Supply Fan
Setscrews
Setscrews are used to lock bearings, sheaves, locking
collars, and fan wheels to their shafts. They must be checked
periodically to see that they have not loosened. If this is not
done, severe equipment damage could occur.
Refer to the values in
and check the tightness of all
setscrews with a torque wrench.
Table 35: Setscrew Minimum Torque Specifications
Setscrew Diameter (in .)
Minimum Torque (ft .lb)
1/4
5 .5
5/16
10 .5
3/8
19 .0
7/16
29 .0
1/2
42 .0
5/8
92 .0
Supply Fan Wheel-to-Funnel Alignment
The fan wheel-to-funnel alignment must be as shown in
to obtain proper air delivery and operating clearance. If
necessary, adjustments are made as follows:
1 .
Verify that the fan shaft has not moved in its bearings.
2 .
Loosen the fan hub setscrews and move the wheel(s)
along the shaft as necessary to obtain the correct
dimension shown in
3 .
Retighten the setscrews to the torque specification given
in
. Tighten the setscrews over the keyway first;
tighten those at 90 degrees to the keyway last.
4 .
Verify that the radial clearance around the fan is uniform.
Figure 95: SWSI Airfoil Wheel-to-Funnel Alignment
Table 36: SWSI Airfoil Wheel-to-Funnel Relationship
Wheel-to-Funnel Relationship (in inches)
Wheel Diameter
A
15
0 .44
18
0 .44
20
0 .44
22
0 .44
24
0 .44
30
0 .56
Refrigerant Charge
The unit nameplate references proper charge for each refrigerant
circuit in case a full charge must be added to the unit.
CAUTION
Severe loss of charge may occur if the high refrigerant
pressure switch is replaced before reclaiming the
refrigerant .
Replace pressure switch after reclaiming
refrigerant. Venting refrigerant to atmosphere is not allowed
per most local laws and/or codes.
Servicing Refrigerant Sensors or
Switches
The Maverick II includes the following refrigerant sensors or
switches.
1 .
Low refrigerant pressure sensing, operating switch,
automatic reset.
a .
Disables associated compressors on a drop in
suction pressure to approximately 35 psig.
b .
Enables associated compressors on a rise in
suction pressure to approximately 60 psig.
2 .
High refrigerant pressure, protective switch, manual reset
at keypad.
The low pressure switch senses refrigerant pressure through
shrader fittings that contain cores. The cores are stop valves
that do not allow refrigerant to flow through the Shrader unless
the device is in place. Therefore, the low pressure switch can
be replaced without reclaiming the refrigerant.
The Shrader that serves the high pressure switch does not
contain a core in order to maximize the functionality of the
safety. Therefore it cannot be replaced unless the refrigerant
has already been reclaimed.
Servicing Optional Electric Heater
WARNING
Hazardous voltage. May cause severe injury or death.
Disconnect electric power before servicing equipment. More
than one disconnect may be required to de-energize the unit.
If the electric heater is not operating properly, a qualified
electrician should perform the following to check if the heater is
damaged:
1 .
Measure continuity through all fuses.
2 .
Check that all electrical connections are tight. Look for
signs of arcing.
3 .
Check the resistance to ground for each circuit. It should
be infinite.
4 .
Check the resistance phase to phase for each circuit.
5 .
Check all contactors.
m
aInTenanCe
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111
IM 1058-8 • MAVERICK II ROOFTOP SYSTEMS
