Heatcraft Mohave, Installation & Operation Manual, Page: 61 / 76

61
Preventive Maintenance
Unit Coolers
At every six month interval, or sooner if local conditions cause clogging or fouling of air
passages through the finned surface, the following items should be checked.
1) Visually inspect unit
• Look for signs of corrosion on fins, cabinet, copper tubing and solder joints.
• Look for excessive or unusual vibration for fan blades
or sheet metal panels when in operation. Identify fan
cell(s) causing vibration and check motor and blade
carefully.
• Look for oil stains on headers, return bends, and coil
fins. Check any suspect areas with an electronic leak
detector.
• Check drain pan to insure that drain is clear of debris,
obstructions or ice buildup and is free draining.
2) Clean evaporator coil and blades
• Periodic cleaning can be accomplished by using a brush,
pressurized water or a commercially available evaporator
coil cleaner or mild detergent. Never use an acid
based cleaner. Follow label directions for appropriate
use. Be sure the product you use is approved for use in
your particular application.
• Flush and rinse coil until no residue remains.
• Pay close attention to drain pan, drain line and trap.
3) Check the operation of all fans and ensure airflow is
unobstructed
• Check that each fan rotates freely and quietly. Replace
any fan motor that does not rotate smoothly or makes an
unusual noise.
• Check all fan set screws and tighten if needed.
• Check all fan blades for signs of stress or wear.
Replace any blades that are worn, cracked or bent.
• Verify that all fan motors are securely fastened to the
motor rail.
• Lubricate motors if applicable.
4) Inspect electrical wiring and components
• Visually inspect all wiring for wear, kinks, bare areas and
discoloration. Replace any wiring found to be damaged.
• Verify that all electrical and ground connections are
secure, tighten if necessary.
• Check operation/calibration of all fan cycle and
defrost controls when used.
• Look for abnormal accumulation of ice patterns and
adj ust defrost cycles accordingly
• Compare actual defrost heater amp draw against unit
data plate.
• Check drain line heat tape for proper operation
(supplied and installed by others).
5) Refrigeration Cycle
• Check unit cooler superheat and compare reading for
your specific application
• Visually inspect coil for even distribution
Air Cooled Condensing Units
Quarterly
1) Visually inspect unit
• Look for signs of oil stains on interconnection piping and
condenser coil. Pay close attention to areas around
solder joints, building penetrations and pipe clamps.
Check any suspect areas with an electronic leak detector.
Repair any leaks found and add refrigerant as needed.
• Check condition of moisture indicator/sightglass in the
sight glass if so equipped. Replace liquid line drier if there
is indication of slight presence of moisture. Replace
refrigerant, oil and drier if moisture concentration is
indicated to be high.
• Check moisture indicator/sightglass for flash gas. If found
check entire system for refrigerant leaks and add
refrigerant as needed after repairing any leaks.
• Check compressor sightglass (if equipped) for
proper oil level.
• Check condition of condenser. Look for accumulation
of dirt and debris (clean as required).
• Check for unusual noise or vibration. Take corrective
action as required.
• Inspect wiring for signs of wear or discoloration and
repair if needed.
• Check and tighten all flare connections.
Semi-Annually
2) Repeat all quarterly inspection items.
3) Clean condenser coil and blades
• Periodic cleaning can be accomplished by using a brush,
pressurized water and a commercially available foam coil
cleaner. If foam cleaner is used, it should not be an acid
based cleaner. Follow label directions for appropriate use.
• Rinse until no residue remains.
4) Check operation of condenser fans
• Check that each fan rotates freely and quietly.
Replace any fan motor that does not rotate smoothly
or makes excessive noise.
• Check all fan blade set screws and tighten as required.
• Check all fan blades for signs of cracks, wear or stress.
Pay close attention to the hub and spider. Replace blades
as required.
• Verify that all motors are mounted securely.
• Lubricate motors if applicable. Do not lubricate
permanently sealed, ball bearing motors.