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TABLE 5 Continued
Code
Diagnostic Codes/Status of Equipment
Action Required to Clear and Recover
E 206
Gas valve second-stage relay failure
Furnace will operate on 1
st
stage for remainder of
the heating demand. Will clear after fault recovered.
If unable to operate 2nd stage, replace control.
E 207
Hot surface ignitor sensed open - Refer to troubleshooting.
Measure resistance of hot surface ignitor. Replace if
open or not within specified range found in IOM.
Resumes normal operation after fault is cleared.
E 223
Low pressure switch failed open.
Check pressure (inches w.c.) of low pressure switch
closing on heat call. Measure operating pressure
(inches w.c.). Inspect vent and combustion air in
ducer for correct operation and restriction. Re
sumes normal operation after fault is cleared
E 224
Low pressure switch failed closed - Refer to troubleshooting.
Check operation of low pressure switch to see if it is
stuck closed on heat call longer than 150 seconds.
Measure operating pressure (inches w.c.). Inspect
vent and combustion air inducer for correct opera
tion and restriction. Resumes normal operation after
fault is cleared.
E 225
High pressure switch failed open - Refer to troubleshooting.
Check pressure (inches w.c.) of high pressure
switch closing on heat call. Measure operating pres
sure (inches w.c.). Inspect vent and combustion air
inducer for correct operation and restriction. Re
sumes normal operation after fault is cleared.
E 226
High pressure switch failed closed - Refer to troubleshooting.
Check operation of high pressure switch closing on
heat call. Measure operating pressure (inches w.c.).
Inspect vent and combustion air inducer for correct
operation and restriction. Resumes normal opera
tion after fault is cleared.
E 227
Low pressure switch open during trial for ignition or run mode. Refer to
troubleshooting.
Check pressure (inches w.c.) of low pressure switch
closing on heat call. Measure operating pressure
(inches w.c.). Inspect vent and combustion air in
ducer for correct operation and restriction. Re
sumes normal operation after fault is cleared.
E 228
Combustion air inducer calibration failure
Unable to perform pressure switch calibration.
Check vent system and pressure switch wiring con
nections. Resumes normal operation after fault is
cleared.
E 229
Ignition on High Fire - Information Only
Code is displayed if 1) low pressure switch fails to
close, then furnace will switch to high speed inducer
to close both low and high pressure switches, then
furnace lights on high fire, or 2) if continuous fan is
active, furnace lights on high fire for 60 seconds to
improve heat exchanger warm up time.
E 240
Low flame current - Run mode - Refer to troubleshooting.
Check micro-amperes of flame sensor using control
diagnostics or field-installed mode. Clean or replace
sensor. Measure voltage of neutral to ground to
ensure good unit ground. Alert clears after current
heat call has been completed.
E 241
Flame sensed out of sequence - Flame still present.
Shut off gas. Check for gas valve leak. Replace, if
necessary. Alert clears when fault is recovered.
E 250
Limit switch circuit open - Refer to troubleshooting.
Check for proper firing rate on furnace. Ensure
there is no blockage in heater. Check for proper air
flow. If limit not closed within 3 minutes, unit will go
into 1-hour soft lockout. Resumes normal operation
after fault is cleared.
E 252
Discharge air temperature too high (gas heat only).
Check temperature rise, air flow and input rate.
Cleared when heat call is finished.
E 270
Soft lockout - Exceeded maximum number of retries. No flame current
sensed.
Check for proper gas flow. Ensure that ignitor is
lighting burner. Check flame sensor current. Clears
when heat call finishes successfully.
