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Ariston E-Combi ONE 24kW Condensing Combi Gas Boiler with Horizontal Flue Kit - ErP A Rated, Xtratech Heat Exchanger, 5-Year Warranty
Ariston E-Combi ONE 24kW Condensing Combi Gas Boiler with Horizontal Flue Kit - ErP A Rated, Xtratech Heat Exchanger, 5-Year Warranty
The Ariston E-Combi ONE 24kW condensing combi boiler is a compact, ErP A-rated gas boiler designed for UK homes with a single bathroom or moderate hot water demand. At the heart of the gas boiler is Ariston’s patented Xtratech™ stainless steel heat exchanger with 142% wider waterways for superior condensing efficiency and reduced blockage risk. The unique AUTO function continuously optimises boiler output to match real-time heating demand, reducing short-cycling and improving seasonal efficiency. Compact at 735 × 400 × 299 mm and weighing just 29.3 kg, it fits most standard boiler locations. Delivers up to 10.4 L/min of domestic hot water on demand. Supplied with standard horizontal flue kit and LPG conversion kit. Endorsed by the Energy Saving Trust. 2-year warranty, extendable to 5 years on registration.
24kW
Output
10.4 L/min
Hot Water
ErP A
Rated
29.3 kg
Weight
5-yr
Warranty
LPG Kit
Included
⚠ Gas Safe Installation Required: This boiler must be installed by a Gas Safe registered engineer. The installer must commission the boiler and complete the benchmark checklist. Annual service by a Gas Safe engineer is required to maintain the extended warranty.
Key Features
Xtratech™ Stainless Steel Heat Exchanger — 142% Wider Waterways
The heart of the E-Combi ONE is Ariston’s patented Xtratech™ single-coil stainless steel heat exchanger, designed with 142% wider waterways than previous generations. Wider channels reduce pressure drops, lower the risk of blockages from system debris, and provide a larger condensing surface for improved heat transfer. Stainless steel construction resists corrosion across a wide pH range, making the exchanger compatible with most system water conditions. It is easy to remove for cleaning or inspection. Tested and certified by TUV Rheinland.
Xtratech™ single coil142% wider waterwaysTUV Rheinland certified
ErP A Rated — Energy Saving Trust Endorsed
The E-Combi ONE holds an ErP A energy efficiency rating for seasonal space heating and is endorsed by the Energy Saving Trust — one of a small number of gas boilers on the market to achieve both. At 30% load (low-temperature return mode), efficiency reaches approximately 99%, meaning the boiler extracts almost all available energy from the gas during normal heating operation.
ErP A ratedEnergy Saving Trust endorsed~99% efficiency at part load
AUTO Function — Intelligent Load Optimisation
The unique AUTO function monitors and adapts the boiler’s operating parameters to match the actual thermal demand of the building in real time. Rather than cycling to a fixed setpoint, AUTO continuously optimises output between minimum and maximum, reducing short-cycling, lowering average flow temperature and improving seasonal efficiency. It is engaged from the boiler’s built-in controls and requires no additional accessories.
AUTO functionContinuous modulationReduces short-cycling
Natural Gas and LPG Compatible — LPG Conversion Kit Included
The E-Combi ONE is supplied as a natural gas boiler but includes an LPG conversion kit as standard, making it suitable for properties without a mains gas supply. Conversion is a straightforward procedure carried out by a Gas Safe registered engineer. No additional kit purchase is required, saving both cost and procurement time.
Natural gas + LPGLPG kit in the boxGas Safe conversion
Lightweight at 29.3 kg — Colour-Coded Connections for Fast Installation
Weighing just 29.3 kg dry, the E-Combi ONE is straightforward to wall-mount without heavy lifting equipment. Connection pipework uses colour-coded ports to reduce installation errors. All connections are in the same positions as previous Ariston boilers, enabling easy like-for-like retrofit without pipework modification. Minimum servicing clearances are just 5mm on left and right.
