Rain Entering Through Barometric Relief – How Can I Stop It?

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Our office building has a Carrier model 48TFE008 equipped with a MicroMetl Economizer model 0688-0201-54920. We have had a zone control system installed. I now have four separate zones each with a separate thermostat.

This zone system closes and opens ducts within the system but does nothing to address the inside fan speed or the return air. Our system is an old plenum ceiling design. I recently experienced an event where a rain storm was driven by very high winds and inundated the ceiling tiles in the plenum system.

The rain came in through the louvers in the barometric relief portion of the economizer. Can you suggest changes to our system to prevent recurrence of this rain event?

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Posted by AndyW
Asked On July 23, 2015 1:03 PM
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Have you checked the minimum position setting on your economizer? Your model is enthalpy controlled and should have the economizer in minimum position during a rain storm. If your minimum position is allowing to much air in, it will be opening the barometric blades proportionally to remove the pressure.

Additionally, under heavy rains as you mentioned, you may want to construct a wind/rain barrier to prevent horizontal rain from getting to the relief dampers.

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Posted by (Questions: 0, Answers: 6)
Answered On July 24, 2015 11:54 AM
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