Air oil n refrigerants Flashcards
What are the capacity ranges for wall and ductless split air conditioners
6000 - 60 000 Btuh
What are the capacity ranges for central air conditioners/resi splits
(-)24 000 - 60 000 Btuh
What are the two functions of isolating AHUs
- Reduce noise caused from noise attenuation (fans and motors)
- Reduce vibration
What are ball/roller bearings made from
Steel
What are sleeve bearings made from
Bronze
Forward curved fans move air by _ air, are common in _ airflow volumes and static pressures up to _“WC,
(can/can’t) be burnt out
pushing, high airflow and up to 4”WC, can be burnt out
Backward inclined fans move air by _ air, are common in _ airflow volumes and static pressures up to _“WC, (can/can’t) be burnt out
throwing/slapping, high/mid airflow and up to 20”WC, can’t be burnt out
Three types of fan blades in backwards inclined fans
Flat, radial tip, and curved airfoil
Formula to calculate belt deflection
BD = S(span length)/64
Because of their location, ductless splits and wall air conditioners don’t do what to the air
Ventilation and exhaust air
Large air handling units are built where
on-site and off-site
What’s r717
Ammonia
What’s r718
Water
What’s the cylinder color for r22
Light green
What’s the cylinder color for r507
Teal
What’s the cylinder color for r134a
Light sky blue
What color is r404a cylinder
Orange
What color is 410a cylinder
Rose
What range number are methane based refrigerants
0-99
What range of refrigerants are propane based refrigerants
200s
As of 2020 what type of refrigerants are banned
HCFCs
Why are halocarbon refrigerants dangerous
Non flammable but breaks down in a flame to produce highly toxic gasses
Flash point
Temperature when a flame can ignite oil vapour
What’s the WC limit of refrigerant cylinder bottles? And what’s the top temperature limit
80% at 70°F or 60% at 120°F
Limit: 125°F
