About Full Airflow Zone System LLC
Full Airflow Zone System LLC is a small family-owned business our primary goal is to improve the way Residential HVAC systems are designed and installed. We feel we have the fiduciary responsibility of facilitating a change in the way residential HVAC systems distribute air. By enlisting EWC to produce our patented control boards we made sure they were manufactured in the U.S. by an established zone control manufacturer. To keep the cost of the FAZSTM control board as low as possible for a new fairly low volume product an existing EWC control board was reprogrammed with our unique control sequences.
Donald Prather had over 40 years of experience in HVAC design, installation, maintenance, and commissioning when he was thinking about the various real-world problem application problems related to airflow in homes that were well insulated and sealed tightly. Homes built to the latest codes were already over 1000 ft2 per ton, low load homes and net zero homes were over 1500 ft2 per ton.
The main problems created by super insulating homes blocking the use of conventional HVAC systems were:
- Low heating and cooling loads resulted in minimal airflow to the rooms leading to uncomfortable areas that became overwhelmed for cooling demand when there were more occupants than the number in the load calculations. Thus, conventional HVAC systems could not deliver air properly for those applications.
- Conventional HVAC systems could not adjust to time of day east/west side related load changes.
- Airflow challenges related to small airflows into large areas caused diffuser throw design issues.
- Humidity removal issues related to equipment speeds ramping down in existing zone applications nullified their use.
- Single speed single zone HVAC system installation always resulted in hot and cold spots in homes.
- Home builders were complaining that they needed a different duct design based on how tract homes were facing.
- Winter summer differences between floors required summer and winter damper positions to adjust airflow seasonally.
While dwelling on these issues Don had an epiphany, we’ve been approaching residential design based on 1940’s engineering and technology. Why are we sending conditioned air into spaces that don’t need the temperature to change? By directing all of the system’s airflow to the one area that needed changing the system would operate more efficiently. That would also solve the issues with low airflow in low load and multi-story home applications.
Immediately Don realized there would be a minimum zone size requirement in order to keep the HVAC equipment from short cycling. He knew zone areas had to be over 25% of the total home load would be safe, and by allowing 5%-10% of the airflow to bypass the closed dampers in the two other zones for air circulation, some minor adjustments could be made after installation if needed. After researching existing zone controls, he found out he would need to write a control scheme that held zone dampers closed based on priority. Thus, the 3 zone FAZSTM control was developed to operate the new zone control scheme.
Based on his design, installation and maintenance experience over the years Don realized that if the control was hard to understand, no one would use it. So, he made the design requirements, and the installation connections as easy as possible to integrate with HVAC equipment currently in use. A design & installation manual is available on this web site. It contains all of the information designers and technician’s need to fully understand how to setup a system.
Contractors are currently using the Full Airflow Zone System control for two and three-story applications so they do not have to install more than one system in a home. The first single floor control was installed in the spring of 2021 along with a duct retrofit. The HVAC system was downsized by ½ ton even though the attic was added as conditioned space with a batt insulation upgrade. The installation resolved east-to-west and north-to-south issues that for years had caused individual rooms to be uncomfortable based on the season. The rooms now remain comfortable year-round. As a bonus the large south facing great room, dining area and kitchen area stay cool on a hot summer day when a party is going on for the first time. Please leave the 1940’s behind and start designing for the future with a FAZSTM.