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Heat pumps · Error codes · Baxi
A02.18Baxi

A02.18 on a Baxi heat pump: OBD Error Object Dictionary Error

Short answer

On a Baxi heat pump, A02.18 means: OBD Error Object Dictionary Error. The heat pump keeps running. An engineer is needed to fix the cause.

Reviewed 23 September 2026 · 2 sources

What it means

On the Assure Split ASHP (AWHP 4.5/6/8 MR + Assure AWHP-IDU 4-8 E)

The manual says: OBD Error Object Dictionary Error.

Part involved: PCB communication wiring.

Likely causes:

  • Reset and.

On the HP60 / Baxi Assure HP55 High Temperature Monobloc ASHP (R290)

The manual says: OBD Error Object Dictionary Error.

Part involved: PCB communication wiring.

Is it safe?

Does the heat pump stop?No
SeverityWarning
Engineer needed?Yes

The heat pump keeps running.

Resetting itself: yes - may disappear spontaneously if conditions improve.

Manual reset: not required.

What you can check

  • Note the exact code shown on the controller and when it appeared.
  • The manual's user steps allow switching the system off and on once to see if the error clears; if the code returns, contact the installer.
  • If the code persists or returns, contact a heat pump engineer.

What the engineer will check

On the Assure Split ASHP (AWHP 4.5/6/8 MR + Assure AWHP-IDU 4-8 E)

  • Reset and.

Who to ask for: heat pump engineer (controls / sensors).

Certification: Manufacturer-trained heat pump engineer.

On the HP60 / Baxi Assure HP55 High Temperature Monobloc ASHP (R290)

  • Diagnose per manufacturer service procedure (manual gives description only).

Who to ask for: heat pump engineer (controls / sensors).

Certification: Manufacturer-trained heat pump engineer.

What you might notice

Sources

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

Reviewed: 23 September 2026