6P2 Boiler Fault Code: What It Means on Every Brand

The 6P2 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 6P2 means	Severity	DIY?
AAriston	The 6P2 code appears on Ariston boilers when the air pressure switch fails to maintain its signal while the boiler is already running — in other words, the fault develops mid-cycle rather… Full guide →	Lockout — engineer likely	No
CChaffoteaux	Fault code 6P2 points to the boiler's air pressure switch (APS) failing to confirm adequate airflow during normal operation. Full guide →	Lockout — engineer likely	No

6P2 brand by brand

Ariston 6P2

The 6P2 code appears on Ariston boilers when the air pressure switch fails to maintain its signal while the boiler is already running — in other words, the fault develops mid-cycle rather than at start-up (which is what the related 6P1 code indicates). The pressure switch is a safety device that monitors the fan's ability to push combustion gases safely up and out through the flue. When the switch loses confidence that airflow is adequate during a heating or hot water call, the boiler cuts out and locks out to prevent dangerous gases building up inside the appliance. The 6P2 code is therefore a mid-operation lockout, whereas 6P1 is a start-up lockout — both point to the same underlying air-pressure-switch circuit, so the diagnostic approach is very similar.

Causes, fixes & costs for Ariston 6P2 → · All Ariston codes

Chaffoteaux 6P2

Fault code 6P2 points to the boiler's air pressure switch (APS) failing to confirm adequate airflow during normal operation. When the boiler fires up, the fan runs and creates a pressure differential across the Venturi — a small tube assembly attached to the fan outlet. This pressure change should physically close the APS membrane and send a confirmation signal to the PCB that the fan is working correctly. If that confirmation doesn't arrive in time, or at all, the boiler locks out and displays 6P2 as a safety precaution, preventing gas from reaching the burner without verified airflow. Note that the closely related code 6P1 covers the same APS contact closure delay but triggers during the start-up sequence rather than mid-operation; 6P2 specifically appears when the fault develops while the appliance is already running.

Causes, fixes & costs for Chaffoteaux 6P2 → · All Chaffoteaux codes

Frequently asked questions

Is the 6P2 fault code the same on every boiler?

Broadly, yes — on Ariston and Chaffoteaux the 6P2 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 6P2 fault myself?

Not usually. On every brand listed, 6P2 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 6P2 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.