Trane RTHD

RTHD-SVX01D-EN 73
Installation Electrical
• Current Limit Control Softload Time: This Setting controls the time con-
stant of the Filtered Current Limit Setpoint. It is settable between 0 and
120 minutes.
• Current Limit Softload Starting Percent: This setting controls the starting
point of the Filtered Current Limit Setpoint. It is adjustable from 40 for
RTHD to 100 percent RLA.
External Base Loading - Optional
Primarily for process control requirements, base loading provides for immedi-
ate start and loading of a chiller up to an externally or remotely adjustable cur-
rent limit setpoint without regard to differential to start or stop, or to leaving
water temperature control. This allows the flexibility to prestart or preload a
chiller in anticipation of a large load application. It also allows you to keep a
chiller on line between processes when leaving water temperature control
would normally cycle the unit.
When the base loading option is installed through TechView it will be control-
lable through DynaView/TechView, External Hardware Interface or Tracer (if
Tracer is installed). Order for precedence for all setpoints, DynaView/Tech-
View then External then Tracer from lowest to highest priority. If one of the
higher priority setpoints drops out due to a bad sensor or communication loss
then base loading shall go to the next lowest priority of command and set-
point. The command settings and control setpoints associated with base
loading are explained below.
Base Loading Control setpoint
This setpoint has three possible sources, an External Analog Input, Dyna-
View/TechView or Tracer.
• DynaView/TechView Base Loading Control Setpoint
The range is 40 - 100 % Compressor Load (Max %RLA). The default is
50%.
• Tracer Base Loading Control Setpoint
The range is 40 - 100 % Compressor Load (Max %RLA). The default is
50%.
• External Base Loading Setpoint
This is an Analog Input that sets the base loading setpoint. This signal can
be controlled by either a 2-10Vdc or 4-20ma Signal based on configuration
information. The equations show the relationship between input and per-
cent compressor load:
If the input is configured as a 4 - 20 mA:
% Load = 3.75 * (mA Input) + 25
If the input is configured as a 2 - 10 Vdc:
% Load = 7.5 * (Vdc Input) + 25
Summit Interface - Optional
CH530 provides an optional interface between the chiller and a Trane Summit
BAS. A Communications interface LLID shall be used to provide "gateway"
functionality between the Chiller and Summit.