555.1 on a Haier Super Aqua Monobloc): Outer circumstance temp. Ta>27°C heating standby

What it means

The manual says: Outer circumstance temp. Ta>27°C heating standby.

Part involved: ambient/oil temperature, mode setting.

Is it safe?

The heat pump keeps running with some functions stopped.

Resetting itself: yes.

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.
• Check controller mode/temperature/timer settings have not been changed; setup (DIP switch) errors need the installer.

What the engineer will check

• Check the standby reason parameters, the mode setting and the oil heater.

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

• Code shown on the wired controller (and/or the outdoor PCB display); heating/hot water may stop or run on backup heater.

Sources

• ATW Service Manual (Super Aqua monobloc) SYJS-03-2019 REV.A ↗ · SYJS-03-2019 REV.A · page p.73 (printed; PDF p.75) · Reviewed 23 September 2026

A code explains what the controller detected, not a confirmed root cause.

Reviewed: 23 September 2026