P9 on a Gree heat pump: AC contactor protection or input zero crossing error
Short answer
On a Gree heat pump, P9 means: AC contactor protection or input zero crossing error. The manual does not say whether the heat pump stops. An engineer is needed to fix the cause. The wording differs by model range — each is shown below.
Reviewed 23 September 2026 · 3 sources
What it means
On the Versati III Monobloc (R32)
The manual says: AC contactor protection or input zero crossing error.
On the Versati III Split / All-in-one (R32)
The manual says: AC contactor protection or input over-zero error.
On the Versati IV Split / All-in-one (R32)
The manual says: AC contactor protection or input over-zero error.
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Engineer needed? | Yes |
The manual does not say whether the heat pump stops.
Resetting itself: unknown.
What you can check
- Note the code shown on the controller and the unit model numbers (on the rating plate label) before contacting your installer.
- Check the heat pump's breaker/isolator at the consumer unit is on; do not open any casing.
What the engineer will check
- Follow the Gree troubleshooting flowchart for this code in the service manual.
- Follow the manufacturer's troubleshooting flowchart for this code.
Who to ask for: Heat pump engineer.
Certification: Heat pump installer competence; F-gas / flammable-refrigerant (R290/R32) handling competence for any refrigerant-circuit work.
What you might notice
Sources
- VERSATI III Air To Water Heat Pump (Monobloc) Service Manual ↗ · page p.122 (printed; PDF p.122) · Reviewed 23 September 2026
- Service Manual for VERSATI R32 SPLIT (VERSATI III Split Type Air To Water Heat Pump) ↗ · page p.109 (printed; PDF p.113) · Reviewed 23 September 2026
- VERSATI IV Split Type Air To Water Heat Pump Service Manual ↗ · page p.67 (printed; PDF p.77) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026