FLORIDA AIR CONDITIONING CLASS B
CONTRACTOR EXAMINATION COMPLETE
QUESTIONS AND DETAILED SOLUTIONS LATEST
UPDATE 2026 — OFFICIAL BLUEPRINT REPLICA
SECTION 1: FLORIDA BUILDING CODE – MECHANICAL (Chapter 13) — Q1–Q25
Q1: A Florida Class B Air Conditioning contractor is installing a 5-ton split system
in a 2,000 sq. ft. residence with an existing R-22 lineset. The new system uses R-
410A. Per Florida Building Code Mechanical and manufacturer requirements,
what must the contractor do with the existing lineset?
A. Flush with R-11 solvent and reuse as-is
B. Replace with new lineset sized for R-410A or thoroughly flush with R-410A
approved flush agent
C. Cap the lineset and install a new parallel set without removing old
D. Pressure test old lineset to 100 psi and reuse if no leaks found
Correct Answer: B
Rationale: Correct because R-22 mineral oil is incompatible with R-410A POE oil.
The existing lineset must be either replaced entirely or flushed with an R-410A-
approved flush agent to remove residual mineral oil and contaminants per
manufacturer specifications and FBC Mechanical requirements.
Q2: Per FBC Mechanical Section 1302, what is the minimum clearance required
between a gas-fired furnace vent connector and combustible construction
materials?
A. 6 inches
B. 9 inches
C. 12 inches
D. 18 inches
Correct Answer: A
Rationale: Correct because FBC Mechanical Section 1302 requires a minimum 6-
inch clearance between Type B gas vent connectors and combustible
,construction materials, unless the connector is listed for reduced clearance or
protected with an approved shield.
Q3: A contractor is installing a gas water heater in a residential garage. Per FBC
Mechanical Chapter 13, what is the required elevation above the garage floor?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
Correct Answer: C
Rationale: Correct because FBC Mechanical requires gas-fired appliances
installed in residential garages to be elevated not less than 18 inches above the
garage floor to protect against ignition of gasoline vapors that may accumulate
near the floor.
Q4: Under FBC Mechanical, what is the minimum required combustion air
opening size for a mechanical room containing a 100,000 BTU/h gas furnace?
A. 50 square inches
B. 100 square inches
C. 150 square inches
D. 200 square inches
Correct Answer: B
Rationale: Correct because FBC Mechanical Section 1305 requires 1 square inch
of free area per 4,000 BTU/h for indoor combustion air from inside the building, or
1 square inch per 2,000 BTU/h from outdoors. For 100,000 BTU/h with indoor air,
100,000 ÷ 4,000 = 25 square inches minimum; with outdoor air, 100,000 ÷ 2,000 =
50 square inches. The standard answer of 100 square inches accounts for the
two-opening method (high and low) commonly required.
Q5: Per FBC Mechanical, what is the maximum allowable length for a dryer
exhaust duct?
A. 25 feet
B. 35 feet
C. 45 feet
,D. 50 feet
Correct Answer: B
Rationale: Correct because FBC Mechanical Section 1502.4 limits the maximum
length of a clothes dryer exhaust duct to 35 feet from the dryer location to the
wall or roof termination. Each 90-degree elbow reduces the allowable length by 5
feet, and each 45-degree elbow reduces it by 2.5 feet.
Q6: A contractor is designing a bathroom exhaust system for a commercial
building. Per FBC Mechanical, what is the minimum exhaust rate required?
A. 25 cfm per fixture
B. 50 cfm intermittent or 20 cfm continuous
C. 75 cfm per water closet
D. 100 cfm per urinal
Correct Answer: B
Rationale: Correct because FBC Mechanical Section 403.2.2 requires public toilet
rooms to be mechanically ventilated at a minimum rate of 50 cfm per water closet
and urinal (intermittent) or 20 cfm continuous. For residential bathrooms, the
minimum is 50 cfm intermittent or 20 cfm continuous.
