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

check for accurate leveling

reset the system switch to Off

adjust the setting lever

recalibrate the thermostat

Question 1 of 20

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

opens its contacts and stops the cooling system compressor

closes its contacts and shuts down the system

closes its contacts and starts the cooling system compressor

opens its contacts and initiates defrost

Question 2 of 20

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

deadband

compensator

differential

evaporator

Question 3 of 20

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

hot gas line

suction line

liquid line

discharge line

Question 4 of 20

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

Relays

Thermistors

Lights

Switches

Question 5 of 20

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

the sensor must be routed through a delay switch

occupants often use the override controls

they have staggered startup

the bimetal elements are heavier and do not respond as quickly

Question 6 of 20

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

thermocouple

time delay relay

limit control

short-cycle time

Question 7 of 20

8. 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?

90%

80%

70%

50%

Question 8 of 20

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

impedance relay

time-delay relay

control relay

induced-draft relay

Question 9 of 20

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

freezestat

thermistor

firestat

thermocouple

Question 10 of 20

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

prevent ice buildup on the outdoor coil

prevent ice buildup on the indoor coil

warm the unit circuits for optimum electrical operation

remove frost buildup throughout the system ductwork

Question 11 of 20

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

preset timers

demand

pump size

time delay relays

Question 12 of 20

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

is easy to repair

has a 10-year warranty

may contain mercury

contains sulfuric acid

Question 13 of 20

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

Question 14 of 20

15. A freezestat is a ________.

digital control

normally open bimetal switch

thermostat that has seized

normally closed bimetal switch

Question 15 of 20

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

Invar®

Elinvar®

nickel

aluminum

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-transfer principle

Heat-transplant principle

Heat-creation principle

Heat-movement principle

Question 17 of 20

18. NEC Article 440, Part V covers ________.

resistors and reactors

the control and protection of fixed electric space heating equipment

requirements for motor compressor controllers

digital control systems

Question 18 of 20

19. 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

evaporator

expansion device

compressor

Question 19 of 20

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

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

melt the cable

enable the system to operate most efficiently

produce only 25% of the rated cable wattage

Question 20 of 20

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