EPA II Flash

Question 1

Testing with soap bubbles is used:

Answer 1

to pinpoint refrigerant leaks

Question 2

Many refrigeration units use an open compressor. Which part of the compressor is most likely to leak if a unit is not used for several months?

Answer 2

The rotating shaft seal

Question 3

When a new system has been assembled (built-up), and is ready for testing, the first thing to do is:

Answer 3

Pressureize with an inert gas and leak check

Question 4

EPA regulations require that all appliances containing more than 50 pounds of refrigerant, except commercial and industrial process refrigeration, be repaired when the leak rate exceed what percent of the charge per year?

Answer 4

15 percent

Question 5

When using recovery and recycling equipment manufactured AFTER 11/15/1993, techs must evacuate an appliance component containing more than 200 pounds of CFC-12 to the following level before making a major repair:

Answer 5

15 inches of Hg vacuum

Question 6

Appliances containing CFC refrigerants can be evacuated to atmospheric pressure when:

Answer 6

Leaks in the appliance make evacuation to the prescribed level unattainable

Question 7

When using recovery and recycling equipment manufactured BEFORE 11/15/1993, techs must evacuate an appliance component containing 10 pounds of CFC-500 to the following level before disposing of the appliance:

Answer 7

4 inches of Hg vacuum

Question 8

What repairs are designated as major repairs under EPA regulations?

Answer 8

Replacement of the compressor, condenser, evaporator, or the auxillary heat transfer coils

Question 9

System-dependent recovery equipment CANNOT be used when?

Answer 9

The appliance contains over 15 pounds of refrigerant

Question 10

You are changing out the compressor of a system containing 40 pounds CFC-502. Your recycling equipment was manufactured AFTER 11/15/1993. In addition to isolating the compressor as much as possible, what else should you do?

Answer 10

Evacuate the isolated section of the system to 10 inches of vacuum hold. If system pressure does not rise, remove the compressor

Question 11

Refrigerant has been recovered from an AC system and held in a refillable cylinder, in order to replace the condenser coil. The refrigerant can:

Answer 11

likely be charged back into the system

Question 12

What else can recovered refrigerant contain?

Answer 12

Acids, moisture, oils

Question 13

Recovering refrigerant from a system in vapor phase will minimize loss of:

Answer 13

Oil

Question 14

With an air-cooled condenser on the roof of a building and the evaporator on the first floor, recovery should first occur:

Answer 14

From the liquid line entering the evaporator

Question 15

In general, what is one routine maintenance task which must be performed on most refrigerant recycling machines?

Answer 15

Change oil and filter

Question 16

After refrigerant liquid has been recovered from the appliance, any remaining vapor is:

Answer 16

Condensed by the recovery system

Question 17

Refrigerant should be removed from the condenser outlet when:

Answer 17

The condenser is below the receiver

Question 18

What should be done before transferring refrigerant to an empty cylinder?

Answer 18

Cylinder should be evacuated

Question 19

During evacuation with large amounts of moisture it may be necessary to increase pressure to counteract freezing with gas such as:

Answer 19

Nitrogen

Question 20

Liquid charging of a CFC-12 refrigeration system with risk of freezing is begun with vapor from a vacuum level to a pressure of approximately:

Answer 20

33 psig

Question 21

Noncondensibles in a refrigerant system result in:

Answer 21

Higher discharge pressure (head pressure)

Question 22

The component directly following the evaporator of a refrigeration system is the:

Answer 22

Accumulator

Question 23

A moisture-indicating sight glass is useful for:

Answer 23

Checking the refrigerant’s moisture content

Question 24

Dry nitrogen should be used to break the first vacuum when dehydrating by the double evacuation method. However, the cylinder must use:

Answer 24

A pressure regulator

Question 25

What should be used to leak in an HFC-134a system for leak checking?

Answer 25

Pressurized nitrogen

Question 26

A refrigerant oil that is hygroscopic:

Answer 26

Readily absorbs moisture

Question 27

The term used to describe the fact that a refrigerant blend has a range of boiling or condensing points at a constant pressure is:

Answer 27

Temperature glide

Question 28

When recovering refrigerant, what should be done to the High-pressure system before recovery?

Answer 28

System must be turned off and remain so, and as much as is possible, all solenoid valves should be open.

Question 29

What side is the receiver on in a High-pressure system?

Answer 29

The high-side

Question 30

High-pressure systems have a tendency to “load up” on moisture when opened. What must be done every time these systems are opened?

Answer 30

Change the filter-drier on the liquid line.

Question 31

What are the 3 positions of a King Valve?

Answer 31

1. Refrigerant flow through main line and service gauge. 2. Refrigerant flow through the main line only (backseated). 3. All ports closed.

Question 32

What is the result of an undercharged system due to leaks?

Answer 32

Increase in superheat

Question 33

What is one benefit each of recovering in the liquid phase and recovering in the vapor phase?

Answer 33

Liquid: faster recovery. Vapor: minimize loss of oil.

Question 34

When using a recovery machine for a different refrigerant, what steps should be performed first?

Answer 34

1. Oil must be drained and replaced with new oil for refrigerant. 2. All filters must be replaced. 3. Unit must be evacuated with another recovery machine or a “pump-out” cycle.

Question 35

What should be done to the recovery tank during recovery?

Answer 35

Cool the tank.

Question 36

What state must the appliance be in for recovery?

Answer 36

Turned off with service valves open, and as many solenoids open as possible.