AWB fault code L 43
Fault code L 43 on an AWB boiler (including ThermoSystem) means: Local NTC 4 open circuit. Reset the appliance once. If the code comes back, a part is usually faulty, often a temperature sensor. You can check the water pressure and settings yourself; leave work on gas-carrying parts to a certified gas engineer.
After a safety alert (gas, flue gas, combustion), reset no more than once and call in a certified gas engineer. If you smell gas, call your national gas emergency number or 112 immediately.
Cause
Fault code L 43 on an AWB boiler indicates: Local NTC 4 open circuit.
Applies to
AWB ThermoSystem, HR 120, HRM 80/2.
Matching parts
AWB parts are available from Instalpunt; shipping to EU countries from €12.95 (€16.95 for more distant countries), usually 3–5 working days.
Based on the cause, these original AWB parts fit (always check the type number of your appliance):
- AWB temperature sensor 6655 4 pcs € 129.37
- AWB NTC sensor for e.g. ThermoSystem HRM 280/3 0020075721 € 27.44
- AWB water pressure sensor € 35.28
Further reading on this cause
Other AWB codes with the same cause
- 06 — Flow NTC fault. NTC is broken or wiring faulty. Check wiring or replace NTC.
- 07 — DHW NTC fault. NTC is broken or wiring faulty. Check wiring or replace NTC.
- 08 — Cylinder NTC fault
- 09 — Water pressure sensor broken or wiring faulty
- 10 — Return NTC
- 19 — Flow NTC fault, dT > 35K 10 times in succession
Fix it yourself or call an engineer?
Always consult the manual for your appliance and work safely. If in doubt or if the fault comes back, call in a qualified professional. A question about a part? Write to us at info@instalpunt.nl.
Frequently asked questions
What does AWB boiler fault code L 43 mean?
Local NTC 4 open circuit.
How do I fix fault code L 43 on an AWB boiler?
First check the cause described above. Then restart the appliance using the reset button. If the message comes back, a part usually needs replacing or the fault needs to be repaired by a qualified professional.
Which parts do I need for AWB fault code L 43?
That depends on the exact cause. In the AWB parts overview at Instalpunt you will find the current price and stock for each part.
Can I fix fault code L 43 myself?
You can reset the appliance and check things like the water pressure or settings yourself. Work on gas-carrying parts must be left to a certified gas engineer.
All AWB boiler faults and codes at a glance →