In brief
Fault code E6 on Gree split systems means the indoor unit is no longer receiving a response from the outdoor unit. Most common cause: loose or cut communication wire (S or 2). First action: confirm the outdoor unit has 230 V, then check the terminal block.
Per Gree Technical Training (Communication Errors) and the Flexx Ultra R32 manual (p.12), E6 is an RS485 indoor/outdoor communication loss lasting more than 60 seconds.
E6 • Gree • All Split ranges
Gree E6: RS485 bus test vs board
Fault code E6 indicates that the indoor unit is no longer receiving a response from the outdoor unit. This is a wiring or power supply issue to the outdoor unit, common on Gree splits and air conditioning units.
Source: Gree Technical Training - Communication Errors · Last verified 9 September 2026
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What does fault code E6 on Gree mean?
Fault code E6 indicates that the indoor unit is no longer receiving a response from the outdoor unit. This is a wiring or power supply issue to the outdoor unit, common on Gree splits and air conditioning units.
Communication cable (S wire or wire 2) cut or loose, no power supply to the outdoor unit, or faulty PCB. An F-Gas registered engineer first checks the terminal block.
Differences between product ranges
| Range | Meaning | Exclusion |
|---|---|---|
| Flexx Ultra R32 / Multi21 Plus | RS485 communication loss >60 s | Do not generalise to ranges without an RS485 manual |
| Classic Gree wall split (non-RS485) | E6 may mean classic S-wire — check the model terminal diagram | SA1 RS485 not applicable |
Symptoms
- The indoor unit blows air but the outdoor unit does not start
- Flashing fault code E6
Safety notice
Isolate power before terminal measurements. Live testing is for qualified electricians or engineers only.
Diagnosis
1. Isolate before any measurement
- Switch off the outdoor breaker and confirm absence of voltage at the terminal block.
- Live DC fluctuation checks on the communication wire, if needed, are for a qualified electrician or F-Gas engineer after isolation.
2. De-energised checks
- Visually check tightness of the S or 2 wire and the terminal block.
- Once isolation is lifted by a qualified person, confirm the outdoor unit is supplied (230 V).
Repair and return to service — Gree fault E6
Restore communication cable continuity (S or 2 wire) between indoor and outdoor units. If wiring matches the OEM diagram and SA1 (RS485) is correct, outdoor main board replacement is a qualified repair — not a software reset.
When should you call an F-Gas engineer?
Call a professional if wiring is correct but E6 persists, if multiple indoor units fail together, or before replacing the outdoor board.
Affected models
- Flexx Ultra R32
- Multi21 Plus
- High Static Slim Duct
- Universal Floor Ceiling
Field context
Appears after a power cut, refrigerant line extension without rewiring communication, or work on the outdoor terminal block. May affect a single indoor unit (partial E6) or all indoor units (global E6).
Technical source data
Gree E6 indicates a loss of RS485 communication between indoor and outdoor units for more than 60 seconds. Service causes: loose or cut communication wire, incorrect communication address (SA1), communication parameter not set to RS485, or faulty PCB after swapping cable between a working indoor unit and the faulty one.
Sources
- flexx-ultra-r32-a-coil-service-manual-a.pdf (p. 12)
- multi21-plus-service-manual-30k-36k-42k-c.pdf (p. 30)
- flexx-ultra-r32-a-coil-service-manual-a.pdf (p. 12)
- multi21-plus-service-manual-30k-36k-42k-c.pdf (p. 30)
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Exact match
E6 — Gree
All Split ranges
Fault code E6 indicates that the indoor unit is no longer receiving a response from the outdoor unit. This is a wiring or power supply issue to the outdoor unit, common on Gree splits and air conditioning units.
Source : Gree Technical Training - Communication Errors
Frequently asked questions
What is the difference between partial E6 and global E6 on Gree?
Partial E6: one or a few indoor units no longer communicate — test by swapping the communication cable from a working indoor unit. Global E6: all indoor units — check outdoor power supply and main terminal block.
Is the SA1 dip-switch related to Gree E6?
Yes, the Flexx manual states to check that the first bit of SA1 on the indoor unit is correctly set for RS485 mode.
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