Trane AFDH, Installation Manual

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60 AFDH-SVN01A-EN
Installation
a. The re-optimization timer is adjustable from 1 to 255-hours, in 1-hour increments. Optimal
chiller performance is most often achieved using the recommend setting value of 24 (which
equals 24-hours).
8. AF Boundary Pressure Coefficient (BPC) Y-Intercept: The BPC Y-Intercept value is used
to determine the location of the BPC in the control algorithm. This front panel value is unique
because it can be changed externally by the user, or internally by the control algorithm.
a. BPC Y-Intercept is adjustable for 0.01 to 2.0 in 0.01 increments. Value = 0.4 is recommended.
9. AF Boundary Pressure Coefficient (BPC) Y-Intercept Maximum: The BPC Y-Intercept is
never allowed to exceed a set maximum value. This value is a manual way to control the
aggressiveness of the efficiency optimizing procedure.
a. As this value is lowered the probability of encountering surge decreases but so does the
potential efficiency improvement at a given operating condition.
b. The maximum boundary pressure setpoint is adjustable from 0.01 to 2.0 in 0.01 increments.
The recommended value is 2.0.
10. AF Pressure Error Deadband: Anytime the Pressure Coefficient (PC) is inside of the pressure
deadband, no further speed reductions are allowed. Thus, the pressure deadband establishes
a region where no background speed decreases will occur.
a. Setting this value large will tend to make the AFDB control algorithm less aggressive at
optimizing efficiency.
b. The pressure error deadband is adjustable from 0.001 to 1.000 in increments of 0.001. The
recommended value to use that has shown to most often contribute to optimal chiller
operation is 0.030.
11. AF Proportional Speed Gain: The proportional speed gain is used to convert the pressure
error calculated by the control algorithm into Delta Hz. The proportional speed gain is
adjustable from 1 to 100 in increments of 1. The recommended setting value is 50.