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Heat pumps · Error codes · Climaveneta / De Longhi Professional
A109Climaveneta / De Longhi Professional · De'Longhi Professional / Climaveneta i-KI MTD / i-KIR MTD DC-inverter air/water heat pump

A109 on a Climaveneta / De Longhi Professional De'Longhi Professional / Climaveneta i-KI MTD / i-KIR MTD DC-inverter air/water heat pump: Low pressure alarm from low pressure switch

Short answer

On a Climaveneta / De Longhi Professional heat pump, A109 means: Low pressure alarm from low pressure switch. The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause.

Reviewed 23 September 2026 · 1 source

What it means

The manual says: Low pressure alarm from low pressure switch.

Likely causes:

  • Refrigerant pressure/charge problem.

Is it safe?

Does the heat pump stop?Yes
Engineer needed?Yes

The heat pump stops until the fault clears or is reset.

Resetting itself: Reset from room controller: press the two indicated buttons 3 s, select and confirm reset (p57).

What you can check

  • Note the code/LED pattern and the model from the rating plate, then contact a heat pump/refrigeration engineer.
  • Check the heat pump's breaker/isolator at the consumer unit is on.

What the engineer will check

  • Check refrigerant circuit pressure and charge.

Who to ask for: refrigeration / heat pump engineer.

Certification: F-gas certification (refrigerant circuit work) and electrical competence.

What you might notice

Sources

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

Reviewed: 23 September 2026