Saunier Duval Repair Service in Eastfield

What does error code 07 mean on a Saunier Duval Themaclassic boiler?

Error 07 on a Saunier Duval Themaclassic boiler indicates a domestic hot water NTC sensor fault. The DHW temperature sensor is faulty or disconnected. Switch off the boiler and contact a Gas Safe registered engineer.

What does error code 10 mean on a Saunier Duval Themaclassic boiler?

Error 10 on a Saunier Duval Themaclassic boiler indicates a central heating return NTC sensor fault. The sensor cable may be defective or disconnected. Switch off the boiler and contact a qualified heating engineer.

What does error 0 & 2 (also shown as 02) mean on a Saunier Duval Ecosy boiler?

Error 0 & 2 on a Saunier Duval Ecosy boiler (display alternates between 0 and 2, also referred to as code 02) indicates no flame ionisation. The boiler is not detecting a flame. Do not attempt to fix this yourself. If you smell gas, do not operate any switches, ventilate the area if safe to do so, leave the property and call the Gas Emergency Service from outside. If there is no gas smell, check your gas supply is on. If gas is available, contact a Gas Safe registered engineer to check the electrode and gas supply.

What does error code 15 mean on a Saunier Duval Isofast boiler?

Error 15 on a Saunier Duval Isofast boiler indicates a gas mechanism fault affecting the gas valve or gas supply control. This is a serious gas safety issue. Do not use the boiler. Switch it off at the power supply immediately. If you smell gas, do not operate any switches, ventilate the area if safe to do so, leave the property and call the Gas Emergency Service from outside. Contact a Gas Safe registered engineer immediately.

What does error F23 mean on a Saunier Duval Condens boiler?

Error F23 on a Saunier Duval Condens boiler indicates a water circulation fault and possible pump failure. Check the pressure gauge - if it shows below 1 bar, you may need to repressurise the system to between 1 and 2 bar. If pressure is normal, this fault typically requires professional diagnosis. Contact a Gas Safe registered engineer.

What is the pre-heating or WARM START function on a Saunier Duval boiler?

The WARM START or pre-heating function reduces waiting time when you turn on a hot water tap. In ON mode, the boiler maintains the heat exchanger at the required temperature between 5am and 11pm for instant hot water. In AUTO mode, the boiler learns your household patterns and pre-heats just before your typical first use of the day. In OFF mode, this function is disabled and you may experience a short delay before hot water arrives.

What is the expansion vessel and why is it important?

The expansion vessel is a small tank inside your boiler that absorbs the increased water volume as the heating system heats up. Without a functioning expansion vessel, system pressure would rise dangerously high when hot and drop when cold. Signs of a faulty expansion vessel include pressure rising significantly when heating is on and dropping when cold, or the pressure relief valve discharging water. Expansion vessel maintenance should be part of the annual service by a qualified engineer.

How do I repressurise my Saunier Duval boiler?

Before approaching the boiler, ensure there is no smell of gas. Locate the filling loop underneath your boiler - this is typically a flexible silver hose with two taps or valves. Ensure the boiler is switched off and has cooled down. Open both filling loop taps slowly to allow water into the system. Watch the pressure gauge and fill until it shows between 1 and 1.5 bar. Close both taps securely once the correct pressure is reached.

How long does a Saunier Duval boiler typically last?

A Saunier Duval boiler can last 15 to 20 years when properly maintained with annual servicing. The actual lifespan depends on usage patterns, water quality in your area, and how well the heating system is maintained. Signs that your boiler may need replacement include frequent breakdowns, difficulty obtaining spare parts, reduced efficiency, and increasingly expensive repairs.

How do I switch my Saunier Duval boiler between summer and winter modes?

The summer/winter switch allows you to disable central heating while keeping hot water available. In winter mode, both heating and hot water functions are active, with domestic hot water having priority. In summer mode, central heating is disabled but hot water remains available. The location and type of switch varies by model - it may be a lever, rotary switch, or push button.