Deck 14: Troubleshooting Electric Control Devices

Question 1

A pilot duty overload has a set of contacts that will open if an overload occurs in the ____________________ side of the overload.

Answer 1

line voltage

Question 2

What is a stack switch?

Answer 2

The stack switch is a heat-actuated control that uses the stack temperature to indicate the presence or absence of combustion.

Question 3

There are two basic types of thermostats used in the industry today: the ____________________ thermostat and the line voltage thermostat.

Answer 3

low voltage

Question 4

What is the most important element of checking line voltage thermostats?

Question 5

Motors are the most important loads in any heating, cooling, or refrigeration system.

Question 6

The ____________________ of a relay or contactor must make good direct contact when energized for the device to function properly.

Question 7

How is the thermal element of a thermal overload checked?

Question 8

The ____________________ can usually be checked by turning the motor by hand to determine if hard or rough spots exist in the rotating movement of the motor.

Question 9

The ____________________ is a device that will trip or open on an overload and must be manually reset.

Question 10

A set of burned or pitted contacts can cause a(n) ____________________ across the contacts.

Question 11

Normally ____________________ contacts must be checked with the device de-energized.

Question 12

What does the low-voltage thermostat operate?

Question 13

The device must be energized to check normally ____________________ contacts.

Question 14

____________________ electric motors will fail in three different areas: windings, centrifugal switch, and bearings.

Question 15

The type of motor has a significant effect on diagnosing the condition of a motor .

Question 16

A line voltage overload has ten or more terminals to check.

Question 17

A(n) ____________________ is a device used to raise or lower the incoming voltage by induction to a more usable voltage for the control system.

Question 18

A resistance check can be used to determine the condition of a set of contacts of a relay or contactor.

Question 19

How are pressure switches used on heating, cooling, and refrigeration systems?

Question 20

The easiest method for diagnosing bearing failure in a hermetic motor is to make a visual inspection.