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7
3. Remove the belt by gently lifting the old belt over one of
the pulleys.
4. Install the new belt by gently sliding the belt over both
pulleys and then sliding the motor and plate away from the
fan housing until proper tension is achieved.
5. Check the alignment of the pulleys, adjust if necessary.
6. Tighten all bolts and torque to 65 to 70 in.-lb (7.4 to
7.9 Nm).
7. Check the tension after a few hours of runtime and read-
just as required.
ADJUSTABLE-PITCH PULLEY ON MOTOR
The motor pulley is an adjustable-pitch type that allows a servicer
to implement changes in the fan wheel speed to match as-installed
ductwork systems. The pulley consists of a fixed flange side that
faces the motor (secured to the motor shaft) and a movable flange
side that can be rotated around the fixed flange side that increases
or reduces the pitch diameter of this driver pulley. (See Fig. 10.)
Fig. 10 — Supply-Fan Pulley Adjustment
As the pitch diameter is changed by adjusting the position of the
movable flange, the centerline on this pulley shifts laterally (along
the motor shaft). This creates a requirement for a realignment of
the pulleys after any adjustment of the movable flange. Reset the
belt tension after each realignment.
Inspect the condition of the motor pulley for signs of wear. Glaz-
ing of the belt contact surfaces and erosion on these surfaces are
signs of improper belt tension and/or belt slippage. Replace pulley
if wear is excessive.
CHANGING THE FAN SPEED:
1. Shut off unit power supply. Use proper lockout/tag-out
procedures.
2. Loosen belt by loosening fan motor mounting nuts. (See
Fig. 8.)
3. Loosen movable pulley flange setscrew. (See Fig. 10.)
4. Screw movable flange toward fixed flange to increase
speed and away from fixed flange to decrease speed.
Increasing fan speed increases load on motor. Do not
exceed the maximum specified speed.
5. Set movable flange at nearest keyway of pulley hub.
Tighten setscrew and torque to 65 to 70 in.-lb (7.4 to
7.9 Nm).
ALIGNING BLOWER AND MOTOR PULLEYS:
1. Loosen blower pulley setscrews.
2. Slide blower pulley along blower shaft. Make angular
alignment by loosening motor mounting plate front and
rear bolts.
3. Tighten blower pulley setscrews and motor mounting
bolts. Torque bolts to 65 to 70 in.-lb (7.4 to 7.9 Nm).
4. Recheck belt tension.
BEARINGS
The fan system uses bearings featuring concentric split locking
collars. A Torx T-25 socket head cap screw is used to tighten the
locking collars. Tighten the locking collar by holding it tightly
against the inner race of the bearing. Tighten the socket head cap
screw. Torque cap screw to 65 to 70 in.-lb (7.4 to 7.9 Nm). See
Fig. 11. Check the condition of the motor pulley for signs of wear.
Glazing of the belt contact surfaces and erosion on these surfaces
are signs of improper belt tension and/or belt slippage. Pulley re-
placement may be necessary.
Fig. 11 — Tightening Locking Collar
STAGED AIR VOLUME CONTROL — 2 SPEED
FAN WITH VARIABLE FREQUENCY DRIVE (VFD)
Staged Air Volume (SAV) Indoor Fan Speed
System
The Staged Air Volume (SAV) system utilizes a fan speed control
board and Variable Frequency Drive (VFD) to automatically ad-
just the indoor fan motor speed in sequence with the unit’s ventila-
tion, cooling, and heating operation. Per ASHRAE 90.1 2010
standard section 6.4.3.10.b, during the first stage of cooling opera-
tion the SAV system will adjust the fan motor to provide two-
thirds (
2
/
3
) of the design airflow rate for the unit. When the call for
the second stage of cooling is required, the SAV system will allow
the design airflow rate for the unit established (100%). During the
heating mode, the SAV system will allow total design airflow rate
(100%) operation. During ventilation mode, the SAV system will
operate the fan motor at
2
/
3
speed.
Identifying Factory Option
This supplement only applies to units that meet the criteria de-
tailed in Table 3. If the unit does not meet that criteria, discard this
document.
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.
STRAIGHT EDGE
MUST BE PARALLEL
WITH BELT
SETSCREWS
MOTOR AND
FANSHAFTS
MUST BE
PARALLEL
FIXED FLANGE
MOVABLE
FLANGE
SINGLE - GROOVE
FAN PULLEY
MOTOR PULLEY
T --- 25 TORX SOCKET
HEAD CAP SCREW
LOCKING COLLAR
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 ...