The company Lochinvar Corp. constantly improves and expands its product range, which includes boilers. The make uses the most advanced technology and innovative features. Thus, it provides high performance water heating, which is known for the ease of maintenance. It is also reflected in the simple troubleshooting of its equipment. Below you will find a table with Lochinvar boiler error codes.
| FAULT | CAUSE | CORRECTIVE ACTION |
|---|---|---|
| E00 | Invalid lockout code. | • Reset control module. |
| • Switch power OFF and ON. | ||
| • Replace control module. | ||
| E01 | The control module has detected parameter settings that are corrupted. | |
| E02 (will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.) | The actual fan RPM is more than 30% above or below the fan speed RPM target. | • Vent/air intake lengths exceed the maximum allowed lengths. |
| • Check for obstruction or blockage in the vent/air intake pipes or at terminations. | ||
| • Check the wiring connections at the fan and at the main control board. | ||
| • Replace the fan. | ||
| • Replace the main control board. | ||
| E04 (will require a manual reset once condition has been corrected. Press the RESET button on the display to reset.) | Blown fuse. | • Replace fuse F2 on the control board |
| Either the optional flow switch or the optional low water cutoff is not making. | • Check pump operation on a call for heat. | |
| • Check for closed valves or obstructions in the 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 or LWCO is not installed. | ||
| E05 (will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.) | Blown fuse. | • Replace fuse F3 on the control board |
| The flame detector circuit is seeing a flame signal when the gas valve is closed. | • Verify flame is not present. If present, turn off gas supply and replace gas valve. | |
| • Check supply voltage for proper polarity. | ||
| • Check external wiring for voltage feedback. | ||
| • Check the flame rod and make sure it is clean. | ||
| • Check the internal wiring for bad connections. | ||
| • Replace main control board. | ||
| E06 | The outlet water temperature has exceeded the setting of the automatic reset high limit. | • Adjust the set point of the auto reset limit to a higher setting up to a maximum of 200°F. |
| • 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 120 vac to boiler pump motor on a call for heat. If voltage is not present, check wiring back to the main control board. | ||
| • Replace the main control board if necessary. | ||
| • If 120 vac is present on a call for heat and the pump is not operating, replace the pump. | ||
| • If operating on something other than an outlet sensor, check temperature setting of the main control board. | ||
| • If the optional manual reset high limit has tripped, check setting of the device. | ||
| • Check resistance of water sensors | ||
| E07 | Thermal fuse on heat exchanger has opened. | • Check the wiring connections to the fuse on the heat exchanger. |
| • Check continuity across the thermal fuse. If open, replace heat exchanger. | ||
| E08 | Louver proving switch open. | • Check wiring to louver proving switch. |
| • Check louver proving switch. | ||
| E09 | 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. | ||
| E10 (will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.) | Air pressure switch contacts are open. | • Check the wiring connections to switch. Wires should be connected to the common and normally closed terminals. |
| • Air intake lengths exceed the maximum allowed lengths. | ||
| • Check for obstruction or blockage in the air intake pipes or at terminations. | ||
| • Check reference hoses connected to the air pressure switch for blockage or obstruction. | ||
| • Inspect the burner. | ||
| • Inspect the heat exchanger. | ||
| • Faulty air pressure switch. Replace switch. | ||
| E11 (will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.) | The unit has lost flame signal four (4) times during a call for heat. | • 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. and LP gas pressures should be between 8-14 inches w.c. | ||
| • 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. | ||
| • 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 or Gas Valve Fail 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 and clean the heat exchanger as necessary. | ||
| • Inspect the burner. | ||
| • Replace the main control board. | ||
| E12 (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 four (4) attempts. | |
| n05 | The fan speed is being increased due to the flame current going below 5 microamps. | |
| E13 | The flue temperature has exceeded 250°F. | • Inspect the heat exchanger. |
| b05 | The flue temperature has exceeded 240°F. | • Inspect the flue sensor and associated wiring. Measure the resistance of the flue sensor |
| n04 | The fan speed is being limited due to the flue temperature exceeding 215°F. | • Verify that the vent/air intake pipes are properly installed and that there are no obstructions. |
| • Replace the main control board. | ||
| E15 (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 210°F manual reset high limit (MRHL) setting. | • 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 120 vac to pump motor on a call for heat. If voltage is not present, check wiring back to the main control board. | ||
| • Replace the main control board if necessary. | ||
| b03 | The outlet water temperature has exceeded 195°F. | |
| n02 | The fan speed is being limited due to the outlet temperature exceeding 185°F. | • If 120 vac is present on a call for heat and the boiler pump is not operating, replace the pump. |
