All Heiwa error codes
This page brings together Heiwa error codes sorted by type of failure: what each code means, its likely causes, and what you can safely check before calling a professional.
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The Heiwa codes on this page, grouped by type of failure.
Temperature sensor — Heiwa
These codes indicate a sensor that’s no longer returning a consistent value. The problem almost always comes from the sensor itself or its connector, rarely from the unit.
Code E1Medium severityair-to-air
Indoor ambient temperature sensor fault
Possible causes
- Faulty ambient thermistor
- Loose connection
What you can check
- Cut power for 30 minutes, then restart
Models affected: HW-12, HW-18, HW-24, HW-09
This issue requires a qualified technician. Do not open the unit.
Code E2Medium severityair-to-air
Indoor anti-freeze protection
Possible causes
- Clogged filter
- Insufficient indoor ventilation
- Low refrigerant level
Models affected: HW-12, HW-18, HW-24
This issue requires a qualified technician. Do not open the unit.
Code E3Medium severityair-to-air
Outdoor temperature sensor fault
Possible causes
- Faulty outdoor thermistor
- Faulty wiring
What you can check
- Cut power for 30 minutes, then restart
Models affected: HW-12, HW-18, HW-24, HW-09
This issue requires a qualified technician. Do not open the unit.
Code E4Medium severityair-to-air
Outdoor coil sensor fault
Possible causes
- Faulty outdoor coil thermistor
What you can check
- Cut power for 30 minutes, then restart
Models affected: HW-12, HW-18, HW-24
This issue requires a qualified technician. Do not open the unit.
All Heiwa codes published on the site
This list updates automatically whenever a new guide is added.
Technical information provided for reference only, based on manufacturer documentation and field feedback. It does not replace a diagnosis by a qualified professional. Found an error on this page? Report it.