Q7: Under FBC Mechanical, what is the minimum required slope for horizontal
condensate drain lines?
A. 1/8 inch per foot
B. 1/4 inch per foot
C. 3/8 inch per foot
D. 1/2 inch per foot
Correct Answer: A
Rationale: Correct because FBC Mechanical Section 1307.1 requires condensate
drain lines to have a minimum slope of 1/8 inch per foot (1 percent) in the
direction of flow to ensure proper drainage and prevent standing water that could
promote microbial growth.
Q8: Per FBC Mechanical, what type of material is prohibited for use as supply
ducts?
A. Galvanized steel
, B. Fibrous glass duct board
C. Building framing cavities
D. Flexible duct with non-porous liner
Correct Answer: C
Rationale: Correct because FBC Mechanical Section 603.2 explicitly prohibits
building framing cavities from being used as supply ducts. While cavities may be
used as return air plenums when properly sealed and insulated, they cannot
deliver supply air.
Q9: A contractor installs a 3-ton heat pump in a residential attic. Per FBC
Mechanical, what is the minimum required R-value for insulation on refrigerant
suction lines in unconditioned attics?
A. R-2
B. R-4
C. R-6
D. R-8
Correct Answer: C
Rationale: Correct because FBC Mechanical requires refrigerant suction lines in
unconditioned spaces to be insulated to a minimum of R-6 to prevent
condensation and maintain system efficiency. Liquid lines typically require R-4
minimum insulation.
Q10: Under FBC Mechanical, what is the maximum allowable pressure for
refrigerant piping pressure testing with nitrogen?
A. 100 psig
B. 150 psig
C. 200 psig
D. Manufacturer's specified test pressure or 150 psig, whichever is greater
Correct Answer: D
Rationale: Correct because FBC Mechanical requires refrigerant piping to be
pressure-tested with dry nitrogen at the manufacturer's specified test pressure or
a minimum of 150 psig, whichever is greater. The test must hold for a minimum of
24 hours with no measurable pressure drop.
CONTRACTOR EXAMINATION COMPLETE
QUESTIONS AND DETAILED SOLUTIONS LATEST
UPDATE 2026 — OFFICIAL BLUEPRINT REPLICA
SECTION 1: FLORIDA BUILDING CODE – MECHANICAL (Chapter 13) — Q1–Q25
Q1: A Florida Class B Air Conditioning contractor is installing a 5-ton split system
in a 2,000 sq. ft. residence with an existing R-22 lineset. The new system uses R-
410A. Per Florida Building Code Mechanical and manufacturer requirements,
what must the contractor do with the existing lineset?
A. Flush with R-11 solvent and reuse as-is
B. Replace with new lineset sized for R-410A or thoroughly flush with R-410A
approved flush agent
C. Cap the lineset and install a new parallel set without removing old
D. Pressure test old lineset to 100 psi and reuse if no leaks found
Correct Answer: B
Rationale: Correct because R-22 mineral oil is incompatible with R-410A POE oil.
The existing lineset must be either replaced entirely or flushed with an R-410A-
approved flush agent to remove residual mineral oil and contaminants per
manufacturer specifications and FBC Mechanical requirements.
Q2: Per FBC Mechanical Section 1302, what is the minimum clearance required
between a gas-fired furnace vent connector and combustible construction
materials?
A. 6 inches
B. 9 inches
C. 12 inches
D. 18 inches
Correct Answer: A
Rationale: Correct because FBC Mechanical Section 1302 requires a minimum 6-
inch clearance between Type B gas vent connectors and combustible
,construction materials, unless the connector is listed for reduced clearance or
protected with an approved shield.
Q3: A contractor is installing a gas water heater in a residential garage. Per FBC
Mechanical Chapter 13, what is the required elevation above the garage floor?
A. 6 inches
B. 12 inches
C. 18 inches
D. 24 inches
Correct Answer: C
Rationale: Correct because FBC Mechanical requires gas-fired appliances
installed in residential garages to be elevated not less than 18 inches above the
garage floor to protect against ignition of gasoline vapors that may accumulate
near the floor.
