A-A-52545 Heaters, Vehicular Compartment 28 Volt, DcThis CID covers two types of heaters of 28 volt (V) direct current (dc) nominal rating, used for heating crew and engine compartments of military vehicles or equipment. Type I heaters are intended for use on military vehicles or equipment which may be required to operate in an ambient temperature to minus 65 degrees Fahrenheit (-65 Degrees F); from which a supply of gasoline is available; when heated air is required without the vehicle engine being operated. Type II heaters are intended for use on military vehicles or equipment from which a supply of heated circulating liquid (engine coolant) is available, which may be required to operate in an ambient temperature to -25 Degrees F.

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A-A-52545B

2.6 Performance.

2.6.1 Type I heater.

2.6.1.1 Heat output. With inlet air temperature at -65 +5F, the type I heaters shall have a heat output as specified in table II.

2.6.1.2 Air discharge rate. The type I heaters when performing at high setting, shall discharge air at not less than the rates specified in table II.

2.6.1.3 Fuel flow. Consumption of gasoline conforming to 2.5 in type I heaters shall not exceed the flow rate values specified in table II.

TABLE II. Type I Heaters.

1/ ft³/min= cubic feet per minute.

2.6.1.4 Current. Using a starting voltage of 24 ± 0.5 Vdc and a test ambient temperature of -65°F, the current shall be not more than the values specified in table II.

2.6.1.5 Overheat switch. The overheat switch shall break the circuit and cut off the flow of fuel when the ventilating air mixed with ambient air is heated to a temperature of 375 +25°F.

2.6.1.6 Cycling. Type I heaters shall start in less than four minutes and purge in less than three minutes when cycled at high setting for 50 cycles at an ambient temperature of -65 +5°F. Each cycle shall consist of starting at high heat, running for 15 minutes, purging, and cooling the heater for 35 minutes with auxilary blower.