HVAC Ductwork Basics

Consistent temperature control and healthy indoor air quality throughout your home rely on HVAC ductwork basics to get the job done. The blower in a typical residential air handler continuously circulates over 1,000 cubic feet per minute of conditioned air as long as the system is cycled on.

Here are some HVAC ductwork basics that show how the elements work together—and how common problems sometimes arise.

• Residential ductwork is actually two systems: supply ducts and return ducts.

• Supply ducts deliver conditioned air to individual rooms, entering through a supply vent on an upper portion of a wall, close to the ceiling.

• Return ducts remove air and convey it back to the air handler to be cooled or heated again. Some houses have return vents in every room, many others have only one central return vent often located in a central hallway.

• Supply and return air volume in the ductwork system is balanced to ensure neutral air pressure inside each room—the optimum condition for temperature control and air quality.

• Most ductwork is not visible in a typical home. Usually, the long spans are routed through areas such as the attic or crawl space. Shorter “branch” ducts that extend into rooms may be installed inside wall cavities.

• Rigid ducts are usually fabricated of rectangular or round sheet metal. Flexible ducts consist of a wire internal coil covered by plastic.

Potential Duct Problems

As ductwork ages, air leaks may develop at joints and other points in the system. Loss of conditioned air into unconditioned zones such as the crawl space or attic is a major contributor to increased operating costs and poor cooling and heating performance. A professional duct inspection including pressure testing can determine the extent of leakage. Proven sealing techniques will restore leaky ductwork to standards.

Thermal gain or loss frequently affects airflow temperature in ducts routed through very hot or cold zones like the attic or crawl space. Insulating exposed ductwork in these unconditioned zones resolves the issue.

Ask the experts at Air Assurance for more about HVAC ductwork basics and professional duct service to maintain indoor comfort and efficiency.

How to Care for Your HVAC Condensor Fan Motor

The condenser is located in the outdoor unit of the HVAC system, along with the compressor and condenser coils. This HVAC condenser fan motor is key to the proper operation of the entire HVAC system, keeping the air conditioner cool as the fan motor turns the blades, blowing air across the condenser coil where the refrigerant is cooled from hot gas into a liquid. During this process, warm air from the house is exhausted outdoors.

It's important to keep the condenser from overheating or working too hard. Regular maintenance includes lubricating the fan and other parts at least once a year, before you turn the air conditioner on for the season.

Condenser Problems

Some of the main things that can go wrong with the condenser are these:

• Motor can go bad. If the motor is incorrectly sized in the unit, it is likely to malfunction.

• If the fan blades are not installed correctly, airflow may be impeded and the motor may overheat.

• An incorrect start run capacitor or incorrectly sized fan blade may cause a condition called overamping.

• Poor air flow can also result from obstructions near the unit, such as weeds, leaves, grass, shrubs and garden furniture. Clear all vegetation and debris away from the condenser so it can properly exhaust warm air.

• Dirty coils can prevent the unit from transferring warm air, which will result in inadequate cooling in the home. The coils should be cleaned annually.

• Refrigerant leaks can develop in the condenser and the lines leading to it. Insufficient refrigerant can result in inadequate cooling, as well as strain on the compressor, leading to breakdown.

To tell if your condenser fan motor is overheating, place your hand on the unit. You can also check the temperature of the condenser fan motor with a regular thermometer, but it's best to hire an HVAC professional with proper equipment to do the job.

For more on your HVAC condenser fan motor and other HVAC parts, contact Air Assurance of Broken Arrow. Call us to schedule repairs, maintenance or new installations; we've served Broken Arrow since 1985.