Backlit Display; Filter Reminders; Fan Selections; Screen Locked - Trane ACONT900AC43UA Service Manual

4 Heat/3 Cool/ Heat Pump
Communicating Programmable 3-Wire Hookup

Setpoint deadband

The number of degrees separating Heating and Cool-
ing setpoints is user adjustable from two to nine de-
grees. When the control is set to Auto, and the cool-
ing setpoint is changed to a cooler setpoint, the heat-
ing setpoint will also change to maintain the selected
deadband. The same action occurs when the Heat-
ing setpoint is changed to a warmer temperature.
The deadband is restricted to a range of five to nine
degrees if ISU 0380 is set to Integrated Temperature
and Humidity Control (ITHC.)

Backlit display

When continuous backlight is disabled, the liquid
crystal display will illuminate only when a touchscreen
key is pressed to improve visibility. The backlight
stays on for 45 seconds after the last touchscreen
key press. When continuous backlight is enabled,
the liquid crystal display will remain illuminated con-
tinuously. The display will dim to half brightness 45
seconds after the last touchscreen key press.

Filter reminders

The Comfort Control can track up to two filter timers
by total fan run time or calendar days. When the
preset timer(s) has expired to remind the homeowner
that it is time to change the filter(s), "Change" then
"Filter" will automatically flash. To reset either filter
timer, simply press the More key to access the filter
timer value and then press the Reset key. Once the
timer has been reset, the filter timer value can be
viewed at any time by simply pressing the More key
until the filter timer is displayed on the screen.
Both the filter timers are auto discoverable ISU set-
tings. If no communicating filtering device has been
discovered, the auto discovered value will default to
zero. To enable one or both timers, change ISU 0500
and/or ISU 0501 to a value other than zero.
(A/T)CONT900AC43UA Installer Guide

Fan selections

Pressing the Fan key selects whether the indoor fan
motor runs in the On, Automatic, or Circulation mode.
In On mode, the fan motor runs continuously. The
fan automatically follows the fan schedule in Auto-
matic mode. Circulation control will provide a vari-
able circulation determined by the Adaptive Intelli-
gent Circulation (AIC) algorithm running the fan be-
tween 20% and 60% of the time. Each scheduled
period (wake, leave, return, sleep) can be pro-
grammed with a specific fan setting (on, automatic,
or circulation.)

Screen locked

Locking the control's touchscreen keys can help pre-
vent unwanted tampering with or changing of control
settings. The Comfort Control can either be fully
locked or partially locked. Both options continuously
display "Screen Locked" on the screen. Changing
ISU number 0670 to zero will unlock the keys and
"Screen Locked" will disappear.

Installer system tests

The built-in Installer System Test mode allows the
serviceperson to quickly and easily test the Comfort
Control's operation with HVAC equipment and makes
diagnostic procedures a snap. System configura-
tion determines which tests are available and the
corresponding number of stages shown (See Table
6, Tests 1-6 for details.)

Default factory settings

The Comfort Control is shipped with a set of factory
default settings. The factory default settings can be
restored at any time using the Installer Setup menu
(See Table 4, ISU number 0710, Page 17.)
Before you perform Auto-Discovery mode (ISU num-
ber 0710), it is recommended that you record all your
user settings. All user settings choices will be reset
C - A 21