Trane CenTraVac Duplex CDHF Operation & Maintenance Manual page 84

Table 3. Values for start reset types
The values for "RESET TYPE" are:
Reset
Type: Disable
The values for "RESET RATIO" for each of the reset types are:
Reset Reset
Type Ratio
Range
Return 10 to 120 percent
Outdoor -80 to 80 percent
The values for "START RESET " for each of the reset types are:
Reset Start
Type Reset
Range
Return 4 to 30°F
(2.2 to 16.7°C)
Outdoor 50 to 130°F
(10 to 54.44°C)
The values for "MAXIMUM RESET" for each of the reset types are:
Reset Maximum
Reset
Range
Return 0 to 20°F
(0.0 to 11.11°C)
Outdoor 0 to 20°F
(0.2 to 11.11°C)
84
Machine Protection
and Adaptive
Control
Outdoor Return
Air Reset Reset
Increment Increment
English SI Units
Units
1 percent 1 percent
1 percent 1 percent
Increment Increment
English SI Units
Units
0.1°F 0.1°C
0.1°F 0.1°C
Increment Increment
English SI Units
Units
0.1°F 0.1°C
0.1°F 0.1°C
Constant Return
CWS' = CWS + 100 percent
(Design Delta Temperature) - (TWE-
Const Return
Reset TWL) and CWS' > or = CWS and
CWS' -CWS < or = Maximum Reset
Notice that Constant Return is
Factory
nothing more than a specific case of
Default
Return Reset offered for operator
Value
convenience.
50 percent
When any type of CWR is enabled,
10 percent
the UCP will step the CWS toward
the desired CWS (based on the above
equations and setup parameters) at a
Factory
rate of 1°F every 5 minutes until the
Default
Active CWS equals the desired
Value
CWS'. This applies when the chiller
10°F (5.6°C)
is running only.
90°F Using the Equation for calculating
(32.22°C)
CWR for Outdoor Air Temperature
Equation:
Factory
Degrees of Reset = Reset Ratio*(Start
Default
Reset - TOD)
Value
The chiller will start at the Differential
5°F
to Start value above a fully reset CWS
(2.78°C)
or CWS for both Return and Outdoor
5°F
Reset.
(2.78°C)
The graph on the next page, shows
the reset function for Outdoor Air
Temperature: Note: This graph
assumes that Maximum Reset is set
to 20 degrees.
Degrees of Reset:
Degrees of Reset = Active CWS -
Front Panel CWS
or
Degrees of Reset = CWS' - CWS
To obtain Active CWS from Degrees
of Reset: Active CWS = Degrees of
Reset + Front Panel CWS
(* = multiply)
CDHF-SVU01C-EN