PILOT CHECKOUT
The pilot flame should envelope the end of the flame sensor.
Refer to Figure 14. To adjust pilot flame, (1) remove pilot
adjustment cover screw, (2) increase or decrease the
clearance for air to the desired level, (3) be sure to replace
cover screw after adjustment to prevent possible gas leakage.
Put the system into operation and observe through complete
cycle to be sure all controls function properly.
BURNER INSTRUCTIONS
To check or change burners, pilot or orifices, CLOSE MAIN
MANUAL SHUT-OFF VALVE AND SHUT OFF ALL ELECTRIC
POWER TO THE UNIT.
1. Remove the screws holding either end of the manifold to
the burner supports.
2. Open the union fitting in the gas supply line just upstream
of the unit gas valve and downstream from the main manual
shut-off valve.
3. Remove the gas piping closure panel.
4. Disconnect wiring to the gas valves and spark ignitors.
Remove the manifold-burner gas valve assembly by lifting
up and pulling back.
Burners are now accessible for service.
Reverse the above procedure to replace the assemblies. Make
sure that burners are level and seat at the rear of the heat
exchanger.
BURNER AIR SHUTTER ADJUSTMENT
Adjust burner shutters so no yellow flame is observed in the
heat exchanger tubes. Refer to Figure 14.
CHECKING SUPPLY AIR CFM
The RPM of the supply air blower will depend on the required CFM,
the unit accessories or options and the static resistances of both
the supply and the return air duct systems. With this information,
the RPM for the supply air blower and the motor pulley adjustment
(turns open) can be determined from the blower performance data
in Table 7.
A high speed drive accessory 1LD0430 (containing a smaller
blower pulley and shorter belts) is available for applications
requiring the supply air blower to produce higher CFM’s and/or
higher static pressures. Refer to Table 10 for blower motor and
drive data.
Note the following:
1. The supply air CFM must be within the limitations shown in
Table 1.
2. Pulleys can be adjusted in half turn increments.
3. The tension on the belts should be adjusted as shown in
Figure 16.
Start the supply air blower motor. Adjust the resistances in both
the supply and the return air duct systems to balance the air
distribution throughout the conditioned space. The job
specifications may require that this balancing be done by
someone other than the equipment installer.
To check the supply air CFM after the initial balancing has been
completed:
1. Remove the two 5/16" dot plugs from the blower motor and
the filter access panels shown in Figure 10.
2. Insert at least 8" of 1/4 inch tubing into each of these holes
for sufficient penetration into the air flow on both sides of
the indoor coil.
NOTE: The tubes must be inserted and held in a position
perpendicular to the air flow so that velocity pres-
sure will not affect the static pressure readings.
FIG. 14 - PROPER FLAME ADJUSTMENT
FIG. 15 - TYPICAL FLAME APPEARANCE
FIG.16 - BELT ADJUSTMENT
530.18-N11Y
18
Unitary Products Group