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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. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
Individual return air systems and central return air systems
Dehydrated with caps on each end
It will have a decrease in superheat
100
2. What sort of pressure will a push-through evaporator have?
Before the vent
1/4'
Positive
Stranded
3. How long should you leave a system off once you kill power before restarting it?
Blended refrigerants
Potential relay and start capacitor
2 minutes
The suction line or the low-pressure side
4. 7' round duct has a ballpark cfm of what?
150
When it is a pull-through evaporator
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
Nominal-sized tubing
5. What do you do after you braze a system?
Pull a vacuum
15% silphos
105 degrees F
S-clips and drives (cleats)
6. What is the typical pressure differance across a TXV?
They are physically larger
L-type
100 psig
105 degrees F
7. How do you calculate the area of a circle?
100
2
Pi x radius squared
Yes
8. What tool is used to expand the diameter of soft copper tubing
Duct with insulation on the inside
L-type
A swaging tool
SEER includes the energy used in the start-up and shut-down cycles
9. What are the three major power-consuming devices on an air-conditioning system?
Inches of water column (in. WC)
40 degrees F
Indoor fan motor - outdoor fan motor - and the compressor
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
10. If the suction pressure rises - what happens to the head pressure?
100 psig
Nitrogen with a small amount of refrigerant
2
It also rises
11. Do you need a vent on a pull-through evaporator?
Yes
2 minutes
Common
40 degrees F
12. What is the typical temperature difference between a high-efficiency condenser and the ambient temperature?
20 degrees F
Individual return air systems and central return air systems
The suction line or the low-pressure side
With a minimum of three evenly spaced self-tapping screws
13. Which type of wire can handle a higher ampacity?
Stranded
Static pressure - velocity pressure - and total pressure
A diffuser
A band 4 inches or more in width
14. What are the components of a hard-start kit?
They are physically larger
Potential relay and start capacitor
400
Yes
15. How do you calculate LRA?
They are physically larger
A diffuser
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
RLA/FLA x 5
16. Which is more efficient - a TXV or a fixed-orifice metering device?
400
Any amount
In series
TXV
17. What is considered normal operating conditions?
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
With an are rating
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
Subtract ambient temperature from 100
18. In what state is the refrigerant in the compressor?
300
45-55%
Vapor
20 A
19. Which is more efficient - a TXV or a fixed-orifice metering device?
15% silphos
It rises
TXV
It will have a decrease in superheat
20. How do you calculate cfm?
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on line
183
21. How many amps can 10 g wire handle?
To lower the amount of pressure drop through the coil
Pi x radius squared
Boil the liquid refrigerant out ot the oil within the crankcase
30 A
22. The load on the evaporater will effect which pressure?
Dehydrated with caps on each end
Suction
On the common terminal
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
23. What is it called when liquid refrigerant gets into the compressor?
TXV
Slugging
TXV
8
24. In what length rolls is soft copper tubing normally available?
Common
25-ft or 50-ft
Duct with insulation on the inside
ACR (air-conditioning refrigeration) tubing
25. Where do you apply flux when soldering?
Subtract ambient temperature from 100
Inclined manometer
45-55%
Outside of the male fitting
26. What kind of copper tubing is used for plumbing and heating applications?
Nominal-sized tubing
Outside of the male fitting
Latent and sensible
Yes
27. What kind of copper tubing is used for plumbing and heating applications?
Nominal-sized tubing
15 A
A piston type metering device
TXV
28. What do you use to check for leaks?
Subtract ambient temperature from 100
Nitrogen with a small amount of refrigerant
30-35 degrees above ambient
Standard
29. If pressure rises - what happens to the superheat?
30 A
It rises
High
When it is a pull-through evaporator
30. Where do you check the amps on a motor?
Heat load
On the common terminal
S-clips and drives (cleats)
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
31. Does a package unit come from the factory pre-charged?
False
Yes
Nitrogen with a small amount of refrigerant
40 degrees F
32. What kind of metering device do high-efficiency units usually use?
S-clips and drives (cleats)
Duct - electrical - and mechanical
150
TXV
33. What sort of pressure will a push-through evaporator have?
20 degrees F
Positive
Nominal-sized tubing
Infiltration and ventilation
34. How do you calculate EER?
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
Btu/hr (output) / wattage (input)
Blended refrigerants
6
35. What do you use to connect square and rectangular ductboard together?
Below 800 degrees F
S-clips and drives (cleats)
SEER includes the energy used in the start-up and shut-down cycles
Inches of water column (in. WC)
36. How does ACR copper pipe come?
SEER includes the energy used in the start-up and shut-down cycles
Common
It will have a decrease in superheat
Dehydrated with caps on each end
37. What kind of refrigeratnts must be added in liquid form?
Btu/hr (output) / wattage (input)
105 degrees F
Blended refrigerants
15% silphos
38. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
45-55%
8-12 degrees F
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
39. What are the two types of return air systems in residential installations?
6
A bypass duct or a dump zone
Individual return air systems and central return air systems
30 A
40. Do you need a trap on a push-through evaporator?
Positive
Yes
True
No
41. Why are some ACR tubing lines insulated?
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
6
45-55%
Subtract ambient temperature from 100
42. If the rpm's are 1750 - how many poles does the motor have?
4
TXV
Infiltration and ventilation
It also rises
43. How many amps can 8 g wire handle?
40 A
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
On the common terminal
40 degrees F
44. How is the high pressure switch wired with the low pressure switch?
Vapor
In parallel
Rise
45 degrees F
45. What is the name of the fitting where the branch line leaves the duct?
The takeoff fitting
5 degrees
Compressor
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
46. The furnace size is calculated by what?
It will have a decrease in superheat
Heat loss
Suction
Compressor
47. Sections of duct board can be fastened together with what?
Staples and tape
2
High
In parallel
48. How is ACR tubing sized?
Outside diameter (OD)
In parallel
20 A
20 degrees F
49. The fan switch opens at what temperature?
105 degrees F
With a minimum of three evenly spaced self-tapping screws
40 degrees F
Duct - electrical - and mechanical
50. How are the high pressure switch and the low pressure switch wired with the compressor contactor?
45 degrees F
In series
40 degrees F
200