ACV · HeatMaster 25–120 TC Evo combined boilers and water heaters · Europe

E96 error code

ACV HeatMaster TC Evo E96 error code – Outdoor sensor open circuit

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Quick answer

What does ACV HeatMaster 25–120 TC Evo combined boilers and water heaters E96 mean?

ACV documents E96 for HeatMaster 25, 35, 45, 70, 85 and 120 TC Evo appliances as “Outdoor sensor open circuit”. An open circuit was detected in the outdoor-temperature sensor circuit.

The code identifies the condition detected by the product; it does not always identify the failed component on its own. Confirm the full code and exact model before ordering parts or attempting a reset.

The ACV HeatMaster 25–120 TC Evo combined boilers and water heaters E96 error code indicates aCV documents E96 for HeatMaster 25, 35, 45, 70, 85 and 120 TC Evo appliances as “Outdoor sensor open circuit”. An open circuit was detected in the outdoor-temperature sensor circuit. This guide explains what the code means, the symptoms and likely causes, the checks that are safe to make, and when to stop and arrange an authorised repair.

Symptoms you may notice

The HeatMaster TC Evo displays E96 and may suspend burner, heating or hot-water operation until the detected condition is corrected.

Common causes

Possible causes include a failed or disconnected sensor, damaged wiring, a loose connector, or a circuit condition outside the controller's expected range.

Before you start troubleshooting

Use the display, rating label or product menu to confirm the exact model. Similar-looking codes can have different meanings across product generations and regions.

  • Record the complete code before switching the equipment off.
  • Check only user-accessible controls, filters and external connections described in the manual.
  • Do not open gas, refrigerant, combustion or electrical compartments.

Troubleshooting steps

Check the outdoor sensor and wiring for an open circuit; replace as required, then restart the appliance.

Can you fix this error code yourself?

The safest next step depends on the exact model and the cause behind the code. External checks may help, but a returning fault needs professional diagnosis.

A successful reset is not proof that the underlying issue is fixed. If E96 reappears, note when it happens and give that information to the service engineer.

Reset instructions

Use only the reset or restart procedure described in the official HeatMaster TC Evo manual. Do not repeatedly reset a returning fault.

Applicable products and models

ACV HeatMaster 25–120 TC Evo combined boilers and water heaters HeatMaster 25, 35, 45, 70, 85 and 120 TC EvoHeatMaster 25–120 TC Evo combined boilers and water heatersHeatMaster 25, 35, 45, 70, 85 and 120 TC Evo2022 onward

When to contact a professional

Contact an ACV-qualified heating engineer if the code returns, the appliance remains locked out, a safety device has operated, or checks require internal access, test equipment or replacement parts.

Frequently asked questions

What does ACV HeatMaster 25–120 TC Evo combined boilers and water heaters E96 mean?

ACV documents E96 for HeatMaster 25, 35, 45, 70, 85 and 120 TC Evo appliances as “Outdoor sensor open circuit”. An open circuit was detected in the outdoor-temperature sensor circuit.

Can I fix ACV HeatMaster 25–120 TC Evo combined boilers and water heaters E96 myself?

Some external checks may be suitable for the user, but the result depends on the exact model and cause. Use the official manual and arrange service if the code returns.

Should I reset the product after code E96?

Use only the reset or restart procedure described in the official HeatMaster TC Evo manual. Do not repeatedly reset a returning fault.

When should I arrange a repair?

Contact an ACV-qualified heating engineer if the code returns, the appliance remains locked out, a safety device has operated, or checks require internal access, test equipment or replacement parts.