Technical Note: Balancing Ducted Units - Price FFU-HE Series Manual

FAN FILTER UNIT - HIGH EFFICIENCY
INSTALLATION & SERVICE INSTRUCTIONS

Technical Note: Balancing Ducted Units

STEP 1: Set FFU on benchtop and balance to desired flow using appropriate speed controller set up (Pages X-X).
STEP 2: Confirm airflow using flow hood and adjust speed controller as required.
STEP 3: Lock primary air control
STEP 4: Install FFU into ceiling grid
STEP 5: Turn FFU's on – ensuring all FFUs on the same system are turned on at the same time.
STEP 5: Unlock primary air control
STEP 6: Measure discharge static pressure at VAV discharge or FFU inlet.
STEP 7: If measured pressure is greater than 0.0" w.g., turn up the FFU in small increments while monitoring the measured
pressure. Increment until pressure approaches 0.0" w.g. Similarly, if measured pressure is negative, turn down the FFU in small
increments, monitoring the measured pressure until it approaches 0.0" w.g.
NOTE: A slightly negative static pressure is also acceptable.
NOTE: Not recommended for FFU-HE units with ECM units with constant airflow program.
If removing the FFU-HE from the duct is not possible, follow the below instructions for balancing:
STEP 1: Install an air pressure measurement device (i.e. Pitot tube) in the inlet of the FFU-HE.
STEP 2: Power up FFU-HE and set the speed controller to approximately 75% of maximum set point.
STEP 3: Power upstream airflow control device, and set airflow to the FFU-HE to 25% less than design flow.
STEP 4: Read the inlet pressure.
STEP 5: Measure airflow using flow hood
STEP 6: Using the table below, adjust FFU-HE controller, or upstream airflow device as required
FFU Airflow
Above Set point
Above Set point
Above Set point
Below Set point
Below Set point
Below Set point
STEP 7: Repeat steps 4-6 unit design airflow is achieved and inlet pressure is neutral (0.0" w.g.).
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FAN FILTER UNIT - HIGH EFFICIENCY - Manual | priceindustries.com
FFU Inlet Static
Above 0'' W.G.
Below 0'' W.G.
0'' W.G.
0'' W.G.
Below 0'' W.G.
Above 0'' W.G.
Action
Lower airflow on airflow control device
Lower FFU control setting
Lower Both FFU and airflow control device
Raise Both FFU and airflow control device
Raise airflow on airflow control device
Raise FFU control setting