Installation Electrical
30
RTAF-SVX001A-EN
The equations for each type of reset are as follows:
Return
CWS' = CWS + RATIO (START RESET - (TWE - TWL))
and CWS' > or = CWS
and CWS' - CWS < or = Maximum Reset
Outdoor
CWS' = CWS + RATIO * (START RESET - TOD)
and CWS' > or = CWS
and CWS' - CWS < or = Maximum Reset
where
CWS' is the new chilled water set point or the “reset CWS”
CWS is the active chilled water set point before any reset
has occurred, e.g. normally Front Panel, Tracer, or ECWS
RESET RATIO is a user adjustable gain
START RESET is a user adjustable reference
TOD is the outdoor temperature
TWE is entering evap. water temperature
TWL is leaving evap. water temperature
MAXIMUM RESET is a user adjustable limit providing the
maximum amount of reset. For all types of reset, CWS' -
CWS < or = Maximum Reset.
In addition to Return and Outdoor Reset, the MP provides
a menu item for the operator to select a Constant Return
Reset. Constant Return Reset will reset the leaving water
temperature set point so as to provide a constant entering
water temperature.The Constant Return Reset equation is
the same as the Return Reset equation except on selection
of Constant Return Reset, the MP will automatically set
Ratio, Start Reset, and Maximum Reset to the following.
RATIO = 100%
START RESET = Design Delta Temp.
MAXIMUM RESET = Design Delta Temp.
The equation for Constant Return is then as follows:
CWS' = CWS + 100% (Design Delta Temp. - (TWE - TWL))
and CWS' > or = CWS
and CWS' - CWS < or = Maximum Reset
When any type of CWR is enabled, the MP will step the
Active CWS toward the desired CWS' (based on the above
equations and setup parameters) at a rate of 1 degree F
every 5 minutes until the Active CWS equals the desired
CWS'. This applies when the chiller is running.
When the chiller is not running, CWS is reset immediately
(within one minute) for Return Reset and at a rate of 1
degree F every 5 minutes for Outdoor Reset. The chiller
will start at the Differential to Start value above a fully reset
CWS or CWS' for both Return and Outdoor Reset.
AFD Drive
Trane TR200 drive is an electronic motor controller that
converts AC mains input into a variable AC waveform
output. The frequency and voltage of the output are
regulated to control the motor speed or torque.
TR200 drive includes the following features:
•
Soft start to minimize inrush current
•
Improved harmonic mitigation with DC link reactor
•
Integrated power fuse
•
Graphical LCD keypad
•
Unit Mounted with factory pre-wiring
•
‘Trane Drive Utility’ for configuration and tracking
See Service Manual BAS-SVM01*-EN for more
information.
Range
Increment
Reset
Type
Reset
Ratio
Start
Reset
Max
Reset
IP
Units
SI
Units
Factory
Default
Return
10 to
120%
4 to 30 F 0 to 20 F 1%
1%
50%
(2.2 to
16.7 C)
(0.0 to
11.1 C)
Outdoor
80 to -
80%
50 to 130
F
0 to 20 F 1%
1%
10%
(10 to
54.4 C)
(0.0 to
11.1 C)
