Bard EIFM-5, Руководство по установке

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Manual 2100-220
Page 7
FIGURE 4
ECONOMIZER OPERATION
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 4.)
If second stage closes on the thermostat, the dampers
return to the closed or minimum position setting and
the compressor starts for mechanical cooling.
MIS-347