ABYC SYSTEMS CERTIFICATION
EXAM REVIEW QUESTIONS AND
ANSWERS
2-3 times the regulator delivery pressure - Answer-At what pressure must the low-side
relief valve of LPG system discharge
20 inches - Answer-what is the minimal allowable distance between LPG relief /
overboard discharge and any opening to cabin or hull interior?
True - Answer-T or F: LPG lockers must be designed to open only directly to the outside
atmosphere.
1/2 inch ID - Answer-LPG lockers must be vented at the bottom of the locker by a
dedicated vent with what minimum diameter?
to a point lower than the locker bottom, but above waterline and not within 20 inches of
any other hull or compartment opening - Answer-Where must LPG locker vents be led
outboard?
False - Answer-T or F: An LPG locker is not required for storage of an an unconnected
(reserve) LPG cylinder.
False - end fittings must be permanently attached (i.e., swaged sleeve or threaded
inserts only) - Answer-T or F: Flexible LPG hose must be connected with double hose
clamps on each connector.
True. Short nut fittings (used in refrigeration) can fail due to vibration fatigue - Answer-T
of F: Metal LPG tubing shall be connected with "long nut" type flare fittings .
34.5 kPa or 5 PSI - Answer-What pressure is used to test LPG fuel supply line and
fittings?
At least 3 minutes - Answer-When testing an installed LPG system using the built-in
pressure gauge, for how long must there be no measurable drop in pressure after
closing the cylinder supply valve?
Ammonia - may cause cracks in brass fittings - Answer-What ingredient should never
be used when cleaning brass LPG fittings?
,False. LPG is heavier than air and will fall when released. - Answer-T or F: LPG is
lighter than air and will rise when released.
True. But it can displace air necessary to breathe and cause asphyxiation. By law LPG
has an odorous gas added to facilitate leak detection by smell. - Answer-T or F: in its
natural form, LPG is non-toxic and has no smell
True - Answer-T or F: Compared to CNG, LPG has a higher caloric value and is stored
at lower pressure.
True - Answer-T or F: CNG is lighter than air.
Evaporation = 45 °F, condensing = 130 °F - Answer-What are the reference evaporation
and condensing temperatures used for AIR cooled air conditioning compressors when
specifying cooling capacity?
Evaporation = 45 °F, condensing = 100 °F - Answer-What are the reference evaporation
and condensing temperatures used for WATER cooled air conditioning compressors
when specifying cooling capacity?
ethylene glycol - Answer-What type of anti-freeze is toxic and not allowed for cooling of
potable water or holding plates of cold storage for food?
True - Answer-If electrical resistance heating elements are installed in air handling
systems, they must have both primary and backup over-temperature protection devices
that interrupt current to the heating element.
UL 181 - Answer-What specification is required for flexible air ducts in AC systems?
False - Answer-T or F: Air conditioning systems that service engine rooms may also
serve accommodation spaces.
True - Answer-T or F: condensate drain lines shall have a trap installed.
3 feet or more (at the hull exterior) - Answer-How far from engine exhaust system output
must evaporator condensate drains terminate?
5 lbs (2.2 kg) - Answer-A high pressure shut-down safety mechanism is a required
feature for refrigerant systems with more than how much refrigerant? (weight)
48 inches - Answer-What is the minimum distance between support clamps for
refrigerant piping?
6 inches (except discharge lines that provide for manual drainage) - Answer-To reduce
the possibility of rupture due to freezing, all A/C overboard discharge lines above the
water line shall be self-draining within what distance of the hull?
, Waist height or higher - Answer-For A/C ducts, how high (typically) should cool air
output "supply" ducts be mounted in the cabin?
Low, near the floor - Answer-For A/C return air ducts, should the cabin intake be
mounted high or low?
Return ducts should be 20% larger than supply ducts - Answer-What is the relative size
difference between AC supply and return ducts?
wood - to minimize condensation - Answer-Should AC discharge (supply) vents be
grilled with metal or wood?
400 cfm / ton - Answer-What is the minimum accepted air flow (in cabin feet per minute)
over the indoor coil on a heat pump (per ton)?
OC may trip if air pressure is too high - Answer-what might happen to OC protection on
a compressor pump if the air filter is excessively dirty?
used to verify cabin air ducting is isolated from engine room ventilation - Answer-What
is a common use for a smoke bomb?
Heating, Air Conditioning, Refrigeration breaker - rated for motor loads typically found in
such applications - Answer-What is HACR breaker?
3.412 BTU's Per hour = 1 Watt - Answer-1 Watt equals how many BTU's per hour?
~ 250% - Answer-By what percentage does a start capacitor increase motor torque?
Helps decrease amperage by increasing power factor (efficiency) and also provide
slight increase in torque. - Answer-What does a motor "run" capacitor do?
Start windings have higher resistance than run windings. - Answer-Which has a higher
resistance: motor start winding or run winding?
a. 0.4 PSI - Answer-Which of the following is a typical working pressure of LP gas (after
the pressure regulator)?
a. 0.4 PSI
b. 14 PSI
c. 24 PSI
d. 300 PSI
B. the diameter of the drain - Answer-According to ABYC, all of the following
considerations need to be given to evaporator condensate drains, EXCEPT:
A. contain a P-trap to prevent ingress of CO
B. the diameter of the drain
EXAM REVIEW QUESTIONS AND
ANSWERS
2-3 times the regulator delivery pressure - Answer-At what pressure must the low-side
relief valve of LPG system discharge
20 inches - Answer-what is the minimal allowable distance between LPG relief /
overboard discharge and any opening to cabin or hull interior?