29.3 kgColour-coded connectionsEasy retrofit
Built-In Mechanical Clock — Ariston NET Compatible
The E-Combi ONE includes a built-in 24-hour mechanical clock for basic heating and hot water scheduling without any external controls. It is also Ariston NET ready — the boiler can be connected to the Ariston NET wi-fi adapter (sold separately) to enable smartphone app control, remote diagnostics and energy monitoring, all without changing the boiler.
Built-in 24hr clockAriston NET readyApp upgradeable
Horizontal Flue Kit Included — Ready for Standard Installation
This package includes the Ariston Standard Horizontal Flue Kit (3318073), covering a typical straight-through external wall installation. The flue system uses 60/100mm coaxial (balanced flue) connections and is designed to minimise on-site cutting and adjustment. Extension kits are available separately for longer flue runs or non-standard configurations.
Horizontal flue kit included60/100mm coaxialEasy standard fit
IPX5D Electrical Protection — Bathroom Safe Siting
The E-Combi ONE carries an IPX5D electrical protection rating, meaning it is protected against water jets from any direction. This allows the boiler to be sited closer to wet areas than a standard IP20 appliance, providing more flexibility for bathroom or kitchen installations in compact properties.
IPX5D ratedSplash-proofFlexible siting
Technical Specifications
| Boiler | |
| Model | E-Combi ONE 24kW — Product Code 3301131 |
| Boiler Type | Condensing combi (heating + hot water, mains pressure) |
| ErP Rating (Heating) | A |
| Seasonal Efficiency (ηs) | ~90%+ seasonal space heating |
| Heat Output Max (CH) | 22 kW |
| Heat Output Max (DHW) | 26 kW |
| Modulation | Yes — with AUTO function |
| Heating | |
| Flow Temp Range (High Temp) | 35°C – 82°C |
| Flow Temp Range (Low Temp / UFH) | 20°C – 45°C |
| Domestic Hot Water | |
| DHW Flow Rate (ΔT 35°C) | 10.4 L/min |
| DHW Temp Range | 36°C – 60°C |
| DHW Pressure Min/Max | 0.2 / 7 bar |
| DHW Min Flow Rate | 2 L/min |
| Physical and Electrical | |
| Dimensions (H×W×D) | 735 × 400 × 299 mm (approx.) |
| Dry Weight | 29.3 kg |
| Electrical Supply | 230V / 50Hz |
| Electrical Protection | IPX5D |
| Flue and Gas | |
| Flue System | Balanced flue (room-sealed), 60/100mm coaxial |
| Flue Kit | Standard horizontal kit included (3318073) |
| Gas Types | Natural gas G20 / LPG (conversion kit included) |
| NOx Emissions | 53 mg/kWh |
| System | |
| Expansion Vessel | 8L built-in |
| Min Ambient Temp | 5°C |
| Servicing Clearances (top/front/bottom) | 300 / 450 / 250 mm |
| Servicing Clearances (left/right) | 5 / 5 mm |
| Included in Package | |
| Boiler | Ariston E-Combi ONE 24kW (3301131) |
| Flue Kit | Standard horizontal flue kit (3318073) |
| LPG Conversion Kit | Included as standard |
| Warranty | |
| Standard Warranty | 2 years |
| Extended Warranty | 5 years on registration within 30 days (via Ariston) |
| Installation Requirement | Gas Safe registered engineer |
| Manufacturer | Ariston Thermo UK Ltd, Milton Keynes |
Frequently Asked Questions
Related Products
Ariston E-Combi ONE 30kW with Horizontal Flue
Higher-output combi for larger homes and multiple bathrooms
$361.85
Original: $1,033.85
-65%Ariston E-Combi ONE 24kW Condensing Combi Gas Boiler with Horizontal Flue Kit - ErP A Rated, Xtratech Heat Exchanger, 5-Year Warranty—
$1,033.85
$361.85More Images
Ariston E-Combi ONE 24kW Condensing Combi Gas Boiler with Horizontal Flue Kit - ErP A Rated, Xtratech Heat Exchanger, 5-Year Warranty
The Ariston E-Combi ONE 24kW condensing combi boiler is a compact, ErP A-rated gas boiler designed for UK homes with a single bathroom or moderate hot water demand. At the heart of the gas boiler is Ariston’s patented Xtratech™ stainless steel heat exchanger with 142% wider waterways for superior condensing efficiency and reduced blockage risk. The unique AUTO function continuously optimises boiler output to match real-time heating demand, reducing short-cycling and improving seasonal efficiency. Compact at 735 × 400 × 299 mm and weighing just 29.3 kg, it fits most standard boiler locations. Delivers up to 10.4 L/min of domestic hot water on demand. Supplied with standard horizontal flue kit and LPG conversion kit. Endorsed by the Energy Saving Trust. 2-year warranty, extendable to 5 years on registration.
