21
SERVICE
Cleaning Evaporator Coil
Do not use high-pressure water or air. Damage to fins may result.
Clean coils with a vacuum cleaner, fresh water, compressed air, or
a bristle brush (not wire). Backflush coil to remove debris. Com
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mercial coil cleaners may also be used to help remove grease and
dirt. Steam cleaning is NOT recommended.
Units installed in corrosive environments should be cleaned as
part of a planned maintenance schedule. In this type of applica
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tion, all accumulations of dirt should be cleaned off the coil.
Take care not to get water in the system ducts or unit insulation.
Lubrication
Fan motors have permanently lubricated bearings.
Indoor Fan Adjustment
To prevent personal injury, be sure wire fan guards (provided by
customer) are secured in place over each fan discharge (or that
fans are ducted) before starting the unit.
TO CHANGE FAN SPEED
1. Shut off unit power supply. Lock out power supply and tag
disconnect locations.
2. Loosen fan belt by loosening fan motor belt adjusting bolts.
Do not loosen fan motor mounting bracket from unit.
3. Loosen movable pulley flange setscrew (Fig. 12).
4. Screw movable flange toward fixed flange to increase fan
speed and away from fixed flange to decrease speed. Increas
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ing fan speed increases load on motor. Do not exceed maxi
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mum allowable fan speed or motor full load amps indicated
on unit nameplate and in Table 5.
5. Set movable flange setscrew at nearest flat of pulley hub and
tighten setscrew.
6. Check pulley alignment and belt tension adjustment as
described below.
7. Check fan operation. Repeat above procedure as required.
Pulley Alignment
Shut off unit power supply. Lock out power supply and tag discon
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nect locations. Loosen fan motor pulley setscrews and slide fan
pulley along fan shaft. Make angular alignment by loosening mo
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tor from mounting bracket (see Fig. 12). Check alignment with a
straightedge.
Belt Tension Adjustment
Shut off unit power supply. Lock out power supply and tag discon
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nect locations. Loosen fan motor mounting plate bolts. Do not
loosen motor mounting bracket from unit. Adjust belt tensioning
bolt until proper belt tension is obtained.
Changing Fan Wheel
If a fan wheel should fail, it may be replaced as follows:
1. Shut off unit power supply. Lock out power supply and tag
disconnect locations.
2. Remove belts from fan pulley.
3. Loosen locking collars on the fan bearings and set screws on
the fan wheels.
4. Remove the shaft through the access panel on either side of
the unit.
5. Remove the fan cut-off plate in the fan discharge.
6. Remove the fan wheel through the fan discharge opening.
7. Replace the wheel, and reverse Steps 1-5 above.
Fan Bearing Replacement
If a fan bearing fails, replace it as follows:
1. Shut off unit power supply. Lock out power supply and tag
disconnect locations.
2. Remove belts from the fan pulley.
3. Support fan shaft.
4. Loosen locking collar on fan bearing.
5. Remove bearing from the shaft.
6. Install new bearing onto the shaft, and reverse Steps 1-3
above.
Concentric Alignment
Shaft and wheels must be concentrically centered with the venturi
or air inlet of the fan housing (see Fig. 13).
Shaft bearings are supported by bearing supports (Fig. 14). If shaft
and wheels are concentrically misaligned from shipping shock, it
is possible to rebend the bearing support arms to the original posi
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tions. Replace the bearing support if it has extensive damage.
Fig. 12 —
Fan Pulley Adjustments
Fig. 13 —
Concentric Alignment
