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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. What kind of metering device do high-efficiency units usually use?
TXV
By increasing the surface of the condenser coil
Pi x radius squared
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
2. What are the components of a hard-start kit?
When the system is under pressure
Potential relay and start capacitor
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
20 degrees above ambient
3. What is the design boiling point for most evaporator coils in residential air conditioning?
Pull a vacuum
Subtract ambient temperature from 100
Compressor
40 degrees F
4. What are the two functions of the air-conditioning system?
To remove humidity and lower dry bulb temperature
40 A
It will be low
8-12 degrees F
5. What gauge is thermostat wire?
150
Fiberglass
40 degrees F
18 gauge
6. How is ACR tubing sized?
300
Outside diameter (OD)
30 degrees F
Side-by-side and over-and-under
7. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
Pistons
True
45 degrees F
Duct - electrical - and mechanical
8. What sort of pressure will a pull-through evaporator have?
Negative
45-55%
Pistons
Below 800 degrees F
9. What is it called when liquid refrigerant gets into the compressor?
45 degrees F
With 4' saddles
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Slugging
10. How is nominal-sized tubing sized?
Suction
Rise
It rises
Inside diameter (ID)
11. What is a package unit?
The takeoff fitting
When it is a pull-through evaporator
The suction line or the low-pressure side
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
12. How are round ducts connected to one another?
Positive
400
30 degrees F
With a minimum of three evenly spaced self-tapping screws
13. How do you calculate EER?
With an are rating
15 A
When it is above a conditioned space
Btu/hr (output) / wattage (input)
14. How is the high pressure switch wired with the low pressure switch?
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
Slugging
8
In parallel
15. What are the three ways a motor can fail electrically?
Shorted winding - open winding - and grounded winding
25-ft or 50-ft
Positive
A dirty evaporator
16. The compressor is cooled by liquid refrigerant. (True of False)
In series
False
A band 4 inches or more in width
20 A
17. What are the two basic duct connection configurations for package units supply and return air ducts?
Yes
5 degrees
Subtract ambient temperature from 100
Over/under and side by side
18. What percentage silver do you use to braze two dissimilar metals such as steel and copper?
Indoor fan motor - outdoor fan motor - and the compressor
When it is above a conditioned space
Pull a vacuum
45-55%
19. What is considered normal operating conditions?
105 degrees F
Common
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
Infiltration and ventilation
20. Superheat should never be below how many degrees
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Staples and tape
5 degrees
ACR (air-conditioning refrigeration) tubing
21. In what state is the refrigerant in the compressor?
Vapor
Inclined manometer
Yes
Blended refrigerants
22. If the rpm's are 1750 - how many poles does the motor have?
Common
4
Side-by-side and over-and-under
Yes
23. What are the components of a hard-start kit?
RLA/FLA x 5
With a minimum of three evenly spaced self-tapping screws
Common
Potential relay and start capacitor
24. At what temperature will soft solder melt?
L-type
Below 800 degrees F
6
When it is a pull-through evaporator
25. What is the range for normal superheat and subcooling?
Pistons
8-12 degrees F
Nominal-sized tubing
30 A
26. How do you calculate the area of a circle?
Pi x radius squared
The takeoff fitting
Nominal-sized tubing
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
27. How many amps can 12 g wire handle?
Slugging
Nominal-sized tubing
20 A
With 4' saddles
28. The fan switch opens at what temperature?
When it is above a conditioned space
105 degrees F
Standard
Inclined manometer
29. What are the three major power-consuming devices on an air-conditioning system?
Potential relay and start capacitor
Indoor fan motor - outdoor fan motor - and the compressor
Over 800 degrees F
Pi x radius squared
30. How will too much refrigerant effect superheat?
It will be low
20 A
Yes
Btu/hr (output) / wattage (input)
31. Sections of duct board can be fastened together with what?
Belt drive and direct drive
Outside of the male fitting
Staples and tape
Average feet per minute X area in square feet (H' x W'/144)
32. How do you calculate LRA?
RLA/FLA x 5
Nominal-sized tubing
200
140 degrees F
33. In what state is the refrigerant in the compressor?
In parallel
Infiltration and ventilation
5 degrees
Vapor
34. Why are some ACR tubing lines insulated?
30 A
Nominal-sized tubing
40 degrees F
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
35. The A/C size is calculated by what?
Yes
20 A
Heat load
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
36. What are the three crafts normally associated with an air-conditioned installation?
With an are rating
30-35 degrees above ambient
Duct - electrical - and mechanical
It also rises
37. What sort of pressure will a push-through evaporator have?
When it is above a conditioned space
30 degrees F
A swaging tool
Positive
38. What sort of pressure will a push-through evaporator have?
8-12 degrees F
Positive
It will be high
Yes
39. Multiple-zone systems often use what to alleviate the problem of excess air when only some zones are calling for conditioning?
Duct - electrical - and mechanical
12000
A bypass duct or a dump zone
High
40. 6' round duct has a ballpark cfm of what?
18 gauge
100
Outside of the male fitting
Positive
41. When do you install a trap on a drain line?
It also rises
Btu/hr (output) / wattage (input)
Over/under and side by side
When it is a pull-through evaporator
42. 8' round duct has a ballpark cfm of what?
The suction line or the low-pressure side
200
With an are rating
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
43. What are the three ways a motor can fail electrically?
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
Shorted winding - open winding - and grounded winding
Heat loss
It rises
44. Will a dirty condenser cause a rise or fall in pressure?
30-35 degrees above ambient
2
Rise
To keep refrigerant from absorbing heat and to prevent condensation from forming on the line
45. In what length rolls is soft copper tubing normally available?
On the common terminal
Yes
25-ft or 50-ft
It rises
46. Do you need a trap on a push-through evaporator?
On the common terminal
No
Yes
30 A
47. How will an overcharge affect an air-conditioning system with a fixed-orifice type metering device?
With a minimum of three evenly spaced self-tapping screws
20 degrees above ambient
It will have a decrease in superheat
Shorted winding - open winding - and grounded winding
48. How many cfm per ton?
400
Vapor
A piston type metering device
A piston type metering device
49. At what temperature does refrigerant condense in a standard-efficiency unit?
Rise
30-35 degrees above ambient
With 4' saddles
Yes
50. How do you calculate cfm?
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