What are HVAC controls and how do they work?

Posted: June 10, 2022

HVAC Controls

Our world is accelerating towards automation and artificial intelligence. Building automation systems (BAS) allow us to automate HVAC systems. It can interact with more complex HVAC systems to give building owners additional control over the heating, cooling, and ventilating equipment. It is helpful for both local and remote locations because the homeowner can check the situation and attend to alarms triggered by it. PartsHnC sells all types of HVAC controls at affordable prices. HVAC controllers are used to automating this internet of things (IoT) HVAC system.

What are the HVAC controls?

HVAC controllers are used to controlling and manage the functionality of the heating and cooling systems in the interior environment of buildings. Indoor environmental parameters such as temperature and moisture are monitored, and heating and cooling are controlled to attain and maintain optimum values. The type of HVAC system determines the control cycle. The fundamental control sequence can then be carried out by a variety of control devices, including pneumatic, electric, analog electronic, and electronic direct digital control (EDDC). You can get an advantage from extra controls that are determined by how buildings are used.

The following list covers all HVAC controls:


Sometimes electrical devices burn because of high voltage electrical supplies or for any other reason. That's when turning the power off is important. Electrical system damage may harm life. Alerting is important for this kind of incident. That is why HVAC systems use alarms to notify you of a burning HVAC system by making noise.

A Circuit Breaker 

A circuit breaker is an important component of the electrical safety equipment for your air conditioner. It aids in the protection of your air conditioner from harm done by overloading or short circuits. When there is a high-voltage current flowing through the electrical wire, then the circuit breaker trips and shuts off the electricity supply until the situation is resolved. The circuit breaker will reset after the issue is resolved.

Control Board 

In your HVAC system, the control board fulfills several functions, such as regulating lights and other components of a device. One of its major responsibilities is taking input data from your system sensors and thermostat. It makes judgments based on that input information and then sends messages to other system components to manage the temperature of your building or room.

Expansion Valve

When the refrigerant comes from the condenser coil with a high temperature and high pressure to the evaporator coil, the expansion valve decreases or controls the pressure of the refrigerant. It plays an important role in the cooling process. If the expansion valve is damaged, then repair or replace it. Because a failed expansion valve overloads your air conditioning work.

Flame sensor 

The gas is ignited by a hot surface ignitor or a spark, and a flame sensor detects the presence of a flame within the furnace. Flame sensor accuracy is important in the furnace heating process. If your furnace shows any burning issues, it may be because of the damaged flame sensor. 

Want to repair your faulty flame sensor by yourself? Then read this article to understand the process of repairing and replacing the flame sensor in a furnace. 

Gas valve 

A furnace gas valve is part of the fuel system of your furnace. Your furnace's gas valve manifold opens and shuts to allow gas to be burned to generate heat. It is completely in charge of delivering and changing the flow of gas pressure into your furnace to keep it lighted while it is in use.


An HVAC gauge measures the pressure of various liquids and gasses in an air conditioning system. It is a gadget that is used to measure a physical quantity. Gauges come in a variety of shapes and sizes, including plug gauges, ring gauges, taper gauges, snap gauges, thread gauges, form gauges, feeler gauges, and indication gauges.

Limit switch 

The furnace blower component is activated and deactivated by the furnace fan limit switch. Two or three limit switches will be installed in the furnace to monitor temperatures in various regions of the furnace. Use quality limit switches for your furnace's work efficiency.


Overheating is caused by clogged air filters, filthy condenser coils, and refrigerant leaks. It reduces the efficiency of the system's operation. The overload protects the compressor by shutting it down when it becomes too hot. 

HVAC Pilot 

In gas-fired equipment, such as your furnace, water heater, and gas fireplace, the pilot light is a small flame that is maintained ablaze. It is a necessary part of gas-burning systems. Replacing a damaged pilot is an easy process, but this heating element may injure you. So call a technician for repair or replacement work. 

Pressure switch 

A furnace pressure switch is a self-contained safety device. It detects negative pressure. At the time of negative pressure, it turns off the furnace. The pressure switch saves your device and home from back-drafting. If you feel your pressure switch is in bad condition, then check the condition with the help of a multimeter. 

Relay Kit 

Like other switches, relays govern the opening and closing of electronic circuit contacts.

Reversing valve 

A reversing valve is used to shift the refrigerant's direction in indoor and outdoor units. Poppet-type and slide-type are types of reversing valves. Reach more about the reversing valve.

Service Valve 

The service valve is a helpful valve for technicians. When you want to replace the refrigerant without opening your air conditioning unit, just open the service valve and replace your refrigerant. The service valve is situated outside of the outdoor unit.


Setpoints are used for both heating and cooling purposes. A heating setpoint is used to heat the room and a cooling setpoint is used to cool the room by setting the setpoint temperature and attempting to maintain it.


Switches are used to control the functions like on/off. All types of HVAC switches are easily available on the PartsHnC platform at a low cost.


Like circuit breakers, pressure switches, and other safety components, the thermocouple is also one of the most important safety components. It's used to confirm whether the furnace's pilot light is on or off.


The thermostat plays a crucial role in maintaining room temperature. Its sensors detect the temperature within your home and transmit input data to your HVAC system. Input assists the system in maintaining the desired temperature inside your room/building by adjusting humidity and heat. 

Time Delay 

Rapid cycling of compressors can damage HVAC equipment, hence time-delay relays are utilized to protect it. 


It works as a timed power source. Your air conditioner's power cord is connected to the timer switch, which is plugged into the wall. The switch can be programmed to turn the air conditioner on or off when a certain amount of time has passed.


The transformer is the part of your furnace that increases or decreases the voltage of the home's alternating current, or AC. This section of your home is responsible for transferring electrical currents from one location to another.


HVAC valves are used to regulate the flow of water in pipes. Valves govern the flow of water, gas, and air in major components of an HVAC system such as the water chiller, air handling units, cold water pumps, and fan coil units.

Wire Harness

In HVAC applications, electrically operated wire harnesses are utilized to control circuit boards in HVAC equipment. Wire harnesses require sleeving in specific dimensions for protection because these systems involve humidity and other risks to electrical components.

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