HVAC Quiz Review #2

Question 1

A flow switch detects the water pressure in a hydronic system.

True or False

Answer 1

False

Question 2

A boiler will vary the temperature of the water depending on the number of zones calling for heat.

True or False

Answer 2

False

Question 3

A circulating pump could be controlled by an end-of-travel switch in a zone valve.

True or False

Answer 3

True

Question 4

The low water cut-off switch and the flow switch on a boiler are “normally closed” devices designed to shut down the systems when triggered.

True or False

Answer 4

False

Question 5

An aquastat and a high limit (in a boiler system) will both have the same temperature setting.

True or False

Answer 5

False

Question 6

Zones in a boiler system could be controlled by either zone valves or seprate circulation pumps.

True or False

Answer 6

True

Question 7

Which of the following zone valves would require a seprate relay to energize the boiler system.

a) 2-wire
b) 3-wire
c) 4-wire

Answer 7

c) 3-wire

Question 8

Why will a boiler shut-down if the main circulation pump seizes?

a) No water flow means increase temperature in boiler, high limit trips
b) High water flow means decrease temperature in boiler, LWCO trips
c) No water flow means increase in temperature in zone, make-up water trips
d) High water flow extinguishes pilot burner, main burner goes out

Answer 8

a) No water will flow means increase temperature in boiler, high limit trips

Question 9

In a combination heating/cooling systems, the main furnace blower is:

a) For heating only
b) For cooling only
c) For heating or cooling
d) Always 3 speeds - low, medium, and high

Answer 9

c) for heating and cooling

Question 10

The refrigerant leaving the evaporator coil is a:

a) Low pressure gas
b) Low pressure liquid
c) High pressure gas
d) High pressure liquid

Answer 10

a) Low pressure gas

Question 11

The refrigerant leaving the condensing coil is a:

a) Low pressure gas
b) Low pressure liquid
c) High pressure gas
d) High pressure liquid

Answer 11

d) High pressure liquid

Question 12

The purpose of the evaporator is to:

a) Release heat from the refrigerant
b) Absorb the heat into the refrigerant

Answer 12

b) Absorb heat into the refrigerant

Question 13

The purpose of the TX valve is to:

a) Heat the refrigerant
b) Raise the pressure of the refrigerant
c) Lower the pressure of the refrigerant
d) Keep the refrigerant pressure constant

Answer 13

c) Lower the pressure of the refrigerant

Question 14

A direct-fired make-up air unit will:

a) Have a heat exchanger
b) Not have a heat exchanger

Answer 14

b) Not have a heat exchanger

Question 15

Which or the following applications would have the evaporator and condenser coils in the same unit?

a) Residential furnace with air conditioning
b) Make-up air unit
c) Rooftop HVAC unit
d) Both A and D

Answer 15

c) Rooftop HVAC unit

Question 16

Which of the following labels indicates the “second stage” of heating on a rooftop HVAC unit?

a) Y1
b) W2
c) G1
d) W1
e) Y2
f) Rc
g) Rh

Answer 16

b) W2

Question 17

A basic furnace is operating normally in a heating cycle, blowing warm air throughout a home. What voltage should be measured across the thermal activated fan control switch?

a) 120V
b) 24V
c) 16-24mV
d) 0V
e) Infinite

Answer 17

d) 0V

Question 18

Which contacts on the relay are used for interlocking purposes?

a) Normally opens
b) Normally closed

Answer 18

b) Normally closed

Question 19

Which terminals of the furnace would connect to the relay contacts?

a) R and C
b) R and Y
c) R and W
d) Y and W
e) R and G
f) W and Y

Answer 19

e) R and G

Question 20

Terminal units are secondary heat exchangers such as radiators or radiant panels.

True or False

Answer 20

True