Multi-Unit Residential HRV/ERV
30
Adding Accessories to the VentZone® System
Due to the operation of the VentZone® System, most Aldes controllers cannot be utilized.
V. MEASURING & BALANCING AIRFLOW
Measure and Balance
The installer must measure and balance the airflow brought in from the outside and the
exhaust airflow so that the difference between the two is less than 10% of the maximum
airflow. This airflow balance is especially important in homes using a combustion device or
in those located in areas where the ground emits radon.
If the airflows are not properly balanced, then:
•
The HRV/ERV may not operate at its maximum efficiency
•
A negative or positive air pressure situation may occur in the house
•
The unit may not defrost properly
Excessive positive pressure may drive moist indoor air into the external walls of the
building, where it may condense (in cold weather) and degrade structure components.
It may also cause key holes to freeze up.
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/ground contact areas. Excessive negative pressure may also cause
the backdrafting of vented combustion equipment.
CAREFULLY READ THE WARNINGS IN THE SECTION “PRECAUTIONS & GUIDELINES”
ON PAGE 5.
Fresh and stale airflow can be measured and balanced
by two methods: Door-Port
Balancing or In-Duct Balancing
Door-Port Balancing (E80-HRG,-HRX only)
Door-port balancing is used to determine and adjust the airflow rates of the supply and
exhaust air streams by measuring the static pressure loss across the HRV/ERV core. The
recommended tool for this procedure is a differential pressure gauge (with a 0.0-0.25 in. w.g.
range) or a digital manometer.
Note: The airflow chart on the door of the unit is for use with the filters that come with the
unit. If other filters are used, in-duct measurements of airflow may be made using pitot tube,
airflow probes, or hot-wire thermal anemometer as described in later sections.