True - Answer-T or F: LPG lockers must be designed to open only directly to the outside
atmosphere.
1/2 inch ID - Answer-LPG lockers must be vented at the bottom of the locker by a
dedicated vent with what minimum diameter?
to a point lower than the locker bottom, but above waterline and not within 20 inches of
any other hull or compartment opening - Answer-Where must LPG locker vents be led
outboard?
False - Answer-T or F: An LPG locker is not required for storage of an an unconnected
(reserve) LPG cylinder.
False - end fittings must be permanently attached (i.e., swaged sleeve or threaded
inserts only) - Answer-T or F: Flexible LPG hose must be connected with double hose
clamps on each connector.
True. Short nut fittings (used in refrigeration) can fail due to vibration fatigue - Answer-T
of F: Metal LPG tubing shall be connected with "long nut" type flare fittings .
34.5 kPa or 5 PSI - Answer-What pressure is used to test LPG fuel supply line and
fittings?
At least 3 minutes - Answer-When testing an installed LPG system using the built-in
pressure gauge, for how long must there be no measurable drop in pressure after
closing the cylinder supply valve?
Ammonia - may cause cracks in brass fittings - Answer-What ingredient should never
be used when cleaning brass LPG fittings?
,False. LPG is heavier than air and will fall when released. - Answer-T or F: LPG is
lighter than air and will rise when released.
True. But it can displace air necessary to breathe and cause asphyxiation. By law LPG
has an odorous gas added to facilitate leak detection by smell. - Answer-T or F: in its
natural form, LPG is non-toxic and has no smell
True - Answer-T or F: Compared to CNG, LPG has a higher caloric value and is stored
at lower pressure.
True - Answer-T or F: CNG is lighter than air.
Evaporation = 45 °F, condensing = 130 °F - Answer-What are the reference evaporation
and condensing temperatures used for AIR cooled air conditioning compressors when
specifying cooling capacity?
Evaporation = 45 °F, condensing = 100 °F - Answer-What are the reference evaporation
and condensing temperatures used for WATER cooled air conditioning compressors
when specifying cooling capacity?
ethylene glycol - Answer-What type of anti-freeze is toxic and not allowed for cooling of
potable water or holding plates of cold storage for food?
True - Answer-If electrical resistance heating elements are installed in air handling
systems, they must have both primary and backup over-temperature protection devices
that interrupt current to the heating element.
UL 181 - Answer-What specification is required for flexible air ducts in AC systems?
False - Answer-T or F: Air conditioning systems that service engine rooms may also
serve accommodation spaces.
True - Answer-T or F: condensate drain lines shall have a trap installed.
3 feet or more (at the hull exterior) - Answer-How far from engine exhaust system output
must evaporator condensate drains terminate?
5 lbs (2.2 kg) - Answer-A high pressure shut-down safety mechanism is a required
feature for refrigerant systems with more than how much refrigerant? (weight)
48 inches - Answer-What is the minimum distance between support clamps for
refrigerant piping?
6 inches (except discharge lines that provide for manual drainage) - Answer-To reduce
the possibility of rupture due to freezing, all A/C overboard discharge lines above the
water line shall be self-draining within what distance of the hull?
, Waist height or higher - Answer-For A/C ducts, how high (typically) should cool air
output "supply" ducts be mounted in the cabin?
Low, near the floor - Answer-For A/C return air ducts, should the cabin intake be
mounted high or low?
Return ducts should be 20% larger than supply ducts - Answer-What is the relative size
difference between AC supply and return ducts?
wood - to minimize condensation - Answer-Should AC discharge (supply) vents be
grilled with metal or wood?
400 cfm / ton - Answer-What is the minimum accepted air flow (in cabin feet per minute)
over the indoor coil on a heat pump (per ton)?
OC may trip if air pressure is too high - Answer-what might happen to OC protection on
a compressor pump if the air filter is excessively dirty?
used to verify cabin air ducting is isolated from engine room ventilation - Answer-What
is a common use for a smoke bomb?
Heating, Air Conditioning, Refrigeration breaker - rated for motor loads typically found in
such applications - Answer-What is HACR breaker?
3.412 BTU's Per hour = 1 Watt - Answer-1 Watt equals how many BTU's per hour?
~ 250% - Answer-By what percentage does a start capacitor increase motor torque?
Helps decrease amperage by increasing power factor (efficiency) and also provide
slight increase in torque. - Answer-What does a motor "run" capacitor do?
Start windings have higher resistance than run windings. - Answer-Which has a higher
resistance: motor start winding or run winding?
a. 0.4 PSI - Answer-Which of the following is a typical working pressure of LP gas (after
the pressure regulator)?
a. 0.4 PSI
b. 14 PSI
c. 24 PSI
d. 300 PSI
B. the diameter of the drain - Answer-According to ABYC, all of the following
considerations need to be given to evaporator condensate drains, EXCEPT:
A. contain a P-trap to prevent ingress of CO
B. the diameter of the drain
