Chapter 9 Flashcards
Meeting that took place to set reduction rates of refrigerants that were destroying the ozone
Montreal protocol
Used to prevent the loss of refrigerant
Low loss fitting
To process refrigerant to like new specifications
Refrigerant Reclaim
Use of a recovery machine to remove refrigerant from a system
Active Recovery
Oil used with HFC refrigerant
Polyolester (POE) oil
blend of two or more refrigerants that behave like a pure refrigerant
Azeotrope
Consists of three oxygen molecules located in the stratosphere
Ozone
When one or more refrigerants in a blend condense or evaporate at different rates than other refrigerants
fractionation
Use of the system compressor or internal pressure to recover refrigerant
passive recovery
non-ozone depleting refrigerant that does not contain chlorine or fluorine
Hydrocarbon (HC)
valve that allows refrigerant to be charged or discharged from a system
Schrader valve
Oil used mainly in automobile refrigeration systems
PAG oil
warming process caused by the atmospheres absorption of heat energy radiated from the Earths surface
Greenhouse effect
Index used to read chemicals that cause damage to the ozone layer in the stratosphere
Ozone Depletion Potential (ODP) index
How do you check a recovery cylinder to see if there is oil in it without removing the valve assembly?
a. Attach a pressure gauge and check the vapor pressure.
b. Remove the refrigerant, weigh the cylinder and compare it to the TW.
c. Heat the cylinder and see if any oil vapor comes out of the vapor valve.
d. Pressurize the cylinder with nitrogen through the vapor valve to see if any oil comes out of the liquid valve.
b. Remove the refrigerant, weigh the cylinder and compare it to the TW.
When using recovery equipment manufactured before November 15, 1993, what is the evacuation level for medium pressure appliances with the charge of less than 200 pounds?
a. O in Hg vacuum
b. 4 in Hg vacuum
c. 10 in Hg vacuum
d. 15 in Hg vacuum
b. 4 inches Hg vacuum
The name/data plate on a hermetic compressor shows a lock rotor amp (LRA) rating of 30A. What is the rated load amp (RLA) rating of the compressor?
a. 25A
b. 10A
c. 6A
d. 5A
c. 6A
(divide LRA by 5; 30 Amps / 5 = 6 Amps)
When naming refrigerants, what does the upper-case letter after the number signify/indicate for R-407A?
a. It is a blended refrigerant.
b. It is an Isomer of R-407
c. Same number of atoms but the molecular arrangement is different.
d. Same ingredients of R-407 but the proportions of the ingredients are different.
d. Same ingredients of R-407 but the proportions of the ingredients are different.
T/F
When working on systems that use. flammable refrigerants, technicians should use non-sparking/spark-proof tools.
True
T/F
Concentration of flammable refrigerant gas in the air above the upper exposure limit (UEL) will not ignite.
True
T/F
Good ozone is in the troposphere.
False
T/F
Ozone is produced through plant photosynthesis and the bonding of standard
oxygen molecules (Oz) with free oxygen (O) atoms.
True
T/F
HC refrigerants are classified in the A3 group meaning they are non-toxic and non-flammable.
False
ASHRAE Flammability and Toxicity Chart
T/F
When using propane as a refrigerant, ensure that it is refrigerant-grade and not fuel grade.
True
T/F
The lower case letter after the refrigerant number indicates that the refrigerant is an isomer of the numbered refrigerant, meaning it has the same molecular makeup but the atoms are arranged differently.
True
T/F
Three groups of mineral oil are naphthenic, aromatic and paraffinic.
True
T/F
HFC refrigerants work best with alkylbenzene oil.
False
CFC and HCFC use Alkylbenzene Oil
T/F
POE oil stored in plastic containers can be contaminated by moisture that penetrates the plastic walls of the container.
True
T/F
If refrigerant is not going to be transported after recovery but reintroduced after a system repair, the liquid density of the refrigerant used to calculate recovery cylinder capacity can be replaced with 77°F instead of 130°F.
True
A high pressure reading in a recovery tank is an indication of what?
Contaminants in the refrigerant
Draw a picture of refrigerant being recovered from a system using the following components:
2-valve three hose manifold, recovery machine filter, dryer, refrigerant scale, and recovery cylinder.
When using the Appion method of recovering refrigerant, at what pressure will you flip the recovery cylinder back to the upright position and open the blue valve on the manifold?
75-100 psig
The fastest method of removing refrigerant from a system is to take it out in the ___________ state.
Liquid State
List four ways to speed up recovering refrigerant from a system.
- Liquid State
- Shorter Hoses
- Recovery Hose
- 4-valve 4-hose manifold
How are the internal components of an oil-less recovery unit lubricated?
By the refrigerant
What is used to store refrigerant from a system when using the passive recovery method?
A recovery cylinder in vacuum
Very high-pressure refrigerants have liquid saturation pressures above 340 pig at a liquid saturation temperature of 104°F. Which refrigerant is an example of a very high-pressure refrigerant?
a. R-134a
b. R744
c. R-12
d. R-410A
b. R744
What is the minimum type of EPA certification required to service medium, high and very high-pressure appliances?
a. Core and Type I
b. Core and Type lI
c. Core and Type Ill
d. Core and Types I, Il and III (Universal)
b. Core and Type lI
How many chlorine atoms does it take to destroy 5,000,000 ozone molecules?
50 Chlorine Atoms
(1 chlorine atom -> 100,000 ozone molecules)
Data/Name plate on a condensing unit shows a factory charge of 149 oz of R-410A refrigerant. Only 3 lbs 14 oz was removed so the leak in the system could be sealed. How much refrigerant leaked out of the system. Give your answer in pounds and ounces.
(oz -> lbs = divide by 16 | lbs -> oz = multiply by 16)
(oz -> lbs = divide by 16 | lbs -> oz = multiply by 16)
Step 1: 149 oz = 9.3126
Step 2: 3lbs 14oz = 3.875
Step 3 9.3126 - 3.875 = 5.4375
Step 4 5.4375 = 5lbs and 7oz
5lbs and 7oz leaked out of the system
When using a solder-on piercing valve, how do you leak check the fitting before piercing the tubing?
Dry Nitrogen
What is the recovery percentage for a small appliance when using a recovery machine manufactured after November 15, 1993?
90%
What device prevents a recovery cylinder from being overfilled with refrigerant and oil when a cylinder is filled only by weight?
Float Switch
