Exam 13: System Startup and Charging

During the __________ process, the field technician introduces refrigerant to the system components and the field installed lines that join them. Once the system is energized, the technician adjusts the refrigerant __________.

On systems operating with thermostatic expansion valves, evaporator superheat in the range of 8 to 12 degrees is considered well within the desired operating range.

Most split-type air conditioning systems come from the factory with a holding charge of refrigerant contained within the condensing unit. This holding charge is measured into the unit and is often the proper amount of refrigerant for a system with 25 feet of piping between the air handler and condensing unit.

Condenser subcooling should ideally be in the range of ____.

On a standard efficiency system, the rule of thumb is that the refrigerant should condense at a temperature approximately equal to the outdoor ambient temperature plus about __________ degrees.

If a condenser is operating with a low saturation temperature and low subcooling, the most likely condition is

Symptoms of a system overcharge may include low condenser saturation temperature.

If a condenser is a high efficiency model, the condenser saturation temperature may be as low as _____ degrees higher than the outdoor ambient temperature.

If the evaporator is operating with a high saturation temperature and low superheat, the most likely condition is

In a perfect vacuum of 29.92, the micron gauge will read ____.

In an air conditioning system operating with R410A as its refrigerant, the coil may start to freeze when the pressure in the evaporator reaches approximately 101 psig.

At design conditions of 75 ° F indoor air temperature and 50% relative humidity, the difference between the supply and return air temperatures should be in the range of __________ degrees.

Once the system is operating correctly, the technician should instruct the homeowner to keep duct registers clear of furnishings to allow the system to maintain the proper air flow rates.

Symptoms of a __________ indicate that refrigerant may need to be added to the system.

Ideally, a residential air conditioning system should be started up under which conditions?

The __________ is the difference between the temperature of the air being supplied to the occupied space and the temperature of the air returning to the air handler.

If a condenser is operating with a high saturation temperature and low subcooling, the most likely condition is

Blended refrigerants must be added to a refrigeration system in the vapor state.

A sling psychrometer is used to measure which air condition?

If the evaporator is operating with a low saturation temperature and high superheat, the most likely condition is