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©Retrotec 2017
5.1.2.
Retrotec calibrated fan: Model 300
The Model 300 fan has 0.25 hp backward curved impeller that uses 48 Volts that comes from the
supplied power supply. Any input voltage from 100 to 280 Volts AC, 50 to 60 Hz is acceptable. Speed is
controlled using the knob on the 300 fan or the Retrotec digital gauge, which will control the fan to any
desired Set Pressure or Set Speed.
The Model 300 Fan has a speed control built into the Fan Top with a power input connection, a speed
control knob, an on/off switch, and the Fan Pressure fittings all on one Control Panel. Two CAT-5
connectors are used to connect to any Retrotec gauge for speed control purposes; not to be connected
to the Internet. The second CAT-5 connection allows this fan to be daisy chained to a second fan,
making them receive the same % speed signal thereby making two fans run in unison. The control signal
from one gauge will run both fans.
.
Figure 4: Retrotec Model 300 has a speed control knob and two Ethernet style Speed Control Ports for daisy chaining
speed controls for running many fans together. The yellow and green color coded tubing connections to the gauge are
shown.
The Model 300 has 4 Flow (Fan Pressure) sensors located inside the fan inlet, and 4 self-referencing
pickups located just above and below the fan inlet which are connected to the single green and yellow
ports.
Figure 5: Fan Pressure sensors are located in the fan inlet.
The 4 Flow sensors are located just inside the fan inlet, behind the protective grill. Together, they
measure the Fan Pressure, from which the fan airflow is calculated in the gauge. If the sensors become
blocked, it is possible to clear them by attaching a pressure tube to the yellow Ref B port, and blowing
air through the tube gently.