169
Adjustments
RETURN FAN MOTOR PLATE
Adjust using a wrench on the adjusting bolts:
1. Loosen holddown bolts. (See Fig. 49.)
2. Turn the adjusting bolts to move the motor mounting plate
toward or away from the fan to loosen or tighten the belts.
Make the same number of turns to each bolt.
3. Retighten holddown bolts.
SUPPLY FAN AND POWER EXHAUST MOTOR PLATE
Adjust using a wrench on the adjusting bolts:
1. Loosen holddown bolts. (See Fig. 50.)
2. Turn the adjusting bolts to move the motor mounting plate
toward or away from the fan to loosen or tighten the belts.
Make the same number of turns to each bolt.
3. Retighten holddown bolts.
Fig. 49 —
Return Fan Motor Plate Adjustment
Fig. 50 —
Supply and Power Exhaust Fan Motor Plate
Adjustment
BELT INSTALLATION AND TENSIONING
1. Turn off unit power.
2. Adjust motor plate so belts can be installed without
stretching over the grooves of the pulley. (Forcing the
belts can result in uneven belt stretching and a mismatched
set of belts.) See Fig. 51.
3. Before tensioning the belts, equalize belt slack so that it is
on the same side of the belt for all belts. Failure to do so
may result in uneven belt stretching.
4. Tighten belts using the motor plate adjusting bolts.
5. Adjust until proper belt tension (
1
/
2
-in. [13 mm] deflection
with one finger centered between pulleys) is obtained. Be
sure to adjust both adjusting bolts the same number of
turns. Excessive belt tension shortens belt life and may
cause bearing and shaft damage.
NOTE: Check the tension at least twice during the first day of
operation, as there is normally a rapid decrease in tension until
the belts have run in. Check tension periodically thereafter and
keep it at the recommended tension.
Fig. 51 —
Motor Plate Adjustment
PULLEY ALIGNMENT
For proper belt life, the motor and fan pulleys must be properly
aligned. To check, first turn off unit power. Place a straightedge
against the motor and fan pulleys. See Fig. 52. If the pulleys are
properly aligned, the straightedge should be parallel to the belts.
If they are not parallel, check that the motor shaft and fan shaft
are parallel. If they are not, adjust the motor plate adjusting
bolts until they are.
After verifying that the shafts are parallel, loosen the setscrews
on the motor pulley. Move pulley on the shaft until the pulleys
are parallel. To move the sheave on the shaft, loosen the belts.
If necessary, blower sheave can also be moved on the shaft.
INSTALLING REPLACEMENT MOTOR PULLEY
To install a field-supplied replacement pulley:
1. Turn off unit power.
2. Loosen belts using motor adjusting bolts until belts can be
removed without stretching them over the grooves of the
pulley.
3. Remove belts.
4. Loosen setscrews on motor pulley.
5. Slide pulley off motor shaft. Make sure setscrews on new
pulley are loose.
6. Slide new pulley onto fan shaft and align it with the fan
pulley as described in Pulley Alignment section above.
7. Tighten setscrews.
8. Install belts and tension properly as described in Pulley
Alignment section above.
CONDENSER FAN ADJUSTMENT (METAL FANS)
1. Turn off unit power.
2. Remove fan guard and loosen fan hub setscrew.
IMPORTANT: When installing or replacing belts, al
-
ways use a complete set of new, matched belts to prevent
potential vibration problems. Mixing belts often results
in premature breakage of the new belts.
HOLD DOWN
BOLTS
HOLD DOWN
BOLTS
ADJUSTING
BOLT
ADJUSTING
BOLT
HOLD DOWN
BOLTS
ADJUSTING
BOLT
Содержание WeatherExpert 48N2
Страница 135: ...135 Fig 18 48 50N Typical Power Schematic Nominal 075 Ton Unit Shown ...
Страница 136: ...136 Fig 19 48 50N Typical Power Schematic Nominal Ton 90 150 Units Shown ...
Страница 137: ...137 Fig 20 48 50N Main Base Board Input Output Connections ...
Страница 138: ...138 Fig 21 48 50N RXB EXB CEM Input Output Connections a48 9307 ...
Страница 139: ...139 Fig 22 48 50N EXV SCB Input Output Connections a48 9308 ...
Страница 140: ...140 Fig 23 48N Typical Modulating Gas Heat Unit Control Wiring ...
Страница 141: ...141 Fig 24 50N Typical Electric Heat Unit Control Wiring ...
Страница 144: ...144 Fig 27 48N Typical Gas Heat Section Wiring Nominal Ton 120 to 150 Units ...
Страница 145: ...145 Fig 28 48 50N Typical Power Component Control Wiring 460 v ...
Страница 146: ...146 Fig 29 48 50N Component Control Wiring 575 v Nominal Ton 075 to 150 Units ...
Страница 147: ...147 Fig 30 48 50N Component Arrangement Power Box ...
Страница 148: ...148 Fig 31 48 50N Component Arrangement Control Box ...
Страница 168: ...168 Fig 47 Sensor and Ignition Position Fig 48 Combustion Blower Details SENSOR DETAILS IGNITION DETAILS ...
Страница 240: ...240 APPENDIX D VFD INFORMATION CONT Fig G VFD Bypass Wiring Diagram WHEN USED ...