24kW
Output
10.4 L/min
Hot Water
ErP A
Rated
29.3 kg
Weight
5-yr
Warranty
LPG Kit
Included
⚠ Gas Safe Installation Required: This boiler must be installed by a Gas Safe registered engineer. The installer must commission the boiler and complete the benchmark checklist. Annual service by a Gas Safe engineer is required to maintain the extended warranty.
Key Features
Xtratech™ Stainless Steel Heat Exchanger — 142% Wider Waterways
The heart of the E-Combi ONE is Ariston’s patented Xtratech™ single-coil stainless steel heat exchanger, designed with 142% wider waterways than previous generations. Wider channels reduce pressure drops, lower the risk of blockages from system debris, and provide a larger condensing surface for improved heat transfer. Stainless steel construction resists corrosion across a wide pH range, making the exchanger compatible with most system water conditions. It is easy to remove for cleaning or inspection. Tested and certified by TUV Rheinland.
Xtratech™ single coil142% wider waterwaysTUV Rheinland certified
ErP A Rated — Energy Saving Trust Endorsed
The E-Combi ONE holds an ErP A energy efficiency rating for seasonal space heating and is endorsed by the Energy Saving Trust — one of a small number of gas boilers on the market to achieve both. At 30% load (low-temperature return mode), efficiency reaches approximately 99%, meaning the boiler extracts almost all available energy from the gas during normal heating operation.
ErP A ratedEnergy Saving Trust endorsed~99% efficiency at part load
AUTO Function — Intelligent Load Optimisation
The unique AUTO function monitors and adapts the boiler’s operating parameters to match the actual thermal demand of the building in real time. Rather than cycling to a fixed setpoint, AUTO continuously optimises output between minimum and maximum, reducing short-cycling, lowering average flow temperature and improving seasonal efficiency. It is engaged from the boiler’s built-in controls and requires no additional accessories.
AUTO functionContinuous modulationReduces short-cycling
Natural Gas and LPG Compatible — LPG Conversion Kit Included
The E-Combi ONE is supplied as a natural gas boiler but includes an LPG conversion kit as standard, making it suitable for properties without a mains gas supply. Conversion is a straightforward procedure carried out by a Gas Safe registered engineer. No additional kit purchase is required, saving both cost and procurement time.
Natural gas + LPGLPG kit in the boxGas Safe conversion
Lightweight at 29.3 kg — Colour-Coded Connections for Fast Installation
Weighing just 29.3 kg dry, the E-Combi ONE is straightforward to wall-mount without heavy lifting equipment. Connection pipework uses colour-coded ports to reduce installation errors. All connections are in the same positions as previous Ariston boilers, enabling easy like-for-like retrofit without pipework modification. Minimum servicing clearances are just 5mm on left and right.
29.3 kgColour-coded connectionsEasy retrofit
Built-In Mechanical Clock — Ariston NET Compatible
The E-Combi ONE includes a built-in 24-hour mechanical clock for basic heating and hot water scheduling without any external controls. It is also Ariston NET ready — the boiler can be connected to the Ariston NET wi-fi adapter (sold separately) to enable smartphone app control, remote diagnostics and energy monitoring, all without changing the boiler.
Built-in 24hr clockAriston NET readyApp upgradeable
Horizontal Flue Kit Included — Ready for Standard Installation
This package includes the Ariston Standard Horizontal Flue Kit (3318073), covering a typical straight-through external wall installation. The flue system uses 60/100mm coaxial (balanced flue) connections and is designed to minimise on-site cutting and adjustment. Extension kits are available separately for longer flue runs or non-standard configurations.
