HVAC Controls and Thermostats

Question 1

What type of thermostat uses a bimetallic strip as its primary sensing element?

Accepted Answer

Mechanical thermostat

Answer

Electronic thermostat

Answer

Pneumatic thermostat

Answer

Digital thermostat

Question 2

What is the 'deadband' in thermostat operation?

Accepted Answer

The temperature range between heating and cooling setpoints where neither system operates

Answer

The maximum allowable temperature swing

Answer

The time delay before a system restarts

Answer

The differential between supply and return air temperature

Question 3

What does DDC stand for in building automation and HVAC controls?

Accepted Answer

Direct Digital Control

Answer

Dual Digital Control

Answer

Dynamic Data Control

Answer

Distributed Device Control

Question 4

Which control type continuously modulates output between 0% and 100% in proportion to the deviation from setpoint?

Accepted Answer

Proportional control

Answer

Two-position control

Answer

Floating control

Answer

Step control

Question 5

What is the primary purpose of a heat anticipator in a mechanical thermostat?

Accepted Answer

To prevent temperature overshoot by shutting off the furnace slightly early

Answer

To speed up the heating cycle

Answer

To increase system energy efficiency

Answer

To lower the heating setpoint automatically

Question 6

In HVAC controls, what does the term 'setpoint' refer to?

Accepted Answer

The desired target value that the control system works to maintain

Answer

The maximum temperature the system can achieve

Answer

The outdoor design temperature for load calculations

Answer

The pressure differential between supply and return ducts

Question 7

What type of sensor is most commonly used in modern electronic thermostats to measure temperature?

Accepted Answer

Thermistor or RTD

Answer

Bimetallic strip

Answer

Mercury bulb

Answer

Bourdon tube