HVAC: EPA 608 Certification Study Guide
After removal of liquid, about how tons vapor will stay in the gadget on a 350 ton R-11 chiller? -
ANS-100lbs
Are there drop-in replacements for R-12 structures? Why or why not? - ANS-No due to the fact
the new refrigerants are incompatible with the oils and lubricants used in R-12 structures.
ASHRAE Standard 15-1994 - ANS-Requires refrigerant sensor to be able to sound alarm and
mechanically begin ventilation device in occupied equipment rooms where refrigerant from leak
will listen
At what point inside the device must you fee a low pressure device and what ought to you start
the charge with? - ANS-Charge through the evaporator charging valve as that is the bottom
point on a low strain device. First price the device with vapor until the refrigeration saturation
temperature reaches 36 tiers F or the vapor pressure reaches sixteen.9" Hg vacuum
Bubble Point - ANS-Occurs while saturation temp in condenser modifications refrigerant from
vapor to liquid
Compound Gauge - ANS-Typically blue and measures low pressure (psig) and vacuum (inHg).
Compressor - ANS-Takes low strain, low temp vapor and changes it to a high-temp,
excessive-stress, superheated vapor and offers it to the condenser
Condenser - ANS-Rejects heat from gadget and changes refrigerant from excessive-temp,
excessive-pressure vapor into high-strain, high-temp liquid
Describe two methods to hurry up restoration - ANS-Pack the restoration cylinder in ice and/or
practice warmth to the appliance. Recover as a good deal as viable in the liquid section.
Dew Point - ANS-Occurs while saturation temp in evaporator reasons refrigerant to change from
liquid to vapor
Does refrigerant exit of the system in low pressure or does air and moisture move in? Why? -
ANS-A low-stress system operates in a vacuum (beneath atmospheric pressure) to enter the
refrigeration machine.
Evaporator - ANS-Absorbs heat into device from area to be cooled. Absorption of heat reasons
refrigerant to boil. Upon leaving, refrigerant changed to low pressure, low temperature vapor
, Find strain for R-22 at 70 degree F. - ANS-121.Four psi
Find the pressure for R-12 at eighty tiers F. - ANS-84.Four psi
Foaming at start-up may be located in what component? What does this suggest? -
ANS-Refrigerant inside the oil will motive oil foaming in the compressor at start-up
High Pressure Gauge - ANS-Red and measures high aspect (discharge) pressure. 0 to 500 psi
How are you able to take a look at if a tank includes excess air or non-condensables? -
ANS-Check stress internal restoration tank after allowing temp of cylinder to stabilize to room
temperature
How are you able to release trapped refrigerants within the oil? - ANS-Necessary to heat and
faucet compressor with mallet several times or use vacuum pump
How can you speed up the vapor recuperation procedure on Type III structures? - ANS-A heater
at the healing vessel side will help evacuate the vapor quicker
How does a centrifugal purge unit paintings? - ANS-A centrifugal purge unit takes its suction
from the top of the condenser, removes the air from the gadget, and returns the refrigerant to
the evaporator.
How many inches of mercury vacuum is needed for HCFC-22 appliances containing greater
than 200lbs. Of refrigerant using system after Nov. 15th, 1993. - ANS-0 Inches Hg
How should you get better refrigerant from a parallel machine? Why? - ANS-Isolate a parallel
compressor device which will recover refrigerant. Failure to isolate a parallel compressor device
will purpose an open equalization with a view to save you refrigerant recovery
How often need to refillable cylinders be hydrostatically tested? - ANS-five years
How must a technician get better refrigerant from a device the use of R-11 or R-123? -
ANS-Remove the liquid first and get better the remaining vapor
How should a technician deal with the oil before removal and why? - ANS-A temperature of one
hundred thirty tiers F must be attained first.
How must a water box be leak examined? - ANS-Be certain water has been eliminated, then
vicinity the leak detector probe in through the drain valve.
