Heatcraft Refrigeration Products Condensing Units H-IM-CU User Manual

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.

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 adjust defrost 

cycles accordingly

• Compare actual defrost heater amp draw against unit data plate.
• Visually inspect heaters to ensure even surface contact with the coil. If 

heaters have crept, decrease defrost termination temperature and be 

sure you have even coil frost patterns. Re-align heaters as needed.

• 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

• 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.

5) Inspect electrical wiring and components

• Verify that all electrical and ground connections are secure, tighten as 

required.

• Check condition of compressor and heater contactors. Look for 

discoloration and pitting. Replace as required.

• Check operation and calibration of all timers, relays pressure controls 

and safety controls.

• Clean electrical cabinet. Look for signs of moisture, dirt, debris, insects 

and wildlife. Take corrective action as required.

• Verify operation of crankcase heater by measuring amp draw.

6) Check refrigeration cycle

• Check suction, discharge and net oil pressure readings. If abnormal take 

appropriate action.

• Check operation of demand cooling, liquid injection or unloaders if so 

equipped.

• Check pressure drop across all filters and driers.  Replace as required.
• Verify that superheat at the compressor conforms to specification. (30°F 

to 45°F)

• Check pressure and safety control settings and verify proper operation.

Annually

7) In addition to quarterly and semiannual maintenance checks, submit an    

     oil sample for analysis

• Look for high concentrations of acid or moisture. Change oil and driers 

until test results read normal.

• Investigate source of high metal concentrations, which normally 

are due to abnormal bearing wear. Look for liquid refrigerant in the 

crankcase, low oil pressure or low superheat as a possible source.

8) Inspect suction accumulator (if equipped)

• If the accumulator is insulated remove insulation and inspect for leaks 

and corrosion.

• Pay close attention to all copper to steel brazed connections
• Wire brush all corroded areas and peeling paint.
• Apply an anticorrosion primer and paint as required.  Re-insulate if 

applicable.