Lochinvar boiler troubleshooting

The family company Lonchivar produces water heating equipment including boilers, from the 1919 onwards. Its products pass necessary certification and strict technical control. The range of Lochinvar equipment is quite rich. Below you will find the system Lonchivar boiler troubleshooting in the form of a table.


FAULTCAUSECORRECTIVE ACTION
No Display- No 120 VAC supplied to unit.Check external line switch, fuse, or breaker.
Check wiring harness connection between display board and main control board. Connect harness at both points.
- Bad display board.Replace board.
- Bad main control board.Replace the main control board.
- Blown fuse.Replace fuse F3 on the main control board
No Burner Operation- Tank temperature set point satisfied.Review temperature setting.
- Unit locked out on fault.Consult display for specific fault.
Unit Does Not Modulate
Above 50%
- Flue sensor open.Verify that the flue sensor is located in the flue outlet.
Check wiring connections at the flue sensor.
Check the resistance of the flue sensor and compare to Table 12C
Noisy Operation- Supply gas problem. Natural gas pressures should be between 4 inches w.c. and 14 inches w.c. LP gas pressures should be between 8 inches w.c. and 14 inches w.c.
- Gas/air mixture problem.Verify that the vent/air intake lengths do not exceed the maximum listed in the General Venting section.
- Dirty/damaged burner.Clean or replace the burner as necessary.
- Low water flow through the heat exchanger.Very pump operation.
- Air in the piping system.Properly purge all air from the piping system.
No Pump Operation
- Blown fuse.Replace fuse F5 on the control board
- Faulty pump.Replace pump.
- Faulty pump relay.Replace pump relay.
- Internal fault on control board.Replace main control board.
Relief Valve Opening- System pressure exceeds relief valve setting.Lower the system pressure below the 150 PSI rating of the supplied relief valve.

Lochinvar Solution boiler troubleshooting

FAULTCAUSECORRECTIVE ACTION
No DisplayNo voltage through the switch.Replace switch.
Bad display board.Replace board.
Bad main control board.Replace the main control board.
Blown fuse.Replace fuse F3 on the main control board
Main control board temperature set point satisfied.Review temperature setting.
Remote thermostat satisfied.Review remote thermostat setting.
No Burner OperationOutside air temperature above Warm Weather Shutdown (WWSD) set point for main control board.Check location of outside air sensor. Check resistance of outdoor air sensor and compare to Table 3D
Unit locked out on fault.Consult display for specific fault.
Ramp delay active.Check ramp delay parameter settings. Optional PC software required.
Turn ramp delay feature off.
Unit Does Not ModulateBoiler controlled by BMS.Check BMS parameter settings. Optional PC software required.
Above 50%Flue sensor open.Verify that the flue sensor is located in the flue outlet.
Check wiring connections at the flue sensor.
Check the resistance of the flue sensor and compare to Table 3C
Supply gas problem. Natural gas pressures should be between 4 inches w.c. (1.0 kPa) and 14 inches w.c. (3.5 kPa). LP gas pressures should be between 8 inches w.c. (2.0 kPa) and 14 inches w.c. (3.2 kPa).
Gas/air mixture problem.Verify that the vent/air intake lengths do not exceed the maximum listed in the General Venting section of the SYNC Installation and Operation Manual.
Noisy OperationDirty/damaged burner.Clean or replace the burner as necessary.
Low water flow through the heat exchanger.Verify that the boiler is piped in a primary/secondary fashion and that the boiler and system pump are running on a call for heat.
Air in the piping system.Properly purge all air from the piping system.
Low system water pressure.Verify system pressure is a minimum of 12 psi (82.7 kPa).
No Pump
Boiler Pump
System Pump or
HW Pump
Blown fuse.Replace fuse F5 on the control board
Faulty pump.Replace pump.
Internal fault on control board.Replace main control board.
Faulty pump relay.Replace relay.
Relief Valve OpeningSystem pressure exceeds relief valve setting.Lower the system pressure below the 50 psi (344.7 kPa) rating of the supplied relief valve or replace the standard relief valve with a higher rated valve up to the maximum pressure of the heat exchanger.
Improperly sized expansion tank.
Reset the pressure switches.
Gas Pressure Switch
(will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.)
Either the manual reset low gas pressure switch or the manual reset high gas pressure switch tripped.Measure the supply gas pressure to determine cause of failure. Natural gas pressures should be between 4-14 inches w.c. (1.0 - 3.5 kPa) and LP gas pressures should be between 8-14 inches w.c. (2.0 - 3.2 kPa).
Correct the supply gas pressure if necessary.
