MIL-DTL-23450D
4.4.5 Superheat setting (see 3.5.2 and 3.5.4). The following test is used to determine the superheat
setting. The following details shall apply:
a. The test fixture shall be as shown on figure 1
b. The size of the bleed orifice for each MS PIN valve shall be as listed in 4.4.2.
c. The air supply shall be turned on and maintained at:
(1) R-12 valves: 110 ±1 pounds per square inch gage (psig) (8.62 ±0.07 bar).
(2) R-22 valves: 125 ±2 psig (8.62 ±0.14 bar).
d. R-12 valves the bulb and 6 inches of capillary are to be at the superheat setting temperature
specified in MS17982 ±0.5 °F (±0.3°C).
e. R-22 valves the bulb and 1/3 (.33) inch (8.47 mm) of capillary are to be at the superheat setting
temperature specified in MS17982 ±0.5°F (±0.3°C).
f. The valve head and the remainder of the capillary are to be at 80°F ±2°F (26.7°C ±1.11°C).
g. With the air supply turned on and the hand valves "A" and "B" open, the outlet pressure shall
indicate the pressure corresponding to the refrigerant saturation temperature. The difference
between the temperature of the thermal bulb and the saturation temperature obtained above shall
be the superheat setting as specified in MS17982 and 3.5.2.
h. Any nonconformance shall constitute failure of this test.
4.4.6 Pressure limit (R-12 Type I) (see 3.5.4). This test applies to valves MS17982-1 and MS17982-2
type I R-12. The pressure setting of the valves shall be tested to determine the pressure limits specified
in 3.5.1. The following details shall apply.
a.
The test fixture shall be as shown on figure 1.
b.
The inlet pressure to the valve shall be 110 ±1 psig (8.62 ±0.07 bar).
The valve head, bulb, and capillary are to be at 80° ±2°F (26.7° ±1.11°C).
c.
d.
With the air supply turned on and hand valves "A" and "B" open, immerse bulb, valve, and
capillary tubing in 80°F (26.7°C) bath for a period of 5 minutes.
e. The bleed orifice in 4.4.2 shall be used for this test.
g. Observe the pressure at the outlet gage.
h. Any nonconformance with the pressure limit requirements of 3.5.4 shall constitute failure of this
test.
4.4.7 Seat leak test (type I and II valves) (see 3.5.5).
4.4.7.1 R-12 valve seat leak test. The valve seat for types I and II R-12 valves shall meet the
requirements specified in 3.5.5. The following details shall apply:
a. The test is to be performed on the fixture described on figure 1.
b. With 110 ±1psig (8.62 ±0.07 bar), applied to the inlet of the fixture and with the expansion valve
set at the bulb reference temperature specified in MS17982, cool the bulb a maximum of 5°F
(-15°C) to correspond with the maximum superheat change specified in MS17982.
c. Then close the outlet valve "A" and allow the pressure to rise.
d. The seat leakage shall be measured by the rise in outlet gage pressure in a measured amount of
elapsed time after closing of hand valve "A".
e. The maximum allowable pressure rise shall not exceed the values shown below.
MS179821 dash number -1, -2, -3, -4, -5, -6, -7, -8, -9, -10 -11, -12
Seat leak pressure
12
25
rise rate
(0.83)
(1.72)
psig/min (bar)
f. Any nonconformance with the above pressure rise rate shall constitute failure of this test (see
3.5.5).
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