Core
What is an ozone molecule made of?
Three oxygen atoms (O3).
Does a PTAC fall under small appliances? What about an MVAC?
PTAC or pressurized terminal air conditioner. Yes
MVAC or motorized vehicle air conditioning systems. No
Which refrigerant can be used for leak detection as a trace gas and pressurized with nitrogen?
a. R-12
b. R-11
c. R-22
d. R-115
c. R-22
When should a low pressure system be leak checked according to ASHRAE guideline 3-1996?
When the system rises from 1 mm Hg to a level above 2.5 mm Hg during vacuum testing
Recovery equipment manufactured before November 15, 1993 must meet what standards?
Capable of recovering 80% of the refrigerant whether or not the compressor is operating or achieve a 4 inch vacuum under conditions of ARI 740.
Which refrigerant is a HFC?
a. R-134A
b. R-123
c. R-22
d. R-12
R-134A
What is the maximum amount of refrigerant a small appliance can have by definition?
5 pounds or less
Type II classification, as identified by EPA, applies to what equipment?
Split air conditioning equipment with five (5) pounds of refrigerant or more
What does a purge unit do and what is a high efficiency purge unit?
Removes the air from the system. High efficiency purge system will expel very little refrigerant
How many inches of Mercury vacuum is required for HCFC-22, for appliances containing more than 200lbs refrigerant, using equipment manufactured after 11/15/1993?
10
The rule of thumb for refilling approved cylinders is a maximum of ___ percent liquid?
80%
The release of vapor from the top of a graduated charging cylinder when filling may:
Not be vented and must be recovered.
Industrial process and commercial refrigeration equipment with over 50 pounds of refrigerant with an annual leak rate of ___ % requires repair under EPA regulations.
c. 35
What needs to be done to leak check a low pressure system?
Increase the pressure in the system by the use of controlled hot water or heater blankets
The required level of evacuation for recovery equipment manufactured after November 15, 1993, on a system containing less than 200 pounds of R-12 refrigerant is:
10 inches Hg
The condition and state of the refrigerant leaving a receiver is?
Subcooled liquid
CFCs will not be manufactured in the United States after:
1995
How can you tell through a sight glass if there is excess moisture in the system?
Look for color changes of the refrigerant
How should a water box be leak tested?
Remove water, then place the leak detector probe in through the drain valve
CFCs will not be manufactured in the United States after:
1995
Will the gases in a ternary blend leak at the same rate and why or why not?
They leak at different rates because they retain their different vapor pressures.
What is the difference between a self-contained recovery tank and a systemdependent recovery tank?
Self-contained (active) recovery equipment uses its own power to recover the refrigerant from systems and is capable of reaching the required recovery rates with or without the compressor operating
A system dependant (passive) recovery tank does not have its own compressor.
If it becomes the owners responsibility to maintain records of all refrigerant added to units that contain more than ___ pounds of refrigerant charge.
50 pounds
After removal of liquid, about how much vapor will remain in the system on a 350 ton R-11 chiller?
100 lbs of vapor after all the liquid has been removed
What are the required levels of evacuation for low pressure systems for equipment manufactured before 11/15/1993 and/or after 11/15/1993?
25” Hg for equipment manufactured before November 15, 1993.
25 mm Hg absolute for equipment manufactured after November 15, 1993.