflow upward, downward,
straight, or any combination of these directions. When unit is
installed in an inverted position, louvers may be positioned in
the same manner.
Combustion Air Pressure Switch
This pressure switch checks for proper combustion air
inducer operation before allowing an ignition trial. The
switch is factory-set. No field adjustment is necessary.
Flame Rollout Switch
The flame rollout switch(es) are located on the burner box
top, behind the ignition control board. This normally closed
switch opens on a temperature rise. Check for adequate
combustion air before manually resetting switch.
CAUTION
Turn off gas and electrical power to unit before per-
forming any maintenance or service operations on this unit.
Remember to follow lighting instructions when putting unit
back into operation after service or maintenance.
The unit heater and vent system shall be inspected once a
year by a licensed professional service technician, or
equivalent.
BURNERS
1)
Periodically examine burner flames for proper
appearance during the heating season.
2)
Before each heating season examine the burners for any
deposits or blockage that may have occurred.
3)
Clean burners as follows:
a.
Turn off both electrical and gas supplies to unit.
b.
Disconnect gas supply piping, high tension and
sensor leads. Remove gas manifold. Remove
burner tray.
c.
Clean burners as necessary. Make sure that burner
heads line up properly to ensure flame crossover.
Check spark gap on electrode and adjust if
required. The gap should be between 0.110" and
0.140" (3mm to 4mm). The gap may be checked
with appropriately sized twist drills or feeler
gauges.
d.
Reinstall burner tray, gas manifold, high tension
and sensor leads. Reconnect gas supply piping.
e.
Restore electrical power and gas supply. Follow
lighting instructions to light unit. Check burner
flame.
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