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NYC THERMOSTAT REPAIRER (CUNY)
PRACTICE EXAM 2026 — QUESTIONS
WITH VERIFIED ANSWERS & COMPLETE
RATIONALES
**1. What is the primary function of a thermostat in an HVAC
system?**
A. To increase air pressure in the system
B. To regulate temperature by sensing room temperature and
controlling the heating/cooling system
C. To filter air contaminants from the environment
D. To measure humidity levels only
**Correct answer:** B
**Rationale:** A thermostat monitors ambient temperature and
signals the HVAC system to heat or cool to maintain the
desired setpoint. According to the CUNY exam notice,
Thermostat Repairers test, maintain, repair and replace various
types of thermostats used for the control of heating, ventilating
and air conditioning systems.
**2. Which type of thermostat uses a bimetallic strip to sense
temperature changes?**
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A. Digital thermostat
B. Programmable thermostat
C. Mechanical thermostat
D. Smart thermostat
**Correct answer:** C
**Rationale:** Mechanical thermostats rely on a bimetallic strip
that bends with temperature changes, activating or deactivating
the circuit. Different metals expand at different rates, causing
the strip to bend and open or close electrical contacts.
--
**3. What voltage is most commonly used in low-voltage
thermostat control circuits?**
A. 120V
B. 240V
C. 24V
D. 480V
**Correct answer:** C
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**Rationale:** Most residential and commercial HVAC
thermostats operate on 24 volts AC, supplied by a step-down
transformer, ensuring safe, low-voltage control of heating and
cooling equipment.
**4. What is the purpose of the "C" wire (common wire) in
modern thermostats?**
A. Cooling signal
B. Common return path for continuous power
C. Compressor control
D. Condenser power
**Correct answer:** B
**Rationale:** The C wire provides a continuous 24V return
path, supplying constant power for smart thermostats with Wi-Fi
and displays. Without it, the thermostat may rely solely on
batteries.
--
**5. What does the "Y" wire typically control in a thermostat
system?**
A. Heating
NYC THERMOSTAT REPAIRER (CUNY)
PRACTICE EXAM 2026 — QUESTIONS
WITH VERIFIED ANSWERS & COMPLETE
RATIONALES
**1. What is the primary function of a thermostat in an HVAC
system?**
A. To increase air pressure in the system
B. To regulate temperature by sensing room temperature and
controlling the heating/cooling system
C. To filter air contaminants from the environment
D. To measure humidity levels only
**Correct answer:** B
**Rationale:** A thermostat monitors ambient temperature and
signals the HVAC system to heat or cool to maintain the
desired setpoint. According to the CUNY exam notice,
Thermostat Repairers test, maintain, repair and replace various
types of thermostats used for the control of heating, ventilating
and air conditioning systems.
**2. Which type of thermostat uses a bimetallic strip to sense
temperature changes?**
,2 | Page
A. Digital thermostat
B. Programmable thermostat
C. Mechanical thermostat
D. Smart thermostat
**Correct answer:** C
**Rationale:** Mechanical thermostats rely on a bimetallic strip
that bends with temperature changes, activating or deactivating
the circuit. Different metals expand at different rates, causing
the strip to bend and open or close electrical contacts.
--
**3. What voltage is most commonly used in low-voltage
thermostat control circuits?**
A. 120V
B. 240V
C. 24V
D. 480V
**Correct answer:** C
, 3 | Page
**Rationale:** Most residential and commercial HVAC
thermostats operate on 24 volts AC, supplied by a step-down
transformer, ensuring safe, low-voltage control of heating and
cooling equipment.
**4. What is the purpose of the "C" wire (common wire) in
modern thermostats?**
A. Cooling signal
B. Common return path for continuous power
C. Compressor control
D. Condenser power
**Correct answer:** B
**Rationale:** The C wire provides a continuous 24V return
path, supplying constant power for smart thermostats with Wi-Fi
and displays. Without it, the thermostat may rely solely on
batteries.
--
**5. What does the "Y" wire typically control in a thermostat
system?**
A. Heating
