"Outside Air from System" not working correctly

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The Dedicated Outdoor Air System that precools/dehumidifies Outdoor Air
before passed to a main AHU is not working correctly. There are three
major issues:

1. The MAIN AHU is pulling more Outdoor Air than provided by the
DEDICATED OUTSIDE AIR UNIT to which it is attached using the "Outside
Air from System" function.

2. Similarly, during "Night Cycle Control", the MAIN AHU is only
supposed to recirculate air to maintain setback and RH conditions.

Incorrectly the MAIN AHU is still brining in outside air even though the
DEDICATED OUTSIDE AIR UNIT is completely off. Where is it getting its
outside air from?

3. The MAIN AHU has Demand Controlled Ventilation such that the Outside
Air Supplied varies across the day. I verified that this is working

Incorrectly the DEDICATED OUTSIDE AIR UNIT maintains a constant flow of
Outdoor Air even though it is a Packaged VAV system. It should modulate
the Outside Air based on the demand by the MAIN AHU.

I have tried all 4 "Minimum OA Control Methods" for the MAIN AHU and

How do I get the MAIN AHU and DEDICATED OUTSIDE AIR UNIT to talk to one

Doebber, Ian's picture
Joined: 2011-09-30
Reputation: 0