AWB fault code F4
Fault code F4 on an AWB boiler (including ThermoBasic and ThermoMaster) means: A defective DHW sensor. 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 F4 on an AWB boiler indicates: A defective DHW sensor.
Applies to
AWB ThermoBasic, ThermoMaster, 24.23 WT, VR 23.29 WT, VR 23T.
Fault code F4 on other AWB series
The same code does not mean the same thing on every series. Check the rating plate to see which series you have:
- F 4 on ThermoMaster, 3HR 24 035004, 3HR 24T 035014, 3HR 28 035008, 3HR 28T 035018: Check the ignition electrode and wiring.
- F 4 on ThermoMaster, 3HR 24 P, 3HR 28 P, 3HR 28 TP, ThermoElegance, HR 35 ST: Ignition fault.
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 flow/return NTC € 14.37
- AWB pressure sensor 10 mm € 88.86
- AWB temperature sensor 6655 4 pcs € 129.37
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 F4 mean?
A defective DHW sensor.
How do I fix fault code F4 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 F4?
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 F4 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 →