Zone Control Systems On The Job

Zoning should be based on separating the areas of the building depending on how they are used.  Common examples of this would be the bedrooms being in one zone and the living areas in another zone in residential building.  In a commercial building you would want to consider the directions the building faces.  Common examples of this would include the south side of the building being in a separate zone from the north side.

On The Job Example

When your customer complains about handing trouble closing their house door on zone control system, this indicates that the pressure-relief device is either not working properly or is not calibrated.  To test the static pressure on the unit, install a U-tube manometer in the supply duct work and operate the systems.  Go to all of the zone-control thermostats and set them to close down the dampers.  Inspect the static pressure with the dampers open and closed.

When they are closed, the pressure-relief dampers should open up to allow the pressure to escape to a secondary location.  If this does not happen, check the manufacture’s specifications to verify proper operation and maintenance procedures.  Never manually disconnect or force the relief dampers open because this will prevent the unit from delivering adequate air during heavy load periods.

Here's a helpful website on zone control systems that includes a useful graphic.