59
Error Code
Definition
of Code
Cause of Problem and Actions Taken to Correct
93
Water
temperature
sensor fault
•
Appears after alert 172, defined below.
•
Check the water temperature sensor wire harness from the sensor to the control
module.
•
Make sure there are no loose connections to the control plug.
•
Check the resistance reading from each of the outside wires to the center
(common) wire. Measure the tank temperature and compare with the chart below.
•
If the ohm readings are not fairly close, replace the sensor.
•
Replace the control module if the problem persists and the sensor and wire
connections are not defective.
105
Flame
detected
out of
sequence
•
Check to see if flame is present inside the combustion chamber before or after the
ignition cycle.
•
If so, check to make sure the gas valve is wired correctly.
•
Check for voltage at the gas valve connection.
•
Replace the gas valve if defective.
•
If no flame is visible outside of the ignition sequence/run cycle, then make sure the
flame sensor is wired to the correct terminal.
•
Make sure the ignition cable is not crossing the flame sensor wire or ignition
ground wires.
•
If problem persists and all other checks have been verified, replace the control
module.
109, 110
Ignition
Failure
Occurred.
•
Burner failed to light or stay lit after 4 retries.
•
Hold condition
– will reattempt ignition after 15 minute waiting period. A log will be
stored in service history.
•
Check gas valve wiring and gas valve operation during the ignition cycle.
•
If burner lights but quickly goes out, check the flame sensor wire or the flame
sensor.
•
If the flame sensor rod is badly corroded with deposits, clean with sandpaper or
replace.
•
Check the inlet gas supply to make sure the pressure is sufficient and does not
drop after the gas valve opens.
•
Make sure the combustion blower is operating during the ignition and run cycle.
•
Check the venting system to make sure the inlet and exhaust terminals and venting
system is not blocked.
122,123
Light-off
Rate
Proving
Failed
•
If blower speed is not verified from the PWM (Pulse Width Modulation) signal within
5 minutes, the previously described error code “62” changes from a hold condition
to this lockout code condition
•
Check the harness and pin terminals for a good connection to the control module.
•
Replace the blower or control module if the wire harness is good.
137
Normally
closed vent
safety
circuit
opened
•
Refer to code 67
172
Water
temperature
sensor
resistance
invalid
•
Hold 93 will be displayed if this value remains out of range
•
Measure the resistance of the water temperature sensor and compare it with the
tank temperature using the chart below.
NOTE
•
If there is do display, check primary/secondary voltage
•
Before troubleshooting always verify the following
o
Gas inlet pressure
o
Static to dynamic gas pressure drop
o
No vent and intake restrictions
o
All wire connections are tight
o
No grounded wires or missing grounds
o
No water leaks
Summary of Contents for LUHE120T
Page 42: ...42 BMS Wiring Diagram...
Page 44: ...44 Lighting and Shutdown Instructions Figure 31 Lighting Instruction Label...
Page 62: ......
Page 63: ......
