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With airflow measuring stations permanently installed,
balancing is done by measuring airflow on one side of the
heat recovery ventilator and then the other. Adjustments
can then be made to the damper to equalize airflows.
When using the temporary method, an FMS is installed
in one air duct of the heat recovery ventilator and the flow
recorded. The FMS is then relocated to the other air duct
and the airflow is recorded again. Dampers can then be
adjusted to equalize airflow. This procedure should be
repeated to ensure that the unit is balanced properly.
Balancing Procedure
Before proceeding with balancing, all windows, over-
head doors and walk-in doors should be closed and
exhaust systems should be turned off.
The connections between the flow stations and the
ducts must be sealed with tape. Mount the magnehelic
gauge in a convenient location where it is level and will
not vibrate or be bumped. Zero the gauge. Measure the
exhaust air first as it is often the lowest due to a longer
duct system.
With the fan speed at maximum, connect the hoses
from the FMS to the magnehelic gauge. If the needle falls
below zero, reverse the hose connections. Ensure that
the damper is wide open. Take a reading from the mag-
nehelic gauge and record it. Remove the FMS and place
it in the supply duct. This process is not necessary if the
FMS is to be permanently mounted.
Repeat the procedure. If the reading is higher in the
supply duct, adjust the damper until the reading is the
same. If the reading is lower, return the FMS to the
exhaust duct and adjust the damper to obtain the same
reading as the supply duct.
System Service
Bi-Monthly Maintenance
Bi-monthly maintenance should include:
Air Filters
The standard foam filters are washable. Under normal
conditions it is recommended that they be cleaned every
two months. More frequent cleaning may be required
under extremely dirty operating conditions. Use a vacuum
cleaner to remove the heaviest portion of accumulated
dirt, then wash with warm water.
A medium efficiency filter for the supply airstream is
available from your supplier. This filter is disposable and
should be replaced when it becomes dirty.
Drain Pans and Interior of Unit
With the filters removed from the unit, the foil faced
insulation surfaces and drain pans should be wiped clean
with a soft cloth and mild cleaning solution. Ensure that
the drain fittings are free from dirt and draining freely.
Annual Maintenance
Annual maintenance should include:
Air Filters
Vacuum and wash standard foam filters. Replace
medium efficiency filter if present.
Drain Pans and Interior of Unit
Wash the foil faced insulation surfaces and wipe the
drain pans with a soft cloth and mild cleaning solution.
Check the drain fittings to ensure they are draining freely.
Flat Plate Heat Exchanger
The flat plate heat exchanger must be handled with
care. In order to ensure maximum efficiency of the parti-
tions, it is recommended that it be washed once a year
following the season of most intense use. Allow the flat
plate heat exchanger to soak for three hours in warm
water and mild soap. Rinse under a heavy stream of
water. When replacing the flat plate heat exchanger sec-
tions, make sure the flutes on the heat exchanger are
positioned in the supply airstream. Failure to do so will
result in low airflow on the exhaust airstream due to sys-
tem pressure trapping or holding condensate in the flutes.
WARNING
Disconnect power before maintaining the unit.
WARNING
Disconnect power before maintaining the unit.
Washable Foam Filter or
MEF Filter - optional
Washable Foam Filter
Washable Foam Filter
MEF Filter - optional
Figure 1: 600 cfm and 1
150
cfm
Figure 2: 700 cfm
