Error code
dF Automatic defrost status
Applies to 4 models
Aero 503 I CN, Aero 504 I CN, Aero 503 O CN, Aero 504 O CN
What this means
The unit is automatically defrosting; indoor and outdoor fans stop temporarily, then heating resumes automatically. This is no error or fault.
What you can check yourself
- Wait for defrosting to finish; normal heating resumes automatically.
Still not resolved? Contact a qualified installer or servicer.
See the official IVT manualA deep link to the manufacturer's own PDF for full technical detail. We link to manuals, we never host them.
Using Claude Code or Meta Muse? Connect HeatPump AI and ask it about dF.