FDNY Q-01 CERTIFICATE OF QUALIFICATION
QUESTIONS AND VERIFIED ANSWERS RECENTLY UPDATED 2026/2027
Covering: Z-51 Written Exam | Refrigeration Systems | Electrical | Safety Codes |
NYC Fire Code
Q.1 Rupture members, when used in parallel with a relief valve,
are not to exceed ___% above designed working pressure.
ANS: 20%
Q.2 Where can a butterfly valve be used?
ANS: On the inlet and outlet of a water pump.
Q.3 What electrical motor protection device automatically
resets itself?
ANS: The thermal protector.
Q.4 746 watts equals how many kilowatt hours?
ANS: 0.746 kilowatt hours.
Q.5 What position is the liquid line service valve normally in?
ANS: Back-seated (fully open).
Q.6 In an operating evaporator, oil stays on top of which
refrigerant?
ANS: Carbon dioxide (R-744).
Q.7 At what pressure does the relief valve blow on a high-
pressure machine?
ANS: 300 psi.
,Q.8 What would indicate a restriction (such as dirt or scale) in
the liquid line?
ANS: Frost immediately after the restriction.
Q.9 What does solubility mean in refrigeration?
ANS: The ability of a refrigerant to mix with other substances.
Q.10 When charging vapor in a compression system, where do
you charge the vapor?
ANS: Suction side of the compressor at the Suction Service Valve.
Q.11 When comparing a brine with a pH of 8 to one with a pH of
10, its alkalinity is:
ANS: 100 times greater.
Q.12 What is the purpose of a liquid line sight glass?
ANS: To detect moisture and verify a full liquid line (no bubbles/flash
gas).
Q.13 What type of compressor uses a piston to compress
refrigerant?
ANS: Reciprocating compressor.
Q.14 What is the refrigeration cycle order?
ANS: Evaporator → Compressor → Condenser → Metering Device
→ back to Evaporator.
Q.15 What does superheat mean in refrigeration?
ANS: The temperature of the refrigerant vapor above its saturation
temperature at a given pressure.
,Q.16 What does subcooling mean?
ANS: The temperature of liquid refrigerant below its saturation
temperature at a given pressure.
Q.17 What is latent heat?
ANS: Heat that causes a change in state without a change in
temperature.
Q.18 What is sensible heat?
ANS: Heat that causes a change in temperature without a change in
state.
Q.19 What unit is used to measure refrigeration capacity?
ANS: Tons of refrigeration (1 ton = 12,000 BTU/hr).
Q.20 What is a BTU?
ANS: British Thermal Unit — the amount of heat required to raise 1 lb
of water 1°F.
SECTION 2: Refrigerants
Q.21 What is the chemical formula for R-22?
ANS: CHClF2 (Chlorodifluoromethane).
Q.22 What refrigerant is known as R-744?
ANS: Carbon dioxide (CO2).
Q.23 What refrigerant is known as R-717?
ANS: Ammonia (NH3).
Q.24 What color cylinder is used for R-22?
ANS: Light green (Clover).
, Q.25 What color cylinder is used for R-134a?
ANS: Light blue (Sky Blue).
Q.26 What color cylinder is used for R-410A?
ANS: Rose/Pink.
Q.27 What color cylinder is used for R-404A?
ANS: Orange.
Q.28 What does ODP stand for?
ANS: Ozone Depletion Potential.
Q.29 What does GWP stand for?
ANS: Global Warming Potential.
Q.30 What does CFC stand for?
ANS: Chlorofluorocarbon.
Q.31 What does HCFC stand for?
ANS: Hydrochlorofluorocarbon.
Q.32 What does HFC stand for?
ANS: Hydrofluorocarbon.
Q.33 Is R-410A an azeotropic or zeotropic blend?
ANS: Near-azeotropic (behaves like a pure refrigerant).
Q.34 What is fractionation?
QUESTIONS AND VERIFIED ANSWERS RECENTLY UPDATED 2026/2027
Covering: Z-51 Written Exam | Refrigeration Systems | Electrical | Safety Codes |
NYC Fire Code
Q.1 Rupture members, when used in parallel with a relief valve,
are not to exceed ___% above designed working pressure.
ANS: 20%
Q.2 Where can a butterfly valve be used?
ANS: On the inlet and outlet of a water pump.
Q.3 What electrical motor protection device automatically
resets itself?
ANS: The thermal protector.
Q.4 746 watts equals how many kilowatt hours?
ANS: 0.746 kilowatt hours.
Q.5 What position is the liquid line service valve normally in?
ANS: Back-seated (fully open).
Q.6 In an operating evaporator, oil stays on top of which
refrigerant?
ANS: Carbon dioxide (R-744).
Q.7 At what pressure does the relief valve blow on a high-
pressure machine?
ANS: 300 psi.
,Q.8 What would indicate a restriction (such as dirt or scale) in
the liquid line?
ANS: Frost immediately after the restriction.
Q.9 What does solubility mean in refrigeration?
ANS: The ability of a refrigerant to mix with other substances.
Q.10 When charging vapor in a compression system, where do
you charge the vapor?
ANS: Suction side of the compressor at the Suction Service Valve.
Q.11 When comparing a brine with a pH of 8 to one with a pH of
10, its alkalinity is:
ANS: 100 times greater.
Q.12 What is the purpose of a liquid line sight glass?
ANS: To detect moisture and verify a full liquid line (no bubbles/flash
gas).
Q.13 What type of compressor uses a piston to compress
refrigerant?
ANS: Reciprocating compressor.
Q.14 What is the refrigeration cycle order?
ANS: Evaporator → Compressor → Condenser → Metering Device
→ back to Evaporator.
Q.15 What does superheat mean in refrigeration?
ANS: The temperature of the refrigerant vapor above its saturation
temperature at a given pressure.
,Q.16 What does subcooling mean?
ANS: The temperature of liquid refrigerant below its saturation
temperature at a given pressure.
Q.17 What is latent heat?
ANS: Heat that causes a change in state without a change in
temperature.
Q.18 What is sensible heat?
ANS: Heat that causes a change in temperature without a change in
state.
Q.19 What unit is used to measure refrigeration capacity?
ANS: Tons of refrigeration (1 ton = 12,000 BTU/hr).
Q.20 What is a BTU?
ANS: British Thermal Unit — the amount of heat required to raise 1 lb
of water 1°F.
SECTION 2: Refrigerants
Q.21 What is the chemical formula for R-22?
ANS: CHClF2 (Chlorodifluoromethane).
Q.22 What refrigerant is known as R-744?
ANS: Carbon dioxide (CO2).
Q.23 What refrigerant is known as R-717?
ANS: Ammonia (NH3).
Q.24 What color cylinder is used for R-22?
ANS: Light green (Clover).
, Q.25 What color cylinder is used for R-134a?
ANS: Light blue (Sky Blue).
Q.26 What color cylinder is used for R-410A?
ANS: Rose/Pink.
Q.27 What color cylinder is used for R-404A?
ANS: Orange.
Q.28 What does ODP stand for?
ANS: Ozone Depletion Potential.
Q.29 What does GWP stand for?
ANS: Global Warming Potential.
Q.30 What does CFC stand for?
ANS: Chlorofluorocarbon.
Q.31 What does HCFC stand for?
ANS: Hydrochlorofluorocarbon.
Q.32 What does HFC stand for?
ANS: Hydrofluorocarbon.
Q.33 Is R-410A an azeotropic or zeotropic blend?
ANS: Near-azeotropic (behaves like a pure refrigerant).
Q.34 What is fractionation?
