SummerAire SHRV2500DD, Installation And Owners Operating Manual, Page: 17 / 27

Read the Application WARNING on the Front Page of This Manual.Prior
to balancing, insure that :
1. All sealing of the ductwork system has been completed.
2. All of the HRV’s components are in place and function properly.
3. Balancing dampers are open.
4. HRV is on High Speed.
5. Air flows in branch lines to specific areas of the building should be adjust-
ed first, prior to balancing the HRV. A smoke pencil used at the grilles is a
good indicator of each branch line’s relative air flow.
6. After taking readings of both the stale air to the HRV duct and fresh air to
the building duct, the lower CFM ( L/s ) velocity reading should be left
alone, while the duct with the higher reading should be dampered to match
the lower reading.
7. Return HRV to appropriate fan speed for normal operation.
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BALANCING PROCEDURE
The follo wing is a method of field balancing an HRV using a Pitot Tube,
advantageous in situations when air flow stations are not installed in the duct-
work. This procedure should be performed with the HRV on High Speed. The
first step is to identify the supply duct to the building and the return duct from
the building. Choose the straightest section of duct between the HRV and any
branches or take-offs.This will be for both the supply and return ducts.
Drill a small hole in the duct ( approx. 3/16” ) 3 feet downstream of any elbows
or bends, and 1 foot upstream of any elbows or bends. These are recommended
distances, but the actual installation may limit the amount of straight duct.
The Pitot Tube should be connected to a Magnahelic gauge or other manometer
capable of reading from 0.0 – 1.0 in. ( 0-500 Pa ) of water, preferably to 3 dig-
its of resolution. The Tube coming out of the top of the Pitot is connected to the
High Pressure side of the gauge. The Tube coming out of the side of the Pitot is
connected to the Low Pressure or reference side of the gauge.
2500DD-Install-ENG 1/17/06 5:56 PM Page 17