Actuators in HVAC systems control the dampers. By utilizing a low voltage signal, the actuator places the damper at any point between fully open and fully closed. A critical element of an HVAC system, proper actuators ensure that zone dampers function properly - without them, the dampers won't function at all.
Dampers are the final control devices for almost all airflow in HVAC systems. Actuators are the interface between the control system and the mechanical system and are critical to accurate control.
Levers located outside of air vents and ducts control damper plates or valves in a manual system. Most manual dampers have a straightforward design that allows operators to intuitively control airflow through the system, and they tend to be relatively durable and maintenance free.
Before lighting a fire, you can tell if the damper is open by placing your hand into the fireplace. If you feel a draft coming down the chimney, it is a good indicator that the damper is open. If you don't feel any cold air coming down the chimney, it means that the damper is closed.
Damper Actuator is a motor-operated rotary actuator in which speed reducer, motor, limit switches, overload switches, opening transmitter and manual handling mechanism are united.
End switches are typically wired to a fan and/or to a light serving as an open/not open indicator. When the damper is powered open, one of the damper blades makes contact with the spring rod of the end switch which in turn makes a connection allowing power to flow to the fan and/or light.
Motorized Fire Damper prevents the passage of flame from one side of a fire rated separation to the other and will be functioning with the help of actuators with either an electric or pneumatic actuator. They are controlled by heat detector signal, fire alarm or some other building control system.
Belimo safety actuators for fire dampers automatically move to their safety position in case of fire and keep dampers closed during the fire. They offer the best protection against the spread of fire and smoke through ducts.
Fire dampers respond to heat, when the temperature reaches a set point the damper slams shut. Smoke dampers respond to the detection of smoke, and close automatically. They can also be activated remotely. They resist the passage of smoke, toxic gases and air through a fire barrier.
How Do Fire Dampers Work? In general, a fire damper works when the heat from the fire causes the normal temperature of a room to rise about 165 degrees Fahrenheit. The fusible link attached to the damper would then melt, causing the damper's door to close.
A motorized damper recieves its signal through low-voltage wires. Run a two-strand low-voltage wire set from the damper's motor to the inside air-conditioning unit, called the air handler. Cut the wire set to length with wire cutters. A two-strand wire set contains two insulated wires wrapped in a plastic sleeve.
An end-switch is a one that makes or breaks to indicate positive proof of equipment position such as a damper. Ex. in HVAC control systems they are used to prove a damper to be open before a fan starts. They may also be used to illuminate position indicating lights or signal an automatic control system of some action.
A zone valve is a combination control when it has an end switch. (A two-wire zone valve has just a motor. A four-wire zone valve has a motor and an end switch.)
PIBCV Modulating Actuator
Actuators are extremely important in HVAC systems. For instance, actuators need to close fire dampers fast enough and under high temperatures during a fire to save lives. Moreover, actuators are responsible for the chilled water flow control and thus, the energy efficiency of air conditioners.
Damped mode: cylinder chambers are connected together through an orifice, the actuator moves with external force, damping suppresses flutter, and a compensator provides emergency fluid.
End switches in each zone valve control the central circulator and the burner. On a call for heat, the valve is opened. When it reaches the fully open position, the end switch “makes” (makes contact), causing the aquastat relay to pull in, starting the circulator and the burner.
It is set for the desired draft conditions using weights and adjustment screws. If the draft inside the chimney is greater than the setpoint, the damper will open and allow air from the boiler room inside the chimney, rather than stealing heat from the boiler.
A fusible link fire damper is a style of fire damper or smoke damper. While automated systems or smoke alarms control some dampers, a fusible link fire damper is controlled by the fire itself. The fusible link is sensitive to high temperatures and remains open until exposed to high heat, such as that from a fire.
The dampers are typically held open by a fusible link which is a device designed to release a component such as a fire shutter or in this case a fire dumper upon detection of a set temperature. When the set high temperature is detected, the fusible link releases and thereby closes the fire damper.
The fireplace damper should always be in the open position whenever you have a fire in the fireplace. Never close the damper or leave the fireplace unattended while there is a fire in the fireplace. This is not only a fire hazard, it can also cause deadly carbon monoxide poisoning.