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. The evaporator is designed to remove what two types of heat?
Latent and sensible
On the common terminal
Btu/hr (output) / wattage (input)
100 psig

2. What is lined duct?
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
Duct with insulation on the inside
8-12 degrees F
30 A

3. What component changes refrigerant from a low pressure gas to a high pressure gas?
15 A
High
Compressor
Negative

4. How do you calculate LRA?
RLA/FLA x 5
15 A
6
105 degrees F

5. What are the two ways that fresh air enters a structure?
Rise
Infiltration and ventilation
A piston type metering device
When the system is under pressure

6. How is flexible duct supported?
A band 4 inches or more in width
Common
Yes
40 degrees F

7. How will too much refrigerant effect superheat?
4
20 degrees above ambient
Positive
It will be low

8. Why are some ACR tubing lines insulated?
20 A
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Before the vent
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line

9. What tool is used to expand the diameter of soft copper tubing
A swaging tool
Over/under and side by side
False
Outside diameter (OD)

10. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
Nominal-sized tubing
Pi x radius squared
When it is above a conditioned space
True

11. How is nominal-sized tubing sized?
True
Suction
Inside diameter (ID)
105 degrees F

12. How do you calculate LRA?
With a minimum of three evenly spaced self-tapping screws
It also rises
Shorted winding - open winding - and grounded winding
RLA/FLA x 5

13. What is the range for normal superheat and subcooling?
8-12 degrees F
Compressor
15 A
With a minimum of three evenly spaced self-tapping screws

14. Where is insulation used on copper tubing used for air-conditioning?
The suction line or the low-pressure side
Outside of the male fitting
A band 4 inches or more in width
Shorted winding - open winding - and grounded winding

15. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
True
15 A
Yes
Slugging

16. How is ACR tubing sized?
Negative
Dehydrated with caps on each end
30-35 degrees above ambient
Outside diameter (OD)

17. How many amps can 8 g wire handle?
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
40 A
Any amount
They are larger

18. What is the design boiling point for most evaporator coils in residential air conditioning?
Duct - electrical - and mechanical
30-35 degrees above ambient
40 degrees F
Side-by-side and over-and-under

19. Do you need a vent on a pull-through evaporator?
Static pressure - velocity pressure - and total pressure
Subtract ambient temperature from 100
Compressor
Yes

20. What is it called when liquid refrigerant gets into the compressor?
Blended refrigerants
Negative
Slugging
100

21. What are the two functions of the air-conditioning system?
Blended refrigerants
A swaging tool
Pull a vacuum
To remove humidity and lower dry bulb temperature

22. When do you install an auxillary drain pan?
L-type
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
When it is above a conditioned space
8

23. How many BTU's per ton?
12000
Any amount
Suction
Indoor fan motor - outdoor fan motor - and the compressor

24. Why are some ACR tubing lines insulated?
A swaging tool
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
Outside of the male fitting
Nominal-sized tubing

25. What is considered normal operating conditions?
5 degrees
Below 800 degrees F
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
12000

26. Why is it necessary to have multiple refrigerant circuits in some evaporator coils?
Slugging
To lower the amount of pressure drop through the coil
It rises
When the system is under pressure

27. If the rpm's are 1750 - how many poles does the motor have?
RLA/FLA x 5
4
40 degrees F
Blended refrigerants

28. 10' round duct has a ballpark cfm of what?
The suction line or the low-pressure side
Outside diameter (OD)
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
400

29. Do you need a vent on a pull-through evaporator?
Yes
100 psig
140 degrees F
2 minutes

30. What is the typical pressure differance across a TXV?
A bypass duct or a dump zone
Dehydrated with caps on each end
2
100 psig

31. Where is insulation used on copper tubing used for air-conditioning?
The suction line or the low-pressure side
A band 4 inches or more in width
High
Yes

32. In what length rolls is soft copper tubing normally available?
25-ft or 50-ft
A band 4 inches or more in width
It rises
400

33. Can refrigerant line sets be altered in length?
When it is above a conditioned space
No
It will be low
Yes

34. How do you calculate EER?
On the common terminal
High
Btu/hr (output) / wattage (input)
RLA/FLA x 5

35. What is the difference between SEER and EER?
No
SEER includes the energy used in the start-up and shut-down cycles
12000
Stranded

36. On what terminal do you check amperage?
400
400
They are larger
Common

37. The evaporator is designed to remove what two types of heat?
Inclined manometer
Latent and sensible
Average feet per minute X area in square feet (H' x W'/144)
Nitrogen with a small amount of refrigerant

38. How do you calculate EER?
Btu/hr (output) / wattage (input)
Latent and sensible
Over/under and side by side
400

39. What do you do after you braze a system?
150
Nitrogen with a small amount of refrigerant
105 degrees F
Pull a vacuum

40. How do you achieve high-efficiency?
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Inside diameter (ID)
45-55%
By increasing the surface of the condenser coil

41. Most duct insulation is made of what?
Fiberglass
100 psig
Belt drive and direct drive
Indoor fan motor - outdoor fan motor - and the compressor

42. 6' round duct has a ballpark cfm of what?
100
With an are rating
On the common terminal
When it is a pull-through evaporator

43. What are the two types of blower drives?
Yes
Belt drive and direct drive
Pistons
4

44. How will too much refrigerant effect subcooling?
Compressor
A diffuser
It will be high
5 degrees

45. Do you need a trap on a push-through evaporator?
150
Heat load
Pi x radius squared
No

46. What type of air conditioning system must be charged using the superheat method?
Average feet per minute X area in square feet (H' x W'/144)
TXV
A piston type metering device
They are larger

47. What is it called when liquid refrigerant gets into the compressor?
Slugging
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
To remove humidity and lower dry bulb temperature
Nominal-sized tubing

48. 9' round duct has a ballpark cfm of what?
6
40 degrees F
300
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.

49. What do you use to check for leaks?
It will be low
Nitrogen with a small amount of refrigerant
Inclined manometer
Before the vent

50. The compressor is cooled by liquid refrigerant. (True of False)
Vapor
Yes
False
Blended refrigerants