Check for a loose or misplaced jumper if pressure switches are not installed.
Flow Switch/ LWCO
(will require a manual reset once condition has been corrected. Press the RESET button on
Either the low water cutoff or the optional flow switch is not making.Check boiler pump operation on a call for heat.
Check for closed valves or obstructions in the boiler piping.
Verify system is full of water and all air has been purged from the system.
Check for loose or misplaced jumpers if flow switch is not installed.
Blown fuse.Replace fuse F2 on the control board
Condensate Drain Blocked
(will require a manual reset once condition has been corrected. Press the RESET button on the display to reset.)
The blocked drain switch has detected excessive condensate build up inside the unit.Check condensate tube from unit to floor drain for proper installation and obstructions.
Inspect condensate trap for blockage. Clean if necessary.
Check for loose wiring connection at wire harness plug.
Bad blocked drain switch. Replace switch.
Flame out of Sequence
(will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.)
The flame detector circuit is seeing a flame signal while no flame is present.Check supply voltage for proper polarity.
Check external wiring for voltage feedback.
Check the flame rod and make sure it is dean.
Check the internal wiring for bad connections.
Replace main control board.
Gas Valve / Connection
(will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.)
The main control board did not detect the gas valve.Check wiring harness connection at the gas valve and at the main control board.
Replace the gas valve wire harness.
Replace the gas valve.
Replace the main control board.
Burner Did Not Light
(will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.)
The unit has failed to prove main burner ignition after one attempt. It will require a manual reset before attempting to fire again.Inspect spark electrode and associated wiring for damage and connection.
Check for proper electrical grounding of the unit.
Check incoming supply gas pressure. Natural gas pressures should be between 4-14 inches w.c. (1.0 - 3.5 kPa) and LP gas pressures should be between 8-14 inches w.c. (2.0 - 3.2 kPa).
Verify that the plastic hose from the gas valve to the air inlet is connected and is not damaged.
Verify that the vent/air intake pipes are correctly installed and that there are no obstructions.
Check for 24 VAC to the gas valve at the 2-pin connection on the side of the main control board during the ignition attempt. If no voltage is present, replace the main control board.
Burner Did Not Light (cont’d)
(will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.)
The unit has failed to prove main burner ignition after one attempt. It will require a manual reset before attempting to fire again.If 24 VAC is present at the main control board, check the wiring between the main control board and the gas valve. Replace the wiring if necessary. Do not disconnect the wiring from the gas valve and attempt to measure voltage at that point. The main control board can detect if the gas valve is not connected and will display the Gas Valve / Connection fault.
If 24 VAC is present, check the outlet of the valve to ensure the valve is flowing gas. With a manometer connected to the outlet tap of the gas valve, when the unit is in the prepurge period, there should be a negative pressure present. When the valve is energized a change in pressure should occur. If the pressure change does not occur, the gas valve is not opening. Replace the gas valve.
Inspect flame sensor and associated wiring.
Inspect the burner.
Replace the main control board.
Flame Lost While Running
(will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.)
The unit was running and lost the flame signal. This condition occurred twice .Inspect spark electrode and associated wiring for damage and connection.
Check for proper electrical grounding of unit.
Check incoming supply gas pressure. Natural gas pressures should be between 4 * 14 inches w.c. (1.0 - 3.5 kPa) and LP gas pressures should be between 8 - 14 inches w.c. (2.0 - 3.2 kPa).
Verify that the plastic hose from the gas valve to the air inlet is connected and is not damaged.
Verify that the vent/air intake pipes are installed correctly and there are no obstructions.
Check for 24 VAC to the gas valve at the 2-pin connection on the side of the main control board during the ignition attempt. If no voltage is present, replace the main control board.
The unit was running and lost the flame signal. This condition occurred twice .If 24 VAC is present at the main control board, check the wiring between the main control board and the gas valve. Replace the wiring if necessary. Do not disconnect the wiring from the gas valve and attempt to measure voltage at that point. The main control board can detect if the gas valve is not connected and will display the Gas Valve / Connection fault.
If 24 VAC is present, check the outlet of the valve to ensure the valve is flowing gas. With a manometer connected to the outlet tap of the gas valve, when the unit is in the prepurge period, there should be a negative pressure present. When the valve is energized a change in pressure should occur. If the pressure change does not occur, the gas valve is not opening. Replace the gas valve.
Inspect flame sensor and associated wiring.
Inspect the burner.
Replace the main control board.
Manual Reset High Limit
(will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.)
The outlet water temperature has exceeded the setting of the high limit.Verify that the system is full of water and that all air has been properly purged from the system.