| • If operating on something other than an outlet sensor, check temperature setting of the main control board. | ||
| • Check resistance of water sensors and compare | ||
| E18 (will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.) | The control module reads an excessive temperature difference between the two outlet sensors. | • Check wiring to sensor. Make sure wiring is connected and not damaged. Reconnect / repair wiring if necessary. |
| • Measure the resistance of the sensor and compare | ||
| • Replace control module. | ||
| E19 (will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.) | One or both of the flue sensors is open or shorted. | • Inspect the flue sensor and associated wiring. Measure the resistance of the flue sensor |
| • Replace the main control board. | ||
| E21 (will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.) | One or both of the outlet sensors has opened or shorted. | • Check the sensor and its associated wiring. Repair or replace the sensor or wiring if damaged. |
| • Measure the resistances of the sensors and compare the resistances | ||
| E22 (will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.) | The inlet sensor is open. | • Check the sensor and its associated wiring. Repair or replace the sensor or wiring if damaged. |
| E23 (will require a manual reset once the condition has been corrected. Press the RESET button on the display to reset.) | The inlet sensor is shorted. | |
| b01 | The temperature has reached the set point + 4°F. | • None |
| b02 | The main control board has received a call for heat too quickly after the previous call for heat has ended. | • The control board will release the call for heat after 60 seconds. |
| • The control board will release the call for heat if the outlet temperature drops 10°F. | ||
| b04 | The temperature rise across the heat exchanger has exceeded 30°F. | • Verify that the system is full of water and that all air has been property purged from the system. |
| • Check for 120 vac to the pump motor on a call for heat. If voltage is not present, check the wiring on the pump relay back to the main control board. Replace the main control board if necessary. | ||
| • If 120 vac is present on a call for heat and the pump is not operating, replace the pump. | ||
| • Scale accumulation in the heat exchanger. Verify that the water chemistry meets the requirements | ||
| n03 | The fan speed is being limited due to the temperature rise across the heat exchanger exceeding 25°F. | |
| b06 | 120 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 transformer. | ||
| • Check 24V. | ||
| n01 | The flue temperature did not change after the burner started firing. | • Verify that the flue sensor is installed. |
| • Check the sensor and its associated wiring. Repair or replace the sensor or wiring if damaged. | ||
| n06 | Tank sensor is not connected. | • Check the tank sensor and its associated wiring. Repair or replace as needed. |
| n07 | The inlet sensor has been disconnected. | • Check the sensors and their associated wiring. Repair or replace the sensor or wiring if damaged. |
| • Measure the resistance of the sensors and compare the resistance | ||
| • Replace the sensor if necessary. | ||
| n08 | The inlet sensor has been shorted. | • Check the sensors and their associated wiring. Repair or replace the sensor or wiring if damaged. |
| • Measure the resistance of the sensors and compare the resistance | ||
| • Replace the sensor if necessary. |
| FAULT | CAUSE | CORRECTIVE ACTION |
|---|---|---|
| – 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. | |
| Noisy Operation | – Dirty/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. | |
| No Pump Operation – Boiler Pump System Pump or | – Blown fuse. | • Replace fuse F1 on the control board |
| Note: Make sure pump amperage does not exceed 1.8 amps. | ||
| DHW Pump | – Faulty pump. | • Replace pump. |
| – Internal fault on control board. | • Replace main control board. | |
| Relief Valve Opening | – System pressure exceeds relief valve setting. | • Lower the system pressure below the 30 psi 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. | ||
| Gas Pressure SW (will require a manual reset once the condition has been corrected. Press the RESET button on the SMART SYSTEM display to reset.) | – Either the optional manual reset low gas pressure switch or the optional manual reset high gas pressure switch tripped. | • Reset the pressure switches. |
| • Measure the supply gas pressure to determine cause of failure. Natural gas pressures should be between 4-14 inches w.c. and LP gas pressures should be between 8-14 inches w.c. | ||
| • Correct the supply gas pressure if necessary. | ||
| • Check for a loose or misplaced jumper if pressure switches are not installed. | ||
| – The gas pressure switch contacts on the Low Voltage Connection Board are open. | • Check for a loose or misplaced jumper on the Low Voltage Connection Board. | |
| • Check for the addition of a device wired across the gas pressure switch terminals on the Low Voltage Connection Board. | ||
| Flow Switch/ LWCO (will require a manual reset once condition has been corrected. Press the RESET button on the SMART SYSTEM display to reset.) | – Either the optional flow switch or the optional low water cutoff 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 or LWCO is not installed. | ||
| – Blown fuse. | • Replace fuse F3 on the control board | |
| Blocked Drain SW (will require a manual reset once condition has been corrected. Press the RESET button on the SMART SYSTEM 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. | ||
