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Residential Air Conditioning

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. Will a dirty condenser cause a rise or fall in pressure?
Pull a vacuum
Rise
A dirty evaporator
Inclined manometer

2. What is the typical temperature difference between a high-efficiency condenser and the ambient temperature?
20 degrees F
Yes
150
To lower the amount of pressure drop through the coil

3. What type of air conditioning system must be charged using the superheat method?
ACR (air-conditioning refrigeration) tubing
A piston type metering device
In series
100 psig

4. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
45-55%
TXV
No
4

5. What do you use to check for leaks?
Nitrogen with a small amount of refrigerant
L-type
When the system is under pressure
Positive

6. What are the two functions of the air-conditioning system?
Before the vent
150
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
To remove humidity and lower dry bulb temperature

7. If the suction pressure rises - what happens to the head pressure?
Yes
Inside diameter (ID)
45-55%
It also rises

8. Most duct insulation is made of what?
Duct with insulation on the inside
Below 800 degrees F
Fiberglass
Compressor

9. When must a copper joint never be soldered or brazed?
18 gauge
When the system is under pressure
6
A band 4 inches or more in width

10. What is the typical pressure differance across a TXV?
A dirty evaporator
20 A
100 psig
6

11. What tool is used to expand the diameter of soft copper tubing
8-12 degrees F
A swaging tool
Pull a vacuum
105 degrees F

12. What is the typical temperature difference between a standard-efficiency condenser and the ambient temperature?
30 degrees F
TXV
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
Yes

13. What can cause a decrease in suction pressure on an air-conditioning system?
A dirty evaporator
Rise
40 A
Nominal-sized tubing

14. At what temperature will soft solder melt?
When the system is under pressure
Below 800 degrees F
Slugging
Duct - electrical - and mechanical

15. What is lined duct?
Duct - electrical - and mechanical
Infiltration and ventilation
Duct with insulation on the inside
They are larger

16. Where do you apply flux when soldering?
Outside of the male fitting
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
40 degrees F
It will have a decrease in superheat

17. Pressure in ductwork is measured In what?
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
100
Pi x radius squared
Inches of water column (in. WC)

18. What is considered normal operating conditions?
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
L-type
They are physically larger
105 degrees F

19. How do you calculate LRA?
Inches of water column (in. WC)
In parallel
Individual return air systems and central return air systems
RLA/FLA x 5

20. How will too much refrigerant effect superheat?
It will be low
Negative
A dirty evaporator
A bypass duct or a dump zone

21. What distributes supply air to a room in a structure?
A diffuser
Over 800 degrees F
Yes
A swaging tool

22. What is the normal evaporator temperature?
1/4'
45 degrees F
Before the vent
It will have a decrease in superheat

23. What kind of refrigeratnts must be added in liquid form?
Blended refrigerants
With a minimum of three evenly spaced self-tapping screws
In parallel
20 degrees F

24. What sort of pressure will a pull-through evaporator have?
30 A
Before the vent
Pull a vacuum
Negative

25. Pressure in ductwork is measured In what?
Duct with insulation on the inside
Potential relay and start capacitor
Inches of water column (in. WC)
40 degrees F

26. What kind of copper tubing is used for refrigeration or air-conditioning applications?
When it is a pull-through evaporator
40 degrees F
ACR (air-conditioning refrigeration) tubing
400

27. If the rpm's are 3450 - how many poles does the motor have?
2
True
A band 4 inches or more in width
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line

28. 6' round duct has a ballpark cfm of what?
100
Average feet per minute X area in square feet (H' x W'/144)
A bypass duct or a dump zone
Potential relay and start capacitor

29. How long should you leave a system off once you kill power before restarting it?
2 minutes
30-35 degrees above ambient
Over 800 degrees F
S-clips and drives (cleats)

30. The evaporator is designed to remove what two types of heat?
RLA/FLA x 5
Latent and sensible
Potential relay and start capacitor
TXV

31. What are the components of a hard-start kit?
105 degrees F
Potential relay and start capacitor
No
Pistons

32. Do you need a vent on a push-through evaporator?
Duct with insulation on the inside
Belt drive and direct drive
15% silphos
Yes

33. What can cause a decrease in suction pressure on an air-conditioning system?
A dirty evaporator
Rise
With a minimum of three evenly spaced self-tapping screws
Indoor fan motor - outdoor fan motor - and the compressor

34. If the rpm's are 1050 - how many poles does the motor have?
Yes
Inches of water column (in. WC)
A dirty evaporator
6

35. How do you achieve high-efficiency?
Outside diameter (OD)
By increasing the surface of the condenser coil
A dirty evaporator
In parallel

36. The furnace size is calculated by what?
Heat loss
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
105 degrees F

37. What percentage silver do you need to use for an are-410 system?
150
25-ft or 50-ft
Over 800 degrees F
15% silphos

38. What is used to measure static air pressure in ducts.
Heat loss
Inclined manometer
Rise
Indoor fan motor - outdoor fan motor - and the compressor

39. 8' round duct has a ballpark cfm of what?
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
200
140 degrees F
With 4' saddles

40. What type of air conditioning system must be charged using the superheat method?
A piston type metering device
8
2
Yes

41. How much does a drain line need to drop per foot of length?

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42. How many BTU's per ton?
When it is a pull-through evaporator
200
12000
18 gauge

43. Which is more efficient - a TXV or a fixed-orifice metering device?
TXV
1/4'
Yes
Btu/hr (output) / wattage (input)

44. What are the two basic duct connection configurations for package units supply and return air ducts?
In parallel
Over/under and side by side
5 degrees
150

45. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
It will have a decrease in superheat
By increasing the surface of the condenser coil
25-ft or 50-ft
Before the vent

46. 10' round duct has a ballpark cfm of what?
400
Outside diameter (OD)
Yes
Common

47. How are the high pressure switch and the low pressure switch wired with the compressor contactor?
In series
30-35 degrees above ambient
Outside of the male fitting
Side-by-side and over-and-under

48. Which is more efficient - a TXV or a fixed-orifice metering device?
300
TXV
Yes
40 A

49. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
True
Slugging
Boil the liquid refrigerant out ot the oil within the crankcase
Blended refrigerants

50. Do you need a trap on a pull-through evaporator?
The suction line or the low-pressure side
It will be low
False
Yes