Saunier Duval Thema MiConnect 26-CS/1-C boiler

Condensing boiler · New equipmentSaunier Duval Thema MiConnect 26-CS/1-C

New boilerSaunier Duval Condensing boilers

Saunier Duval Thema MiConnect 26-CS/1-C boiler

VAT includedIn stock

The Thema MiConnect 26-CS/1-C offers 2.9-20.0 kW of heating at 80/60 °C with natural gas and 25.7 kW nominal for domestic hot water. It combines AquaFast Warm Start, wired MiSet, and a depth of 344 mm. The specific flow rate D30 is 12.2 l/min; the indicated sanitary limiter is 8 l/min. With wired MiSet. Installation not included. VAT and mainland shipping included.

Heating power (80/60 °C, G20): 2.9-20.0 kW
Specific flow rate for domestic hot water (ΔT 30 K): 12.2 l/min
Dimensions (height x width x depth): 740 x 418 x 344 mm

Condensing boiler

The model, at a glance

Saunier Duval Thema MiConnect 26 with wired MiSet: 2.9-20.0 kW in heating G20, DHW D30 of 12.2 l/min and 344 mm deep.

Heating power (80/60 °C, G20): 2.9-20.0 kW
Specific flow rate for domestic hot water (ΔT 30 K): 12.2 l/min
Dimensions (height x width x depth): 740 x 418 x 344 mm

Read the full description and what it includes.

The Saunier Duval Thema MiConnect 26-CS/1-C combines heating from 2.9 to 20.0 kW at 80/60 °C and nominal domestic hot water production of 25.7 kW with natural gas. At heating temperatures of 50/30 °C, the useful range is from 3.3 to 21.7 kW. Its minimum allows for assessing performance in apartments or areas with moderate demand, always comparing it with the actual load and the adjustment of the emitters.

The hot water combines AquaFast Warm Start and SmartShower, functions that prepare the service and maintain the sanitary mode during brief pauses in the shower. The specific test flow rate is 12.2 l/min at ΔT 30 K, while the indicated limiter is 8 l/min. These are different values: the test thermal capacity should not be confused with the configured flow rate or with a guarantee of simultaneous showers. The 8-liter expansion vessel corresponds to heating.

The reference 125125140 is offered with wired MiSet. MiGo Link allows for control study via an app as an additional option, without converting the standard control to radio or including the connection module. The primary heat exchanger is made of stainless steel, and the unit has an energy class A for heating and domestic hot water, XL profile, and an acoustic power of 47 dB. A+ is not attributed to any combination of accessories.

The dimensions of 740 x 418 x 344 mm weigh 29.6 kg without water or packaging. It requires space for drainage, connections, and maintenance: 50 mm on each side, 160 mm at the bottom, and 500 mm for front access. The minimum power varies with the gas: in propane, it starts at 5.1 kW at 80/60 °C. The maximum electrical consumption is 120 W, with a maximum of 75 W for heating and 88 W for domestic hot water. These values allow for the comparison of electrical supply and thermal demand without mixing them.

What is included in the purchase?

With MiSet wired. Installation not included.

Price including VAT and shipping to mainland Spain. Installation, adaptations, and commissioning are valued separately.

Consult the manufacturer's PDFs ↓

Guide

What to check before installing this boiler

The choice of equipment does not replace the inspection of the installation by a qualified professional.

Confirm the model and commercial reference, the type of gas, and the supply configuration in the manufacturer's documentation.
Ask a qualified installer to assess the heating and domestic hot water demand; compare measured flow rates at the same temperature difference.
Check dimensions, connections, flue gas evacuation, condensate drainage, and controls compatible with the existing installation.
Confirm the included accessories and the delivery time before scheduling the installation. The online purchase of the equipment does not include installation or commissioning.

Technical data

Technical data of Saunier Duval Thema MiConnect 26-CS/1-C

Brand: Saunier Duval
Model: Saunier Duval Thema MiConnect 26-CS/1-C boiler
Status: New
Supply scope: With MiSet wired. Installation not included.
Shipping: Included in mainland Spain. Please confirm the deadline.
Commercial reference: 125125140

Specifications and dimensions of the model

Compare each magnitude under its testing conditions: heating, domestic hot water, efficiency, and dimensions.

