Saunier Duval Appliance Repair in Davenport & Cale Green

What does error F18 mean on a Saunier Duval Condens boiler?

Error F18 on a Saunier Duval Condens boiler indicates a user interface fault. The control panel is faulty. Contact a qualified heating engineer as the user interface may need replacement.

What does error code 08 mean on a Saunier Duval Themaclassic boiler?

Error 08 on a Saunier Duval Themaclassic boiler indicates a return NTC sensor fault. The return water temperature sensor is faulty or disconnected. Switch off the boiler and contact a qualified heating engineer.

What does 2.7bar mean on a Saunier Duval Themaclassic boiler?

The 2.7bar display on a Saunier Duval Themaclassic boiler indicates high water pressure. You may need to release water via a radiator bleed valve. If unsure, contact a Gas Safe registered engineer.

What does error F14 mean on a Saunier Duval Condens boiler?

Error F14 on a Saunier Duval Condens boiler indicates the central heating flow has exceeded 95°C. This is a temperature control issue that may indicate circulation problems. Contact a Gas Safe registered engineer.

What does error F16 mean on a Saunier Duval Condens boiler?

Error F16 on a Saunier Duval Condens boiler indicates a flame detection fault - the boiler has detected a flame for more than 5 seconds after the burner stopped. 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 as the gas valve may be defective.

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.

How does condensation mode work on a Saunier Duval boiler?

Condensing boilers recover heat from flue gases by condensing water vapour, which significantly improves efficiency. For optimal condensation, the return water temperature should be below 50°C. This allows the boiler to extract maximum heat from the combustion gases. Properly configured condensing operation can reduce gas consumption by up to 30% compared to older non-condensing boilers.

Why is my Saunier Duval boiler making a banging or kettling noise?

Banging, popping, or whistling noises (known as kettling) typically indicate that water is overheating inside the boiler. This is often caused by limescale buildup on the heat exchanger, restricted water flow, a failing circulation pump, or incorrect thermostat settings. Air trapped in the system can also cause gurgling sounds.

How do I use the temperature controls on a Saunier Duval boiler?

Most Saunier Duval boilers have two temperature selectors: one for domestic hot water and one for central heating. For domestic hot water, the range is typically 38°C to 60°C, with an ECO setting suitable for everyday use. For central heating, the range is typically 38°C to 73°C.

Why does my Saunier Duval boiler provide hot water but not heating?

The most common causes are: the boiler may be set to summer mode (hot water only), the room thermostat may be set too low, thermostatic radiator valves may be turned down or off, or there may be a fault with the diverter valve (3-way valve) which directs hot water between the heating circuit and hot water outlet.