TM 9-4120-388-14
Section I. DESCRIPTION AND USE OF OPERATOR'S CONTROLS AND INDICATORS
2-1. GENERAL. The 18,000 BTU/HR Air Conditioner is designed for a variety of installations and for operation under
a wide range of climatic conditions. It is also designed for continuous or intermittent operation as a self-contained unit or
may be connected to or used with external filtering equipment for operation under nuclear-biological-chemical (NBC) en-
vironmental conditions. Operators must be aware of any peculiarities or operational limitations for their specfic installation.
See the appropriate shelter or system manual for instructions peculiar to your specific installation.
2-2. OPERATOR'S CONTROLS. See Figure 2-1 and Figure 2-2 for a
general description of
the controls that an
oper-
ator will normally be concerned with. For specfic operating instructions, see Section III and Section IV of this chapter.
INDICATORS. The refrigerant sight glass (Figure 2-2) is
the only visual indicator used on
the 18,000 BTU/HR Air
Conditioner. The sight glass is a port or window through which the refrigerant condition can be seen. Liquid refrigerant
actually flows through the sight glass chamber only during cooling cycles when the air conditioner is in operation in the
COOL mode. The unit must be operated approximately 15 minutes in maximum cooling prior to checking condition of re-
frigerant at sight glass. The sight glass is equipped with a center indicator that is moisture sensitive. Dry refrigerant is indi-
cated by green, it turns chartreuse when the moisture content becomes undesirable, and to yellow when the level becomes
unacceptable. Excessive moisture in the refrigerant may damage or possibly destroy the compressor. If the liquid refriger-
ant observed in the sight glass has an opaque, milky appearance, or frequent bubbles appear, the volume of refrigerant
is low and the system should be charged. Either moisture or low charge indications should be reported to direct support
maintenance.
Do not operate the air conditioner in the COOL mode if the refrigerant color has
reached the yellow band or if numerous bubbles appear in the sight glass. COOL
mode operation may be continued with the refrigerant color in the yellow-green
band or with only an occasional bubble appearing in the window, but the sight
glass should be rechecked after each four hours of operation to insure that the
condition has not become worse.
Section Il. OPERATOR PREVENTIVE MAINTENANCE CHECKS AND SERVICES (PMCS)
2-4 GENERAL. Preventive Maintenance Checks and Services (PMCS) are essential to the efficient operation of the
air conditioner and to prevent possible damage that might occur through neglect or failure to observe warning symptoms
in a timely manner. Checks and services performed by operators are limited to those functions which are described in
a.
Before You Operate. Always keep in mind and observe the WARNINGS and CAUTIONS. Perform your before (B)
PMCS.
b. While you Operate. Always keep in mind and observe the WARNINGS and CAUTIONS. Perform your during (D)
PMCS.
After You Operate. Be sure to perform your after (A) PMCS.
c.
If Your Equipment Fails to Operate. Troubleshoot with proper equipment. Report any deficiencies using DA
d.
Form 2404. See DA PAM 738-750 for instructions.
Perform weekly as well as before operations PMCS if:
e.
(1) You are the assigned operator and have not operated the item since the last weekly check.
(2) You are operating the item for the first time.
NOTE
If the equipment must be kept in continuous operation, be sure and service only those
items that can be checked and serviced without disturbing operation. Make the complete
checks and services when the equipment can be shut down.