48
RT-SVX34V-EN
Table 18. Supply air fan drive selections—50 Hz (continued)
Nominal
Tons (kW)
7.5 HP (5.6 kW) 10 HP (7.5 kW) 15 HP (10 kW) 20 HP (15 kW)
RPM Drive No. RPM Drive No. RPM Drive No. RPM Drive No.
33 (108)
417 H
437 J
479 K
521 L
562 M
604 N
42 (146)
437 J
479 K
521 L
562 M
604 N 604 N
646 P
Exhaust Fan Operation
To start the optional power exhaust fans, use the
economizer test procedures in - to drive the economizer
dampers to the open position. The exhaust fans will start
when the damper position is equal to or greater than the
exhaust fan setpoint. If optional power exhaust is selected,
an access door must be field-installed on the horizontal
return ductwork to provide access to exhaust fan motors.
The exhaust fan will start anytime the economizer damper
position is equal to or greater than the exhaust fan setpoint.
WARNING
Rotating Components!
Failure to disconnect power before servicing could
result in rotating components cutting and slashing
technician which could result in death or serious
injury.
Disconnect all electric power, including remote
disconnects before servicing. Follow proper lockout/
tagout procedures to ensure the power can not be
inadvertently energized.
Verify that the fans are operating properly and the CFM is
within the job specifications. Refer to power exhaust fan
performance tables beginning with for the exhaust fan
performance characteristics.
Available power adjustments:
• The relief fan comes on based on the Relief Enable
Position setpoint that is user adjustable within the
Symbio 700 user interface or mobile app. The relief fan
will energize anytime the outdoor air damper is equal to
or greater than the value of this setpoint. The setpoint
default is 25%.
• Physical damper blade stops limit the amount of
exhaust airflow by limiting the maximum opening of the
damper blades. These stops (sliding brackets secured
with wing-nuts) are present under the rain hood on the
non-modulating power exhaust option. There is one
stop on each side of each damper. The practical range
of blade position control is between 1.5" and 4.0" blade
opening. The damper is wide-open at 4.0". The stops
on each side of a damper must be in the same position,
such that the damper blade connecting member
contacts the stops at the same time.
• If configured for Fresh Air Damper Tracking, the
modulating power exhaust actuator tracks the position
of the economizer damper actuator such that the power
exhaust dampers proportionally follow or track the fresh
air damper position.
• When the Statitrac option is selected, the exhaust
actuator will operate independently of the economizer
in order to relieve positive building pressure. If a Space
Pressure Transducer failure occurs, the unit will revert
back to fresh air tracking control.
• The proportional offset between the dampers is
adjustable. With direct-drive ultra-low-leak exhaust
options, actuator stroke can be adjusted as described
in “Economizer (O/A) Dampers,” p. 51. The stroke limit
can be set between 33% and 100% of full stroke.
Note: The barometric damper continues to function as a
pressure relief damper up to the maximum stop
position.
To adjust the damper blade stops, refer to figure
Figure 37, p. 50 to Figure 40, p. 51.
If the fan speed needs to be changed from the current
operating speed, refer to the unit wiring diagram and the
XTB1 and XTB2 terminal strip located in the economizer
section.
Startup
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