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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. The fan switch opens at what temperature?
8-12 degrees F
105 degrees F
Shorted winding - open winding - and grounded winding
When the system is under pressure
2. How is flexible duct supported?
A band 4 inches or more in width
They are physically larger
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
25-ft or 50-ft
3. Where do you install a trap on a drain line?
Before the vent
45-55%
By increasing the surface of the condenser coil
Belt drive and direct drive
4. The compressor is cooled by liquid refrigerant. (True of False)
30-35 degrees above ambient
They are physically larger
False
40 degrees F
5. How do you achieve high-efficiency?
5 degrees
False
20 degrees above ambient
By increasing the surface of the condenser coil
6. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
A diffuser
On the common terminal
45-55%
Static pressure - velocity pressure - and total pressure
7. The refrigerant within the evaporator will typically boil at what temperature when it is 75 degrees inside with a relative humidity of 50%?
Stranded
40 degrees F
Before the vent
Belt drive and direct drive
8. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
40 A
SEER includes the energy used in the start-up and shut-down cycles
Pistons
True
9. What are the two functions of the air-conditioning system?
Nominal-sized tubing
To remove humidity and lower dry bulb temperature
Static pressure - velocity pressure - and total pressure
100 psig
10. The load on the evaporater will effect which pressure?
Dehydrated with caps on each end
When the system is under pressure
Over 800 degrees F
Suction
11. If the rpm's are 750 - how many poles does the motor have?
30-35 degrees above ambient
On the common terminal
8
100
12. How will too much refrigerant effect superheat?
S-clips and drives (cleats)
Inside diameter (ID)
It will be low
To lower the amount of pressure drop through the coil
13. If the suction pressure rises - what happens to the head pressure?
It also rises
Pull a vacuum
Average feet per minute X area in square feet (H' x W'/144)
Below 800 degrees F
14. What is it called when liquid refrigerant gets into the compressor?
Standard
No
2
Slugging
15. When do you install a trap on a drain line?
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
When it is a pull-through evaporator
200
Average feet per minute X area in square feet (H' x W'/144)
16. What do you use to connect square and rectangular ductboard together?
Belt drive and direct drive
S-clips and drives (cleats)
45 degrees F
With an are rating
17. What is the typical temperature difference between a standard-efficiency condenser and the ambient temperature?
30 degrees F
It also rises
Inches of water column (in. WC)
6
18. At what temperature will brazing melt?
8
Vapor
A band 4 inches or more in width
Over 800 degrees F
19. What sort of pressure will a push-through evaporator have?
140 degrees F
Positive
Nitrogen with a small amount of refrigerant
Subtract ambient temperature from 100
20. A reciprocating compressor has what sort of moving parts?
12000
Pistons
15 A
A dirty evaporator
21. How much superheat do you need to prevent liquid refrigerant from entering the compressor?
Any amount
Vapor
Suction
Pull a vacuum
22. What are the three ways a motor can fail electrically?
105 degrees F
When it is a pull-through evaporator
Compressor
Shorted winding - open winding - and grounded winding
23. Where do you check the amps on a motor?
Common
On the common terminal
Indoor fan motor - outdoor fan motor - and the compressor
S-clips and drives (cleats)
24. What is considered normal operating conditions?
Individual return air systems and central return air systems
30 A
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
A diffuser
25. What is the difference between SEER and EER?
ACR (air-conditioning refrigeration) tubing
Positive
ACR (air-conditioning refrigeration) tubing
SEER includes the energy used in the start-up and shut-down cycles
26. What is used to measure static air pressure in ducts.
200
Inches of water column (in. WC)
400
Inclined manometer
27. What kind of copper tubing is used for plumbing and heating applications?
6
Nominal-sized tubing
Pistons
Outside of the male fitting
28. In what length rolls is soft copper tubing normally available?
False
25-ft or 50-ft
Indoor fan motor - outdoor fan motor - and the compressor
To remove humidity and lower dry bulb temperature
29. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
True
ACR (air-conditioning refrigeration) tubing
When it is above a conditioned space
By increasing the surface of the condenser coil
30. How are round ducts supported?
31. When must a copper joint never be soldered or brazed?
Yes
When the system is under pressure
Duct - electrical - and mechanical
Indoor fan motor - outdoor fan motor - and the compressor
32. If the rpm's are 1750 - how many poles does the motor have?
When it is a pull-through evaporator
It will be high
4
The suction line or the low-pressure side
33. Why are some ACR tubing lines insulated?
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
30-35 degrees above ambient
They are larger
Below 800 degrees F
34. What do you use to check for leaks?
Nitrogen with a small amount of refrigerant
40 A
Pistons
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
35. What can cause a decrease in suction pressure on an air-conditioning system?
Btu/hr (output) / wattage (input)
A dirty evaporator
Pull a vacuum
Subtract ambient temperature from 100
36. When do you install an auxillary drain pan?
15 A
When it is above a conditioned space
12000
Belt drive and direct drive
37. Where do you apply flux when soldering?
Yes
Outside of the male fitting
On the common terminal
False
38. Pressure in ductwork is measured In what?
Slugging
TXV
Inches of water column (in. WC)
25-ft or 50-ft
39. How are the condenser coils different on a high-efficiency unit?
With a minimum of three evenly spaced self-tapping screws
They are larger
Shorted winding - open winding - and grounded winding
Blended refrigerants
40. When do you install an auxillary drain pan?
True
Negative
Individual return air systems and central return air systems
When it is above a conditioned space
41. How are the high pressure switch and the low pressure switch wired with the compressor contactor?
In series
It will have a decrease in superheat
Subtract ambient temperature from 100
High
42. Where is insulation used on copper tubing used for air-conditioning?
The suction line or the low-pressure side
Shorted winding - open winding - and grounded winding
18 gauge
False
43. Where do you apply flux when soldering?
Belt drive and direct drive
6
Outside of the male fitting
Potential relay and start capacitor
44. What is considered normal operating conditions?
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
2
400
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
45. 10 SEER is classified as what kind of efficiency?
Standard
A piston type metering device
Negative
Infiltration and ventilation
46. At what temperature does refrigerant condense in a standard-efficiency unit?
In series
When it is a pull-through evaporator
300
30-35 degrees above ambient
47. What standard weight copper tubing is most often used in the heating and air-conditioning industry?
L-type
Duct with insulation on the inside
400
Over/under and side by side
48. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
8-12 degrees F
It will have a decrease in superheat
Dehydrated with caps on each end
A dirty evaporator
49. Do you need a vent on a pull-through evaporator?
A diffuser
25-ft or 50-ft
It will be high
Yes
50. The evaporator is designed to remove what two types of heat?
Blended refrigerants
Latent and sensible
25-ft or 50-ft
Stranded