Examination — Local Jurisdiction
Practice Exam 2026 | 100 Questions &
Answers with Detailed Rationales |
Complete Exam Prep & Study Guide
1. A hydronic heating system uses a closed-loop expansion tank. The system is
filled to its required cold pressure, but the pressure rises rapidly toward the
relief-valve setting as the water reaches operating temperature. What is
the most likely cause?
A. The circulator is oversized
B. The expansion tank has lost its air charge or is undersized
C. The boiler firing rate is too low
D. The system has excessive pipe insulation
Answer: B. The expansion tank has lost its air charge or is undersized
Rationale: A closed hydronic system requires an expansion tank to absorb the
increase in water volume as temperature rises. A failed, improperly charged, or
undersized tank causes excessive operating pressure.
, 2. In a forced-air heating system, a high-temperature limit switch repeatedly
opens even though the blower motor is operating. Which condition should
be investigated first?
A. Oversized thermostat wire
B. Restricted airflow across the heat exchanger
C. Excessive refrigerant charge
D. Low outdoor humidity
Answer: B. Restricted airflow across the heat exchanger
Rationale: Restricted return or supply airflow can cause the heat exchanger
temperature to rise above the limit setting. Dirty filters, blocked ducts, closed
dampers, and inadequate blower operation are common causes.
3. A gas-fired appliance has a manifold pressure below the manufacturer's
specified range. What is the most appropriate first action?
A. Increase the gas pressure without testing
B. Replace the heat exchanger
C. Verify inlet pressure and regulator operation
D. Increase the thermostat differential
Answer: C. Verify inlet pressure and regulator operation
Rationale: Manifold pressure depends on adequate inlet pressure and proper
regulator operation. The technician should diagnose the supply system before
adjusting the appliance regulator.
4. What is the primary purpose of a flame safeguard system on a commercial
gas-fired appliance?
A. Increase combustion efficiency
B. Prevent operation without proven flame
C. Reduce water pressure
D. Control refrigerant flow
Answer: B. Prevent operation without proven flame
,Rationale: Flame safeguard controls monitor ignition and flame establishment
and shut down fuel flow when safe combustion cannot be verified.
5. A cooling coil is significantly below the design temperature while airflow is
normal, and ice begins forming on the coil. Which condition is most likely?
A. Excessive condenser airflow
B. Low evaporator airflow or an abnormal refrigerant condition
C. Excessive outdoor ventilation
D. High chilled-water temperature
Answer: B. Low evaporator airflow or an abnormal refrigerant condition
Rationale: Coil icing commonly results from inadequate airflow or refrigeration-
system conditions that drive evaporator temperature excessively low. Both
airflow and refrigerant-side conditions should be checked.
6. A duct system has excessive static pressure and insufficient airflow. Which
modification is most likely to improve system performance?
A. Reduce the duct cross-sectional area
B. Remove unnecessary restrictions and properly size the ductwork
C. Increase filter resistance
D. Close additional supply dampers
Answer: B. Remove unnecessary restrictions and properly size the ductwork
Rationale: Excessive static pressure reduces fan airflow. Proper duct sizing and
removal of restrictions reduce system resistance and restore designed airflow.
7. What is the primary function of a trap installed beneath a condensate
drain?
A. Increase condensate temperature
B. Prevent air from entering the drain system through the equipment
C. Increase refrigerant pressure
D. Eliminate the need for a drain
, Answer: B. Prevent air from entering the drain system through the equipment
Rationale: Negative-pressure equipment can draw air through an open
condensate drain. A properly designed trap maintains the required water seal
and permits condensate drainage.
8. A refrigeration system has a compressor with abnormally high discharge
pressure. Which condition could cause this symptom?
A. Excessively low outdoor temperature
B. Dirty condenser coil
C. Low condensing temperature
D. Excessive evaporator airflow only
Answer: B. Dirty condenser coil
Rationale: A dirty condenser reduces heat rejection and raises condensing
temperature and discharge pressure. Other causes include inadequate
condenser airflow and overcharge.
9. A variable-air-volume terminal is delivering too little air despite adequate
central fan capacity. What should be checked first?
A. The building's domestic-water pressure
B. The terminal's damper, actuator, and control signal
C. Boiler water chemistry
D. Compressor oil level
Answer: B. The terminal's damper, actuator, and control signal
Rationale: A malfunctioning actuator, damper, or control signal can restrict
airflow at the terminal even when sufficient airflow is available upstream.
10.Which measurement is most useful for determining whether an air-
conditioning system is providing adequate sensible cooling?
A. Supply-air temperature and airflow
B. Gas manifold pressure only