Buildings that have stale air when equipped with fresh air economizers
| Scotty McGregor
When the air inside a commerical building feels stale or stuffy, check the economizer for proper operation
In all commerical building, the supply air fan should run continously when the building is occupied. This allows air to be drawn in from the outside through the economizer. The damper in the economizer should be be set to provied 10% to 20% fresh air.
IE 2000 CFM Unit, 10% would be 200CFM of outside air. this only requires a slight gap in the damper opening.
Remove one of the intake filters to reveal the dampers. When the fan is running the damper will drive to the minimum. Depending on the damper type and location, filters ect. will determind of far open the damper will have to be to get 10% to 20% fresh air.
Below is a Carrier economizer the uses a siding style damper. The miniumum position is set by the adjsutable slider control on the left side.
Other use an adjustment located on the damper motor. The Honeywell control shown below is very touching, 1/8 of a turn will cause the damper to move a lot.