Lennox iComfort S30 Installation And Setup Manual page 55

Table 1 Alert Codes and Troubleshooting
Applicable
Alert Priority
System
Code Condition
Component(s)
272 Critical Furnace
273 Critical Furnace
274 Critical Furnace
275 Critical Furnace
276 Critical Furnace
290 Critical Furnace
291 Critical Furnace
Furnace or air
292 Critical
handler
294 Critical Furnace
Critical alerts are displayed on the Home screen, in the Homeowner alert button, and in the Installer alert button.
Minor and moderate alerts are found only in the Installer alert button.
Actual Displayed Alert
Component or System Operational State and Troubleshooting Tip
Text
The furnace low pressure switch is open during run mode. The system will
go into WatchGuard mode.
√ Check operation of low pressure switch to see if it is stuck open during a
heat call.
WatchGuard - Lo Press
Switch Open Run Mode √ Measure operating pressure (inches w. c.).
√ Inspect vent and combustion air inducer for correct operation and restric­
tion.
√ Check for blocked CEHB or condensate drain and cracked hoses.
The furnace flame is going off during a heating cycle. The system will go
into WatchGuard mode.
√ Check micro-amperes of flame sensor using thermostat diagnostics.
WatchGuard - Flame fail
in Run Mode √ Clean or replace sensor.
√ Measure voltage of neutral to ground to ensure good unit ground.
√ Clean face of burner assembly.
The furnace limit switch has been open for more than three minutes. The
system will go into WatchGuard mode.
WatchGuard - Primary
Limit Switch Open √ Check firing rate and air flow.
√ Check for air blockage.
The furnace flame is out of sequence. The system will go into WatchGuard
mode.
WatchGuard - Flame Out
of Seq. No Flame √ Shut off gas.
√ Check for gas valve leak.
The furnace is not able to calibrate or the high pressure switch opened or
failed to close in run mode. The system will go into WatchGuard mode.
WatchGuard - Calibration
Failure √ Check vent system
√ Check pressure switch wiring connections.
There is a problem with the furnace ignition circuit. The system will go into
WatchGuard mode.
√ Measure resistance of hot surface igniter.
Ignition Circuit Problem
√ Replace the hot surface igniter; it is not within specifications.
√ Measure voltage to igniter.
The heating airflow is below the minimum required level. The system will go
into WatchGuard mode.
Heat Airflow Restricted
Below Min √ Check for dirty air filter(s) and other air flow restrictions.
√ Check blower performance.
The indoor unit blower motor will not start. The system will go into
WatchGuard mode.
√ Indoor blower motor unable to start.
Indoor Blower Motor Start
Problem
√ This could be due to seized bearing, stuck wheel, and obstructions.
√ Replace motor, motor module or wheel if assembly does not operate or
meet performance standards.
There is over current in the furnace inducer motor. The system will go into
WatchGuard mode.
Inducer Motor
√ Check combustion blower bearings, wiring and amps.
Overcurrent
√ Replace furnace inducer motor if it does not operate or does not meet per­
formance standards.
55
How to clear alert code
Automatically clears when a heat
call ends successfully.
Automatically clears when a heat
call ends successfully.
Automatically clears when a heat
call ends successfully.
Automatically clears on successful
ignition.
Automatically clears when the fur­
nace calibrates itself successfully.
Automatically clears on successful
ignition
Automatically clears when a heat
call ends successfully.
Automatically clears after the in­
door blower motor starts success­
fully.
Automatically clears after inducer
motor current is sensed to be in-
range after the ignition following
either WatchGuard mode or unit
reset.