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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 is the range for normal superheat and subcooling?
A piston type metering device
140 degrees F
8-12 degrees F
6
2. What are the two basic duct connection configurations for package units supply and return air ducts?
A swaging tool
High
15% silphos
Over/under and side by side
3. What are normal conditions - as defined by the ARI.
False
20 degrees F
Dehydrated with caps on each end
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
4. What is the design boiling point for most evaporator coils in residential air conditioning?
Inches of water column (in. WC)
False
40 degrees F
Nominal-sized tubing
5. Where is insulation used on copper tubing used for air-conditioning?
400
Yes
The suction line or the low-pressure side
It rises
6. What are the components of a hard-start kit?
Yes
Potential relay and start capacitor
Duct - electrical - and mechanical
ACR (air-conditioning refrigeration) tubing
7. How are round ducts supported?
8. When do you install a trap on a drain line?
When it is a pull-through evaporator
To remove humidity and lower dry bulb temperature
30 degrees F
15% silphos
9. How are round ducts supported?
10. Where do you apply flux when soldering?
Infiltration and ventilation
Outside of the male fitting
Compressor
140 degrees F
11. How do you calculate LRA?
Yes
105 degrees F
RLA/FLA x 5
Compressor
12. Square sheet metal duct is normally fabricated in a sheet metal shop and assembled in the field. (True or False)
Vapor
True
30 degrees F
Rise
13. How does ACR copper pipe come?
Vapor
The suction line or the low-pressure side
Dehydrated with caps on each end
Any amount
14. Does a package unit come from the factory pre-charged?
They are larger
Belt drive and direct drive
Yes
Below 800 degrees F
15. What gauge is thermostat wire?
RLA/FLA x 5
18 gauge
30-35 degrees above ambient
100 psig
16. How will too much refrigerant effect subcooling?
25-ft or 50-ft
It will be high
Pi x radius squared
By increasing the surface of the condenser coil
17. How many amps can 8 g wire handle?
Duct - electrical - and mechanical
5 degrees
They are larger
40 A
18. What sort of pressure will a pull-through evaporator have?
With a minimum of three evenly spaced self-tapping screws
To remove humidity and lower dry bulb temperature
A piston type metering device
Negative
19. How long should you leave a system off once you kill power before restarting it?
Dehydrated with caps on each end
40 degrees F
2 minutes
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
20. How many BTU's per ton?
Rise
It will have a decrease in superheat
12000
Compressor
21. What are the two types of return air systems in residential installations?
Potential relay and start capacitor
True
Yes
Individual return air systems and central return air systems
22. When must a copper joint never be soldered or brazed?
On the common terminal
True
Yes
When the system is under pressure
23. What are the three major power-consuming devices on an air-conditioning system?
Heat loss
12000
Indoor fan motor - outdoor fan motor - and the compressor
It also rises
24. 6' round duct has a ballpark cfm of what?
100
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
Belt drive and direct drive
2
25. The crankcase heater on an air-conditioning compressor is used to what?
Subtract ambient temperature from 100
Boil the liquid refrigerant out ot the oil within the crankcase
Yes
It will have a decrease in superheat
26. Which is more efficient - a TXV or a fixed-orifice metering device?
Before the vent
TXV
Compressor
Inside diameter (ID)
27. What is a package unit?
Over/under and side by side
20 degrees above ambient
An air-conditioning system that has all four components (compressor - condenser - metering device - and evaporator) in one housing.
Suction
28. What type of air conditioning system must be charged using the superheat method?
Shorted winding - open winding - and grounded winding
Boil the liquid refrigerant out ot the oil within the crankcase
A piston type metering device
It will have a decrease in superheat
29. What are the four materials used to make duct?
Nitrogen with a small amount of refrigerant
Sheet metal - galvanized sheet metal - fiberglass - and flexduct
4
4
30. How do you calculate EER?
Btu/hr (output) / wattage (input)
200
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
Stranded
31. What is the typical pressure differance across a TXV?
Below 800 degrees F
100 psig
2 minutes
400
32. Where do you install a trap on a drain line?
Before the vent
Belt drive and direct drive
100
20 A
33. What type of air conditioning system must be charged using the superheat method?
A piston type metering device
TXV
Compressor
TXV
34. How is ACR tubing sized?
Outside diameter (OD)
25-ft or 50-ft
To lower the amount of pressure drop through the coil
Before the vent
35. When do you install an auxillary drain pan?
Indoor fan motor - outdoor fan motor - and the compressor
When it is above a conditioned space
RLA/FLA x 5
2
36. How many amps can 12 g wire handle?
They are physically larger
40 degrees F
12000
20 A
37. What is considered normal operating conditions?
150
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
A bypass duct or a dump zone
They are larger
38. What are the three pressures created by moving air in ductwork?
In series
Static pressure - velocity pressure - and total pressure
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
With a minimum of three evenly spaced self-tapping screws
39. How much superheat do you need to prevent liquid refrigerant from entering the compressor?
Inclined manometer
20 A
Any amount
Potential relay and start capacitor
40. If the rpm's are 750 - how many poles does the motor have?
Infiltration and ventilation
Common
8
When it is a pull-through evaporator
41. The load on the evaporater will effect which pressure?
8
No
Suction
30-35 degrees above ambient
42. What is the normal evaporator temperature?
45 degrees F
Indoor fan motor - outdoor fan motor - and the compressor
It also rises
It will be low
43. What is the typical pressure differance across a TXV?
Nitrogen with a small amount of refrigerant
30 A
Latent and sensible
100 psig
44. What are the two types of package units?
Side-by-side and over-and-under
6
Blended refrigerants
Pi x radius squared
45. How are the high pressure switch and the low pressure switch wired with the compressor contactor?
High
In series
Nominal-sized tubing
It will have a decrease in superheat
46. How much superheat do you need to prevent liquid refrigerant from entering the compressor?
95 degrees F outside - 80 degrees F inside - and 50% relative humidity
Slugging
Any amount
2 minutes
47. What kind of copper tubing is used for plumbing and heating applications?
It also rises
False
Nominal-sized tubing
A bypass duct or a dump zone
48. What do you use to connect square and rectangular ductboard together?
S-clips and drives (cleats)
4
Inches of water column (in. WC)
400
49. At what temperature does refrigerant condense in a standard-efficiency unit?
S-clips and drives (cleats)
75 degrees F dry bulb indoor - 95 degrees F drybulb outdoor - and 50% relative humidity
30-35 degrees above ambient
Potential relay and start capacitor
50. The compressor is cooled by liquid refrigerant. (True of False)
8
Side-by-side and over-and-under
Suction
False