48/50PD
To inspect blower wheel, open heat section door. Using a flashlight, look into the flue exhaust duct to inspect. If cleaning is required, remove motor and wheel assembly by removing the screws holding the flue box cover to the flue box. Remove the screws holding the inducer housing to the inlet plate. The wheel can then be removed from the motor shaft and cleaned with a detergent or solvent. Replace the wheel onto the motor shaft in the correct position and reassemble the flue cover onto the flue box.
Lubrication
Compressors
Each compressor is charged with the correct amount of oil at the factory.
!CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in damage to unit components.
The compressor is in a Puron refrigerant system and uses a polyolester (POE) oil. This oil is extremely hygroscopic, meaning it absorbs water readily. POE oils can absorb 15 times as much water as other oils designed for HCFC and CFC refrigerants. Avoid exposure of the oil to the atmosphere.
Polyolester (POE) compressor lubricants are known to cause long term damage to some synthetic roofing materials. Exposure, even if immediately cleaned up, may cause roofing materials to become brittle (leading to cracking) within a year. When performing any service which may risk exposure of compressor oil to the roof, take appropriate precautions to protect roofing. Procedures which risk oil leakage include compressor replacement, repairing refrigerant leaks, and replacing refrigerant components. To prepare rooftop:
1.Cover extended roof work area with an impermeable plastic dropcloth or tarp. Make sure a 10 x 10 ft area around the work area is covered.
2.Cover area in front of the unit service panel with a terry cloth shop towel to absorb lubricant spills and prevent
3.Place terry cloth shop towel inside the unit directly under components to be serviced to prevent spills through the bottom of the unit.
4.Perform the required service.
5.Remove an dispose of any oil contaminated material per local codes.
Indoor Fan Shaft Bearings
The indoor fan has permanently sealed bearings. No field lubrication is necessary.
Condenser and Evaporator-Fan Motor Bearings
The
Economizer or Manual Outside Air Damper
If blade adjustment is required, refer to unit or accessory installation instructions.
Evaporator Fan Service and Replacement
The units feature a
1.Turn off unit power.
2.Open the fan section access door.
3.Remove two no. 10 screws at front of
4.Disconnect the electrical wires connected to the
5.Fan deck can now be slid out to access serviceable components.
!CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in damage to the unit.
DO NOT SLIDE FAN DECK OUT PAST THE FAN DECK STOP. If further access is required, the fan deck must be supported. Make sure plugs and wiring are not pinched between fan housing and unit sheet metal post.
6.To replace fan deck to operating position, slide fan deck back into the unit. Secure with the two no. 10 screws removed in Step 3.
7.
8.Close fan section access door.
9.Restore power to unit.
C08661
Fig. 30 -
Evaporator Fan Performance Adjustment
Fan motor pulleys are factory set for speed shown in Appendix D. To change fan speeds:
1.Shut off unit power supply.
2.Loosen nuts on the 4 carriage bolts in the mounting base. Using adjusting bolts and plate, slide motor and remove belt.
3.Loosen
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 maximum speed specified in Appendix D.
See Appendix D for air quantity limits.
5.Set movable flange at nearest keyway of pulley hub and tighten setscrew. (See Appendix D for speed change for each full turn of pulley flange.)
6.Replace belts.
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