TM 5-3805-281-24-1
Tests
4. Slowly increase pressure. Switch must have continuity
until pressure increases to high pressure switch
opening pressure specification.
High Pressure Switch (Normally Closed)--Specification
Opens on Increasing Pressure ............ 2760 138 kPa (27.6 1.38 bar)
(400 20 psi)
High Pressure Switch (Normally Closed)--Specification
Closes on Decreasing Pressure................. 1310 138 kPa (13.11 1.38
bar) (190 20 psi)
5. The low pressure switch can also be checked when
installed in air conditioning system, however, pressure
is slow to increase to test specification. High test
switch is not easily tested in system.
Connect an 3-gauge manifold for R134a to service
fittings at compressor. Cover condenser with paper or
plastic to stop air flow. Operate air conditioner on
maximum cooling. Note high-side pressure when high
pressure switch opens and then closes.
9031
25
CED,TX14795,4346 1904MAR982/2
7
LEAK TESTING
3. If a leak detector is used, move the leak detector
1. Inspect all lines, fittings, and components for oily or
probe under the hoses and around the connections
dusty spots. When refrigerant leaks from the
at a rate of 25 mm (1 in.) per second.
system, a small amount of oil is carried out with it.
4. Some refrigerant manufacturers add dye to
2. A soap and water solution can be sprayed on the
refrigerant to aid in leak detection.
components in the system to form bubbles at the
source of the leak.
TX,9031,UU3168 1913AUG961/1