Horizontal flue kit included60/100mm coaxialEasy standard fit
IPX5D Electrical Protection — Bathroom Safe Siting
The E-Combi ONE carries an IPX5D electrical protection rating, meaning it is protected against water jets from any direction. This allows the boiler to be sited closer to wet areas than a standard IP20 appliance, providing more flexibility for bathroom or kitchen installations in compact properties.
IPX5D ratedSplash-proofFlexible siting
Technical Specifications
| Boiler | |
| Model | E-Combi ONE 24kW — Product Code 3301131 |
| Boiler Type | Condensing combi (heating + hot water, mains pressure) |
| ErP Rating (Heating) | A |
| Seasonal Efficiency (ηs) | ~90%+ seasonal space heating |
| Heat Output Max (CH) | 22 kW |
| Heat Output Max (DHW) | 26 kW |
| Modulation | Yes — with AUTO function |
| Heating | |
| Flow Temp Range (High Temp) | 35°C – 82°C |
| Flow Temp Range (Low Temp / UFH) | 20°C – 45°C |
| Domestic Hot Water | |
| DHW Flow Rate (ΔT 35°C) | 10.4 L/min |
| DHW Temp Range | 36°C – 60°C |
| DHW Pressure Min/Max | 0.2 / 7 bar |
| DHW Min Flow Rate | 2 L/min |
| Physical and Electrical | |
| Dimensions (H×W×D) | 735 × 400 × 299 mm (approx.) |
| Dry Weight | 29.3 kg |
| Electrical Supply | 230V / 50Hz |
| Electrical Protection | IPX5D |
| Flue and Gas | |
| Flue System | Balanced flue (room-sealed), 60/100mm coaxial |
| Flue Kit | Standard horizontal kit included (3318073) |
| Gas Types | Natural gas G20 / LPG (conversion kit included) |
| NOx Emissions | 53 mg/kWh |
| System | |
| Expansion Vessel | 8L built-in |
| Min Ambient Temp | 5°C |
| Servicing Clearances (top/front/bottom) | 300 / 450 / 250 mm |
| Servicing Clearances (left/right) | 5 / 5 mm |
| Included in Package | |
| Boiler | Ariston E-Combi ONE 24kW (3301131) |
| Flue Kit | Standard horizontal flue kit (3318073) |
| LPG Conversion Kit | Included as standard |
| Warranty | |
| Standard Warranty | 2 years |
| Extended Warranty | 5 years on registration within 30 days (via Ariston) |
| Installation Requirement | Gas Safe registered engineer |
| Manufacturer | Ariston Thermo UK Ltd, Milton Keynes |
Frequently Asked Questions
Related Products
Ariston E-Combi ONE 30kW with Horizontal Flue
Higher-output combi for larger homes and multiple bathrooms
Product Information
Product Information
Shipping & Returns
Shipping & Returns
Description
The Ariston E-Combi ONE 24kW condensing combi boiler is a compact, ErP A-rated gas boiler designed for UK homes with a single bathroom or moderate hot water demand. At the heart of the gas boiler is Ariston’s patented Xtratech™ stainless steel heat exchanger with 142% wider waterways for superior condensing efficiency and reduced blockage risk. The unique AUTO function continuously optimises boiler output to match real-time heating demand, reducing short-cycling and improving seasonal efficiency. Compact at 735 × 400 × 299 mm and weighing just 29.3 kg, it fits most standard boiler locations. Delivers up to 10.4 L/min of domestic hot water on demand. Supplied with standard horizontal flue kit and LPG conversion kit. Endorsed by the Energy Saving Trust. 2-year warranty, extendable to 5 years on registration.
24kW
Output
10.4 L/min
Hot Water
ErP A
Rated
29.3 kg
Weight
5-yr
Warranty
LPG Kit
Included
⚠ Gas Safe Installation Required: This boiler must be installed by a Gas Safe registered engineer. The installer must commission the boiler and complete the benchmark checklist. Annual service by a Gas Safe engineer is required to maintain the extended warranty.
