607 Boiler Fault Code: What It Means on Every Brand

The 607 fault code appears on 2 boiler brands — Ariston and Chaffoteaux — and on all of them it points to the same kind of problem. The details still differ by brand (thresholds, sub-codes, reset procedure), so use the table below to jump to the page for your boiler.

Lockout — engineer likely 2 brands use this code

Which brand is your boiler?

The brand is printed on the front casing. Tap your brand for the full causes, fixes and repair costs.

Brand	What 607 means	Severity	DIY?
AAriston	Fault code 607 on an Ariston boiler means the air pressure switch has registered a closed (active) state before the fan has even started up. Full guide →	Lockout — engineer likely	No
CChaffoteaux	Fault code 607 (sometimes displayed as 6P1 on certain Chaffoteaux models) signals that the boiler's draught-proving system has detected inadequate airflow through the flue. Full guide →	Lockout — engineer likely	No

607 brand by brand

Ariston 607

Fault code 607 on an Ariston boiler means the air pressure switch has registered a closed (active) state before the fan has even started up. In normal operation, the fan runs first to clear the flue, and only once it has built up sufficient draught does the pressure switch close to confirm everything is safe. When the boiler detects the switch is already closed at the point it should be open — before ignition has begun — it locks out and displays 607 as a flue-gas safety precaution. The most consistent cause is a problem in the fan, flue, or pressure-sensing circuit, though in some cases a wiring fault or PCB communication issue can produce the same code.

Causes, fixes & costs for Ariston 607 → · All Ariston codes

Chaffoteaux 607

Fault code 607 (sometimes displayed as 6P1 on certain Chaffoteaux models) signals that the boiler's draught-proving system has detected inadequate airflow through the flue. In other words, combustion gases are not being expelled from the boiler efficiently enough for the unit to operate safely. The boiler's control board monitors flue draught continuously via a pressure sensor; when airflow falls below the required threshold, the boiler locks out and displays 607 to prevent potentially dangerous combustion conditions. This is categorised as a fan and flue fault and requires investigation before normal operation can resume.

Causes, fixes & costs for Chaffoteaux 607 → · All Chaffoteaux codes

Frequently asked questions

Is the 607 fault code the same on every boiler?

Broadly, yes — on Ariston and Chaffoteaux the 607 code points to the same class of fault, and the recommended response is similar. Model-specific details such as sub-codes and reset procedures still vary, so follow the page for your own brand.

Can I fix a 607 fault myself?

Not usually. On every brand listed, 607 points to a fault that needs a suitably registered engineer to diagnose and repair. A single reset to rule out a transient glitch is reasonable; repeated resets are not.

Who should I call about a 607 fault?

For gas boilers, a Gas Safe registered engineer — it is a legal requirement for any work on the appliance. If you smell gas at any point, leave the property and call the National Gas Emergency line on 0800 111 999.

General guidance only — not a substitute for professional advice, and not certified by a registered engineer. Any work on a gas appliance must be carried out by a Gas Safe registered engineer. If you smell gas, call 0800 111 999.