California B2 Residential Remodeling – HVAC
Free Exam

The result of the compressor capacity being reduced when the suction pressure is reduced balances the evaporator load.

As water evaporates, it cools. This is the basic principal behind evaporative cooling. The wet bulb temperature is caused by the evaporation of water at a given pressure.

The relative humidity is the amount of water vapor in the air divided by the amount of water in the air at saturation at the same temperature and pressure. Direct readings of relative humidity can be obtained from a hygrometer.

It takes a certain amount of heat to raise the temperature of the air. The amount of heat needed to warm a given amount of air is called the specific heat. For most HVAC applications, the specific heat of air at one atmosphere can be taken at 0.24 Btu/lb. degrees F. This means it takes 0.24 Btu to raise the temperature of one pound of air by one degree Fahrenheit.

If the compressor is not starting and there is no hum, any of the following can be a reason:
-open power switch on blown fuse
-broken electrical connection
-the overload is stuck
-frozen defective
-tight compressor
-high head pressure
-thermostat set too high
-solenoid valve closed

1 boiler HP is equal to 33,480 BTU per hour, 34.5 lb. water evap. per hour from and at 212 degrees Fahrenheit, and 9.8 KW. 1 KW equals 3413 BTU per hour.

The use of nitrogen will not cause refrigerant leaks in a brazed joint.

When working with wiring controls, the compressor will turn on when you join the red wire to the yellow wire.

Refrigerants are recognized by a standard color code. The assignations are the following:
R-11 Orange
R-12White
R-22 Green
R-500 Yellow

A year-round system provides for both heating and cooling needs. Combination heating-cooling thermostats are of two basic kinds: one in which separate heating and cooling thermostats are mounted together on a sub-base, and one in which the mechanical elements of both are combined under a common cover.

A British Thermal Unit (BTU)is the quantity of heat required to raise the temperature of one pound of water 1 degree Fahrenheit. It is equal to 1055 joules, 1.055 kilojoules, and 252.15 calories.

As the heat rises, the temperature of the refrigerant pressure increases.

For connecting two pieces of flex duct together use a 4” long coupling.

When working with wiring controls, the unit will run in heat when joining the red wire to the white wire.

If the gas ignition controller is turned on and the pilot is working but the main burner is not responding the problem can be the result of a defective ignition controller.