System Lights; Diagnostic/Bypass Button - Lennox Harmony II Zone Control System Installation Instructions Manual

System Lights

The following section describes how to use the control pan-
el and the control center lights to do the following:
Determine what mode the system is operating in
D
Help the technician to troubleshoot problems in the
D
zone control system
A−Control Panel LEDs
Mode LEDs
Amber LEDs on the control panel indicate the operating
mode (for example, the LED above the word ZONE indi-
cates the system is in zone control mode).
Service Light
A flashing red LED inside the control panel (See figure 27)
indicates an error condition has been logged in the control
center, and either the inside unit or zone control system re-
quire service. The service technician can then read the
codes from the control center to determine the nature of the
error.
NOTE − The service light located in the master thermostat
(heat pumps only) provides a separate function indicating
that the outdoor unit requires service. The service light in
zone 2, zone 3, and zone 4 thermostats is not functional.
Control Panel Service Light
Red light flashes when the system needs service.
Error codes will be stored in control center for readout by
the technician.
Figure 28
B−Control Center LEDs
The zone control system operation is indicated by light emit-
ting diodes (LEDs) located in the control center. You can use
the LEDs for system troubleshooting. There are three kinds
of LEDs: thermostat, diagnostic, and output. See figure 16
for location.
Input (Thermostat) LEDs
Located along the left side of the control center are the
thermostat LEDs. See figure 7. These LEDs indicate a call
for heating or cooling. Each zone has three thermostat
LEDs: green, − noting a Y1 (compressor) demand, red −
noting a W1 (heating demand) and yellow − noting a O (re-
versing valve) demand. These LEDs are labeled accord-
ing to the zone and demand. For example, a lit LED la-
beled 3Y would indicate there is a call for compressor in
zone 3.
Diagnostic LEDs
These diagnostic LEDs (called DIAGS) are located in the
middle of the the control center. These LEDs aid the techni-
cian in troubleshooting problems. When an operating error
is found, the LEDs are turned on in a pattern (code). A list-
ing of the trouble codes is shown in Tables 7, 8, and 9. See
the troubleshooting section for more information.
Output LEDs
All other LEDs on the control center indicate a specific output
status − zone dampers, furnace out and outdoor unit. These
red LEDs are located on the right side of the control center
next to each output terminal block. See figure 8. When an
output is powered or active, the corresponding LED will be lit.
The LEDs are labeled according to output and function. For
example, if the 2DZ is lit, the damper in zone 2 has been en-
ergized to close. When 2DZ LED goes out, the damper is de−
energized and the damper opens and allows air to flow to that
zone.
Diagnostic/Bypass Button (SW1)
Pressing and releasing (clicking) the black diagnostic/by-
pass button (SW1) provides help on initial startup and
checkout and when troubleshooting problems in the zone
control system. See figure 2. This is button located on the
control center provides three functions:
Single click: Readout of stored error codes
D
Double click: Bypass current time delay
D
Single long push: Display control panel status
D
NOTE − The Diagnostic/Bypass button responds slowly to
commands. Allow several seconds after clicking the button
for the control system to respond.
A−Single Click (Display Error Codes)
Press the button once while the system is operating. Allow
several seconds for the system to respond. The system will
respond by momentarily lighting all four DIAG LEDs then
displaying the error code, if one is stored in memory. This
allows a visual check to verify that all four LEDs are opera-
tional before displaying an error code.
The control center stores the two most recent error codes
with the most recent being displayed first. If an error code is
being displayed before the technician presses the button,
an error condition is currently present and the displayed
code represents the first of the two codes stored. When the
technician presses the button, the previous code will be
displayed. The error code is displayed for 10 seconds.
While the error code is displayed, each additional single
click refreshes the 10 second delay.
Page 29