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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. If the rpm's are 3450 - how many poles does the motor have?
2
TXV
Duct - electrical - and mechanical
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
2. On what terminal do you check amperage?
Common
They are larger
A diffuser
RLA/FLA x 5
3. What can cause a decrease in suction pressure on an air-conditioning system?
A dirty evaporator
6
Yes
20 A
4. Do you need a vent on a push-through evaporator?
400
Yes
With a minimum of three evenly spaced self-tapping screws
To lower the amount of pressure drop through the coil
5. Which is more efficient - a TXV or a fixed-orifice metering device?
TXV
100
18 gauge
Compressor
6. 8' round duct has a ballpark cfm of what?
Nitrogen with a small amount of refrigerant
100
200
40 A
7. Which is more efficient - a TXV or a fixed-orifice metering device?
The takeoff fitting
400
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
TXV
8. What is the range for normal superheat and subcooling?
8-12 degrees F
On the common terminal
It will be low
Inches of water column (in. WC)
9. What is used to measure static air pressure in ducts.
Inclined manometer
15 A
TXV
Nitrogen with a small amount of refrigerant
10. How do you calculate ballpark superheat?
Yes
15% silphos
Subtract ambient temperature from 100
The suction line or the low-pressure side
11. Where do you check the amps on a motor?
A swaging tool
Standard
Indoor fan motor - outdoor fan motor - and the compressor
On the common terminal
12. If the rpm's are 1050 - how many poles does the motor have?
20 degrees above ambient
6
30 A
40 degrees F
13. How do you calculate ballpark superheat?
Nominal-sized tubing
Subtract ambient temperature from 100
It will have a decrease in superheat
L-type
14. The crankcase heater on an air-conditioning compressor is used to what?
40 degrees F
Any amount
Pi x radius squared
Boil the liquid refrigerant out ot the oil within the crankcase
15. The A/C size is calculated by what?
On the common terminal
Heat load
140 degrees F
Suction
16. What component changes refrigerant from a low pressure gas to a high pressure gas?
Compressor
Inches of water column (in. WC)
With a minimum of three evenly spaced self-tapping screws
2
17. How do you calculate cfm?
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183
18. How many cfm per ton?
A band 4 inches or more in width
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
15 A
400
19. Pressure in ductwork is measured In what?
Inclined manometer
100 psig
Inches of water column (in. WC)
The takeoff fitting
20. Sections of duct board can be fastened together with what?
Staples and tape
TXV
Over 800 degrees F
Before the vent
21. What are normal conditions - as defined by the ARI.
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
Pull a vacuum
A dirty evaporator
SEER includes the energy used in the start-up and shut-down cycles
22. What is used to measure static air pressure in ducts.
They are physically larger
Inclined manometer
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
Over/under and side by side
23. What are the two functions of the air-conditioning system?
When the system is under pressure
A band 4 inches or more in width
SEER includes the energy used in the start-up and shut-down cycles
To remove humidity and lower dry bulb temperature
24. What kind of refrigeratnts must be added in liquid form?
Positive
Shorted winding - open winding - and grounded winding
Blended refrigerants
6
25. The evaporator is designed to remove what two types of heat?
12000
It also rises
Latent and sensible
Common
26. When do you install a trap on a drain line?
It will be high
When it is a pull-through evaporator
Stranded
Compressor
27. How will too much refrigerant effect subcooling?
They are larger
It will be high
Latent and sensible
200
28. What are the two types of return air systems in residential installations?
Individual return air systems and central return air systems
300
Belt drive and direct drive
By increasing the surface of the condenser coil
29. What is a package unit?
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Indoor fan motor - outdoor fan motor - and the compressor
Before the vent
Pistons
30. What is it called when liquid refrigerant gets into the compressor?
It will be low
Negative
Slugging
It also rises
31. How is ACR tubing sized?
Blended refrigerants
Outside diameter (OD)
Inclined manometer
Yes
32. How long should you leave a system off once you kill power before restarting it?
Yes
2 minutes
Dehydrated with caps on each end
Heat load
33. What sort of pressure will a pull-through evaporator have?
40 A
Negative
It will have a decrease in superheat
Yes
34. Do you need a trap on a pull-through evaporator?
Individual return air systems and central return air systems
20 degrees above ambient
Infiltration and ventilation
Yes
35. The load on the evaporater will effect which pressure?
Suction
12000
Heat load
The takeoff fitting
36. Superheat should never be below how many degrees
It also rises
2
To lower the amount of pressure drop through the coil
5 degrees
37. Will a dirty condenser cause a rise or fall in pressure?
With 4' saddles
Compressor
30-35 degrees above ambient
Rise
38. How is flexible duct supported?
Yes
True
A band 4 inches or more in width
Stranded
39. What is the typical temperature difference between a standard-efficiency condenser and the ambient temperature?
Pull a vacuum
Dehydrated with caps on each end
Over/under and side by side
30 degrees F
40. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
It will be high
Nitrogen with a small amount of refrigerant
A diffuser
It will have a decrease in superheat
41. How much does a drain line need to drop per foot of length?
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183
42. What component changes refrigerant from a low pressure gas to a high pressure gas?
Compressor
20 degrees above ambient
It will be low
300
43. Where is insulation used on copper tubing used for air-conditioning?
Rise
Common
Outside diameter (OD)
The suction line or the low-pressure side
44. How many amps can 14 g wire handle?
105 degrees F
5 degrees
15 A
Duct with insulation on the inside
45. What percentage silver do you need to use for an are-410 system?
15% silphos
It will be high
Stranded
100 psig
46. Which type of wire can handle a higher ampacity?
Positive
Stranded
It rises
5 degrees
47. 9' round duct has a ballpark cfm of what?
To remove humidity and lower dry bulb temperature
Average feet per minute X area in square feet (H' x W'/144)
300
Potential relay and start capacitor
48. The A/C size is calculated by what?
20 A
Staples and tape
Heat load
Infiltration and ventilation
49. What type of air conditioning system must be charged using the superheat method?
Potential relay and start capacitor
Boil the liquid refrigerant out ot the oil within the crankcase
A piston type metering device
200
50. How do you calculate the area of a circle?
Pi x radius squared
It will be high
200
4