safety precautions and first-aid information are also
HYDRAULIC SYSTEM
included.
In the hydraulic system of the A/M32C-17 (fig.
On the job, use the maintenance requirements cards
11-22), the hydraulic pump is belt-driven from the
(MRCs) for the A/M32C-17 as your primary reference
electrical clutch. The pump draws fluid from the
when inspecting and servicing the unit. However, as
reservoir and pumps it through the relief valve to the fan
the MRCs contain only the minimum requirements,
motor and to the remote control valve. It returns the
for more detail, refer to the technical manual
fluid to the reservoir through the oil cooler and oil filter.
Organizational, Intermediate, and Depot Maintenance
The pressure transducer has a capillary line
with Illustrated Parts Breakdown, Mobile Air
connected in the refrigerant line to sense refrigerant
Conditioning Unit, Model A/M32C-17, NAVAIR
head pressure. If the refrigerant head pressure is high,
19-60-87.
the pressure transducer closes the remote pressure
NOTE: If there is a conflict between information in
control valve to permit the motor to operate at a
NAVAIR 19-60-87 and the MRCs, the MRCs take
relatively high speed. If the refrigerant head pressure is
precedence.
low, the pressure transducer opens the remote pressure
control valve to allow the fluid to pass through the
Prior to working on an air-conditioning refrigera-
remote control valve to the oil cooler, oil filter, and
tion system that involves the possibility of release of
reservoir. This action results in the motor slowing
refrigerant into the atmosphere, you must be certified
down, reducing the amount of airflow through the
and meet the requirements of the United States
condenser. This causes an increase in pressure on the
Environmental Protection Agency's (EPA) certification
high side of the system.
requirements for universal technicians, as required by
EPA Regulation 40 CFR, Part 82, Subpart F. This
MAINTENANCE
certification does not ensure that you are a trained
air-conditioner technician, but it does ensure that you
The A/M32C-17 is a heavy-duty, well constructed
are fully aware of the laws, rules, and regulations
air-conditioning unit. But, like other equipment, it
required to service the three types of systems, as well as
requires regular servicing and inspections to maintain
the common core issues.
peak performance. It is beyond the scope of this text to
cover all of the related maintenance procedures;
Refrigeration Servicing Equipment
therefore, only general procedures are discussed briefly
in the following text. This will include information
Repair and service work on refrigeration systems
on servicing, troubleshooting, and repair. Applicable
involves two major considerations--containing the
REFRIGERANT PRESSURE
PRESSURE
TRANSDUCER
MECHANICAL
LINKAGE
REMOTE
FAN
PUMP
CONTROL VALVE
DRAIN
RELIEF
VALVE
MOTOR
REFRIGERANT
COIL
RESERVOIR
OIL
COOLER
FILTER
ASf11022
Figure 11-22.--Hydraulic system.
11-24
