Deck 15: Troubleshooting Basic Controls

Question 1

If an air conditioning system is calling for cooling and the compressor is running but the indoor (evaporator) fan is not running, which terminal on the thermostat will the technician most likely check first?

A) G
B) R
C) Y
D) W

Answer 1

A

Question 2

Transformers are rated using ____.

A) volt-amperes
B) volt-ohms
C) amperes-ohms
D) volt-resistance

Answer 2

A

Question 3

A control can be which of the following?

A) electrical
B) mechanical
C) electrical and mechanical
D) all of the above

Answer 3

D

Question 4

The cooling anticipator in a thermostat is usually an adjustable type.

Question 5

When checking thermostat circuits, an insulated jumper wire is a handy tool.

Question 6

Electrical controls are divided into two categories: power-consuming and _________________________.

Question 7

The _____ is nothing more than a set of switches.

A) transformer
B) coil
C) motor
D) thermostat

Question 8

A(n) ____ is the easiest diagram to use to follow a circuit. This diagram normally can be studied briefly, and the circuit function should become obvious.

A) pictorial diagram
B) ladder diagram
C) layout
D) oblique drawing

Question 9

The continuity through a heat relay is checked using a(n) ____.

A) ohmmeter
B) voltmeter
C) clamp-on ammeter
D) micron gauge

Question 10

An electrical diagram showing the approximate location of the components is called a(n) ____.

A) pictorial diagram
B) ladder diagram
C) layout
D) oblique drawing

Question 11

When conditions are correct, the rheostat will pass power through the device onto the system components to be controlled.

Question 12

The line side of a switch is the ____.

A) side the load is connected to
B) neutral side of the circuit
C) side the power source is connected to
D) side with the white wire

Question 13

The heat anticipator in a thermostat is usually an adjustable type.

Question 14

When using a ten-wrap multiplier, the reading on the meter must be multiplied by ten.

Question 15

A 10-wrap amperage multiplier is used with a(n) ____.

A) voltmeter
B) clamp-on ammeter
C) ohmmeter
D) megger

Question 16

If line one of a circuit had a potential of 120 V and line two was neutral, the potential voltage (difference) between line one and line two would be zero volts.

Question 17

A 120-V/24-V control transformer has a VA rating of 20. The maximum amperage the transformer will put out is 0.8 amps.

Question 18

An electrical power consuming component ____.

A) is normally wired in series in an electrical circuit
B) is normally used to pass power to another component
C) is often a basic switch
D) is also known as a load

Question 19

While troubleshooting a 24-V control circuit consisting of a thermostat, a pressure control, and a contactor coil, the technician reads 24 volts across the thermostat, 0 volts across the pressure control, and 0 volts across the contactor coil. The technician makes the following statements. The following statements are all considered to be true.

A) The transformer is burned out.
B) The thermostat is open.
C) The contactor coil is energized.

Question 20

An example of a power consuming device would be a(n) ____ while an example of a non-power consuming device would be a(n) ____.

A) single-pole single-throw switch, light bulb
B) light bulb, electric motor
C) electric motor, light bulb
D) light bulb, single-pole single-throw switch

Question 21

Non-power-consuming, or power-passing, devices are commonly referred to as ____________________.

Question 22

In a high voltage circuit, is the fan motor a power-passing or power-consuming device?

Question 23

In a residential air conditioning system, how are the outdoor fan and compressor wired with respect to each other?

Question 24

What is the amperage capacity of a 240-V/24-V control transformer with a 40 VA rating?

Question 25

When applying a voltmeter to measure the voltage of a power source, on what range is the meter set?

Question 26

One way to troubleshoot a(n) ____________________ on a heating and cooling system is to first turn the fan selector switch to the FAN ON position and see if the fan starts.

Question 27

How is the heat anticipator normally wired to the heating contacts?

Question 28

Explain how to read very low currents in a control circuit using a clamp-on amp meter.

Question 29

While checking a simple series 115-V circuit containing a fuse, a switch, and a light bulb, the technician's voltmeter reads 115 volts across the light bulb socket. The light bulb is not on. He correctly concludes that the ____________________ is defective.

Question 30

What three devices are usually found in series with the "Y" terminal of a low voltage control circuit?

Question 31

How is the cooling anticipator normally wired to the cooling contacts?

Question 32

Without _________________________ voltage, there is no low voltage.

Question 33

What are the three components that have to operate when a residential air conditioning system is in the cooling mode?