Test your basic knowledge |

Residential Air Conditioning

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. Multiple-zone systems often use what to alleviate the problem of excess air when only some zones are calling for conditioning?
The takeoff fitting
A bypass duct or a dump zone
18 gauge
20 degrees F

2. The fan switch closes at what temperature?
150
SEER includes the energy used in the start-up and shut-down cycles
The suction line or the low-pressure side
140 degrees F

3. If the rpm's are 3450 - how many poles does the motor have?
2
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
A piston type metering device
A band 4 inches or more in width

4. What kind of metering device do high-efficiency units usually use?
In parallel
TXV
When the system is under pressure
Pull a vacuum

5. How are the high pressure switch and the low pressure switch wired with the compressor contactor?
Suction
In series
Before the vent
RLA/FLA x 5

6. What standard weight copper tubing is most often used in the heating and air-conditioning industry?
L-type
1/4'
100 psig
18 gauge

7. What is it called when liquid refrigerant gets into the compressor?
ACR (air-conditioning refrigeration) tubing
Slugging
High
Yes

8. What component changes refrigerant from a low pressure gas to a high pressure gas?
The takeoff fitting
The suction line or the low-pressure side
Compressor
They are larger

9. Does a package unit come from the factory pre-charged?
Yes
When it is above a conditioned space
Standard
TXV

10. How are the condenser coils different on a high-efficiency unit?
40 A
Yes
They are larger
140 degrees F

11. 10 SEER is classified as what kind of efficiency?
40 degrees F
Over/under and side by side
With an are rating
Standard

12. How do you calculate the area of a circle?
A bypass duct or a dump zone
Potential relay and start capacitor
Pi x radius squared
A band 4 inches or more in width

13. What is the normal evaporator temperature?
Duct - electrical - and mechanical
Boil the liquid refrigerant out ot the oil within the crankcase
45 degrees F
Outside of the male fitting

14. The refrigerant within the evaporator will typically boil at what temperature when it is 75 degrees inside with a relative humidity of 50%?
Belt drive and direct drive
Infiltration and ventilation
When it is a pull-through evaporator
40 degrees F

15. Which type of wire can handle a higher ampacity?
Heat loss
By increasing the surface of the condenser coil
Stranded
Yes

16. Superheat should never be below how many degrees
The takeoff fitting
30 degrees F
RLA/FLA x 5
5 degrees

17. Sections of duct board can be fastened together with what?
Staples and tape
6
Fiberglass
They are physically larger

18. What distributes supply air to a room in a structure?
With a minimum of three evenly spaced self-tapping screws
A diffuser
To remove humidity and lower dry bulb temperature
Yes

19. 10' round duct has a ballpark cfm of what?
30-35 degrees above ambient
By increasing the surface of the condenser coil
400
15 A

20. The evaporator is designed to remove what two types of heat?
Negative
Duct with insulation on the inside
Latent and sensible
Standard

21. How are high-efficiency condenser coils different from standard-efficiency condenser coils?
When the system is under pressure
Yes
They are physically larger
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.

22. What is the range for normal superheat and subcooling?
8-12 degrees F
Negative
They are physically larger
It will be low

23. How do you calculate EER?
Btu/hr (output) / wattage (input)
Staples and tape
Pistons
Pi x radius squared

24. What kind of copper tubing is used for plumbing and heating applications?
A diffuser
SEER includes the energy used in the start-up and shut-down cycles
Boil the liquid refrigerant out ot the oil within the crankcase
Nominal-sized tubing

25. Why is it necessary to have multiple refrigerant circuits in some evaporator coils?
Nitrogen with a small amount of refrigerant
Nominal-sized tubing
To lower the amount of pressure drop through the coil
When the system is under pressure

26. What are the two basic duct connection configurations for package units supply and return air ducts?
TXV
100
8
Over/under and side by side

27. 9' round duct has a ballpark cfm of what?
A diffuser
300
When it is a pull-through evaporator
A dirty evaporator

28. Do you need a vent on a push-through evaporator?
TXV
Yes
Over 800 degrees F
S-clips and drives (cleats)

29. What are the components of a hard-start kit?
Suction
Outside diameter (OD)
With an are rating
Potential relay and start capacitor

30. What are the two ways that fresh air enters a structure?
Btu/hr (output) / wattage (input)
Slugging
Infiltration and ventilation
In series

31. How is insulation around a duct rated?
Before the vent
Inclined manometer
With an are rating
Yes

32. What is the typical pressure differance across a TXV?
100 psig
40 degrees F
True
Staples and tape

33. Why are some ACR tubing lines insulated?
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
Duct - electrical - and mechanical
200
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line

34. How is the high pressure switch wired with the low pressure switch?
In parallel
Pull a vacuum
40 degrees F
18 gauge

35. What are the three ways a motor can fail electrically?
Shorted winding - open winding - and grounded winding
TXV
True
Over/under and side by side

36. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
45-55%
Belt drive and direct drive
Duct with insulation on the inside
Subtract ambient temperature from 100

37. How many cfm per ton?
Positive
Nitrogen with a small amount of refrigerant
It also rises
400

38. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
True
20 degrees above ambient
They are larger
40 A

39. Do you need a trap on a pull-through evaporator?
45-55%
A piston type metering device
Yes
The takeoff fitting

40. If the rpm's are 750 - how many poles does the motor have?
It rises
30 A
8
Outside diameter (OD)

41. If pressure rises - what happens to the superheat?
It rises
2
Stranded
Pull a vacuum

42. How many amps can 8 g wire handle?
40 A
Positive
Heat load
Staples and tape

43. How is flexible duct supported?
300
A band 4 inches or more in width
Staples and tape
200

44. Why are some ACR tubing lines insulated?
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
5 degrees
Pi x radius squared
When the system is under pressure

45. What percentage silver do you need to use for an are-410 system?
Common
15% silphos
It will be high
RLA/FLA x 5

46. How will too much refrigerant effect subcooling?
It will be high
40 degrees F
A band 4 inches or more in width
40 degrees F

47. How many amps can 12 g wire handle?
Heat load
To lower the amount of pressure drop through the coil
20 A
Inside diameter (ID)

48. How much superheat do you need to prevent liquid refrigerant from entering the compressor?
In parallel
Fiberglass
Pull a vacuum
Any amount

49. How are the high pressure switch and the low pressure switch wired with the compressor contactor?
Positive
With an are rating
150
In series

50. Do you need a trap on a push-through evaporator?
Yes
No
40 degrees F
Blended refrigerants