| APS / HEX Temp Sw Open (will require a manual reset once the condition has been corrected. Press the RESET button on the SMART SYSTEM display to reset.) | Either the air pressure switch contacts are open, or the O-temp heat exchanger switch has opened. | • Check the wiring connections to switch. Wires should be connected to the common and normally closed terminals. |
| • Air intake lengths exceed the maximum allowed lengths. | ||
| • Check for obstruction or blockage in the air intake pipes or at terminations. | ||
| • Check reference hoses connected to the air pressure switch for blockage or obstruction. | ||
| • Inspect the burner. | ||
| • Inspect the heat exchanger. | ||
| • Faulty air pressure switch. Replace switch. | ||
| Anti-cycling | • Inspect the back of the inner combustion chamber at burner level for refractory breakdown / missing. Replace heat exchanger if refractory is broken and unit has fired. | |
| • Check continuity across two contacts. Wires should be connected at both poles of the normally closed switch. | ||
| • Faulty O-Temp HEX Switch. Replace switch. | ||
| The main control board has received a call for heat too quickly after the previous call for heat has ended. | • The control board will release the call for heat after a set time period. | |
| • The control board will release the call for heat if the outlet temperature drops too quickly. | ||
| Flame Fail Ign (will require a manual reset once the condition has been corrected. Press the RESET button on the SMART SYSTEM display to reset.) | The unit has failed to prove main burner ignition after four (4) attempts. | • 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. and LP gas pressures should be between 8-14 inches w.c. | ||
| The unit has failed to prove main burner ignition after four (4) attempts. | • 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. | ||
| • 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 or Gas Valve Fail 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 and clean the heat exchanger as necessary. | ||
| • Inspect the burner. | ||
| • Replace the main control board. | ||
| Flame Sequence (will require a manual reset once the condition has been corrected. Press the RESET button on the SMART SYSTEM 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 clean. | ||
| • Check the internal wiring for bad connections. | ||
| • Replace main control board. | ||
| Outlet ARHL | The outlet water temperature has exceeded the setting of the automatic reset high limit. | • Adjust the set point of the auto reset limit to a higher setting up to a maximum of 200°F. |
| • 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 120 vac to boiler pump motor on a call for heat. If voltage is not present, check wiring back to the main control board. | ||
| • Replace the main control board 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 something other than an outlet sensor, check temperature setting of the main control board. | ||
| • If the optional manual reset high limit has tripped, check setting of the device. | ||
| • Check resistance of water sensors. | ||
| • Replace high limit. | ||
| Outlet MRHL (will require a manual reset once the condition has been corrected. Press the RESET button on the SMART SYSTEM display to reset.) | The outlet water temperature has exceeded the setting of the manual reset high limit. | • Adjust the set point of the manual reset limit to a higher setting up to a maximum of 210°F. |
| • 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 120 vac to boiler pump motor on a call for heat. If voltage is not present, check wiring back to the main control board. | ||
| Fan Low/High OR Fan Speed Low/High (will require a manual reset once the condition has been corrected. Press the RESET button on the SMART SYSTEM display to reset.) | The actual fan RPM is 30% lower than what is being called for. | • Vent/air intake lengths exceed the maximum allowed lengths. |
| • Check for obstruction or blockage in the vent/air intake pipes or at terminations. | ||
| • Check the wiring connections at the fan and at the main control board. | ||
| • Replace the fan. | ||
| • Replace the main control board. | ||
| Blown fuse. | • Replace fuse F2 on the control board | |
| GV/Relay Fail (will require a manual reset once the condition has been corrected. Press the RESET button on the SMART SYSTEM 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 Yalve. | ||
| • Replace the main control board. | ||
| Sensor Open (will require a manual reset once the condition has been corrected. Press the RESET button on the SMART SYSTEM display to reset.) | Either the inlet water or outlet water temperature sensor has been disconnected. | • Check the sensors and their associated wiring. Repair or replace the sensor or wiring if damaged. |
| • Measure the resistance of the sensors and compare the resistance | ||
| • Replace the sensor if necessary. |
| Code | Fault |
|---|---|
| FO | Short circuit in ionisation circuit |
| F1 | Blocked condensate drain |
| F2 | High temperature limit exceeded |
| F4 | Wrong fan speed |
| F5 | No flame after 5 ignition attempts |
| F6 | Flame lost (4 times) during running |
| EO | Outlet temperature sensor shorted or interrupted |
| E2 | Inlet temperature sensor shorted or interrupted |
| E5 | Flow temperature sensor shorted or interrupted |
| E6 | Low water flow (A8) has occurred 4 times |
| PP | Parameters programmed into controller |
| PE | Incorrect parameters programmed into controller |
| nc | Heater control has failed |
| NC | Cascade communication has failed |
| H1 | Gas valve wiring interrupted |