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1. Connecting a 120V heating cable to a 240V circuit will ________.

cause the system to operate within acceptable standards, but at less than full efficiency

enable the system to operate most efficiently

melt the cable

produce only 25% of the rated cable wattage

Question 1 of 20

2. Automatic changeover thermostats have a minimum interlock setting, also known as the ________.

evaporator

deadband

differential

compensator

Question 2 of 20

3. The purpose of the defrost cycle in a heat pump is to ________.

warm the unit circuits for optimum electrical operation

remove frost buildup throughout the system ductwork

prevent ice buildup on the outdoor coil

prevent ice buildup on the indoor coil

Question 3 of 20

4. If lighting units and other appliances are also supplied, the rating of cord- and plug-connected room air conditioners must not exceed what percentage of the branch circuit rating?

70%

90%

50%

80%

Question 4 of 20

5. The thermostat terminal that connects to the reversing valve control in a heat pump is ________.

Question 5 of 20

6. A device that uses dissimilar metals to control electron flow is known as a(n) ________.

thermocouple

firestat

freezestat

thermistor

Question 6 of 20

7. Thermostats with bimetal sensing elements typically use a combination of copper or brass and ________.

Elinvar®

Invar®

nickel

aluminum

Question 7 of 20

8. If a mercury thermostat seems out of adjustment, the first thing to do is ________.

reset the system switch to Off

adjust the setting lever

recalibrate the thermostat

check for accurate leveling

Question 8 of 20

9. Multi-stage thermostats provide energy savings by cycling on stages of heating or cooling based on ________.

time delay relays

preset timers

pump size

demand

Question 9 of 20

10. In a cooling system, the heat absorbed by the refrigerant is transferred to the cooler outdoor air in a heat exchanger known as a(n) ________.

condenser

expansion device

evaporator

compressor

Question 10 of 20

11. When the bimetal coil in a cooling-only thermostat heats up and unwinds, the mercury switch ________.

closes its contacts and starts the cooling system compressor

opens its contacts and stops the cooling system compressor

opens its contacts and initiates defrost

closes its contacts and shuts down the system

Question 11 of 20

12. The tubing that carries heat-laden refrigerant gas from the evaporator to the compressor is known as the ________.

liquid line

suction line

hot gas line

discharge line

Question 12 of 20

13. Conventional line-voltage thermostats do not provide precise temperature control because ________.

they have staggered startup

the sensor must be routed through a delay switch

the bimetal elements are heavier and do not respond as quickly

occupants often use the override controls

Question 13 of 20

14. A freezestat is a ________.

normally open bimetal switch

thermostat that has seized

digital control

normally closed bimetal switch

Question 14 of 20

15. Which of the following is an example of an external analog device?

Relays

Switches

Thermistors

Lights

Question 15 of 20

16. A conventional thermostat should not be thrown into the regular trash because it ________.

contains sulfuric acid

is easy to repair

may contain mercury

has a 10-year warranty

Question 16 of 20

17. Which of the following principles states that heat is created in one place and carried to another by means of air or water?

Heat-creation principle

Heat-movement principle

Heat-transfer principle

Heat-transplant principle

Question 17 of 20

18. NEC Article 440, Part V covers ________.

requirements for motor compressor controllers

the control and protection of fixed electric space heating equipment

resistors and reactors

digital control systems

Question 18 of 20

19. If a lockout relay becomes defective, it should be replaced with an exact duplicate, sometimes called a(n) ________.

time-delay relay

induced-draft relay

control relay

impedance relay

Question 19 of 20

20. To increase furnace efficiency, the startup of the furnace blower is delayed using a ________.

thermocouple

time delay relay

limit control

short-cycle time

Question 20 of 20

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