Relative Humidity Test.

TM 11-6780-225-35

e. Water Temperature Test.

rected in paragraph 2-8a(2), TM 11-6780-22512.

(1) Operate the water heater at its full capacity for 1

(2) Place a thermometer in one of the drying

hour.

cabinets.

(3) With all operating controls at the full on

(2) The water temperature shall be 150°F (65.5°C)

position, the thermometer shall indicate a temperature of

+5".

105°F (41°C) +5° for a period of 1 hour.

f. Water Pressure Test.

d. Relative Humidity Test.

(1) Operate the water system from a water

(1) With the dehumidifier humidistat set to 40

source under pressure (TM 11-6780-225-12).

and all other equipment set to OFF with the darkroom

(2) Observe that the water pump operates

secure, operate the dehumidifier for 2 hours.

from 0 psi to 40 psi as indicated. by the inlet pressure

(2) Measure the relative humidity of the

indicator.

forward compartment of the darkroom with a sling

(3) Turn the adjustment screw of the pressure

psychrometer. The dry bulb and wet bulb temperature

switch (fig. 5-9) with a screwdriver so that the operation

difference shall be 13°, indicating a temperature of 60°F

(15.5°C) and a relative humidity of 39 =5 .

of the water pump conforms to step (2) above.

5-2