Vaillant fault code F.752
Fault code F.752 on a Vaillant heat pump (including aroTHERM Monoblock) means: The parameter ""Max. duration of the power interruption"" is set incorrectly (see ""Heat pump setting parameters"" in the appendix), inverter box damaged, inverter box cooler is blocked, incorrect supply voltage. Reset the appliance once. If the code comes back, a part is usually faulty, often the compressor or inverter module.
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 F.752 on a Vaillant heat pump indicates: The parameter ""Max. duration of the power interruption"" is set incorrectly (see ""Heat pump setting parameters"" in the appendix), inverter box damaged, inverter box cooler is blocked, incorrect supply voltage.
Applies to
Vaillant aroTHERM Monoblock, VWL 115/2 A 400 V, VWL 155/2 A 400V, VWL 55/2 A 230V, VWL 55/3 A 230 V, VWL 85/2 A 230 V, VWL 85/3 A 230 V.
Fault code F.752 on other Vaillant series
The same code does not mean the same thing on every series. Check the rating plate to see which series you have:
- F.752 on aroTHERM split, aroTHERM split uniTOWER, VWL 127 5 IS _ VWL 105 5 AS, VWL 127 5 IS _ VWL 125 5 AS, VWL 128 5 IS _ VWL 105 5 AS, VWL 128 5 IS _ VWL 125 5 AS: Internal electronics fault on the inverter PCB, mains voltage outside 70V – 282V.
- F.752 on Hydraulisch station, VWZ MEH 97/6 w _ VWL 35_6 A 230V, VWZ MEH 97_6 w _ VWL 105_6 A, VWZ MEH 97_6 w _ VWL 125_6 A, VWZ MEH 97_6 w _ VWL 55_6 A 230V, VWZ MEH 97_6 w _ VWL 65_6 A 230V: Internal electronics fault on the inverter PCB, mains voltage outside 70 V – 282 V.
Matching parts
Vaillant parts are available from Instalpunt; shipping to EU countries from €12.95 (€16.95 for more distant countries), usually 3–5 working days.
Parts per Vaillant-series: ecoTEC plus · ecoTEC pro.
Based on the cause, these original Vaillant parts fit (always check the type number of your appliance):
- Vaillant compressor resistor for e.g. aroTHERM Pro VWL 75/7.1 A 230V 0020176079 € 40.51
- Vaillant compressor heater for e.g. aroTHERM VWL 75/6 A 0020175853 € 50.97
- Vaillant compressor insulation 5k € 57.50
Further reading on this cause
Other Vaillant codes with the same cause
- F.103 — Parameter ""Max. duration of the circuit breaker"" is set incorrectly (see ""Heat pump…
- F.1117 — Soft starter defective or incorrectly connected, fuse defective, poorly tightened…
- F.514 — Temperature sensor at compressor inlet defective or not connected
- F.517 — Temperature sensor at compressor outlet defective or not connected
- F.726 — Compressor overheated, e.g. due to use outside its application limits, maximum ambient…
- F.729 — Compressor outlet temperature lower than 0 °C for more than 10 minutes or compressor…
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 Vaillant heat pump fault code F.752 mean?
The parameter ""Max. duration of the power interruption"" is set incorrectly (see ""Heat pump setting parameters"" in the appendix), inverter box damaged, inverter box cooler is blocked, incorrect supply voltage.
How do I fix fault code F.752 on a Vaillant heat pump?
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 Vaillant fault code F.752?
That depends on the exact cause. In the Vaillant parts overview at Instalpunt you will find the current price and stock for each part.
Can I fix fault code F.752 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 Vaillant heat pump faults and codes at a glance →