Nefit boiler faults: fault codes, causes and parts (page 3 of 5)

Codes 301 to 450 of the 619 fault codes for Nefit. Looking for a specific code? Use the search on the first page.

Nefit boiler fault codes 301 to 450 of 619

The code list is split over 5 pages. Looking for a specific code? Use the search on the first page: it searches all 619 codes in one go.

Code	Cause
2F 271	The measured temperature difference between the flow and safety temperature sensors is too large.
2F 271	Temperature difference fault
2F 338	Start test aborted too often
2F 345	The flow temperature sensor measures no temperature rise after a burner start.
2F 578	During the sensor test a temperature difference that is too large was measured between the flow and return temperature sensor.
2H 358	The diverter valve is being unblocked.
2H 358	The diverter valve is being unblocked.
2L 266	The pump test has failed.
2L 266	The pressure sensor has measured insufficient flow on the central heating side. This check is repeated every 5 minutes.
2L 266	The sensors in the boiler measure a deviating temperature.
2L 266	After four attempts the pressure sensor was unable to measure a pressure rise on the central heating side.
2L 329	The pressure sensor measures no water flow
2L 329	The pressure sensor measures no water flow.
2P	Safety sensor temperature rising too quickly Too many radiators closed, open more radiators. Bypass is fitted too close to the boiler, fit bypass at least 6 metres from the boiler. Boiler output of the appliance is too large for the system, adjust the boiler output. The safety sensor may be faulty or worn
2P	Safety sensor temperature rises too quickly
2P 212	Temperature fault: The flow or safety sensor has measured a value greater than 5 K/sec.
2P 212	The temperature measured by the flow temperature sensor or the safety temperature sensor rises too quickly.
2P 212	The temperature measured by the flow temperature sensor or the safety temperature sensor rises too quickly.
2P 212	The temperature measured by the flow temperature sensor or the safety temperature sensor rises too quickly
2P 341	The sensors in the boiler measure a deviating temperature.
2P 341	The temperature measured by the flow temperature sensor or the return temperature sensor rises too quickly.
2P 342	The temperature measured by the flow temperature sensor rises too quickly.
2U	Open the air separator one turn (if it was closed).
2U	Open the air separator one turn (if it is closed)
2U	Open the air separator one turn (if it was closed)
2U 213	Central heating water temperature difference fault
2U 213	The measured temperature difference between the flow and return temperature sensors is too large.
2U 213	The measured temperature difference between the flow and the return temperature sensors is too large.
2U 213	The measured temperature between the flow and return temperature sensor is too large.
2U 349	The temperature difference measured at low load between the flow and return temperature sensors is too large.
2U 349	The temperature difference measured at low load between the flow and return temperature sensors is too large.
2U 349	The temperature difference measured at low load between the flow temperature sensor and the return temperature sensor is too large.
2Y 281	Water pressure fault: The pump is seized or running dry.
2Y 281	The pump is seized or running dry.
2Y 282	The pump control signal is missing.
2Y 282	Pump fault
305	Boiler temporarily unable to start after domestic hot water priority
306	After gas shut-off: flame is detected
323	Communication fault of the controller
328	Mains supply briefly interrupted
341	Appliance temperature rises too quickly
342	Temperature rise in domestic hot water mode too rapid
350	Short circuit of flow temperature sensor
351	Open circuit of flow temperature sensor
356	Supply voltage for the heat source is too low
357	Venting programme
358	Pump test programme active
360	Incorrect coding plug
362	Service coding plug recognised
363	System fault in appliance electronics: fault during test of the ionisation signal
364	Solenoid valve EV2 leaking
365	Solenoid valve EV1 leaking
3A 264	Fan tacho signal fault. The fan tacho signal was lost during the operating phase.
3A 264	The control signal or the voltage of the fan has been lost during operation.
3A 264	The control signal or the voltage of the fan has been lost during operation.
3C	Appliance does not start, there may be an open circuit in the electrical circuit, check that the connection (pink / pink or, with the old cable colours, brown-white / pink) in the wiring harness under the UBA is not loose. Check the UBA by temporarily connecting another UBA.
3C	Appliance does not start, there may be an open circuit in the electrical circuit.
3C 217	The fan speed is irregular during start-up.
3C 217	Air transport fault. No air transport after a set time.
3C 217	The fan runs irregularly during start-up.
3F 273	The boiler was switched off for a maximum of 2 minutes because the boiler has been in continuous operation for 24 hours.
3F 273	The boiler has been switched off for a maximum of 2 minutes because the boiler has been in continuous operation for 24 hours. This is a safety check.
3F 273	The boiler was switched off for a maximum of 2 minutes.
3F 273	The appliance was switched off for a few seconds because the appliance has been in continuous operation for 24 hours.
3L 214	Fan does not run during the start-up phase.
3L 214	The fan does not run during the start-up phase (0C).
3L 214	Tacho signal fault
3L 214	The fan does not run during the start-up phase (code “0C”).
3P 216	The fan is running too slowly.
3P 216	Fan fault
3P 216	Fan fault: The fan runs too slowly.
3P 216	The fan speed is too low.
3Y 215	The fan is running too fast.
3Y 215	The fan speed is too high.
3Y 215	Fan fault: The fan runs too fast.
3Y 215	Lockout fault: The fan runs too fast.
3Y 215	Lockout fault code: the fan runs too fast.
4 222	The contacts of the flow temperature sensor are short-circuited.
4 222	The contacts of the flow temperature sensor are short-circuited.
4A	Flow sensor temperature is too high (> 101 C) The flow sensor and/or return sensor faulty, worn, contaminated. Measure the resistance of the flow sensor.
4A	Flow sensor temperature is too high (> 101 °C)
