AWB fault code F74
Fault code F74 on an AWB boiler (including ThermoMaster) means: Pressure sensor short circuit Pressure sensor wiring harness short circuit. Pressure sensor faulty. 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 F74 on an AWB boiler indicates: Pressure sensor short circuit Pressure sensor wiring harness short circuit. Pressure sensor faulty.
Fixing fault code F74: step by step
- Reset the appliance once; a one-off measuring error will then clear.
- Where you can reach it without opening the sealed combustion section, check that the sensor plug is seated firmly and the wiring is undamaged.
- If the code comes back, the sensor or its wiring is usually faulty (short or open circuit). Sensors in the sealed combustion section should be replaced by a qualified heating engineer.
Applies to
AWB ThermoMaster, CXV 35 A.
Fault code F74 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.74 on ThermoElegance, 25A/3: Water pressure sensor signal in wrong range (too low).
- F.74 on ThermoGrand, 45S, 65S: Water pressure sensor signal in wrong range (too high).
- F74 on ThermoElegance, 3 A (N NL), 35A, 4 A (N NL) A/2, 4 SOLO A (N NL), 5 A (N NL): Defective water pressure sensor in the heating system.
- F74 on ThermoMaster, CXV 30 A: Pressure sensor short circuit.
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 € 14.95
- AWB pressure sensor 10 mm € 92.42
- AWB temperature sensor 6655 4 pcs € 134.55
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 F74 mean?
Pressure sensor short circuit Pressure sensor wiring harness short circuit. Pressure sensor faulty.
How do I fix fault code F74 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 F74?
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 F74 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 →