HRV Duct Sizing Question With Damper - HVAC - DIY Chatroom Home Improvement Forum

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Old 04-19-2013, 02:30 PM   #1
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HRV Duct Sizing Question with Damper

I'm trying to design an HRV ducting system and I had a few theoretical questions in regard to using a damper.

I'd like to have two main trunks that come off the HRV: trunk A and trunk B. These two trunks will be pulling the air OUT of the rooms.

Trunk A will serve a kitchen and two bathrooms.
Trunk B will two crawlspaces.

If I place a normally open damper on trunk B, and I energize the damper, the damper will close.

My expectation is that the CFM amount will fall to zero in Trunk B and will increase in Trunk A.

Should I size the Trunk A and the Trunk A branches to accomodate the CFM when the Trunk B damper is closed, or when it is open?


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Old 04-20-2013, 03:21 AM   #2
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Trunk A should be sized to 125% of the air you want to go through it when ever the HRV is running.


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cfm , damper , duct , hrv , size

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