Vaillant fault code F.737
Fault code F.737 on a Vaillant heat pump (including Hydraulisch station and aroTHERM split) means: Temperature in the emitter circuit (heating mode) or ambient circuit (cooling mode) too high for compressor operation, supply of external heat into the ambient circuit, refrigerant circuit overfilled, flow in the emitter circuit too low. 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.737 on a Vaillant heat pump indicates: Temperature in the emitter circuit (heating mode) or ambient circuit (cooling mode) too high for compressor operation, supply of external heat into the ambient circuit, refrigerant circuit overfilled, flow in the emitter circuit too low.
Applies to
Vaillant Hydraulisch station, 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, VWL 57 5 IS _ VWL 35 5 AS, VWL 57 5 IS _ VWL 55 5 AS, VWL 58 5 IS _ VWL 35 5 AS, VWL 58 5 IS _ VWL 55 5 AS.
Matching parts
Vaillant parts are available from Instalpunt; shipping to EU countries from €17.95 (€24.95 for more distant countries), usually 3–5 working days.
Parts by Vaillant series: ecoTEC plus · ecoTEC pro.
Based on the cause, these original Vaillant parts fit (always check the type number of your appliance):
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.737 mean?
Temperature in the emitter circuit (heating mode) or ambient circuit (cooling mode) too high for compressor operation, supply of external heat into the ambient circuit, refrigerant circuit overfilled, flow in the emitter circuit too low.
How do I fix fault code F.737 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.737?
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.737 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 →