Fujitsu Mini-Split Not Heating: Causes and Fixes
Quick Answer
Fujitsu mini-split not heating: Fujitsu uses a different defrost strategy than Mitsubishi. Fujitsu's defrost cycle reverses the refrigerant flow briefly (switching to cooling mode) to melt ice off the outdoor coil. During defrost, warm air temporarily blows from the indoor unit (it is actually in cooling mode). This surprises some users who think the unit switched modes.
Fujitsu mini-split not heating: Fujitsu uses a different defrost strategy than Mitsubishi. Fujitsu's defrost cycle reverses the refrigerant flow briefly (switching to cooling mode) to melt ice off the outdoor coil. During defrost, warm air temporarily blows from the indoor unit (it is actually in cooling mode). This surprises some users who think the unit switched modes. Fujitsu XLTH models are rated for heating down to -15F. Standard models may show operation light blinking with 2-flash pattern below their rated minimum ambient.
What Does the NOT-HEATING Code Mean?
Fujitsu mini-split not heating: see brand-specific guide above.
Most Likely Causes
Based on aggregated repair data, here is the probability breakdown for this error code:
Symptoms You May Notice
- Fujitsu Mini-Split Not Heating symptom
Can you reset a Fujitsu minisplit to clear the NOT-HEATING code?
Unplug 60 seconds.
Tools Required for Diagnosis
Diagnostic Checklist
Follow these steps in order. We start with the easiest external fixes before opening up the machine.
Follow brand-specific diagnosis above.
Follow brand-specific diagnosis above.
Check error codes and secondary causes.
Professional diagnosis if basic checks fail.
Frequently Asked Questions
Fujitsu minisplit repair cost?
Repair or replace?
DIY?
Last verified for technical accuracy on March 15, 2026