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Continuous, excessive, positive pressure may drive moist indoor air into the external walls of the building. Once
inside the external walls, moist air may condense (in cold weather) and degrade structural components or cause
locks to freeze.
Continuous, excessive, negative pressure may have several undesirable effects. In some geographic locations, soil
gases such as methane and radon gas may be drawn into the home through basement or ground contact areas,
and may also cause the backdrafting of vented combustion equipment.
Attention
Balancing the Airflows
Balan
cing the airflows is critical to ensuring that the amount of air introduced from the outside of
the building equals the amount of air exhausted to the outside of the building. If these two airflows
are not properly balanced, the following issues may occur:
A positive or negative pressure in the house
ERV not operate at its maximum efficiency
The unit not defrost properly
Airflow Measuring Gauge
A digital manometer is a suitable instrument for the balancing of
airflows.
99-BAL-KIT Airflow Balancing Kit
Kit includes a digital manometer, pitot tube, hose and tool bag.
Figure A
Digital Manometer
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DICITAL IANDIETER
Gauge Attachments
When sampling an airflow, various attachments are available
for use on a digital manometer. Consult with your Lifebreath
distributor for available options such as a pitot tube, flow
measuring station, and an airflow measuring probe.
Figure B illustrates a digital manometer with a pitot tube
attachment. This combination will measure the system air
velocity pressure accurately, regardless of the duct size or
shape (either round or rectangular).
Figure B
Digital manometer with a
pitot tube attachment
DUCT
AIR
FLOW
Pitot tube
Digital
manometer
