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

pump size

demand

preset timers

time delay relays

Question 1 of 20

2. NEC Article 440, Part V covers ________.

the control and protection of fixed electric space heating equipment

digital control systems

requirements for motor compressor controllers

resistors and reactors

Question 2 of 20

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

freezestat

thermocouple

firestat

thermistor

Question 3 of 20

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

prevent ice buildup on the outdoor coil

remove frost buildup throughout the system ductwork

warm the unit circuits for optimum electrical operation

prevent ice buildup on the indoor coil

Question 4 of 20

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

recalibrate the thermostat

reset the system switch to Off

adjust the setting lever

check for accurate leveling

Question 5 of 20

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

Question 6 of 20

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

closes its contacts and shuts down the system

opens its contacts and initiates defrost

closes its contacts and starts the cooling system compressor

opens its contacts and stops the cooling system compressor

Question 7 of 20

8. A freezestat is a ________.

normally open bimetal switch

normally closed bimetal switch

thermostat that has seized

digital control

Question 8 of 20

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

time-delay relay

impedance relay

induced-draft relay

control relay

Question 9 of 20

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

melt the cable

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

produce only 25% of the rated cable wattage

enable the system to operate most efficiently

Question 10 of 20

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

short-cycle time

time delay relay

limit control

thermocouple

Question 11 of 20

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

contains sulfuric acid

is easy to repair

has a 10-year warranty

may contain mercury

Question 12 of 20

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

Heat-movement principle

Heat-transplant principle

Heat-transfer principle

Heat-creation principle

Question 13 of 20

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

nickel

aluminum

Elinvar®

Invar®

Question 14 of 20

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

Relays

Lights

Thermistors

Switches

Question 15 of 20

16. 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?

50%

70%

90%

80%

Question 16 of 20

17. 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) ________.

expansion device

condenser

evaporator

compressor

Question 17 of 20

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

discharge line

hot gas line

suction line

liquid line

Question 18 of 20

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

occupants often use the override controls

the sensor must be routed through a delay switch

they have staggered startup

the bimetal elements are heavier and do not respond as quickly

Question 19 of 20

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

deadband

compensator

differential

evaporator

Question 20 of 20

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