VB Series Indoor LS Manual
13
Code
Fault
Remedy
16
Over Temperature
Warning
Check for restrictions in air flow around unit and vent terminal.
Check for low water flow in a circulating system causing short-cycling.
Check for foreign materials in combustion chamber and/or exhaust piping.
Check for clogged heat exchanger.
32
Outgoing Water
Temperature Sensor
Fault
Check sensor wiring for damage.
Measure resistance of sensor.
Clean sensor of scale build-up.
Replace sensor.
33
Heat Exchanger
Outgoing Temperature
Sensor Fault
Check sensor wiring for damage.
Measure resistance of sensor.
Clean sensor of scale build-up.
Replace sensor.
34
Combustion Air
Temperature Sensor
Fault
Check for restrictions in air flow around unit and vent terminal.
Check sensor wiring for damage.
Measure resistance of sensor.
Clean sensor of scale build-up.
Ensure fan blade is tight on motor shaft and is in good condition.
Replace sensor.
52
Modulating Solenoid
Valve Signal Abnormal
Check modulating gas solenoid valve wiring harness for loose or damaged terminals.
Measure resistance of valve coil.
61
Combustion Fan Failure
Ensure fan will turn freely.
Check wiring harness to motor for damaged and/or loose connections.
Measure resistance of motor winding.
65
Water Flow Control Fault
The water flow control valve has failed to close during the bath fill function. Immediately turn
off the water and discontinue the bath fill function. Contact a state qualified or licensed
contractor to service the appliance.
71
Solenoid Valve Circuit
Fault
Replace the PC Board.
72
Flame Sensing Device
Fault
Ensure flame rod is touching flame when unit fires.
Check all wiring to flame rod for damage.
Remove flame rod and check for carbon build-up; clean with sand paper.
Check inside burner chamber for any foreign material blocking flame at flame rod.
Measure micro amp output of sensor circuit with flame present.
Replace flame rod.
LC
Scale Build-up in Heat
Exchanger (when
checking maintenance
code history, “00” is
substituted for “LC”)
Flush heat exchanger. Refer to instructions in manual.
Replace heat exchanger.
NOTE: The LC code is the only error code that will allow the unit to keep running. The
display will alternate between the LC code and the temperature setting. The controller will
continue to beep. The LC code will reset if power is turned off and then on.
No
code
Nothing happens when
water flow is activated.
Clean inlet water supply filter.
On new installations ensure hot and cold water lines are not reversed.
Check for bleed over. Isolate unit from building by turning off cold water line to building.
Isolate the circulating system if present. Open your pressure relief valve; if water is
flowing, there is bleed over in your plumbing.
Ensure you have at least the minimum flow rate required to fire unit.
Ensure turbine spins freely.
Measure the resistance of the water flow control sensor.
Check for DC shorts at components.
31
Burner Sensor Error
Measure resistance of sensor.
Replace sensor.
73
Burner Sensor Circuit
Error
Check sensor wiring and PC board for damage.
Replace sensor.
14
Thermal Fuse
Check gas type of unit and ensure it matches gas type being used.
Check for restrictions in air flow around unit and vent terminal.
Check for low water flow in a circulating system causing short-cycling.
Ensure dip switches are set to the proper position.
Check for foreign materials in combustion chamber and/or exhaust piping.
Check heat exchanger for cracks and/or separations.
Check heat exchanger surface for hot spots which indicate blockage due to scale build-up.
Refer to instructions in manual for flushing heat exchanger.
Measure resistance of safety circuit.
Ensure high fire and low fire manifold pressure is correct.
Check for improper conversion of product.
Error Codes
