HVAC Controls and Thermostats 2

Question 1

What communication protocol, standardized by ASHRAE, was specifically designed for building automation systems?

Accepted Answer

BACnet

Answer

Modbus

Answer

LonWorks

Answer

Profibus

Question 2

What does PID stand for in HVAC control systems?

Accepted Answer

Proportional-Integral-Derivative

Answer

Pneumatic Integrated Damper

Answer

Pressure-Induced Differential

Answer

Programmable Interface Device

Question 3

What is the primary function of an economizer in an HVAC control system?

Accepted Answer

To use outdoor air for free cooling when outdoor conditions are favorable

Answer

To reduce the refrigerant charge in a system

Answer

To limit maximum heating output during peak demand

Answer

To control indoor humidity by bypassing the cooling coil

Question 4

In a zone control system, what device modulates airflow to individual zones based on each zone's thermostat demand?

Accepted Answer

Zone damper or VAV box

Answer

Balancing damper

Answer

Fire damper

Answer

Pressure relief valve

Question 5

What is 'hunting' in an HVAC control system?

Accepted Answer

Continuous oscillation of the controlled variable above and below setpoint due to overcorrection

Answer

Searching for the optimal setpoint value

Answer

Increasing system capacity to find the maximum output

Answer

Locating a refrigerant leak using electronic detectors

Question 6

What is the primary energy-saving feature of a programmable thermostat?

Accepted Answer

Automatic temperature setback during unoccupied periods

Answer

Higher heating setpoints during occupied periods

Answer

Continuous fan operation to improve air circulation

Answer

Integrated humidistat control for dehumidification

Question 7

What does an enthalpy controller measure to determine if economizer free-cooling is beneficial?

Accepted Answer

Both outdoor air temperature and humidity to calculate total heat content

Answer

Only outdoor air dry-bulb temperature

Answer

Indoor CO2 levels and occupancy

Answer

Refrigerant pressure and temperature