Air oil n refrigerants

Question 1

What are the capacity ranges for wall and ductless split air conditioners

Answer 1

6000 - 60 000 Btuh

Question 2

What are the capacity ranges for central air conditioners/resi splits

Answer 2

(-)24 000 - 60 000 Btuh

Question 3

What are the two functions of isolating AHUs

Answer 3

1. Reduce noise caused from noise attenuation (fans and motors)
2. Reduce vibration

Question 4

What are ball/roller bearings made from

Answer 4

Steel

Question 5

What are sleeve bearings made from

Answer 5

Bronze

Question 6

Forward curved fans move air by _ air, are common in _ airflow volumes and static pressures up to _“WC,
(can/can’t) be burnt out

Answer 6

pushing, high airflow and up to 4”WC, can be burnt out

Question 7

Backward inclined fans move air by _ air, are common in _ airflow volumes and static pressures up to _“WC, (can/can’t) be burnt out

Answer 7

throwing/slapping, high/mid airflow and up to 20”WC, can’t be burnt out

Question 8

Three types of fan blades in backwards inclined fans

Answer 8

Flat, radial tip, and curved airfoil

Question 9

Formula to calculate belt deflection

Answer 9

BD = S(span length)/64

Question 10

Because of their location, ductless splits and wall air conditioners don’t do what to the air

Answer 10

Ventilation and exhaust air

Question 11

Large air handling units are built where

Answer 11

on-site and off-site

Question 12

What’s r717

Answer 12

Ammonia

Question 13

What’s r718

Answer 13

Water

Question 14

What’s the cylinder color for r22

Answer 14

Light green

Question 15

What’s the cylinder color for r507

Answer 15

Teal

Question 16

What’s the cylinder color for r134a

Answer 16

Light sky blue

Question 17

What color is r404a cylinder

Answer 17

Orange

Question 18

What color is 410a cylinder

Answer 18

Rose

Question 19

What range number are methane based refrigerants

Answer 19

0-99

Question 20

What range of refrigerants are propane based refrigerants

Answer 20

200s

Question 21

As of 2020 what type of refrigerants are banned

Answer 21

HCFCs

Question 22

Why are halocarbon refrigerants dangerous

Answer 22

Non flammable but breaks down in a flame to produce highly toxic gasses

Question 23

Flash point

Answer 23

Temperature when a flame can ignite oil vapour

Question 24

What’s the WC limit of refrigerant cylinder bottles? And what’s the top temperature limit

Answer 24

80% at 70°F or 60% at 120°F
Limit: 125°F

Question 25

What’s TW and WC

Answer 25

Tare weight (empty) and water capacity (full of water at 60F)

Question 26

What must you do to a leaking system with blended refrigerant

Answer 26

Check it’s pressure against ambient temperature to check for the right refrigerant

Question 27

What are the three types of electronic detection for leaks

Answer 27

Electrochemical (electric current when gas), dielectric (gas acts as insulation), and ultrasonic (sound)

Question 28

How many microns are in an inch

Answer 28

760 000 microns

Question 29

What’s r744

Answer 29

CO2

Question 30

AHRI

Answer 30

Air conditioning heating and refrigeration institute

Question 31

What are the capacity ranges for portable air conditioners

Answer 31

6000 - 18 000 Btuh

Question 32

Centrifugal fans displaces (more/less) volume of air than axial fans

Answer 32

Less