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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. 7' round duct has a ballpark cfm of what?
In series
On the common terminal
Btu/hr (output) / wattage (input)
150
2. What is the typical temperature difference between a standard-efficiency condenser and the ambient temperature?
By increasing the surface of the condenser coil
30 degrees F
S-clips and drives (cleats)
With a minimum of three evenly spaced self-tapping screws
3. What standard weight copper tubing is most often used in the heating and air-conditioning industry?
Suction
TXV
L-type
15 A
4. If the rpm's are 1750 - how many poles does the motor have?
4
Boil the liquid refrigerant out ot the oil within the crankcase
Latent and sensible
Dehydrated with caps on each end
5. What are the two types of package units?
Btu/hr (output) / wattage (input)
Side-by-side and over-and-under
Common
When it is above a conditioned space
6. The evaporator is designed to remove what two types of heat?
L-type
Latent and sensible
8
Potential relay and start capacitor
7. How long should you leave a system off once you kill power before restarting it?
400
105 degrees F
2 minutes
By increasing the surface of the condenser coil
8. What is lined duct?
Common
Suction
Duct with insulation on the inside
Subtract ambient temperature from 100
9. How many BTU's per ton?
45-55%
Latent and sensible
Belt drive and direct drive
12000
10. What are the two types of package units?
When it is above a conditioned space
When the system is under pressure
Positive
Side-by-side and over-and-under
11. In what state is the refrigerant in the compressor?
Vapor
300
To lower the amount of pressure drop through the coil
It will have a decrease in superheat
12. How many amps can 10 g wire handle?
40 A
They are larger
It also rises
30 A
13. How does ACR copper pipe come?
Yes
A bypass duct or a dump zone
200
Dehydrated with caps on each end
14. When do you install an auxillary drain pan?
30-35 degrees above ambient
In series
12000
When it is above a conditioned space
15. At what temperature will brazing melt?
Suction
20 degrees above ambient
20 A
Over 800 degrees F
16. Can refrigerant line sets be altered in length?
Yes
It will have a decrease in superheat
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
False
17. If the suction pressure rises - what happens to the head pressure?
When the system is under pressure
It also rises
Pistons
Pistons
18. If the rpm's are 1050 - how many poles does the motor have?
Belt drive and direct drive
Yes
6
40 A
19. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
Shorted winding - open winding - and grounded winding
Average feet per minute X area in square feet (H' x W'/144)
Common
It will have a decrease in superheat
20. How do you calculate the area of a circle?
Pi x radius squared
20 degrees above ambient
Heat load
Heat loss
21. At what temperature will brazing melt?
A dirty evaporator
Over 800 degrees F
Individual return air systems and central return air systems
Outside diameter (OD)
22. If pressure rises - what happens to the superheat?
In parallel
It rises
TXV
400
23. How will too much refrigerant effect superheat?
Before the vent
In parallel
It will be low
15 A
24. Why are some ACR tubing lines insulated?
Common
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
Indoor fan motor - outdoor fan motor - and the compressor
150
25. Superheat should never be below how many degrees
140 degrees F
5 degrees
40 degrees F
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
26. What is the typical temperature difference between a high-efficiency condenser and the ambient temperature?
20 degrees F
Below 800 degrees F
It rises
Latent and sensible
27. Do you need a trap on a pull-through evaporator?
Heat loss
Yes
L-type
S-clips and drives (cleats)
28. If the rpm's are 1050 - how many poles does the motor have?
With 4' saddles
A diffuser
Common
6
29. What percentage silver do you need to use for an are-410 system?
15% silphos
Fiberglass
Outside diameter (OD)
Standard
30. What distributes supply air to a room in a structure?
It will be low
400
A diffuser
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
31. How much does a drain line need to drop per foot of length?
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on line
183
32. 9' round duct has a ballpark cfm of what?
300
Heat load
When it is above a conditioned space
Latent and sensible
33. Can refrigerant line sets be altered in length?
Potential relay and start capacitor
Yes
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
It will be low
34. How many cfm per ton?
400
Nitrogen with a small amount of refrigerant
TXV
Outside of the male fitting
35. What is it called when liquid refrigerant gets into the compressor?
Standard
Outside of the male fitting
Slugging
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
36. What sort of pressure will a pull-through evaporator have?
Inches of water column (in. WC)
2 minutes
Outside diameter (OD)
Negative
37. What tool is used to expand the diameter of soft copper tubing
A swaging tool
Inclined manometer
8-12 degrees F
S-clips and drives (cleats)
38. What is the name of the fitting where the branch line leaves the duct?
To remove humidity and lower dry bulb temperature
25-ft or 50-ft
Infiltration and ventilation
The takeoff fitting
39. How are the condenser coils different on a high-efficiency unit?
They are larger
Rise
Inside diameter (ID)
Nitrogen with a small amount of refrigerant
40. Why is it necessary to have multiple refrigerant circuits in some evaporator coils?
Below 800 degrees F
S-clips and drives (cleats)
A dirty evaporator
To lower the amount of pressure drop through the coil
41. What are the three pressures created by moving air in ductwork?
Pi x radius squared
Static pressure - velocity pressure - and total pressure
Subtract ambient temperature from 100
Stranded
42. What gauge is thermostat wire?
Dehydrated with caps on each end
Stranded
2 minutes
18 gauge
43. At what temperature does refrigerant condense in a standard-efficiency unit?
A bypass duct or a dump zone
When the system is under pressure
30-35 degrees above ambient
Any amount
44. How many amps can 8 g wire handle?
40 A
RLA/FLA x 5
Pi x radius squared
True
45. How many amps can 14 g wire handle?
15 A
False
SEER includes the energy used in the start-up and shut-down cycles
Shorted winding - open winding - and grounded winding
46. What kind of metering device do high-efficiency units usually use?
TXV
Pull a vacuum
15% silphos
2
47. How many amps can 10 g wire handle?
30 A
It rises
By increasing the surface of the condenser coil
Outside diameter (OD)
48. 7' round duct has a ballpark cfm of what?
100
When it is above a conditioned space
150
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
49. How does ACR copper pipe come?
Dehydrated with caps on each end
Duct with insulation on the inside
The takeoff fitting
It will be low
50. What do you use to check for leaks?
Vapor
Nitrogen with a small amount of refrigerant
Common
The suction line or the low-pressure side