In a ddc vav system this strategy is fairly easy to implement because the necessary real time information is already available digitally.
Outdoor air damper control.
Exhaust air damper x h.
The return damper damper 2 figure 1 and outside air damper damper 3 figure 1 are controlled via discharge air or mixed air temperature as part of the economizer cycle.
Set the timer to meet desired or code mandated ventilation requirements.
Manual dampers are turned by a handle on the outside of a duct.
This is a quick way to tell if something is amiss with your damper control.
As the outside air damper opens beyond minimum the return damper moves toward a closed position.
The system includes a small temperature control panel housing a 24 v control transformer and timeclock.
When an outdoor air inlet is ducted to the return side of the hvac system s central air handler install a motorized damper that can close the air intake.
Install controls to provide intermittent fresh air based on a timer.
Its operation can be manual or automatic.
A properly designed installed operated and maintained oa damper will preclude the entry of water rain snow into the ah system and will stop the flow of air into the system when it is closed.
The return air temperature the 70 return air damper position.
Warm up cycle control wcc 1.
From rectangle to round hvac dampers johnson controls offers air damper controls in a diverse range of models that prevent outside air from penetrating your building.
Finally the bas sends this outdoor airflow setpoint to the rooftop unit which modulates a flow measuring outdoor air damper to maintain this new setpoint.
The outdoor air damper shall open whenever the fan is energized and closed when the fan is off.
Outside air damper will close.
A damper may be used to cut off central air conditioning heating or cooling to an unused room or to regulate it for room by room temperature and climate control.