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7
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9
Global IFS
Fan Powered Box
FAN POWERED BOX & TERMINAL UNIT
MAINTENANCE
Troubleshooting Guide
1. The terminal is louder than expected. What might be
causing
this?
a. The first thing to look for is any foreign material in the fan or
terminal casing, like packing material or small parts shipped
with the unit. Ensure the power is off, and spin the fan wheel
to make sure it is balanced so it is not making contact with
the fan housing.
b. Once it’s confirmed that the fan and terminal casing are free
of foreign material and balanced, ensure the terminal is the
correct size. Check the label for the model and size, and
match that against the schedule to ensure the correct size
was selected and installed. A terminal that is too small for the
application will cause high air velocity and excessive noise.
c. If an electric coil is present, ensure there is sufficient
downstream static pressure of 0.2 inches water gauge to
prevent any chatter of the air proving switch.
2. The terminal is not providing the specified primary air
volume. How do I adjust the primary air volume?
a. First, the airflow may simply need to be balanced correctly to
ensure the primary airflow isn’t short circuiting into the
plenum. See page 6 for air balancing procedures.
b. Check the controller. Make sure it is set up according to the
wiring diagram. There should be a wiring diagram mounted
inside the door of the controls enclosure, or contact
airmovement@priceindustries. com for assistance.
c. Next, ensure the following items are operating correctly:
i. Cycle the thermostat to see if a signal is being sent to
the controller and the controller is reacting
appropriately.
ii. Check the operation of the damper actuator and the
linkage.
iii. Check the flow sensor and tubing for block
3. The fan air volume is too low. How do I adjust the fan
air
volume?
a. Measure the downstream static pressure. It needs to be at
least 0.1 in wg (0.2 in wg for a Size 60 FDC or if an electric coil
is present). If the downstream static pressure is too low, the
blower motor will overheat, turn off, and restart after it
cools, and will continue in this cycle.
b. Once the downstream static pressure is confirmed, check the
supply voltage is the same as stated on the wiring diagram.
The supply voltage must be identical to the wiring diagram.
c. For ECM applications, the motor will be furnished with one
of two programs:
i. High Turndown flow program: This program will maintain
constant motor torque to vary the airflow with
fluctuations in static pressure.
ii. Pressure Independent program: This program
will maintain the desired airflow by varying the motor
torque to compensate for changes in static pressure.
Check the product label to confirm which program was
supplied with your motor, and determine if the program
matches the behavior of the fan with respect to duct
static pressure. If it is not operating as described for the
appropriate program, contact
airmovement@priceindustries for assistance.
ci. Next, check the filter for excessive dust build-up, and then
check the fan, any coils, and the inside of the terminal casing
for particle blockage, or loose insulation. If needed, changed
the filter and clear any blockages.
cii. Check the fan rotation to ensure it is spinning in the
direction marked on the blower casing. If the fan is not
energized for morning warm-up, for example, the warm
primary air may short-circuit through the return opening to
the plenum, inducing the fan to spin in the wrong direction.
When the fan is energized, it will continue to spin in the
wrong direction, which will sharply decrease fan flow.
ciii. Finally, inspect the ductwork for leaks or obstructions, sharp
elbows near the fan inlet, or improperly designed turning
vanes. Any of these items can decrease the fan’s efficiency.
4.
The fan will not operate. How do I get it to start?
a.
Check the wiring diagram provided with the
terminal unit.
Make sure that all the wiring
inside the electrical
enclosure matches the
wiring diagram exactly.
b.
If the fan is cycling on and off, it may be
insufficient
downstream static pressure causing
the motor to
overheat and cycle. Ensure the
downstream static
pressure is a minimum of 0.1
in wg (0.2 in wg for a Size 60
FDC or if an electric
heater is installed).
c.
Cycle the thermostat to full heating and verify
the signal
output from the thermostat to the
controller.
d.
Check the disconnect switch or breaker.
e.
Ensure the fan wheel is not touching the blower
casing.