Lennox Harmony III User Manual

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6.2. Diagnostic LED Error Codes
When the zone control system nds a problem (error condition), it will turn on
one or more of the diagnostic LEDs on the zone control. These LEDs can be lit in
several different patterns, each pattern corresponding to a different error condition.
The following table shows each possible display pattern, a description of the error,
and ways to correct the error.
Some of the errors found in table will cause a fail-safe or shutdown condition. The
systemwillshutdownaftertheerrorispresentforaboutveseconds.Duringa
shutdown condition, all dampers will open, there is no demand to the air conditioner
unitorfurnace.Normaloperationwillresumevesecondsaftertheerrorhasbeen
corrected.
The blower may run during a fail-safe condition after a heating demand. This is due
to the operation of the integrated control inside the furnace.
Ifashutdownconditionoccurswhilethereisacallforcooling,ave-minutetimer
is initiated before cooling can be called for again. The timer begins at the time of
the shutdown condition and does not affect the response to, nor is affected by, a
heating demand.
Troubleshooting diagrams in this instruction identify common areas to check when
troubleshootingspecicequipment.Thediagramsprovidecheckpointsrelatedto
connectivity and operation of system equipment. Use these diagrams, along with
installation information contained throughout this manual, to identify and correct
problems.
Table 15. Diagnostics Codes
Code
#
(0-off;1-on)
Diag
LED1234
Fault Indicated Remedy
Fail-safe
(System
Shut
Down)
0 0000 Normal operation No remedial action required.
1 1000
Insufcient
cooling
Occurs when there is a call for cooling and the Discharge Air Sensor does not sense a decrease in supply air temperature indicating the cooling
is not functioning properly.
No
2 0100
Defrost time > 20
minutes
The defrost board should never allow a defrost for greater than 20 minutes. If this error occurs, check the outdoor unit to see if it is stuck in
defrost mode. The zone control system will use the backup heat during this error and not the heat pump.
No
3 1100
Unsteady
thermostat input
This error occurs when a thermostat changes state repeatedly and rapidly, indicating that the thermostat is making intermittent contact and needs
attention. The offending thermostat will be ignored for four minutes after the zone control system detects the problem. After four minutes if the
signal from the thermostat is steady again, it will be recognized by the zone control system. Disconnect thermostats until error goes away. This
will identify the source of bad input. If error remains after all inputs have been disconnected, replace zone control panel.
No
4 0010
Defrost while gas
heat selected
System detected defrost signal at W1-Def terminal block while the jumper is selected for the furnace. May be caused by:
• Wrong selection for indoor unit jumper.
• Outdoorunitterminalblockmisred.
• Zone control system failure.
Check unit installation instructions for correct wiring. If no signal is present at W1, then replace zone control panel.
Yes
5 1010
Discharge
Air Sensor
(DAS) detects
high heating
temperature
This condition may occur any time the discharge probe senses air warmer than 160ºF for furnace or 135ºF for heat pump. If system is in zone
mode when this code is set, the system continues in zone mode, shuts off equipment, and runs continuous blower to satisfy demand. The heat
pumporfurnacewillremainoffforaminimumofveminutesanduntiltheDASsenses130ºF.
Add more air to zone or redistribute zones to divide air more evenly.
No
6 0110
Zone air jumper
not selected
Air selected for fewer than two zones. No air is selected for zone 1 or, 3. If a zone air selection jumper is left off of a zone that issues a heat or
cool demand. In this case the system will assume that a PIAB of 100 is required to service the zone.
Make a zone air jumper selection. If jumpers are in place, replace the zone control panel.
No
7 1110
Open or shorted
DAS
If system is operating, system will be forced into central mode. The compressor will cycle from high to off in cooling. The compressor will cycle
from high to off in heating. The furnace will operate normally in gas heat. Replace discharge probe. If error persists, replace zone control panel.
No
8 0001
Simultaneous
heat and cool
call from same
thermostat
In addition, possible inconsistent thermostat signals. Verify thermostats are correctly connected to the zone control panel. If error persists after
you check the thermostats and jumper selections or try another thermostat model or brand. Demand will be ignored from the zone sending the
bad signals. See “Table 14. Time Delays” on page 60.
No

Lennox Harmony III Specifications

General

Brand	Lennox
Model	Harmony III
Category	Control Systems
Language	English