Startup
72 RT-SVX34F-EN
Exhaust Fan Operation
To start the optional power exhaust fans, use the
economizer test procedures in Table 31, p. 56 - Table 36,
p. 58 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.
Verify that the fans are operating properly and the CFM is
within the job specifications. Refer to power exhaust fan
performance tables beginning with Table 49, p. 73 for the
exhaust fan performance characteristics.
Available power adjustments:
1. The power exhaust fan(s) comes on based on the
position of the of the exhaust fan setpoint
potentiometer on the RTOM (Reliatel Options Module).
The setpoint is factory set at 25%. The exhaust fan(s)
will come on anytime the economizer damper position
is equal to or greater than the active exhaust fan
setpoint.
2. 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.
3. 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.
4. 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.
5. The proportional offset between the dampers is
adjusted under the rain hood by hole position selection
on the power exhaust actuator jack shaft on the
damper linkage arm.
Note: The damper is a barometric damper that continues
to function as a pressure relief damper up to the
maximum stop position.
Table 48. Supply air fan drive selections — 50 Hz
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
23 (80)
458A ——————
500B ——————
541C ——————
583—583D————
625 — 625
(a)
(a) For YC gas/electric only.
E ————
25 (88)
458A ——————
500B ——————
541C ——————
583—583D————
625—625E ————
29 (103)
500B ——————
541—541C ————
583—583D————
658 — — — 658
(b)
(b) For TC and TE Cooling only and with electric Heat units only.
F——
664 — — — 664
(a)
G——
33 (118)
417—417H ————
437—437J ————
479—479K ————
521 — — — 521 L — —
562 — — — 562 M — —
604 — — — 604 N — —
42 (146)
437—437J ————
479—479K ————
521 — — — 521 L — —
562 — — — 562 M — —
604—————604N
WARNING
Rotating Components!
The following procedure involves working with live and
exposed rotating components. Have a qualified or
licensed service individual who has been properly
trained in handling exposed rotating components,
perform these tasks. Failure to follow all safety
precautions could result in rotating components
cutting and slashing technician which could result in
death or serious injury.
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