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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. What is used to measure static air pressure in ducts.
Inclined manometer
A diffuser
Fiberglass
Common
2. How many amps can 12 g wire handle?
When it is above a conditioned space
20 A
Individual return air systems and central return air systems
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
3. How is nominal-sized tubing sized?
18 gauge
Yes
Inside diameter (ID)
Static pressure - velocity pressure - and total pressure
4. What is the typical temperature difference between a standard-efficiency condenser and the ambient temperature?
Duct - electrical - and mechanical
30 degrees F
2 minutes
When the system is under pressure
5. What do you use to connect square and rectangular ductboard together?
40 degrees F
S-clips and drives (cleats)
Dehydrated with caps on each end
20 A
6. How many BTU's per ton?
Stranded
12000
8
105 degrees F
7. How is the high pressure switch wired with the low pressure switch?
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
18 gauge
200
In parallel
8. When must a copper joint never be soldered or brazed?
It also rises
400
20 A
When the system is under pressure
9. How long should you leave a system off once you kill power before restarting it?
2 minutes
RLA/FLA x 5
TXV
Duct with insulation on the inside
10. How are round ducts connected to one another?
Outside diameter (OD)
2 minutes
Individual return air systems and central return air systems
With a minimum of three evenly spaced self-tapping screws
11. What are the two types of return air systems in residential installations?
Outside diameter (OD)
Boil the liquid refrigerant out ot the oil within the crankcase
Individual return air systems and central return air systems
Dehydrated with caps on each end
12. What are the two types of package units?
Side-by-side and over-and-under
Compressor
Inclined manometer
Slugging
13. If the rpm's are 1050 - how many poles does the motor have?
6
On the common terminal
It also rises
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
14. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
Inches of water column (in. WC)
It will have a decrease in superheat
In parallel
Common
15. What are the three pressures created by moving air in ductwork?
Duct - electrical - and mechanical
Yes
Static pressure - velocity pressure - and total pressure
Suction
16. 8' round duct has a ballpark cfm of what?
200
Nominal-sized tubing
The suction line or the low-pressure side
Inside diameter (ID)
17. What tool is used to expand the diameter of soft copper tubing
100
A swaging tool
It also rises
True
18. Sections of duct board can be fastened together with what?
Heat loss
40 degrees F
Yes
Staples and tape
19. If the rpm's are 1750 - how many poles does the motor have?
Nitrogen with a small amount of refrigerant
400
4
With an are rating
20. Which is more efficient - a TXV or a fixed-orifice metering device?
Subtract ambient temperature from 100
30 degrees F
A diffuser
TXV
21. How do you calculate EER?
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
To remove humidity and lower dry bulb temperature
2
Btu/hr (output) / wattage (input)
22. Do you need a trap on a pull-through evaporator?
Yes
Positive
By increasing the surface of the condenser coil
SEER includes the energy used in the start-up and shut-down cycles
23. If the rpm's are 750 - how many poles does the motor have?
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
8
140 degrees F
300
24. If the rpm's are 3450 - how many poles does the motor have?
L-type
Pi x radius squared
2
Any amount
25. Do you need a vent on a push-through evaporator?
Yes
Any amount
Vapor
Slugging
26. How do you calculate cfm?
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183
27. At what temperature does refrigerant condense in a high-efficiency unit?
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
Over 800 degrees F
20 degrees above ambient
2 minutes
28. What sort of pressure will a push-through evaporator have?
400
Over/under and side by side
High
Positive
29. What standard weight copper tubing is most often used in the heating and air-conditioning industry?
Standard
30 degrees F
L-type
18 gauge
30. At what temperature does refrigerant condense in a standard-efficiency unit?
They are larger
30-35 degrees above ambient
RLA/FLA x 5
When the system is under pressure
31. What are the four materials used to make duct?
30 A
300
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
32. What do you do after you braze a system?
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
8
Side-by-side and over-and-under
Pull a vacuum
33. What is considered normal operating conditions?
40 degrees F
Average feet per minute X area in square feet (H' x W'/144)
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
Heat loss
34. 9' round duct has a ballpark cfm of what?
The takeoff fitting
20 degrees above ambient
300
30 degrees F
35. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
ACR (air-conditioning refrigeration) tubing
By increasing the surface of the condenser coil
It will have a decrease in superheat
A diffuser
36. 10' round duct has a ballpark cfm of what?
When the system is under pressure
Individual return air systems and central return air systems
Nitrogen with a small amount of refrigerant
400
37. How many amps can 12 g wire handle?
False
Nominal-sized tubing
Duct - electrical - and mechanical
20 A
38. The A/C size is calculated by what?
20 degrees F
It will be high
Heat load
In parallel
39. The A/C size is calculated by what?
By increasing the surface of the condenser coil
Below 800 degrees F
S-clips and drives (cleats)
Heat load
40. At what temperature will soft solder melt?
ACR (air-conditioning refrigeration) tubing
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
False
Below 800 degrees F
41. How are the condenser coils different on a high-efficiency unit?
40 degrees F
Heat load
They are larger
To lower the amount of pressure drop through the coil
42. What sort of pressure will a push-through evaporator have?
45 degrees F
L-type
Positive
Individual return air systems and central return air systems
43. What is the typical temperature difference between a standard-efficiency condenser and the ambient temperature?
To lower the amount of pressure drop through the coil
Negative
30 degrees F
400
44. Which type of wire can handle a higher ampacity?
Duct - electrical - and mechanical
20 A
Outside diameter (OD)
Stranded
45. If the suction pressure rises - what happens to the head pressure?
Heat loss
It rises
It also rises
400
46. How long should you leave a system off once you kill power before restarting it?
Outside of the male fitting
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
True
2 minutes
47. If the rpm's are 1750 - how many poles does the motor have?
30 degrees F
A dirty evaporator
Any amount
4
48. 6' round duct has a ballpark cfm of what?
100
Outside diameter (OD)
A piston type metering device
4
49. What are the two functions of the air-conditioning system?
In series
No
400
To remove humidity and lower dry bulb temperature
50. The fan switch closes at what temperature?
140 degrees F
45-55%
Latent and sensible
TXV