ATAG 109 Fault Code (i-Range (2019 and newer))

Safety disclaimer

Fault code summary

Manufacturer

ATAG

Fault code

109

Fault type

High pressure, Pressure sensor

Severity

Not specified

Reset

ATAG distinguishes blocking codes from error codes; a locked boiler may require reset and/or service intervention.

Applicable models

ATAG iC, ATAG iS, ATAG iR

Quick answer

Pressure above Pmax.

What does this fault code mean?

Pressure above Pmax.

Common causes

• System pressure above Pmax.

Symptoms

• The ATAG display shows error code 109.

What can the homeowner safely check?

• Read the pressure gauge and contact the installer.

Boiler reset information

ATAG distinguishes blocking codes from error codes; a locked boiler may require reset and/or service intervention.

When should I call an engineer?

Contact a suitably qualified heating engineer when the fault persists, the boiler locks out, or the manufacturer instructions do not resolve it. For gas appliance work in the UK, use a Gas Safe registered engineer.

Engineer diagnosis

• Check system pressure, expansion provision and pressure sensing.

Applicable boiler models

• ATAG iC
• ATAG iS
• ATAG iR

Related fault codes

• 101 — i-Range (2019 and newer)

  Overheat.

  Read fault code
• 102 — i-Range (2019 and newer)

  Pressure sensor error.

  Read fault code
• 103 — i-Range (2019 and newer)

  Flow check failed three times (flow-check sequence 1, 3 or 4; last check 1).

  Read fault code
• 104 — i-Range (2019 and newer)

  Flow check failed.

  Read fault code
• 105 — i-Range (2019 and newer)

  Flow check failed three times (flow-check sequence 1, 3 or 4; last check 3).

  Read fault code
• 106 — i-Range (2019 and newer)

  Flow check failed three times (flow-check sequence 1, 3 or 4; last check 4).

  Read fault code
• 107 — i-Range (2019 and newer)

  Flow check 5 failed.

  Read fault code
• 108 — i-Range (2019 and newer)

  Pressure below Pmin (less than 0.5 bar); filling is needed.

  Read fault code

Manufacturer documentation

2019 & newer range: 109 — Pressure > Pmax.

Last verified

2026-09-12

Frequently asked questions