4A 218	The flow temperature sensor has measured a temperature higher than 105 °C.
4A 218	The flow sensor has measured a central heating water temperature higher than 105 °C.
4A 332	The flow temperature sensor has measured a temperature higher than 105 °C.
4A 332	The flow temperature sensor has measured a temperature higher than 110 °C.
4C	Fuse F2 is faulty. Burner thermostat has become too hot. The flow temperature is too high Too many radiators closed, open more radiators. Bypass is fitted too close to the boiler, fit bypass at least 6 metres from the boiler.
4C	Fuse F2 is defective. Burner thermostat has overheated. The flow temperature is too high.
4C 224	Heat exchanger limit thermostat or flue gas limit thermostat has tripped.
4C 224	The safety temperature sensor has measured an excessively high temperature and is open.
4C 224	The burner thermostat has measured a temperature that is too high and is open.
4C 224	The limit thermostat or burner thermostat has measured a temperature that is too high and is open.
4E 278	The sensor test has failed
4E 347	The return temperature sensor has measured a higher central heating water temperature than the flow temperature sensor. A restart follows after 10 minutes.
4E 347	The return temperature sensor has measured a higher central heating water temperature than the flow temperature sensor. A restart follows after 10 minutes.
4E 375	The contacts of the external sensor (e.g. solar sensor) are short-circuited.
4E 376	The contacts of the external sensor (e.g. solar sensor) are open circuit.
4F	The temperature of the safety sensor is higher than 101C There is too much resistance in the central heating circuit, the bypass is incorrectly installed or set. The safety sensor may be faulty or worn. The pump receives no voltage. Water level in the central heating circuit is too low.
4F	The temperature of the safety sensor is higher than 101 °C
4F 219	The flow sensor has measured a central heating water temperature higher than 105 °C.
4F 219	The safety sensor has measured a central heating water temperature higher than 105 °C.
4F 219	The safety temperature sensor has measured a temperature higher than 105 °C.
4F 219	The safety temperature sensor has measured a temperature higher than 105 °C.
4L	The safety sensor is short-circuited The sensor is faulty. Measure the resistance of the sensor
4L	The safety sensor is short-circuited
4L 220	The contacts of the safety sensor are short-circuited or the safety sensor has measured a central heating water temperature higher than 130 °C.
4L 220	The contacts of the safety sensor are short-circuited, or the safety sensor has measured a central heating water temperature higher than 130 °C.
4L 220	The contacts of the safety temperature sensor are short-circuited or the safety temperature sensor has measured a temperature higher than 130 °C.
4L 220	The contacts of the safety temperature sensor are short-circuited or the safety temperature sensor has measured a temperature higher than 130 °C.
4P	The safety sensor makes no contact The sensor is faulty. Measure the resistance of the sensor
4P	The safety sensor makes no contact
4P 221	The contacts of the safety sensor are short-circuited or the safety sensor has measured a central heating water temperature higher than 130 °C.
4P 221	The contacts of the safety sensor are short-circuited, or the safety sensor has measured a central heating water temperature higher than 130 °C.
4P 221	The contacts of the safety temperature sensor are open circuit.
4U	The flow sensor is short-circuited The flow sensor and/or return sensor faulty, worn, contaminated. The safety sensor may be faulty or worn
4U	The flow sensor is short-circuited
4U 222	The contacts of the flow sensor are open circuit
4U 222	The contacts of the flow temperature sensor are short-circuited.
4U 350	The contacts of the flow temperature sensor are short-circuited.
4U 522	A sensor test is being carried out. The boiler waits until the test has passed.
4U 522	A sensor test is being carried out
4Y	The flow sensor makes no contact The flow sensor and/or return sensor faulty, worn, contaminated. The safety sensor may be faulty or worn.
4Y	The flow sensor makes no contact
4Y 223	The contacts of the flow sensor are open circuit.
4Y 223	The contacts of the flow temperature sensor are open-circuit.
4Y 351	The contacts of the flow temperature sensor are open circuit.
5A	UBA locked out: Fault caused by use of Service Tool
5A	UBA locked out Fault caused by use of Service Tool
5C	UBA locked out
5C 226	Service Tool has been connected.
5F	Service Tool: service test takes too long.
5F	UBA locked out
5H 268	Operating code: Component test phase.
5H 268	Component test phase
5P 552	A reset has been carried out more often than permitted by a controller or room thermostat connected to the boiler.
5Y	UBA locked out
5Y	Service Tool: service test takes too long or a boiler parameter has been changed.
5Y	Nefit Service Tool: service test takes too long or a boiler parameter has been changed.
604	System fault in burner control unit
6A	No ionisation occurs after the ignition phase, a flame is present but the flame is lost while the fan speeds up The burner receives too little gas or there is air in the gas pipe
6A	No ionisation occurs after the ignition phase, but the glow plug/fan do work
6A	No ionisation occurs after the ignition phase, the glow plug does not work
6A	No ionisation occurs after the ignition phase, the fan is not running The fan is not working properly: check fan connectors, fuses.
6A 227	The burner does not ignite
6A 227	Ionisation current fault The ionisation current is too high. The indicator flashes at a frequency of 1 Hz. No central heating operation and no domestic hot water.
6A 227	Insufficient ionisation current has been measured after the burner ignited.
6A 227	Insufficient ionisation current measured after the burner ignited
6C	Ionisation occurs after the heat demand has ended, the gas valve does not close
6C	Ionisation occurs after the heat demand has ended, the gas valve does not close
6C 228	An ionisation current was measured before the burner started.
6C 228	Ionisation current fault: Ionisation current was measured after the burner went out.

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