Right Side View - Bryant HRVBBLHA Installation Instructions Manual

FRESH AIR
FROM OUTSIDE
FLOW
COLLAR
12"
(300mm)
30"
(760mm)
FRONT

RIGHT SIDE VIEW

BALANCING HRV
Balancing intake and exhaust airflow is very important for
proper system operation and optimum performance when
applying an HRV. Unit balancing prevents a positive and/or
negative pressure within the home. Balancing the HRV is
done by applying temporary flow collars and permanent
balancing dampers to the fresh air intake and stale air
exhaust ducts (See Fig. 15).
Note: Temporary flow collars are not needed with the new
HRVBBLHA models since the air flow pressure taps are
incorporated in the access door (See Fig. 14).
Airflow is determined by connecting a magnehelic gage to
the temporary flow collar (See Fig. 16). Both flow collars
and magnehelic gage are included in the accessory
start---up balancing kit.
If supply ---air from outside is greater than exhaust---air from
the house, an imbalance can result over pressurizing the
home. If exhaust---air is
combustion appliances may backdraft, bringing exhaust
fumes into the house. A balanced condition will ensure
optimum performance, provide satisfied customers, and
avoid expensive callbacks.
Before proceeding with balancing, all windows, doors, and
fireplace flues should be tightly closed. No exhaust
systems such as range top exhausts, dryer exhaust, fume
hoods, bath or roof fans should be in operation. The
forced ---air furnace (if used for circulation) should be
operating in continuous fan mode for normal operating
speed.
Step 1.—Balancing Dampers
Balancing dampers (sometimes called butterfly dampers)
are provided with the HRVBBLHA. The dampers for the
HRVBBSVU and HRVBBLVU are field supplied and should
STALE AIR
TO OUTSIDE
(300mm)
BALANCING
DAMPER
12"
(300mm)
TEMPORARY
FLOW COLLAR
Fig. 15 --- Balancing HRVBBSVU and HRVBBLVU
greater than supply ---air,
FRESH AIR
FROM OUTSIDE
12"
BALANCING
DAMPER
TEMPORARY
FLOW COLLAR
FRONT
RIGHT SIDE VIEW
be permanently located in fresh ---air intake and stale ---air
exhaust ducts between HRV and exterior wall (See Fig. 14
and 15). Some field modification may be required to ensure
proper installation of balancing dampers while located in
flexible duct. Insulating over these dampers is strongly
recommended after balancing is complete to prevent
condensation problems.
Step 2.—Flow Collar
Flow collars are temporary and should be installed as close
to HRV as possible and in straightest sections of duct to
ensure accuracy (See Fig. 14). If only 1 flow collar is
available, install collar in stale ---air duct of HRV, and record
airflow. Next, install collar in the fresh ---air duct and record
airflow. If 2 flow collars are available, it will be much easier
to read airflow and properly adjust dampers to balance
unit.
With speed control at maximum speed (high ---speed
operation) and continuous air exchange occurring with
outside, connect hoses from flow collar to a magnehelic
gage (See Fig. 16). The gage must be leveled and zeroed
before use to read accurately. If needle falls below zero,
reverse hose connections.
Measure exhaust air first, it is typically the lowest pressure
due to nature of system and duct work. Next, measure
fresh air. If fresh air reading is higher than exhaust reading,
adjust damper until reading is same. If reading is lower,
return to exhaust damper and adjust to obtain same
reading. You can use label on flow collar to convert static
pressure into airflow.
Once HRV is balanced and dampers are adjusted to
equalize airflow, use tape or drive screws to prevent
damper blades from moving. Remove flow collars and
10
STALE AIR
TO OUTSIDE
12" 12"
(300mm) (300mm)
BALANCING
DAMPER
TEMPORARY
FLOW COLLAR
A05351