Phason
VTC-1D user manual
11140010
9
Operation
Example 1: shut-off (OSB) mode
Set point
Differential
Off set-back
Idle speed
80°F 6°F 5°F 20%
When the temperature is below 75°F, the fan is off.
When the temperature increases to 75°F (the off set-back temperature) the fan operates at full speed for
three seconds (for de-icing), then at idle speed (20%). The fan runs at idle speed when the temperature is
between 75°F and 80°F (the temperature set point).
When the temperature is between 80°F and 86°F (the differential temperature), fan speed changes
proportionally with the temperature. If the temperature increases, fan speed increases. If the temperature
decreases, fan speed decreases.
When the temperature is at or above 86°F, the fan operates at maximum speed.
The fan runs at full speed
Fan speed increases with an increase in
temperature; decreases with a decrease in
temperature
The fan is off
Fan speed
The fan runs at idle speed
75°
80°
86°
Idle speed
Temperature set point
Differential
(6° above the
temperature set point)
Off set-back
(5° below the
temperature set point)
