[Equest-users] OA damper barely modulating

[Charles Land]

The problem is you do not have a minimum outside air percentage specified under your system.  On top of that you have specified a cfm per sqft for outside air under each of your zones.  This is causing your model to use a specified amount of oa anytime the system is running. This will allow your unit to economize.  You will also need to make a min oa schedule if you want your oa damper to close during unoccupied hours.

From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Patrick O'Donnell
Sent: Tuesday, March 02, 2010 3:18 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] OA damper barely modulating


Hi all,

I had similar OA damper question last week which the OA damper was stuck open with 100% OA (which was resolved thanks to the board!)  I have a new issue...

The system is a: boiler + chiller + VAV with HW reheat and air-side economizer.   The problem is the OA damper is open about the same % (about .45 which is equal to the min dsn OA CFM) whenever the air-side system is operating in my hourly reports all year.  I am thinking that this should open up close to 100% at least some times of the year and close back down to min OA during unoccupied modes, etc.  The as-designed system is capable of it I am just don't think my model is set up to work that way.

I am thinking with this as-designed system, I have gotten over zealous with modifying defaults and have not entered or incorrectly entered some values on cooling/heating controls, OA, economizer, or a combination of a few things.  I have manipulated all of these things trying to figure this out but without luck.

Could someone please take a quick look at the model attached and let me know if they see anything suspect?  Your input and help is greatly appreciated! Thanks,

-Patrick

<<Retail1.inp>> <<Retail1.pd2>>
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