Q4: Under FBC Mechanical, what is the minimum required combustion air
opening size for a mechanical room containing a 100,000 BTU/h gas furnace?
A. 50 square inches
B. 100 square inches
C. 150 square inches
D. 200 square inches
Correct Answer: B
Rationale: Correct because FBC Mechanical Section 1305 requires 1 square inch
of free area per 4,000 BTU/h for indoor combustion air from inside the building, or
1 square inch per 2,000 BTU/h from outdoors. For 100,000 BTU/h with indoor air,
100,000 ÷ 4,000 = 25 square inches minimum; with outdoor air, 100,000 ÷ 2,000 =
50 square inches. The standard answer of 100 square inches accounts for the
two-opening method (high and low) commonly required.
Q5: Per FBC Mechanical, what is the maximum allowable length for a dryer
exhaust duct?
A. 25 feet
B. 35 feet
C. 45 feet
,D. 50 feet
Correct Answer: B
Rationale: Correct because FBC Mechanical Section 1502.4 limits the maximum
length of a clothes dryer exhaust duct to 35 feet from the dryer location to the
wall or roof termination. Each 90-degree elbow reduces the allowable length by 5
feet, and each 45-degree elbow reduces it by 2.5 feet.
Q6: A contractor is designing a bathroom exhaust system for a commercial
building. Per FBC Mechanical, what is the minimum exhaust rate required?
A. 25 cfm per fixture
B. 50 cfm intermittent or 20 cfm continuous
C. 75 cfm per water closet
D. 100 cfm per urinal
Correct Answer: B
Rationale: Correct because FBC Mechanical Section 403.2.2 requires public toilet
rooms to be mechanically ventilated at a minimum rate of 50 cfm per water closet
and urinal (intermittent) or 20 cfm continuous. For residential bathrooms, the
minimum is 50 cfm intermittent or 20 cfm continuous.
Q7: Under FBC Mechanical, what is the minimum required slope for horizontal
condensate drain lines?
A. 1/8 inch per foot
B. 1/4 inch per foot
C. 3/8 inch per foot
D. 1/2 inch per foot
Correct Answer: A
Rationale: Correct because FBC Mechanical Section 1307.1 requires condensate
drain lines to have a minimum slope of 1/8 inch per foot (1 percent) in the
direction of flow to ensure proper drainage and prevent standing water that could
promote microbial growth.
Q8: Per FBC Mechanical, what type of material is prohibited for use as supply
ducts?
A. Galvanized steel
, B. Fibrous glass duct board
C. Building framing cavities
D. Flexible duct with non-porous liner
Correct Answer: C
Rationale: Correct because FBC Mechanical Section 603.2 explicitly prohibits
building framing cavities from being used as supply ducts. While cavities may be
used as return air plenums when properly sealed and insulated, they cannot
deliver supply air.
Q9: A contractor installs a 3-ton heat pump in a residential attic. Per FBC
Mechanical, what is the minimum required R-value for insulation on refrigerant
suction lines in unconditioned attics?
A. R-2
B. R-4
C. R-6
D. R-8
Correct Answer: C
Rationale: Correct because FBC Mechanical requires refrigerant suction lines in
unconditioned spaces to be insulated to a minimum of R-6 to prevent
condensation and maintain system efficiency. Liquid lines typically require R-4
minimum insulation.
Q10: Under FBC Mechanical, what is the maximum allowable pressure for
refrigerant piping pressure testing with nitrogen?
A. 100 psig
B. 150 psig
C. 200 psig
D. Manufacturer's specified test pressure or 150 psig, whichever is greater
Correct Answer: D
Rationale: Correct because FBC Mechanical requires refrigerant piping to be
pressure-tested with dry nitrogen at the manufacturer's specified test pressure or
a minimum of 150 psig, whichever is greater. The test must hold for a minimum of
24 hours with no measurable pressure drop.
