404 HVAC Pre-Test

Suction gas temperature minus saturated suction temperature equals

• subcooling

• condensing temperature

• superheat

• evaporator operating temperature

When soldering, solder is drawn into the joint by

• the heat of the torch.

• capillary action.

• gravity.

• flux.

On centrifugal pumps, if it is ever necessary to reduce pump flow temporarily, do so by

• throttling the discharge

• throttling the suction line

• both A and B

• none of the above

The seal in a compressor is necessary to prevent

• refrigerant from leaking out at the rotating shaft.

• air from leaking out at the rotating shaft.

• oil from leaking out at the rotating shaft.

• Both A and C from above.

Which of the following gases must never be used to pressurize or leak test a refrigeration system?

• nitrogen

• oxygen

• CO2

• helium

A dual-element fuse has:

• two normal one-time fuse links

• a thermal cutout only

• a thermal cutout and a normal fuse link

• the ability to carry locked-rotor current of a motor but not to protect against short circuits.

The refrigerant line that connects the condenser to the metering device is the ___________ line.

• discharge

• expansion

• liquid

• suction

When a three-phase motor single-phases, it:

• draws power from the two remaining phases

• draws power from only one phase

• always short-cycles

• runs cooler

When an object is refrigerated:

• some of its heat energy is destroyed.

• heat is removed from it.

• more cooling is added.

• its molecules move faster.

If refrigerant condenses at a temperature of 105 degrees F and the water leaves the condenser at a temperature of 95 degrees F, the ___________.

• condenser approach temperature will be 10 degrees

• condenser approach temperature will be 95 degrees

• evaporator (chiller) approach temperature will be 10 degrees

• evaporator (chiller) approach temperature will be 105 degrees