Deck 41: Troubleshooting

Question 1

The liquid line temperature is used to determine the ____ of a condenser.

A) superheat
B) lowside pressure
C) suction pressure
D) subcooling

Answer 1

D

Question 2

With a rise in outdoor temperature, the head pressure will rise.

Answer 2

True

Question 3

The instrument to use to check for a short in the compressor motor winding is a(n) ____.

A) ohmmeter
B) ammeter
C) voltmeter
D) milliammeter

Answer 3

A

Question 4

A service valve can be used to ____.

A) check the electrical service to the compressor
B) isolate the refrigerant so the system can be serviced
C) check the air flow across the evaporator
D) check the ambient temperature at the condenser

Question 5

As a rule of thumb, the air leaving the evaporator will be about ____ than the air entering the evaporator.

A) 10-15° warmer
B) 10-15° cooler
C) 17-20° cooler
D) 17-20° warmer

Question 6

Reducing the CFM through the evaporator will cause the amperage draw of the compressor to ____________________.

Question 7

The best way to tell if a compressor's discharge line is at the correct temperature is to grab hold of it.

Question 8

Why do we measure temperatures at the evaporator rather than the suction pressure?

Question 9

On a 95°F day, the R-22 refrigerant pressure on the high side should be about ____ psig.

A) 108
B) 182
C) 243
D) 297

Question 10

On most gauge manifolds, the suction or low side gauge is located on the ____________________.

Question 11

Temperature difference is used to describe the difference in the inlet and _________ temperature of a heat exchanger.

Question 12

Reducing the CFM through the evaporator will cause the head pressure to ____________________.

Question 13

If a compressor has a partially shorted winding, it could run for a while, overheat, and shut off.

Question 14

Why should a technician visually inspect the equipment before installing gauges?

Question 15

When checking the electrical circuits of an air-conditioning system, each parallel circuit should be isolated and checked separately.

Question 16

Two types of fixed-bore metering devices are capillary tubes and _________________________.

Question 17

A typical evaporator superheat reading at the evaporator outlet for a central air-conditioning system on a 95°F day would be ____°F.

A) 5-7
B) 8-10
C) 10-12
D) 12-15

Question 18

Subcooling occurs in the evaporator as well as the condenser.

Question 19

To accurately add refrigerant to a system, a condenser ambient temperature of ____°F should be simulated.

A) 75
B) 85
C) 95
D) 100

Question 20

Superheat occurs in the condenser as well as the evaporator.

Question 22

What is the process that normally begins the electrical troubleshooting of the system?

Question 23

How would too much refrigerant affect the operation of a system with capillary tubes?

Question 24

While passing through the condenser, refrigerant is in three different states. What are they?

Question 25

When is it necessary to connect gauges onto a system?

Question 26

Why is the head pressure raised to 278 psig to check the subcooling of the system?

Question 27

Where is the correct location for a sight glass in order to check the charge?

Question 28

If a technician finds the circuit protection for an air-conditioning component has been tripped, what should the technician do?