Carrier 17/19EX - Manual (Page 91)

Water/Brine Reset
Three types of chilled water or brine reset are available and can be viewed or modified on the
Equipment Configuration table Config selection.
The LID default screen status message indicates when the chilled water reset is active. The
Control Point temperature on the Status01 table indicates the machine’s current reset
temperature.
To activate a reset type, input all configuration information for that reset type in the Config
table. Then input the reset type number in the SELECT/ENABLE RESET TYPE input line.
1. Reset Type 1 (Requires optional 8-input module) — Automatic chilled water temperature
reset based on a 4 to 20 mA input signal. This type permits up to ±30° F (±16° C) of
automatic reset to the chilled water or brine temperature set point, based on the input from
a 4 to 20 mA signal. This signal is hardwired into the number one 8-input module.
If the 4-20 mA signal is externally powered from the 8-input module, the signal is wired to
terminals J1-5(+) and J1-6(–). If the signal is to be internally powered by the 8-input module
(for example, when using variable resistance), the signal is wired to J1-7(+) and J1-6(–).
The PIC must now be configured on the Service2 table to ensure that the appropriate power
source is identified.
2. Reset Type 2 (Requires optional 8-input module) — Automatic chilled water temperature
reset based on a remote temperature sensor input. This type permits ±30° F (±16° C) of