PREVENTIVE MAINTENANCE CHECKS AND SERVICES ON COMPRESSORS
You must ensure the Model M5A Compressor-Dehydrator continues to function
efficiently. This lesson introduces the general operation of the compressor, its controls
and indicators, safety precautions you need to follow, and the procedures you use for
COMPRESSOR COMPONENT FUNCTIONS
In order to perform PMCS and other maintenance tasks to keep the compressor
running smoothly, you need to be aware of the compressor's components and their
specific functions. Refer to figures 1-1 and 1-2.
a. Safety Relief Valve. This over-pressure relief valve is factory set to release
pressure when it has reached a value of 125 pounds per square inch (psi).
(1) This provides a safety release of pressure if the pressure switch does
not operate properly.
(2) If this valve is not operating properly and the pressure switch failed to
stop compression at the proper pressure, the compressor storage tank could explode
from over pressure.
b. Dryness Indicator. The dryness indicator (also known as a humidity
indicator) is a paper that changes color when moisture is present.
When the indicator is blue, there is dry air in the storage tank.
(2) If the indicator is pink, the air has moisture in it. You should purge the
unit of moisture before use.
c. Flow Control Valves. The flow control valve is a check valve that will allow
limited back flow from the storage tank.
(1) During the filling or pumping cycle of the compressor, the flow control
valve allows flow in the direction of the storage tank only. Refer to paragraph 1-3a.
(2) During the drying or purging cycle, air can flow through a small orifice in
the flow control valve to allow regeneration of the desiccant. Refer to paragraph 1-3b.