28
4034-102 Rev F
02/04
HRV200PLUS INSTALLATION INSTRUCTIONS
4. Flow Station Balancing Procedure
(see Figure 17)
The following is a method of field balancing an HRV using a flow station. The procedure should be performed with the
HRV200PLUS on high speed.
The first step is to operate all mechanical systems on high speed, which have an influence on the ventilation system, i.e. the HRV
itself and the forced air furnace or air handler if applicable. This will provide the maximum pressure that the HRV200PLUS will need
to overcome, and allow for a more accurate balance of the ventilator.
Note:
Always balance the system using the FRESH AIR FIREPLACE EXHAUST duct and the WARMSIDE AIR SUPPLY duct.
Install the flow station 18 downstream of any elbows or bends, and one foot upstream of any elbows or bends. These are
recommended distances but the actual installation may limit the amount of straight duct.
The flow station should be connected to a magnehelic gauge or other manometer capable of reading from 0 to 0.25 in. (0 - 62 PA)
of water, preferably to three digits of resolution.
Take readings from both exhaust ducts and the warmside air supply. Determine which duct has the highest air flow (highest reading
on the gauge). Then damper that air flow back to match the lower reading from the other duct. The flows should now be balanced.
See Figure 17. Actual air flow can be determined from the gauge reading. The value read on the gauge is called the velocity
pressure. The flow station comes with a chart that will give the air flow velocity based on the velocity pressure indicated by the
gauge. This velocity will be in either feet per minute or meters per second.
The accuracy of the air flow reading will be affected by how close to any elbows or bends the readings are taken. See Figure 17.
If the ALTERNATE 5TH PORT is used for alternative exhaust, both the fireplace and exhaust air streams must be balanced
individually with the incoming fresh air stream. Individually, each exhaust stream needs to be within 10% of the incoming air
stream.
Figure 17 - Flow Station Balancing
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