MIL-DTL-3155D(SH)
4.5.2.2 Valve opening point temperature. Valve opening point temperature shall be determined with the
thermostats set at any setting within the adjustable range; the temperature at the thermostats shall then be lowered to
1 °F below the opening point to determine that there is a definite increase in the flow of steam.
4.5.2.3 Valve closing point temperature. Valve closing point temperature shall be determined with the
thermostats set at any setting within the adjustable range; the temperature at the thermostats shall then be increased
1 °F above the closing point to determine that the valve will close fully and is steamtight.
4.5.2.4 Rate of condensate measurement. With a 25-psig back pressure at the valve outlet, the rate of
condensate shall be measured when the temperature at the thermostat is 1 °F, 2 °F, and 3 °F below the opening point
of the control valve.
4.5.2.5 Design change check test. When design changes are approved by NAVSEA for a particular size and
model of valve or type of thermostat which may alter the performance of the temperature-regulating valve, tests
specified in 4.5.2 shall be conducted on that size and model valve on the first item produced under the contract or
order.
4.5.3 Pressure test (valves). Each valve body shall be tested with 150-psig air pressure while immersed in
water or 150-psig hydrostatic pressure with the valve open to test the strength of the body and detect porosity.
Visible deformation or porosity or other signs of weakness shall be cause for rejection.
4.5.4 Thermostat control point test. Each Type L and each Type R thermostat shall be tested to determine
whether the fully open and fully closed points are within specified limits when thermostats are set at the
mid-position of their adjustable temperature range. Each Type W thermostat shall be tested to determine whether
the fully open point is as specified in 3.4.7.3.
4.5.5 Leakage test. The valve seats and poppets of each temperature-regulating valve shall be tested to
determine the tightness and resistance to leakage at a minimum steam pressure of 50 psig on the inlet side of the
valve and the outlet side open to the atmosphere. The test for valves with Type L or Type R thermostat shall be
made with the thermostat set at the mid-position of the adjustable range in an ambient temperature from 3 to 6 °F
above the set point.
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