HVAC EPA 608 Certification Study
Guide with complete definitions
2025.
Are there drop-in replacements for R-12 systems? Why or why not? - Answer No
because the new refrigerants are incompatible with the oils and lubricants used in
R-12 systems.
What type of oil is used in R-134a and what oils will it mix with? - Answer Ester
based oils and they do not mix with other oils
What type of lubricant is used with HCFCs? - Answer Alkylbenzene lubricant
What should be done before charging a new system with refrigerant? - Answer
The unit should first be pressurized with NITROGEN (inert gas) and leak checked
What are the leak repair requirements for comfort cooling appliances and
commercial appliances containing 50 pounds or more of refrigerant? - Answer
The leak rate exceeds 15% in comfort cooling appliances
The leak rate exceeds 35% in all commercial and industrial process refrigeration
,Using large vacuum pumps can lead to freezing of water in the system. What are
two ways the technician can help prevent freezing? - Answer Increase pressure by
introducing nitrogen to counteract freezing. Liquid charging of an R-12
refrigeration system should begin with vapor from a vacuum level to a pressure of
approximately 33 psig followed by a liquid charge through the liquid-line service
valve.
Foaming at start-up may be found in what component? What does this mean? -
Answer Refrigerant in the oil will cause oil foaming in the compressor at start-up
When evacuating a vapor compression system how many microns does the
vacuum need to achieve? - Answer 500 microns (or 29.90" Hg)
Why should you never start a hermetic compressor when under deep vacuum? -
Answer The motor winding could be damaged if energized
What is a receiver? Where is it located and what is the state of the refrigerant
after leaving the receiver? - Answer Systems using thermal expansion valves will
have a receiver/tank on the outlet side of the condenser, designed to hold liquid
refrigerant.
, When leaving the condenser directly or the receiver, the refrigerant remains a
high pressure/high temperature liquid until it goes to the metering device.
What is the liquid line? - Answer The line between the condenser and the
metering device is also referred to as the liquid line
What criteria must recovery equipment manufactured after Nov. 15th, 1993
meet? - Answer Certified by EPA laboratory, equipped with low-loss fittings, and
meet stringent vacuum standards. System-dependent recovery equipment cannot
be used on appliances containing more than 15lbs. of refrigerant
How many inches of mercury vacuum is required for HCFC-22 appliances
containing more than 200lbs. of refrigerant using equipment after Nov. 15th,
1993. - Answer 0 Inches Hg
What does the EPA consider major repairs? - Answer Any maintenance, service or
repair involving the removal or any or all of the following components:
compressor, condenser, evaporator or an auxillary heat exchanger coil.
What exceptions are there for evacuation for non-major repairs? - Answer Repairs
to leaky equipment: repairs to leaky equipment and non-major repairs
Guide with complete definitions
2025.
Are there drop-in replacements for R-12 systems? Why or why not? - Answer No
because the new refrigerants are incompatible with the oils and lubricants used in
R-12 systems.
What type of oil is used in R-134a and what oils will it mix with? - Answer Ester
based oils and they do not mix with other oils
What type of lubricant is used with HCFCs? - Answer Alkylbenzene lubricant
What should be done before charging a new system with refrigerant? - Answer
The unit should first be pressurized with NITROGEN (inert gas) and leak checked
What are the leak repair requirements for comfort cooling appliances and
commercial appliances containing 50 pounds or more of refrigerant? - Answer
The leak rate exceeds 15% in comfort cooling appliances
The leak rate exceeds 35% in all commercial and industrial process refrigeration
,Using large vacuum pumps can lead to freezing of water in the system. What are
two ways the technician can help prevent freezing? - Answer Increase pressure by
introducing nitrogen to counteract freezing. Liquid charging of an R-12
refrigeration system should begin with vapor from a vacuum level to a pressure of
approximately 33 psig followed by a liquid charge through the liquid-line service
valve.
Foaming at start-up may be found in what component? What does this mean? -
Answer Refrigerant in the oil will cause oil foaming in the compressor at start-up
When evacuating a vapor compression system how many microns does the
vacuum need to achieve? - Answer 500 microns (or 29.90" Hg)
Why should you never start a hermetic compressor when under deep vacuum? -
Answer The motor winding could be damaged if energized
What is a receiver? Where is it located and what is the state of the refrigerant
after leaving the receiver? - Answer Systems using thermal expansion valves will
have a receiver/tank on the outlet side of the condenser, designed to hold liquid
refrigerant.
, When leaving the condenser directly or the receiver, the refrigerant remains a
high pressure/high temperature liquid until it goes to the metering device.
What is the liquid line? - Answer The line between the condenser and the
metering device is also referred to as the liquid line
What criteria must recovery equipment manufactured after Nov. 15th, 1993
meet? - Answer Certified by EPA laboratory, equipped with low-loss fittings, and
meet stringent vacuum standards. System-dependent recovery equipment cannot
be used on appliances containing more than 15lbs. of refrigerant
How many inches of mercury vacuum is required for HCFC-22 appliances
containing more than 200lbs. of refrigerant using equipment after Nov. 15th,
1993. - Answer 0 Inches Hg
What does the EPA consider major repairs? - Answer Any maintenance, service or
repair involving the removal or any or all of the following components:
compressor, condenser, evaporator or an auxillary heat exchanger coil.
What exceptions are there for evacuation for non-major repairs? - Answer Repairs
to leaky equipment: repairs to leaky equipment and non-major repairs
