Fan-Powered Units - Trane Symbio 210 Installation, Operation And Maintenance Manual

Calibration, Operation Modes, and Control

Fan-Powered Units

The Symbio 210 controllers provide the following three (3) fan options when in space temperature
control mode:
•
•
•
ECM Fan
This controller supports an electronically commutated motor (ECM). The controller turns the ECM
fan ON and OFF. It does not change the ECM fan airflow dynamically. The fan operates at a single
speed to match the fan flow setpoint. The fan flow correction factor is a direct multiplier used to
determine fan speed, and can be adjusted if the measured flow rate does not meet the fan flow
setpoint. To assist with flow balancing the fan flow rate is stored as a configuration item. The
minimum and maximum flow settings are predetermined at the factory and should not be adjusted
in the field. For units configured in the field, the maximum flow should not be set higher than the
nominal airflow of the VAV box.
Series Fan
The series fan is always controlled as a one-speed ON/OFF fan. The fan continuously operates in
the occupied or occupied standby mode and cycles ON and OFF with calls for heating or cooling
in the unoccupied mode. The series fan operates in a manner that prevents reverse rotational
operation. The series fan is turned ON whenever one of the following occurs:
•
•
•
Series Fan Operation During Calibration
During calibration, the series fan is OFF for 10 seconds during calibration after the air valve closes
all the way. It remains OFF after the 10 seconds expires if:
•
•
Otherwise the series fan is turned ON when the 10-second period expires.
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One-speed ON/OFF series fan
One-speed ON/OFF parallel fan
Flow control parallel fan
Target airflow control point is greater than zero.
Target air valve position is not Closed.
Actual air valve position is not Closed.
System mode (communicated application mode or communicated heat/cool mode) is OFF.
Occupancy mode status is unoccupied.
BAS-SVX084A-EN