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Heat pumps
Heat pumps · Error codes · NIBE
358NIBE · NIBE, all models

358 on a NIBE heat pump: Internal OPT error: Alarm from the gas boiler

Short answer

On a NIBE heat pump, 358 means: Internal OPT error: Alarm from the gas boiler. The manual does not say whether the heat pump stops. An engineer is needed to fix the cause.

Reviewed 23 September 2026 · 1 source

What it means

The manual says: Internal OPT error: Alarm from the gas boiler.

When it shows: Alarm from the gas boiler.

Is it safe?

Does the heat pump stop?Not stated
SeverityFault — needs a manual reset once the cause is fixed
Engineer needed?Yes

The manual does not say whether the heat pump stops.

Resetting itself: no/unknown - None, manual reset.

Manual reset: Reset from the controller alarm menu ('reset alarm' / 'Reset alarm and try again'); alarm recurs if the cause remains - NIBE: None, manual reset.

What you can check

  • Read the alarm text and the 'info/action' help on the controller display (VVM/SMO or S-series smartguide). NIBE's manuals let the homeowner select 'reset alarm' ('Reset alarm and try again' on S-series); if the lamp returns to normal the alarm has cleared. If it comes back, do not keep resetting: select 'aid mode' ('Auxiliary operation' on S-series) if offered, so any electric additional heat keeps heat/hot water going, and contact your installer.

What the engineer will check

  • See NIBE alarm list and relevant installer/service manual.

Who to ask for: NIBE-trained heat pump installer (NIBE PRO / VIP).

Certification: None specific beyond competent heat pump installer; electrical work to BS 7671.

Sources

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

Reviewed: 23 September 2026