Vaillant Group • Founded 1963 • France
Repair and spare parts for Saunier Duval boilers in Madrid
Specialised technical service for the entire Saunier Duval range in Madrid. Repair of ThemaFast, ThemaClassic, Thalia Plus, and Isotwin boilers, with quick diagnostics and original spare parts.
💡 Direct response
Saunier Duval is a French brand of boilers founded in 1963 and acquired by the Vaillant Group in 2003. It shares the technical platform and PCB with the equivalent Vaillant models, which makes it easier to locate spare parts. Its boilers ThemaFast și ThemaClassic They are among the most installed in Madrid and the metropolitan area between 2005 and 2018.
🏆 Vaillant Group
Spare parts shared with the equivalent Vaillant range. Availability guaranteed up to 15 years after discontinuation.
High efficiency
Thalia Plus and ThemaFast condensing models, class A. Compatible with Exacontrol and OpenTherm control.
📦 Spare parts in stock
Original and OEM equivalents. Express shipping 24-48h throughout Spain.
Saunier Duval product range
Condensing boilers
- ThemaFast F - Condensing combi boiler, sealed forced draught. The most installed range in Madrid.
- Thalia Plus – high-efficiency condensing, compatible with renewable energies and hybrid heat pump.
- Isotwin F – Condensing boiler with integrated stratified DHW tank (30 L). For buildings with high demand.
Standard and conventional boilers
- ThemaClassic C - Boiler for heating only, sealed forced draught. Widely used in Madrid 1998-2010.
- Themaplus C – advanced version of the ThemaClassic, with digital display and more regulation functions.
- Opalia - Wall-mounted atmospheric boiler, requires conventional chimney. Common in flats with classic installation.
Most common fault codes
Saunier Duval shares the codes of the Vaillant platform in condensing models. The most common ones:
| Code | Meaning | Common cause |
|---|---|---|
| F.01 | Flame sensor | Dirty ionization electrode or control board |
| F.07 | Spontaneous flame | Defective gas valve or short circuit in sensor |
| F.11 | DHW NTC sensor | Domestic hot water (DHW) sensor fault |
| F.22 | Low pressure | Water below 0.5 bar: refill or repair leak |
| F.28 | Ignition fault | Gas cut off, electrode or gas valve |
| F.29 | No re-ignition | Ionization electrode or control board |
| F.75 | No pressure detected | Circulator pump or faulty pressure sensor |
Saunier Duval spare parts: own stock and 24-hour delivery
Saunier Duval spare parts are largely shared with the equivalent Vaillant range, which improves their availability. We ship in 24-48 hours to all of Spain:
- PCBs (ThemaFast, ThemaClassic, Thalia Plus)
- Circulator pumps and hydraulic groups
- NTC sensors for heating, DHW, and flue gases
- Gas valves and solenoid valves
- Extractors, fans, and electrodes
- Heat exchangers and gaskets
Frequently Asked Questions about Saunier Duval Boilers
The most frequently asked questions we receive about Saunier Duval boilers:
Are they the same? Vaillant Group (acquisition 2003), but they are distinct brands. They share the same technical platform and many internal components (PCBs, valves, sensors), but have different external designs and some specific components. This facilitates the location of spare parts, but not all are directly interchangeable.
The ThemaFast F It is a combi boiler (heating + instant DHW), with a plate heat exchanger for hot water. The ThemaClassic C It is heating only, without integrated DHW production (the dwelling has another unit for hot water). Both are sealed forced draught, very common in Madrid between 2000 and 2015.
F.28 indicates ignition faultThe boiler attempted to ignite unsuccessfully and locked out for safety. Check that the gas valve is open and the gas pressure is correct. If the gas is fine, it could be a dirty ignition electrode, a faulty gas valve, or the control board. Reset using the reset button and if it recurs, call the technician.
If the boiler is over 15 years old or has recurring faults, it is usually more cost-effective to replace it with a condensing boiler (Thalia Plus or equivalent). The average gas savings is 25-30% in Madrid, and the investment is typically recovered in 5-7 years. For equipment less than 10 years old and in good condition, repair is almost always more economical.
The most common causes are: blocked plate heat exchanger due to limescale (common in Madrid's water), Defective DHW NTC sensor (F.11) stuck 3-way valve sau faulty flow meter (does not detect DHW flow). If the boiler heats for heating but not for the tap, the heat exchanger or the 3-way valve are the main suspects.
Annual inspection, according to RITE regulations and manufacturer's recommendation. The maintenance includes cleaning the burner, inspecting the heat exchanger, verifying combustion, and issuing the official certificate. In homes with a maintenance contract, priority response to faults is guaranteed.
Does your Saunier Duval boiler need servicing?
Indicate the model and the fault code. We will guide you before the visit.