Condensing boiler · New equipmentSaunier Duval Thema MiConnect 31-CS/1-C
Saunier Duval Thema MiConnect 31-CS/1-C boiler
Heating and hot water for everyday use, combined in a gas boiler.
- Gas
- Natural gas Convertible to propane
- Wi-Fi
- Optional MiGo Link
- Heating
- 3.4-25.0 kW 80/60 °C
- Domestic hot water flow rate
- 14.8 l/min ΔT 30 K
Gas and Wi-Fi: compatibility and accessories
Gas and conversion: It accepts natural gas G20 and conversion to propane G31 through the manufacturer's adjustment procedure. Compatibility with butane G30 is not offered without explicit documentation for this version. The conversion and commissioning are the responsibility of a qualified professional; they are not included in the purchase. Source 1 ↗ Source 2 ↗ Source 3 ↗
Wi-Fi and supply: Optional MiGo Link solution for control from the app. It is purchased separately; the wired or radio controls of the set do not imply that the connection module is included. Source 1 ↗ Source 2 ↗ Source 3 ↗
Description
Saunier Duval combines home heating and hot water for taps and showers. When choosing it, both water usage and heating needs are important: a home with multiple showers running at the same time requires a different assessment.
Domestic hot water is prepared when you turn on the tap, without an integrated storage tank. It is important to check how many water points you will use at the same time and the available space to replace the boiler.
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 of Saunier Duval Thema MiConnect 31-CS/1-C
- Brand
- Saunier Duval
- Model
- Saunier Duval Thema MiConnect 31-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
- 125125143
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)
- 3.4-25.0 kW
Heating - Useful heating output (50/30 °C, G20)
- 3.9-27.3 kW
Heating - Useful heating power with propane (80/60 °C, G31)
- 8.0-24.8 kW
Heating - Useful heating power with propane (50/30 °C, G31)
- 8.9-26.7 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)
- 31.0 kW
Hot water - Specific flow rate DHW D (ΔT 30 K, EN 13203-1)
- 14.8 l/min
Hot water - Minimum flow rate of domestic hot water
- 1.5 l/min
Hot water - Domestic hot water flow limiter
- 10 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
- 32.4 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
- 77 W
Electricity - Maximum electrical consumption in domestic hot water
- 83 W
Electricity - Maximum power consumption
- 105 W
Electricity - Standby power consumption
- 2 W
Electricity - Degree of protection
- IPX5D
Electricity
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.
- Technical data and installation manual Thema MiConnectPDF · 92 pages · Saunier DuvalView original on the manufacturer's website ↗
- Technical sheet: Thema MiConnect with MiSetPDF · 2 pages · Saunier DuvalView original on the manufacturer's website ↗
- Energy label Thema Condens 31-CS/1PDF · 1 page · Saunier DuvalView original on the manufacturer's website ↗
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: condensing boilers 125125143
Can the Thema MiConnect 31 heat a house of 180 m²?
As an example of calculation, 180 m² with a supposed loss of 80 W/m² require 14.4 kW. The model offers 3.4-25.0 kW at 80/60 °C with natural gas, so that hypothetical load falls within the range. This is not a certification for 180 m²: climate, height, insulation, and emitters can change the requirement. If an area only requires 3 kW, it falls below the minimum. The installer must verify the total load and the active zones; the 31 kW corresponds to domestic hot water, not to the maximum heating power under those conditions.
Does the Thema MiConnect 31 allow for two simultaneous showers of 8 l/min?
The combined demand would be 16 l/min. Its specific flow rate is 14.8 l/min at ΔT 30 K and the indicated domestic hot water limiter is 10 l/min: those two showers cannot be guaranteed. It is also not enough to simply add two low-consumption showers and compare only with the test flow rate, because the limiter, mixing, pressure, and temperature of the cold water are involved. Compared to the Thema 26, the sanitary capacity increases, but it does not include a storage reserve to cover peak consumption.
Does it have a storage tank or are the 8 liters a reserve for showers?
The 8 liters are from the heating expansion vessel, not from a domestic hot water tank. This Thema produces DHW on demand. AquaFast Warm Start reduces preparation time, and SmartShower maintains the sanitary mode during brief interruptions, without increasing the continuous flow or adding a water reserve. For a home with several frequent showers at the same time, it is advisable to compare a storage solution sized according to usable liters and recovery, not just the XL label.
Does it take up more space than the Thema MiConnect 26 and fit in the same cabinet?
The body retains the dimensions of 740 x 418 x 344 mm of the Thema 26, but weighs 32.4 kg without water or packaging compared to 29.6 kg. The installation requires 50 mm of clearance on each side, 160 mm below, and 500 mm of front access. With a 60/100 duct, the upper distance is 165 or 248 mm depending on the plan. Sharing external measurements does not guarantee that the flue, support, or connections can be reused without reviewing the installation.
What does reference 125125143 include and how does it differ from MiSet Radio?
The reference 125125143 identifies the version with wired MiSet. MiSet Radio corresponds to a different line: sharing 31-CS/1 does not validate the same regulation set. The connection with the mobile device requires the appropriate MiGo Link solution, which is optional for this offer with MiSet. A WiFi accessory, flue, or installation is not assumed to be included unless expressly stated in the supply. The unit has class A for heating and domestic hot water; a higher class system requires its specific combination of controls.
Why is the minimum power important when comparing natural gas and propane?
At 80/60 °C, this model starts at 3.4 kW with natural gas G20 and 8.0 kW with propane G31; the maximums are 25.0 and 24.8 kW respectively. In propane, an area that requires 5 kW would fall below the minimum and could experience more starts and stops. Therefore, the G20 range should not be transferred to a home using propane. The version and commissioning must be verified by a qualified professional. The maximum electrical consumption of 105 W does not represent the heating power.
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.
