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Test your basic knowledge |
Residential Air Conditioning
Start Test
Study First
Subjects
:
engineering
,
nate
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. Can refrigerant line sets be altered in length?
Yes
45-55%
6
100 psig
2. A reciprocating compressor has what sort of moving parts?
L-type
With a minimum of three evenly spaced self-tapping screws
A bypass duct or a dump zone
Pistons
3. How are the condenser coils different on a high-efficiency unit?
They are larger
8
Suction
25-ft or 50-ft
4. Where do you check the amps on a motor?
Outside of the male fitting
On the common terminal
Yes
When it is a pull-through evaporator
5. What are the two types of package units?
Side-by-side and over-and-under
A dirty evaporator
20 degrees F
Btu/hr (output) / wattage (input)
6. If pressure rises - what happens to the superheat?
It rises
20 degrees F
Belt drive and direct drive
Boil the liquid refrigerant out ot the oil within the crankcase
7. On what terminal do you check amperage?
Standard
300
Common
They are larger
8. 9' round duct has a ballpark cfm of what?
300
6
It will have a decrease in superheat
Over 800 degrees F
9. What is it called when liquid refrigerant gets into the compressor?
Over 800 degrees F
400
Fiberglass
Slugging
10. Pressure in ductwork is measured In what?
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
False
They are larger
Inches of water column (in. WC)
11. Multiple-zone systems often use what to alleviate the problem of excess air when only some zones are calling for conditioning?
A bypass duct or a dump zone
A swaging tool
To remove humidity and lower dry bulb temperature
Compressor
12. Do you need a trap on a push-through evaporator?
30 A
No
Yes
Outside of the male fitting
13. How do you calculate the area of a circle?
Dehydrated with caps on each end
On the common terminal
No
Pi x radius squared
14. If the rpm's are 3450 - how many poles does the motor have?
2
20 A
With a minimum of three evenly spaced self-tapping screws
L-type
15. What kind of refrigeratnts must be added in liquid form?
Yes
Outside diameter (OD)
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
Blended refrigerants
16. What is the typical temperature difference between a standard-efficiency condenser and the ambient temperature?
When the system is under pressure
True
30 degrees F
Suction
17. The compressor is cooled by liquid refrigerant. (True of False)
False
Yes
Yes
2 minutes
18. What are the three major power-consuming devices on an air-conditioning system?
105 degrees F
Indoor fan motor - outdoor fan motor - and the compressor
Belt drive and direct drive
To lower the amount of pressure drop through the coil
19. How do you calculate cfm?
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183
20. If the rpm's are 750 - how many poles does the motor have?
TXV
Nominal-sized tubing
8
45-55%
21. What standard weight copper tubing is most often used in the heating and air-conditioning industry?
4
L-type
Subtract ambient temperature from 100
105 degrees F
22. How many amps can 8 g wire handle?
TXV
Pull a vacuum
They are physically larger
40 A
23. How is nominal-sized tubing sized?
Any amount
Boil the liquid refrigerant out ot the oil within the crankcase
Heat load
Inside diameter (ID)
24. What is the design boiling point for most evaporator coils in residential air conditioning?
400
True
TXV
40 degrees F
25. How is flexible duct supported?
A band 4 inches or more in width
To remove humidity and lower dry bulb temperature
Heat load
100
26. What is used to measure static air pressure in ducts.
A dirty evaporator
18 gauge
Inclined manometer
Inside diameter (ID)
27. In what length rolls is soft copper tubing normally available?
Subtract ambient temperature from 100
25-ft or 50-ft
Rise
L-type
28. How many cfm per ton?
Inches of water column (in. WC)
400
45-55%
A bypass duct or a dump zone
29. What component changes refrigerant from a low pressure gas to a high pressure gas?
Pi x radius squared
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Compressor
A swaging tool
30. If the suction pressure rises - what happens to the head pressure?
Below 800 degrees F
True
1/4'
It also rises
31. The evaporator is designed to remove what two types of heat?
Rise
Latent and sensible
To lower the amount of pressure drop through the coil
S-clips and drives (cleats)
32. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
45-55%
Over 800 degrees F
The takeoff fitting
Compressor
33. What is the typical pressure differance across a TXV?
1/4'
Stranded
100 psig
Indoor fan motor - outdoor fan motor - and the compressor
34. What are the three crafts normally associated with an air-conditioned installation?
2
Infiltration and ventilation
400
Duct - electrical - and mechanical
35. How many BTU's per ton?
ACR (air-conditioning refrigeration) tubing
12000
8-12 degrees F
High
36. What is the typical pressure differance across a TXV?
They are larger
20 degrees above ambient
100 psig
Standard
37. Sections of duct board can be fastened together with what?
Staples and tape
Compressor
2 minutes
In parallel
38. If the suction pressure rises - what happens to the head pressure?
Yes
The suction line or the low-pressure side
Static pressure - velocity pressure - and total pressure
It also rises
39. What are normal conditions - as defined by the ARI.
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
Average feet per minute X area in square feet (H' x W'/144)
30 degrees F
40 A
40. If the rpm's are 3450 - how many poles does the motor have?
Nitrogen with a small amount of refrigerant
The suction line or the low-pressure side
2
It rises
41. When do you install an auxillary drain pan?
When it is above a conditioned space
By increasing the surface of the condenser coil
Outside diameter (OD)
20 A
42. How much superheat do you need to prevent liquid refrigerant from entering the compressor?
20 degrees F
It also rises
Any amount
Indoor fan motor - outdoor fan motor - and the compressor
43. What are the two types of blower drives?
ACR (air-conditioning refrigeration) tubing
Belt drive and direct drive
Vapor
L-type
44. Which type of wire can handle a higher ampacity?
With a minimum of three evenly spaced self-tapping screws
Stranded
400
False
45. The fan switch closes at what temperature?
100
Standard
400
140 degrees F
46. Where do you install a trap on a drain line?
150
Before the vent
High
Yes
47. What are the three major power-consuming devices on an air-conditioning system?
20 degrees F
Vapor
Indoor fan motor - outdoor fan motor - and the compressor
A bypass duct or a dump zone
48. How is flexible duct supported?
A band 4 inches or more in width
40 A
400
They are physically larger
49. The fan switch opens at what temperature?
Fiberglass
105 degrees F
4
Negative
50. At what temperature will soft solder melt?
Heat loss
20 A
Below 800 degrees F
Negative