Greenheck Vari-Flow Air Management System(476251) - Manual (Page 11)

11 Vari-Flow Air Management System
Sequence of Operation
Normal Operation
1. Press the fans on/off button on the Vari-Flow keypad
or touch screen to turn the fans on (manual mode).
a. Vari-Flow will turn on all exhaust and supply fans.
b. The Vari-Flow system starts the fans at idle
speed and automatically adjusts exhaust fan
speeds between the low speed setpoint (50%
default) and high speed setpoint (100% default)
based on actual cooking loads as sensed by
the temperature sensors mounted in the hood
capture area. This is determined by the low
temperature setpoint (90°F default) and high
temperature setpoint (115°F default).
c. The Vari-Flow system adjusts the supply speed
based on a weighted average of the exhaust
fan speed. *If static pressure sensor is used for
supply airflow control it will adjust the supply
speed based on static pressure.
2. Press the fans button on the Vari-Flow keypad or
touch screen again to turn off the fans.
a. The Vari-Flow system may go into auto mode if
conditions 3.a-3.c are met.
3. Temperature interlock mode (auto mode).
a. If the temperature in the hood goes above the
temperature interlock on setpoint (115°F default)
and the fans are currently off, the Vari-Flow will
automatically turn on the associated exhaust
and/or supply fans.
b. If the temperature in the hood goes below the
temperature interlock off setpoint (90°F default)
and the fans are not currently turned on manually
the fans will turn off after the temperature
interlock off delay time setpoint (10 minute
default).
c. If the fans were turned on manually and the
user attempts to turn off the fans with the hood
temperature not meeting condition b the fan(s)
will remain on until such conditions are met.
4. With the fan(s) on via manual or auto mode, the
100% override button will force the exhaust fan(s)
that are currently on to full speed for the 100%
override off delay setpoint. The supply fan will adjust
speed the same as 1.c.
5. Pressing the 100% override button on the Vari-Flow
keypad or touch screen again will turn the 100%
override off and return the fans to the speed as
discussed in 1.b.
6. Pressing the hood lights on/off button on the Vari-
Flow keypad or touch screen will turn on the hood
lights.
7. Pressing the hood lights on/off button on the Vari-
Flow keypad/touch screen again will turn off the
hood lights.
Fire Operation:
1. With the fire system microswitch wired to terminal
C1 and NC1 and the fire system in a fire state, the
following will occur:
a. System fault will appear on keypad or touch
screen.
b. Vari-Flow will force the exhaust fan(s) to full
speed.
c. Vari-Flow will force the supply fan(s) off.
d. Vari-Flow will send 115 VAC signal to shunt trip
breaker coil (breaker provided by others).
e. Vari-Flow will force the lights off (if selected with
lights out in fire).
f. Vari-Flow will force the electric gas valve off (if
selected with gas valve reset option).
Fault Operation:
1. Temperature sensor fault.
a. System fault will appear on keypad or touch
screen.
b. Associated fan(s) will be turned on and forced to
full speed until fault is rectified.
2. Exhaust VFD fault.
a. System fault will appear on keypad or touch
screen.
b. All fans will be turned on and forced to full speed.
It will remain this way until the fault is rectified.
3. Supply VFD fault.
a. System fault will appear on keypad or touch
screen.
b. All fans will be turned on and forced to full
speed (for the event that if the fault clears it will
automatically run the fans at full speed). It will
remain this way until the fault is rectified.
4. Supply airflow proving fault - if equipped.
a. System fault will appear on keypad or touch
screen.
b. Exhaust fans will not turn on until supply airflow
has been proven. It will remain this way until the
fault is rectified.
5. Pressure sensor fault - if equipped.
a. System fault will appear on keypad or touch
screen.
b. Supply fan speed will automatically be controlled
via weighted average until the fault is rectified.
6. High temperature alarm - if equipped.
a. System fault will appear on keypad or touch
screen.
b. Vari-Flow will send 115 VAC signal to shunt trip
breaker coil (breaker provided by others).
c. Vari-Flow will force the electric gas valve off (if
selected with gas valve reset option).
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