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9
7. Loosen the four mounting bracket bolts and lock washers.
8. Remove four bolts, four flat washers, four lock washers
and four nuts attaching the motor mounting plate to the
unit. Discard all lock washers.
9. Remove motor and motor mounting bracket from unit.
10. Remove four bolts, flat washers, lock washers and single
external-tooth lock washer attaching motor to the motor
mounting plate. Discard all lock washers and external-
tooth lock washer.
11. Lift motor from motor mounting plate and set aside.
12. Slide motor mounting band from old motor.
13. Slide motor mounting band onto new motor and set motor
onto the motor mounting plate.
14. Remove variable pitch pulley from old motor and attach it
to the new motor.
15. Inspect variable pitch pulley for cracks and wear. Replace
the pulley if necessary.
16. Secure the pulley to the motor by tightening the pulley set-
screw to the motor shaft.
17. Insert four bolts and flat washers through mounting holes
on the motor into holes on the motor mounting plate.
18. On one bolt, place a new external-tooth lock washer
between the motor and motor mounting band.
19. Ensure the teeth of the external-tooth lock washer make
contact with the painted base of the motor. This washer is
essential for properly grounding motor.
20. Install four new lock washers and four nuts on the bolts on
the bottom of the motor mounting plate.
NOTE: Do not tighten the mounting bolts at this time.
21. Set new motor and motor mounting bracket back onto the
unit. See Fig. 15.
22. Install four bolts, four flat washers, four new lock washers
and four nuts attaching the motor assembly to the unit.
NOTE: Do not tighten the mounting bolts at this time.
23. Install motor drive V-belt to motor pulley and blower
wheel pulley. See the CAUTION above.
24. Align the motor pulley and blower wheel pulley using a
straight edge. See Fig. 10.
25. Adjust the V-belt tension using adjustment tool.
26. Turn two jack bolts clockwise, moving the motor assembly
away from the blower pulley, increasing the V-belt tension.
27. Tighten the four bolts securing the motor mounting brack-
ets to the unit. Torque four bolts to 120 ± 12 in.-lb (14 ±1.4
Nm).
28. Remove cover on motor connection box.
29. Re-connect all electrical leads to the motor and replace the
connection box cover.
30. Re-connect all electrical power to the unit. Remove lock-
out tags on all electrical power sources.
31. Start unit and allow to run for a designated period.
32. Shut off unit and make any necessary adjustments to the V-
belt tension or the motor and blower wheel pulley alignment.
When replacing the motor, also replace the external-tooth lock
washer (star washer) under the motor mounting base; this is part of
the motor grounding system. Ensure the teeth on the lock washer
are in contact with the motor’s painted base. Tighten motor
mounting bolts to 120 ± 12 in.-lb.
Changing Fan Wheel Speed
Changing fan wheel speed by changing pulleys: The horsepower
rating of the belt is primarily dictated by the pitch diameter of the
smaller pulley in the drive system (typically the motor pulley in
these units). Do not install a replacement motor pulley with a
smaller pitch diameter than provided on the original factory pul-
ley. Change fan wheel speed by changing the fan pulley (larger
pitch diameter to reduce wheel speed, smaller pitch diameter to in-
crease wheel speed) or select a new system (both pulleys and
matching belt).
Before changing pulleys to increase fan wheel speed, check the
fan performance at the target speed and airflow rate to determine
new motor loading (bhp). Use the fan performance tables or use
the Packaged Rooftop Builder software program. Confirm that the
motor in this unit is capable of operating at the new operating con-
dition. Fan shaft loading increases dramatically as wheel speed is
increased.
To reduce vibration, replace the motor’s adjustable pitch pulley
with a fixed pitch pulley (after the final airflow balance adjust-
ment). This will reduce the amount of vibration generated by the
motor/belt-drive system.
REMOTE VFD KEYPAD REFERENCE
See Tables 4 and 5 for SRT unit VFD parameters.
CAUTION
EQUIPMENT DAMAGE HAZARD
Failure to follow this CAUTION can result in premature wear
and damage to equipment.
Do not use a screwdriver or a pry bar to place the new V-belt in
the pulley groove. This can cause stress on the V-belt and the
pulley resulting in premature wear on the V-belt and damage
to the pulley.
Summary of Contents for WeatherMaster 48HC04 Series
Page 37: ...37 Fig 60 Integrated Gas Control IGC Board RED LED STATUS ...
Page 45: ...45 Fig 65 RTU Open Overlay for Economizer Wiring ...
Page 46: ...46 Fig 66 VFD Overlay for W2770 Controller Wiring ...
Page 98: ...98 Fig E 48HC A07 YAC Control Diagram 208 230 3 60 460 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 100: ...100 Fig G 48HC D11YAC Control Diagram 208 230 3 60 460 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 101: ...101 Fig H 48HC D12 YAC Control Diagram 208 230 3 60 460 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 102: ...102 Fig I 48HC A04 A06 YAC Power Diagram 208 230 1 60 APPENDIX D WIRING DIAGRAMS ...
Page 103: ...103 Fig J 48HC A04 A06 YAC Power Diagram 208 230 3 60 460 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 104: ...104 Fig K 48HC A04 A06 YAC Power Diagram 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 107: ...107 Fig N 48HC A07 A12 YAC Power Diagram 208 230 3 60 460 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 108: ...108 Fig O 48HC A07 A12 YAC Power Diagram 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 109: ...109 Fig P 48HC D08 D09 YAC Power Diagram 230 460 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 110: ...110 Fig Q 48HC D08 D09 YAC Power Diagram 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 111: ...111 Fig R 48HC D11 YAC Power Diagram 208 230 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 112: ...112 Fig S 48HC D11 YAC Power Diagram 460 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 113: ...113 Fig T 48HC D11 YAC Power Diagram 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 114: ...114 Fig U 48HC D12 YAC Power Diagram 230 460 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 115: ...115 Fig V 48HC D12 YAC Power Diagram 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 116: ...116 Fig W 48HC D14 YAC Control Diagram 208 230 3 60 460 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 117: ...117 Fig X 48HC D14 YAC Power Diagram 208 230 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 118: ...118 Fig Y 48HC D14 YAC Power Diagram 460 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 119: ...119 Fig Z 48HC D14 YAC Power Diagram 575 3 60 APPENDIX D WIRING DIAGRAMS ...
Page 142: ...142 Fig AW PremierLink System Control Wiring Diagram System APPENDIX D WIRING DIAGRAMS ...
Page 144: ...144 Fig AY RTU Open Wiring Diagram APPENDIX D WIRING DIAGRAMS ...