610 Boiler Fault Code: What It Means on Every Brand

The 610 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 610 means	Severity	DIY?
AAriston	Ariston fault code 610 sits within the boiler's Group 6 fault category, which covers faults associated with the air inlet, flue, and heat exchanger area of the appliance. Full guide →	Lockout — engineer likely	No
CChaffoteaux	Fault code 610 on a Chaffoteaux boiler signals that the internal thermal fuse (sometimes called the thermofusible or overheat thermostat) has opened. Full guide →	Lockout — engineer likely	No

610 brand by brand

Ariston 610

Ariston fault code 610 sits within the boiler's Group 6 fault category, which covers faults associated with the air inlet, flue, and heat exchanger area of the appliance. In practice this code has two closely related meanings depending on the specific model and firmware variant. The most common interpretation seen by UK engineers is that the boiler's internal thermal fuse has blown or tripped — a safety cut-out that activates when the appliance detects dangerously high temperatures. The second interpretation, documented in the Ariston Sensys manual library as '6 10', describes an open-circuit fault on the heat exchanger sensor itself. Because both meanings point to the same physical area of the boiler and require the same diagnostic approach, they are covered together on this page. Either way, the boiler will lock out and refuse to fire until the underlying cause is identified and resolved by a Gas Safe registered engineer.

Causes, fixes & costs for Ariston 610 → · All Ariston codes

Chaffoteaux 610

Fault code 610 on a Chaffoteaux boiler signals that the internal thermal fuse (sometimes called the thermofusible or overheat thermostat) has opened. This safety device sits close to the heat exchanger and acts like a heat-triggered circuit breaker: when the water or component temperature climbs beyond safe limits, it cuts power to prevent damage or danger. Code 610 is therefore a lockout condition — the boiler has shut itself down because something caused it to overheat. Simply replacing the fuse or resetting the boiler without finding the underlying cause will almost always result in the fault returning, and could mask a serious problem.

Causes, fixes & costs for Chaffoteaux 610 → · All Chaffoteaux codes

Frequently asked questions

Is the 610 fault code the same on every boiler?

Broadly, yes — on Ariston and Chaffoteaux the 610 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 610 fault myself?

Not usually. On every brand listed, 610 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 610 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.