Updated January 18, 2024

An HVAC damper is a simple device that keeps your home or business comfortable by regulating airflow in the living space. HVAC dampers are usually installed at each air opening in a building, such as windows and exterior doorways.

Types of HVAC dampers

You probably recognize the five types of HVAC dampers in residential and commercial HVAC systems. Of course, there are other types of dampers, but here we will focus on the first five most commonly used dampers.

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1. Guillotine-style Dampers

Guillotine-style dampers are commonly referred to as “diamond-shaped” because they resemble a diamond or rectangle when viewed from the side. These dampers function like three-way valves and close off the supply and return ends of a duct when in the closed position. This type of damper is most often used for an indoor fan coil unit installation, where it functions as both an air supply damper and an air exhaust damper for the coil unit in one unit.

Guillotine-style dampers are regarded as the most versatile type of damper, as they can be positioned horizontally or vertically. In addition, these dampers are ideal for use in small spaces because they don’t require a large opening in the wall or floor.

They are easy to install, operate quietly, and are reliable. They are available in various sizes and suitable for applications where liquid or gas is the medium being controlled.

2. Radial-style Dampers

Radial-style dampers are used to control the flow of air in an air duct. They are generally used when a balanced flow of air is required; this means that the relative humidity in both directions must be at a similar level, regardless of whether there is air flowing through or not.

A typical example of this application would be the supply of conditioned and unconditioned air to a room through a single supply duct. In such cases, the radial-style damper will stop the conditioned air from flowing into the supply duct when it is not required.

The radial-style dampers are made of wire rope, offered in the full line of core options, and clad in the same materials as standard dampers. The radial style allows for a more flexible design than a split-batten design.

3. Blade-style Dampers

The blade-style damper is a direct-acting blade damper with a flat, rectangular shape. They are commonly used to control the supply or exhaust of air. Blade dampers are typically open at full travel and have an air gap between the moving and stationary channel walls.

The moving channel moves in a straight line, whereas the stationary channel, depending on its location in the stack or duct, will be angled so that when in operation, it will have to be tilted for minimum restriction.

They are available in various sizes, configurations, and types of materials.

4. Rectangular-style Dampers

Rectangular style dampers are typically used in air movement applications that are not continuous. Examples include ventilation systems, supply and exhaust ducts, and processing equipment.

Rectangular-style dampers are a common choice for horizontal and vertical runs in larger commercial buildings and large residences. They are constructed to be reliable and long-lasting while also being simple in design.

5. Shutter-style Dampers

Shutter-style dampers are most commonly used to control airflow in forced-air heating, ventilation, and air-conditioning systems. They consist of a thermally controlled damper that opens by centrifugal force when pressure forces the disc to rotate past a set point.

A shutter-style damper is manually controlled to regulate airflow through the HVAC system. While they are available in several sizes, it is most often found in residential applications and can be used as a dampening device on unitary ducts or supply air grilles.

Common Problems With HVAC Dampers

A variety of problems can arise when an HVAC system is not properly maintained or serviced. Below are some of the most common issues with dampers:

1. Failed Linkage

Failed linkage is a common problem with HVAC dampers that results in the damper resting all the way open. Failed linkage can be caused by many things: The linkage is too weak, there is a worn or broken connecting part of the linkage system, or the actuator end may have been removed from its housing too much.

If the linkage has failed, your options are limited. You may be able to get an estimate from a professional and then hire someone to repair it, or you may need to buy a new one.

2. Failed Actuator

A failed actuator will either not open or close. The problem can be caused by a bad motor, a stuck piston rod (the part that makes the damper move), a failure of the control wiring, or a bad control board.

The main problem with a failed actuator is that it can affect the operation of your heat pump and air conditioner. The purpose of a damper is to control airflow into or out of your furnace or air conditioner’s plenum chamber. Without an active damper, the condenser can overheat, resulting in poor efficiency, shortened life, and decreased performance.

3. Obstruction

Dampers can be obstructed by leaves, snow, ice, and other debris that may blow into the air conditioning system.

When the damper is obstructed, it can cause a host of problems. For example, the damper may be unable to open and close without causing damage, or it could damage the blower motor or other components in the system.

It could also allow outside air into your home’s duct system, and it may cause your HVAC equipment to run for more extended periods than normal — or at least increase your energy costs as you have to put up with higher temperatures in your home or office.

Benefits of HVAC Dampers

HVAC Dampers are a cost-effective solution to many residential and commercial comfort problems. Here are some of the benefits of HVAC dampers:

1. Prevent Energy Waste in Your Home

HVAC dampers prevent energy waste in your home. This is because they can reduce the airflow or increase it based on the need of your house.

2. Keep Your Room Temperatures Constant

We have all experienced that feeling when the temperature in our rooms feels just right. Keeping the temperature steady helps control electrical use, keeps furniture from fading, and saves money on your monthly utility bills.

Get Professional Help

Installing, repairing, or maintaining an HVAC damper requires the knowledge and expertise of a professional electrician. In the Greater St. Louis area, you can rely on Agers Heating & Air Conditioning to do the job right the first time. Our team of highly trained experts can handle everything to do with an HVAC damper.

We also offer many other services, including furnace repair, AC repair and replacement, furnace maintenance, ductless, AC maintenance, furnace installation, heat pumps, and indoor air quality. Our commercial services include air filtration, heat pumps and maintenance plans. To learn more about your HVAC damper, contact Agers Heating & Air Conditioning today.

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