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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.
Pull a vacuum
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Inclined manometer
Over/under and side by side
2. What are the two ways that fresh air enters a structure?
4
Infiltration and ventilation
Inches of water column (in. WC)
40 A
3. A reciprocating compressor has what sort of moving parts?
True
Blended refrigerants
Pistons
Rise
4. Multiple-zone systems often use what to alleviate the problem of excess air when only some zones are calling for conditioning?
When it is a pull-through evaporator
A bypass duct or a dump zone
With a minimum of three evenly spaced self-tapping screws
Yes
5. What is the typical temperature difference between a high-efficiency condenser and the ambient temperature?
20 degrees F
30 degrees F
Nitrogen with a small amount of refrigerant
Pi x radius squared
6. 10 SEER is classified as what kind of efficiency?
Standard
8-12 degrees F
20 degrees above ambient
When it is a pull-through evaporator
7. 13 SEER is classified as what kind of efficiency?
Shorted winding - open winding - and grounded winding
To lower the amount of pressure drop through the coil
High
Dehydrated with caps on each end
8. What is the name of the fitting where the branch line leaves the duct?
The takeoff fitting
100 psig
In series
30 A
9. At what temperature does refrigerant condense in a standard-efficiency unit?
30-35 degrees above ambient
Fiberglass
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
100
10. In what state is the refrigerant in the compressor?
They are physically larger
Yes
Vapor
ACR (air-conditioning refrigeration) tubing
11. What are the three major power-consuming devices on an air-conditioning system?
SEER includes the energy used in the start-up and shut-down cycles
Nominal-sized tubing
Indoor fan motor - outdoor fan motor - and the compressor
45-55%
12. Why are some ACR tubing lines insulated?
Inches of water column (in. WC)
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
A dirty evaporator
By increasing the surface of the condenser coil
13. What component changes refrigerant from a low pressure gas to a high pressure gas?
Compressor
It will be low
Stranded
In series
14. 10' round duct has a ballpark cfm of what?
400
RLA/FLA x 5
20 degrees F
Static pressure - velocity pressure - and total pressure
15. What are the two functions of the air-conditioning system?
False
Compressor
Latent and sensible
To remove humidity and lower dry bulb temperature
16. At what temperature does refrigerant condense in a high-efficiency unit?
Indoor fan motor - outdoor fan motor - and the compressor
20 degrees above ambient
A dirty evaporator
Dehydrated with caps on each end
17. What are the two basic duct connection configurations for package units supply and return air ducts?
True
100
TXV
Over/under and side by side
18. What are the two types of package units?
15 A
Side-by-side and over-and-under
SEER includes the energy used in the start-up and shut-down cycles
Individual return air systems and central return air systems
19. How are the high pressure switch and the low pressure switch wired with the compressor contactor?
Yes
Btu/hr (output) / wattage (input)
In series
Yes
20. How is ACR tubing sized?
Outside diameter (OD)
By increasing the surface of the condenser coil
Shorted winding - open winding - and grounded winding
Below 800 degrees F
21. What is the range for normal superheat and subcooling?
When it is a pull-through evaporator
15% silphos
8-12 degrees F
When it is above a conditioned space
22. What standard weight copper tubing is most often used in the heating and air-conditioning industry?
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
In series
L-type
Pull a vacuum
23. What are the two types of return air systems in residential installations?
Individual return air systems and central return air systems
To remove humidity and lower dry bulb temperature
140 degrees F
100
24. 13 SEER is classified as what kind of efficiency?
High
20 degrees F
Inches of water column (in. WC)
Average feet per minute X area in square feet (H' x W'/144)
25. How many BTU's per ton?
Standard
When it is a pull-through evaporator
12000
Static pressure - velocity pressure - and total pressure
26. On what terminal do you check amperage?
Belt drive and direct drive
150
Common
Individual return air systems and central return air systems
27. How do you calculate the area of a circle?
25-ft or 50-ft
Pi x radius squared
200
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
28. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
45-55%
Stranded
Negative
Duct - electrical - and mechanical
29. 10' round duct has a ballpark cfm of what?
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
15 A
400
S-clips and drives (cleats)
30. How are the high pressure switch and the low pressure switch wired with the compressor contactor?
Individual return air systems and central return air systems
400
In series
Individual return air systems and central return air systems
31. What kind of copper tubing is used for refrigeration or air-conditioning applications?
Over 800 degrees F
ACR (air-conditioning refrigeration) tubing
True
L-type
32. What is considered normal operating conditions?
40 degrees F
140 degrees F
105 degrees F
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
33. What percentage silver do you need to use for an are-410 system?
15% silphos
2 minutes
They are physically larger
By increasing the surface of the condenser coil
34. How will too much refrigerant effect superheat?
100 psig
It will be low
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
L-type
35. How long should you leave a system off once you kill power before restarting it?
40 A
2 minutes
It rises
Below 800 degrees F
36. How much does a drain line need to drop per foot of length?
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183
37. What are the three crafts normally associated with an air-conditioned installation?
Duct with insulation on the inside
45 degrees F
Duct - electrical - and mechanical
Potential relay and start capacitor
38. How are round ducts connected to one another?
The takeoff fitting
6
Heat loss
With a minimum of three evenly spaced self-tapping screws
39. What is it called when liquid refrigerant gets into the compressor?
Slugging
Suction
To lower the amount of pressure drop through the coil
8-12 degrees F
40. How does ACR copper pipe come?
40 degrees F
To remove humidity and lower dry bulb temperature
Dehydrated with caps on each end
Yes
41. What sort of pressure will a push-through evaporator have?
Positive
Duct with insulation on the inside
The suction line or the low-pressure side
Heat loss
42. Pressure in ductwork is measured In what?
Yes
40 A
High
Inches of water column (in. WC)
43. How much does a drain line need to drop per foot of length?
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183
44. What are the two types of blower drives?
100 psig
Belt drive and direct drive
By increasing the surface of the condenser coil
1/4'
45. What are the two types of return air systems in residential installations?
A diffuser
Slugging
Inclined manometer
Individual return air systems and central return air systems
46. On what terminal do you check amperage?
Shorted winding - open winding - and grounded winding
Heat load
Inside diameter (ID)
Common
47. If pressure rises - what happens to the superheat?
In parallel
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
It rises
Heat loss
48. At what temperature will brazing melt?
Belt drive and direct drive
When the system is under pressure
By increasing the surface of the condenser coil
Over 800 degrees F
49. How are the condenser coils different on a high-efficiency unit?
They are larger
Any amount
Belt drive and direct drive
A piston type metering device
50. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
Over/under and side by side
TXV
True
SEER includes the energy used in the start-up and shut-down cycles