R123
HCFC
CFC's were no longer manufactored or imported into the US after
1995
When using nitrogen to pressurize a system you should always?
charge through a pressure regulator
The EPA requires the installation of a service repair aperture or process stub on all appliances using s class 1 or 2 substance as a refrigerant. the main purpose is to make it easier to
recover refrigerant
R500
CFC
It has been illegal to vent subsistutes for CFC and HCFC refrigerants since
November 1995
Synthetic lubricant presently used with tenerary blends containing HCFC is
alkylbenzene
Refrigerant enters the exspansion or throttling device is a
liquid
R410A
HFC
R22
HCFC
Refrigerant leaves the system as a
high pressure liquid
In a refrigeration system the device that changes a low pressure vapor to a high pressure vapor is the
compressor
Ozone Depletion potential is
a measure of the abilit of CFC's & HCFC's to destroy the ozone
In a refrigeration system, high pressure vapor is converted to high pressure liquid in the
condenser
R13
is a "very high pressure refrigerant" under EPA regulations
A hermetic compressor must never be operated when
there is a dehydration vacuum in the system
Recovery equipment that relies upopn the pressure of the refrigerant in the appliance would be considered
System-Dependent
ozone in the stratosphere above the earth consists of
molecules of 3 oxygen atoms
Azeotropic refrigerant mixture can
act like a single-component refrigerant over its entire range
Refrigerant that enters the compressor under normal operating condidtions is a
low pressure liquid
R12
CFC
ester based oils can be mixed with
no other oils
R134a
HFC
Self contained recovery devices
has its own means of drawing refrigerant out of the system and is capable of removing the refrigerant (liquid and/or vapor) from an appliance without the assistance
The evaporation temperature of R134a at )psig is
-15F
The EPA regulations requires that any appliances containing more than 50 pounds of refrigerant must be repaired when the leak rate exceeds_____ of the charge per year
15%
CFC's will no longer be manufactured or imported to the US after
1995
Recovery equpiment used for the service or repair of small appliances must be certified by an EPA approved lab if the recovery equipment was made after
Novemnber 1993
Recovery devices that were manufactured after November 1993 and are used for recovery of refrigerant from small appliances must be capable of
recovering 90% of the refrigerant when the compressor is operating or achieving a 4" vacuum under the conditions of ARI-740-1993
When ever nitrogen is used to pressurize or blow debris out of the system, the nitrogen
can be vented
A passive system-dependent recovery device for a small appliance
captures refrigerant in a non-pressurized container
According to the EPA which recovery equipment maintenance practices should be preformed on a regular basis?
check recovery tank for refrigerant leaks
A standard vacuum pump designed specifically for evacuatiopn and dehydration can
never be used as a recovery device in combination with pressurized container
Heat pumps that use R134a should be leaked checked with
pressurized nitrogen
The EPA regulations require that any appliances containing more than 50lbs of refrigerant must be repaired when the leak rate exceeds____ of the charge per year
15%
Recovered refrigerant may contain
oils, moisture, acids
Refrigerant should be removed from the condenser outlet if the
condenser is below the reciever
R11, R12
CFC
R410A requires recovery tanks rated for at least
400psig
After refrigerant liquid has been removed from a system any reamaining vapor is
condensed by the recovery system
R410A requires a high pressure manifold gauge and hose set. They must have a
4000psig burst pressure and 800psig working pressure
To change the compressor on a system containing 40lbs of R500, using a recycling machine the was made after 11-15-93 you must isolate the compressor then
Evacuate the isolated section of the system to 10" of the vacuum and hold. If system pressure does not rise, remove the compressor
A system can be evacuated to only atmospheric pressure when
leaks in the system make evacuation to prescribed level unattainable
When using recovery or recycling equipment that was made after 11-15-93 you must evacuate a system containing more than 200lbs of CFC-12 to ____ before making a major repair
15 inches if HG vacuum
Noncondensables in a system cause a
higher discharge pressure
When charging an R410A system that uses a water cooled condenser you must first charge with vapor to a pressure of at least
120psig before switching to liquid charging
Oil foaming usally occurs in the
compressor
When charging an R12 refrigeration system that uses a water-cooled condenser, you must first charge with vapor to a pressure of at least
35 psig before switching to liquid charging
Every air conditioning or refrigeration should be protected by a
pressure relief device
According to ASHRAE guideline 3-1996 if the pressure in a system rises from 1mm Hg to a level above
2.5 mm Hg during a standing vacuum test the system should be checked for leaks
A typical setting for the high pressure cut out control on a recovery unit used for evacuating the refrigerant from a low pressure chiller is
10 psig
To determine how much vapor to charge into an evacuated chiller you should charge with vapor until
the system pressure corresponds to a refrigerant saturation tempature of 36F
refrigerant 11 at 14.7 psia will boil about
74.5F