ECONOMIZER – WA, WL & WH SERIES
FEATURES
•One piece construction – easy to install with no mechanical linkage adjustment required.
•Exhaust air damper – built in with positive closed position. Provides exhaust air capability to prevent pressurization of tight buildings.
•Actuator motor – 24 volt, power open, spring return with built in torque limiting switch.
•Proportioning type control – for maximum “Free Cooling” economy and comfort with up to 100% outside air.
•Enthalpy control to monitor outdoor temperature and humidity – adjustable.
•Minimum position potentiometer – adjustable to control minimum damper blade position.
•Mixed air sensor to monitor outdoor and return air to automatically modulate damper position.
ECONOMIZER SEQUENCE OF OPERATION
CONDITION A – COOL OUTDOORS
First stage cooling closes and powers the economizer dampers to economizer mode and the indoor blower starts. Mixed Air Sensor senses a mixture of return air and outdoor air and modulates the dampers accordingly. Compressor operation is inhibited. (See Figure 6.)
If second stage closes on the thermostat, the dampers return to the closed or minimum position setting and the compressor starts for mechanical cooling.
FIGURE 6
ECONOMIZER OPERATION
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