Figure 5-18.--Radar liquid cooling system.
Liquid Coolant Pump
temperature/flow controller to modulate an airflow
valve and limit preconditioned air to the heat
The liquid coolant pump (fig. 5-19, item B)
exchanger. The coolant is filtered and the system
assembly is a self-priming, submerged, centrifugal
monitored for filter contamination, ram air door
pump with a cylindrical two-section reservoir and a fill
actuator position, low pressure, high temperature, and
level gauging mechanism. Air bleeding of the reservoir
coolant quantity.
is done by manually actuating a bleed valve connected
to the reservoir. The gauging mechanism in the pump
COMPONENTS
unit combines inputs from coolant temperature and
Components of the radar liquid cooling system
reservoir piston position to change a fluid level
include a cooling liquid-to-air heat exchanger, a liquid
indicator on the service panel and produces a signal to
coolant pump, an airflow valve, a ground cooling fan, a
the digital display indicator (DDI) to display a low fluid
filter, a low-pressure sensor, and temperature sensors.
maintenance code.
Cooling Liquid-to-Air Heat Exchanger
The liquid-to-air heat exchanger (fig. 5-19, item A)
extracts heat from the liquid coolant that flows through
the two pass counter flow channels within the heat
exchanger. A single-pass air circuit dissipates heat
extracted by the heat exchanger. A thermostatic
temperature control valve is mounted in the inlet/outlet
manifold of the heat exchanger, and senses coolant
temperature. The control valve mixes bypass and core
fluid to maintain a delivery temperature of 80 to 90F
to the radar transmitter. In the cold position (bypass
valve fully closed), a bleed flow of 0.05 to 0.10 gallons
per minute (gpm) is provided to aid in purging the core
Figure 5-19.--Radar liquid cooling system component locator.
during system servicing.
5-17
