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SchwankAir Controller
Frost protection function
Unit with water heating
Only applies to units with internal sensor.
The frost protection function is intended to prevent
the water coil from freezing.
When the fan is in operation the valve actuator
opens the valve at an internal temperature below
+59 °F regardless of whether there is a heating
requirement. If the internal unit temperature
continues to drop, e.g. at low ambient
temperatures, insufficient flow line temperatures,
low flow or fault valve function, the frost protection
alarm A3 will be triggered when the internal unit
temperature drops +41°F. The fan then also stops
and when the mixing cabinet is used the dampers
is also closed.
With return temp. sensor connected an advanced
alarm function occurs. At return temperatures less
than +59 °F the actuator will open regardless of
the heat demand. Alarm is triggered at return
tempe44 °F and the fan also stops.
When the fan is not running there is a heat
retention function that opens the valve when the
water’s return temperature falls below +77 °F
regardless of heat demand.
Note! In event of repeated alarms, overheating
alarms and frost protection alarms, carry out
a thorough check and if the fault cause cannot
be found contact authorised installer or Schwank.
Air curtains
Decrease heat
Heat off
Alarm Start ramp-up
Full speed
Unit with water heating
98
º
F
104
º
F
122
º
F
129
º
F
Unit with electrical heating
except
116
º
F
125
º
F
134
º
F
1411
º
F
Overheat protection - temperature limits