Useful heating output (80/60 °C, G20): 2.9-20.0 kW
Heating
Useful heating output (50/30 °C, G20): 3.3-21.7 kW
Heating
Useful heating power with propane (80/60 °C, G31): 5.1-19.9 kW
Heating
Useful heating power with propane (50/30 °C, G31): 5.5-21.2 kW
Heating
Heating temperature adjustment: 15-80 °C
Heating
Maximum heating pressure: 3 bar
Heating
Heating expansion vessel: 8 l; it is not a domestic hot water storage.
Heating
Nominal power of domestic hot water (G20): 25.7 kW
Hot water
Specific flow rate DHW D (ΔT 30 K, EN 13203-1): 12.2 l/min
Hot water
Minimum flow rate of domestic hot water: 1.5 l/min
Hot water
Domestic hot water flow limiter: 8 l/min
Hot water
Permissible service pressure of domestic hot water: 0.3-10 bar
Hot water
Required connection pressure for domestic hot water: 0.7 bar
Hot water
Adjustment of domestic hot water temperature: 35-60 °C
Hot water
Preparation of domestic hot water: AquaFast Warm Start and SmartShower
Hot water
Primary heat exchanger: Stainless steel
Construction
Control of the offered reference: MiSet wiring
Regulation
Connection with application: Optional MiGo Link for this MiSet set
Regulation
Dimensions (height x width x depth): 740 x 418 x 344 mm
Dimensions and installation
Weight without packaging or water: 29.6 kg
Dimensions and installation
Minimum lateral distance: 50 mm per side
Dimensions and installation
Minimum lower distance: 160 mm
Dimensions and installation
Front access space: 500 mm
Dimensions and installation
Upper space with duct 60/100: 165 or 248 mm, according to the installation plan
Dimensions and installation
Heating energy class of the appliance: A
Efficiency and sound
Energy class of domestic hot water: A
Efficiency and sound
Sanitary profile: XL
Efficiency and sound
Acoustic power: 47 dB
Efficiency and sound
Seasonal ErP efficiency: 94 %
Efficiency and sound
Electrical supply: 230 V, 50 Hz
Electricity
Maximum electrical consumption in heating: 75 W
Electricity
Maximum electrical consumption in domestic hot water: 88 W
Electricity
Maximum power consumption: 120 W
Electricity
Standby power consumption: 2 W
Electricity
Degree of protection: IPX5D
Electricity

Manufacturer's sources

PDF and documentation of the model

Original documents, unmodified. Refer to the installation plan and the conditions of each data point before selecting the equipment.

The gallery sheets are summaries of Uniclima based on these documents. The external volume diagram does not represent connections, accessories, or service distances.

Frequently Asked Questions

Frequently asked questions: condensing boilers 125125140

Does the Thema MiConnect 26 work for a 90 m² apartment with radiators?

With a presumed thermal loss of 80 W/m², a 90 m² floor would require 7.2 kW. This demand falls within the range of 2.9-20.0 kW at 80/60 °C with natural gas; it does not mean that 90 m² is a surface guaranteed by the manufacturer. An area that only demands 2 kW is below the minimum and may cause frequent starts and stops. The installer must calculate the actual losses and check radiators, temperatures, and usage by zones; the 26 in the name does not represent 26 kW of heating.

Can I use two showers at the same time with the Thema MiConnect 26?

Two showers of 8 l/min add up to 16 l/min. The boiler specifies a flow rate of 12.2 l/min at ΔT 30 K, which is below that demand, and a sanitary limiter of 8 l/min. The test flow rate and the limiter are not the same: the 12.2 l/min should not be used as a promise of available flow in all taps. For simultaneous use, it is advisable to consider another solution depending on the temperature of the cold water, mixers, and pressure. AquaFast improves preparation but does not provide a reserve to maintain two showers.

Does AquaFast Warm Start mean that it has a hot water tank?

It is not a backup domestic hot water accumulator. AquaFast Warm Start prepares the production of DHW to reduce waiting time, and SmartShower maintains the sanitary mode during brief interruptions of a shower. These functions do not add stored liters or eliminate the cold water that may remain in a long pipe. The 8-liter tank belongs to the heating circuit and does not supply water to the shower. This Thema should not be confused with the IsoTwin or IsoMax accumulation families.

What space does the Thema 26 need inside a cabinet?

The body measures 740 x 418 x 344 mm and weighs 29.6 kg without water or packaging. It is necessary to reserve 50 mm on each side, 160 mm below, and 500 mm for front access. Above, the installation with duct 60/100 requires 165 or 248 mm depending on the plan; other diameters have different distances. A space exactly the same as the body is not sufficient. The installer must check the flue gas outlet, the connections, the support, and ensure that access for maintenance remains available.

Does reference 125125140 come with a wireless thermostat and mobile control?

This reference corresponds to the set with wired MiSet, not to MiSet Radio. The family allows connection with the application via MiGo Link, but that module is optional in this set and is not included just by the name MiConnect. Before replacing a thermostat, its connection and existing configuration must be checked. The class A of the device does not automatically become A+ just because it has an application.

Does it maintain the same minimum power when operating with propane?

At 80/60 °C, the Thema 26 declares 2.9-20.0 kW with natural gas G20 and 5.1-19.9 kW with propane G31. A low-demand area may be better suited to the minimum of G20 than to that of G31. The admission of propane requires checking the authorized version and commissioning by a qualified professional; it is not an adjustment that the buyer should make. The values in kW are thermal: the maximum published electrical consumption is 120 W, which is a different magnitude.

Does the price include installation and shipping?

Includes VAT and shipping to mainland Spain. Installation and adaptations are valued separately. With MiSet wired. Installation not included.