How to Zone a Forced Air HVAC System

Posted by Anonymous , 9/5/2007 Tags:ZoneForcedAirHVACSystem
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How to Zone a Forced Air HVAC System

Introduction

When accommodating a large dwelling, it's a good idea to zone your forced air HVAC system to ensure proper air circulation and reasonable temperature settings. The second story of a multi-story building tends to have extreme temperature differences from the first floor if not properly controlled by a forced air HVAC system. Follow these steps to learn how to zone your building.

Instructions

Difficulty: Challenging

Steps

1

Step One

Decide how you're going to zone the building and the quantity of zones you would like to have. If you're going to zone a multi-story building then you would normally zone it by stories. Each zone should be close to the same size.
2

Step Two

Plan ducting that will connect each zone to an individual branch of the main duct. This should be close to the HVAC system but it is possible to have the main duct far away from the HVAC system.
3

Step Three

Make the ducting for each zone large enough to accommodate the air volume of the forced air HVAC system. If you have a two-zone system, then the ducts should be 25 percent larger than a one zone system while a four zone system should be 50 percent larger.
4

Step Four

Determine the location of the dampers. Run two-conductor thermostat wire from the forced air HVAC system to the location of the dampers.
5

Step Five

Install a thermostat in each zone. Run wire from the HVAC system to the thermostat.

Tips & Warnings

  • When a damper is closed, the back pressure can increase and damage the HVAC system if you do not increase the duct size to accommodate the multiple zones.
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