How will activating a defrost timer aid in recovery method? - ANS-Help vaporize any trapped
liquid refrigerant
After removal of liquid, about how tons vapor will stay in the gadget on a 350 ton R-11 chiller? -
ANS-100lbs
Are there drop-in replacements for R-12 structures? Why or why not? - ANS-No due to the fact
the new refrigerants are incompatible with the oils and lubricants used in R-12 structures.
ASHRAE Standard 15-1994 - ANS-Requires refrigerant sensor to be able to sound alarm and
mechanically begin ventilation device in occupied equipment rooms where refrigerant from leak
will listen
At what point inside the device must you fee a low pressure device and what ought to you start
the charge with? - ANS-Charge through the evaporator charging valve as that is the bottom
point on a low strain device. First price the device with vapor until the refrigeration saturation
temperature reaches 36 tiers F or the vapor pressure reaches sixteen.9" Hg vacuum
Bubble Point - ANS-Occurs while saturation temp in condenser modifications refrigerant from
vapor to liquid
Compound Gauge - ANS-Typically blue and measures low pressure (psig) and vacuum (inHg).
Compressor - ANS-Takes low strain, low temp vapor and changes it to a high-temp,
excessive-stress, superheated vapor and offers it to the condenser
Condenser - ANS-Rejects heat from gadget and changes refrigerant from excessive-temp,
excessive-pressure vapor into high-strain, high-temp liquid
Describe two methods to hurry up restoration - ANS-Pack the restoration cylinder in ice and/or
practice warmth to the appliance. Recover as a good deal as viable in the liquid section.
Dew Point - ANS-Occurs while saturation temp in evaporator reasons refrigerant to change from
liquid to vapor
Does refrigerant exit of the system in low pressure or does air and moisture move in? Why? -
ANS-A low-stress system operates in a vacuum (beneath atmospheric pressure) to enter the
refrigeration machine.
Evaporator - ANS-Absorbs heat into device from area to be cooled. Absorption of heat reasons
refrigerant to boil. Upon leaving, refrigerant changed to low pressure, low temperature vapor
, Find strain for R-22 at 70 degree F. - ANS-121.Four psi
Find the pressure for R-12 at eighty tiers F. - ANS-84.Four psi
Foaming at start-up may be located in what component? What does this suggest? -
ANS-Refrigerant inside the oil will motive oil foaming in the compressor at start-up
High Pressure Gauge - ANS-Red and measures high aspect (discharge) pressure. 0 to 500 psi
How are you able to take a look at if a tank includes excess air or non-condensables? -
ANS-Check stress internal restoration tank after allowing temp of cylinder to stabilize to room
temperature
How are you able to release trapped refrigerants within the oil? - ANS-Necessary to heat and
faucet compressor with mallet several times or use vacuum pump
How can you speed up the vapor recuperation procedure on Type III structures? - ANS-A heater
at the healing vessel side will help evacuate the vapor quicker
How does a centrifugal purge unit paintings? - ANS-A centrifugal purge unit takes its suction
from the top of the condenser, removes the air from the gadget, and returns the refrigerant to
the evaporator.
How many inches of mercury vacuum is needed for HCFC-22 appliances containing greater
than 200lbs. Of refrigerant using system after Nov. 15th, 1993. - ANS-0 Inches Hg
How should you get better refrigerant from a parallel machine? Why? - ANS-Isolate a parallel
compressor device which will recover refrigerant. Failure to isolate a parallel compressor device
will purpose an open equalization with a view to save you refrigerant recovery
How often need to refillable cylinders be hydrostatically tested? - ANS-five years
How must a technician get better refrigerant from a device the use of R-11 or R-123? -
ANS-Remove the liquid first and get better the remaining vapor
How should a technician deal with the oil before removal and why? - ANS-A temperature of one
hundred thirty tiers F must be attained first.
How must a water box be leak examined? - ANS-Be certain water has been eliminated, then
vicinity the leak detector probe in through the drain valve.
How will activating a defrost timer aid in recovery method? - ANS-Help vaporize any trapped
liquid refrigerant
