Deck 13: System Startup and Charging

Question 1

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

A) 30
B) 20
C) 10
D) 5

Answer 1

B

Question 2

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.

Answer 2

True

Question 3

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.

Answer 3

True

Question 4

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

A) 25,400
B) 500
C) 250
D) 25

Question 5

Condenser subcooling should ideally be in the range of ____.

A) 15 and 20 degrees
B) 20 and 30 degrees
C) 5 and 10 degrees
D) 0 and 5 degrees

Question 6

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

A) the condenser is operating with a deficiency of refrigerant
B) the condenser is operating with an excess of refrigerant
C) there is reduced airflow through the condenser coil
D) there is excessive airflow through the condenser coil

Question 7

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

A) Condenser saturation temperature of 225° F and an indoor temperature of 85° F
B) Condenser saturation temperature of 115° F and an indoor temperature of 85° F
C) Condenser saturation temperature of 125° F and an indoor temperature of 75° F
D) Condenser saturation temperature of 75° F and an indoor temperature of 115° F

Question 8

A sling psychrometer is used to measure which air condition?

A) wet bulb temperature
B) dry bulb temperature
C) both a and b

Question 9

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

Question 10

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.

A) evaporator coil temperature
B) evaporator temperature differential
C) condenser temperature differential
D) occupied space adjustment

Question 11

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

Question 12

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.

A) 10
B) 20
C) 30
D) 50

Question 13

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

A) the condenser is operating with a deficiency of refrigerant
B) the condenser is operating with an excessive amount of refrigerant
C) there is insufficient airflow through the condenser coil
D) there is excessive airflow through the condenser coil

Question 14

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.

Question 15

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.

Question 16

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

A) an underfed evapoartor coil
B) an overfed evapoartor coil
C) insufficent airfow through the evaporator coil
D) excessive airfow through the evaporator coil

Question 17

Symptoms of a __________ indicate that excess refrigerant may need to be removed from the system

A) system overcharge
B) system undercharge

Question 18

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

A) an underfed evaporator coil
B) an overfed evaporator coil
C) insufficient airflow through the evapoator coil
D) excessive airflow through the evapoator coil

Question 19

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

A) system overcharge
B) system undercharge

Question 20

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.

A) 15 to 30
B) 16 to 36
C) 17 to 20
D) 20 to 30

Question 21

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 __________.