ABYC SYSTEMS CERTIFICATION
QUESTIONS AND ANSWERS
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?
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
C. drains overboard or into a bilge area other than shared by an engine
D. orient the containment pan to facilitate complete drainage
Both are correct - Answer-Tech A says that crushed or restricted ducting may cause
icing in the evaporator. Tech B says that dirty air filters at the evaporator may cause
icing. Which is correct? A, B, Both, or Neither?
It may explode. - Answer-What may happen to an air-conditioner starting capacitor if it
is exposed to constant line voltage?
24 hours - Answer-For how long must a bilge pump be capable of continual operation at
design voltage and maximal amperage?
7 hours without creating a fire hazard (exception: integral auto-shut-off by design) -
Answer-For how long must a bilge pump be capable of operating while dry?
Piston, Impeller, Diaphragm, Centrifugal - Answer-Name the four main categories of
pump types
intake or discharge lift (head)
discharge hose length
hose bends (qty and radius)
hose interior roughness (corrugation)
cross-sectional reductions (check valves, thru-hulls, etc.) - Answer-Name four
mechanical (non-electrical) factors that affect pump efficiency
Seacock valve and vented loop (or siphon break) - Answer-what two items are
necessary for a pump to discharge below waterline?
when necessary to prevent automatic cycling due to back-flow from discharge line -
Answer-What is the only allowable use case for a check-valve in a bilge pump system?
inability to pass solids or abrasive material - Answer-What is the major downfall of gear-
type (variable volume) pumps?
False - Answer-T or F: Centrifugal pumps are self-priming
False - Answer-T or F: Centrifugal pumps may be damaged by running dry
QUESTIONS AND ANSWERS
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?
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
C. drains overboard or into a bilge area other than shared by an engine
D. orient the containment pan to facilitate complete drainage
Both are correct - Answer-Tech A says that crushed or restricted ducting may cause
icing in the evaporator. Tech B says that dirty air filters at the evaporator may cause
icing. Which is correct? A, B, Both, or Neither?
It may explode. - Answer-What may happen to an air-conditioner starting capacitor if it
is exposed to constant line voltage?
24 hours - Answer-For how long must a bilge pump be capable of continual operation at
design voltage and maximal amperage?
7 hours without creating a fire hazard (exception: integral auto-shut-off by design) -
Answer-For how long must a bilge pump be capable of operating while dry?
Piston, Impeller, Diaphragm, Centrifugal - Answer-Name the four main categories of
pump types
intake or discharge lift (head)
discharge hose length
hose bends (qty and radius)
hose interior roughness (corrugation)
cross-sectional reductions (check valves, thru-hulls, etc.) - Answer-Name four
mechanical (non-electrical) factors that affect pump efficiency
Seacock valve and vented loop (or siphon break) - Answer-what two items are
necessary for a pump to discharge below waterline?
when necessary to prevent automatic cycling due to back-flow from discharge line -
Answer-What is the only allowable use case for a check-valve in a bilge pump system?
inability to pass solids or abrasive material - Answer-What is the major downfall of gear-
type (variable volume) pumps?
False - Answer-T or F: Centrifugal pumps are self-priming
False - Answer-T or F: Centrifugal pumps may be damaged by running dry
