TM 5-4120-361-14 air conditioner (figure 1-2), are automatically opened and closed by the action of the refrigerant system. The condenser louvers cannot be manually opened and closed. i. Compressor Circuit Breaker. The compressor circult breaker is a safety device which provides overcurrent protection for the compressor. The compressor circuit breaker is not a con- trol switch to be used for operating the unit. This breaker should always be kept in the ON position. If  the  breaker trips to the OFF position, a defective compressor or related defective elec- trical components, or faulty wiring, is indicated. Inadequate input power voltage will also cause the circuit breaker  to  trip. The unit control cir- cuit is also connected to auxiliary contacts on the compressor circuit breaker. When this circuit breaker trips to OFF, it disconnects the control circuit allowing the time delay relay to reset and the refrigerant system pres- sures  to  equalize. Manually resetting the compressor circuit breaker to ON re- stores electrical continuity. j. Control Circuit Breaker. The control circuit breaker iS a safety de- vice which provides overcurrent protec- tion for the control circuit of the unit. The control circuit breaker is not a control switch to be used for op- erating  the  unit. This breaker should always be maintained in the ON position. If the breaker trips to the OFF posi- tion, an electrical defect in the con- trol circuit is indicated and corrective action should be taken. Manually reset- ting the circuit breaker to ON restores electrical continuity. Section  II. PREVENTIVE MAINTENANCE CHECKS AND SERVICES 2-3. General. To insure that the air conditioner is ready for operation at all times, it must be inspected systematically so that defects may be discovered and corrected before they result in serious damage or failure. The necessary preventive main- tenance checks and services (PMCS) to be performed are listed and described in paragraph  2-4. The item numbers indi- cate the sequence of minimum inspection requirements. a. Before  you  operate. Always keep in mind the CAUTIONS and WARNINGS. Per- form your before (B) PMCS. b. While you operate. Always keep in mind the CAUTIONS and WARNINGS. Per- form your during (D) PMCS. After you operate. Be sure to perfrm your after (A) PMCS. d. If your equipment fails to oper- ate Troubleshoot with proper equip- ment. Report any deficiencies using the proper forms, see TM 38-750. Defects discovered during operation of the unit will be noted for future correction to be made as soon as opera- tion of the unit has ceased. Stop  oper- ation immediately if during operation a deficiency is noted which would damage the equipment if operation were contin- ued. All deficiencies and shortcomings will be recorded, together with the corrective action taken, on DA Form 2404 nity 2-4. Servi at the earliest possible opportu- Daily Preventive Maintenance ces. This paragraph contains a tabulated listing of preventive maintenance ser- vices which must be performed by the op- erator. The item numbers are listed consecutively and indicate the sequence of minimum requirements. Refer to table 2-1 for the daily preventive maintenance services. NOTE Use the numbers in the Item No.   Column as a source of item numbers for the “TM Number” column on DA Form 2404, Equip- ment Inspection and Mainte- nance Worksheet, in recording results  at  PMCS. 2-4