Verify that the boiler is piped properly into the heating system.
Check voltage to boiler pump motor on a call for heat. If voltage is not present, check wiring back to the pump relay.
Replace the pump relay if necessary.
If 120 VAC is present on a call for heat and the boiler pump is not operating, replace the pump.
If the system pump is a variable speed pump, ensure that the system flow is not less than the boiler flow.
If operating on either an inlet or system supply sensor, check temperature setting of the main control board.
If the high limit has tripped, check setting of the device.
Check resistance of water sensors
Replace high limit.
Automatic Reset High Limit / HEX- Temp SW
(will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.)
Either the auto-reset high limit (optional), or the O-temp heat exchanger switch as opened.Automatic Reset High Limit:
Verify that the system is full of water and that all air has been properly purged from the system.
Verify that the boiler is piped properly into the heating system.
Check voltage to boiler pump motor on a call for heat. If voltage is not present, check wiring back to the pump relay.
Replace the pump relay if necessary.
If 120 VAC is present on a call for heat and the boiler pump is not operating, replace the pump.
If the system pump is a variable speed pump, ensure that the system flow is not less than the boiler flow.
If operating on either an inlet or system supply sensor, check temperature setting of the main control board.
If the high limit has tripped, check setting of the device.
Check resistance of water sensors and compare to Table 3B
Replace high limit.
Measure the resistance of the sensors and compare the resistance
Replace the sensor if necessary.
Flue Sensor Open / Removed
(will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.)
The flue sensor has been disconnected or removed from the flue.Check the sensor and its associated wiring. Repair or replace the sensor or wiring if damaged.
Measure the resistance of the sensors and compare
Replace the sensor in flue.
Replace the sensor if necessary.
Louver Proving Switch
(will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.)
An optional remote proving switch is not making.Check function of remote devices.
Check for loose or misplaced jumper if proving switch is not installed.
Tank OpenSensors equipped with an internal limit (such as the Lochinvar Squire" Indirect Tank), the limit has opened due to temperature (195°F) or the sensor has become disconnected.Check the tank temperature.
Repair or replace the sensor wiring if damaged.
Replace the sensor if necessary.
Flap Valve Stuck OpenFlap valve contacts are in an open position.Check the wiring connections to the flap valve switch. Replace or repair wiring if necessary.
Check for obstruction in the vent / air intake pipes or at terminations.
Verify combustion air blower is operating. Replace if necessary.
Replace flap valve switch.
Flap valve contacts are in a dosed position.Check wiring connections to the flap valve switch. Replace or repair wiring if necessary.
Check flap valve for obstruction or blockage.
Replace flap valve switch.
Too Many Resets - Try LaterToo many manual resets have occurred during a 15 minute period.Wait 15 minutes and try again.
Turn power off to unit, wait 30 seconds and then turn power back on.
Voltage Too Low120 VAC input to the main control board has dropped below 80 VAC.Check 120 VAC supply to the transformer.
Check wiring connections at the low voltage terminal strip.
Check the wire size/length to remote devices.
Replace the main control board.
Internal FaultThe main control board has detected an internal fault.
Writing to MemosThe main control board has detected an internal fault.
CRC ParametersThe main control board has detected an internal fault.
No Error StoredThe main control board has detected an internal fault.Press the RESET button on the SMART TOUCH display panel.
Flue Temp ShutdownThe stack temperature has exceeded the set parameters for the boiler.Inspect the heat exchanger.
Inspect the flue sensor and associated wiring. Measure the resistance of the flue sensor and compare to Table 3C
Verify that the vent/air intake pipes are properly installed and that there are no obstructions.
Replace the main control board.
Delta T ShutdownThe temperature rise across the heat exchanger has exceeded the set parameters for the boiler.Verify that the system is full of water and that all air has been properly purged from the system.
Verify that the boiler is piped properly into the heating system.
Check for voltage to the boiler pump motor on a call for heat. If voltage is not present, check the wiring back to the pump relay. Replace the pump relay if necessary.
If 120 VAC is present on a call for heat and the boiler pump is not operating, replace the pump.
Verify that the boiler pump is set to the proper speed or that the pump is the proper size.
Outlet Temp ShutdownOutlet water temperature has exceeded the maximum outlet water temperature.Verify that the system is full of water and that all air has been properly purged from the system.
Verify that the boiler is piped properly into the heating system.
Check for voltage to the boiler pump motor on a call for heat. If voltage is not present, check wiring back to the pump relay. Replace the pump relay if necessary.
If 120 VAC is present on a call for heat and the boiler pump is not operating, replace the pump.