Key Features
Xtratech™ Stainless Steel Heat Exchanger — 142% Wider Waterways
The heart of the E-Combi ONE is Ariston’s patented Xtratech™ single-coil stainless steel heat exchanger, designed with 142% wider waterways than previous generations. Wider channels reduce pressure drops, lower the risk of blockages from system debris, and provide a larger condensing surface for improved heat transfer. Stainless steel construction resists corrosion across a wide pH range, making the exchanger compatible with most system water conditions. It is easy to remove for cleaning or inspection. Tested and certified by TUV Rheinland.
Xtratech™ single coil142% wider waterwaysTUV Rheinland certified
ErP A Rated — Energy Saving Trust Endorsed
The E-Combi ONE holds an ErP A energy efficiency rating for seasonal space heating and is endorsed by the Energy Saving Trust — one of a small number of gas boilers on the market to achieve both. At 30% load (low-temperature return mode), efficiency reaches approximately 99%, meaning the boiler extracts almost all available energy from the gas during normal heating operation.
ErP A ratedEnergy Saving Trust endorsed~99% efficiency at part load
AUTO Function — Intelligent Load Optimisation
The unique AUTO function monitors and adapts the boiler’s operating parameters to match the actual thermal demand of the building in real time. Rather than cycling to a fixed setpoint, AUTO continuously optimises output between minimum and maximum, reducing short-cycling, lowering average flow temperature and improving seasonal efficiency. It is engaged from the boiler’s built-in controls and requires no additional accessories.
AUTO functionContinuous modulationReduces short-cycling
Natural Gas and LPG Compatible — LPG Conversion Kit Included
The E-Combi ONE is supplied as a natural gas boiler but includes an LPG conversion kit as standard, making it suitable for properties without a mains gas supply. Conversion is a straightforward procedure carried out by a Gas Safe registered engineer. No additional kit purchase is required, saving both cost and procurement time.
Natural gas + LPGLPG kit in the boxGas Safe conversion
Lightweight at 29.3 kg — Colour-Coded Connections for Fast Installation
Weighing just 29.3 kg dry, the E-Combi ONE is straightforward to wall-mount without heavy lifting equipment. Connection pipework uses colour-coded ports to reduce installation errors. All connections are in the same positions as previous Ariston boilers, enabling easy like-for-like retrofit without pipework modification. Minimum servicing clearances are just 5mm on left and right.
29.3 kgColour-coded connectionsEasy retrofit
Built-In Mechanical Clock — Ariston NET Compatible
The E-Combi ONE includes a built-in 24-hour mechanical clock for basic heating and hot water scheduling without any external controls. It is also Ariston NET ready — the boiler can be connected to the Ariston NET wi-fi adapter (sold separately) to enable smartphone app control, remote diagnostics and energy monitoring, all without changing the boiler.
Built-in 24hr clockAriston NET readyApp upgradeable
Horizontal Flue Kit Included — Ready for Standard Installation
This package includes the Ariston Standard Horizontal Flue Kit (3318073), covering a typical straight-through external wall installation. The flue system uses 60/100mm coaxial (balanced flue) connections and is designed to minimise on-site cutting and adjustment. Extension kits are available separately for longer flue runs or non-standard configurations.
Horizontal flue kit included60/100mm coaxialEasy standard fit
IPX5D Electrical Protection — Bathroom Safe Siting
The E-Combi ONE carries an IPX5D electrical protection rating, meaning it is protected against water jets from any direction. This allows the boiler to be sited closer to wet areas than a standard IP20 appliance, providing more flexibility for bathroom or kitchen installations in compact properties.
IPX5D ratedSplash-proofFlexible siting
Technical Specifications
| Boiler | |
| Model | E-Combi ONE 24kW — Product Code 3301131 |
| Boiler Type | Condensing combi (heating + hot water, mains pressure) |
| ErP Rating (Heating) | A |
| Seasonal Efficiency (ηs) | ~90%+ seasonal space heating |
| Heat Output Max (CH) | 22 kW |
| Heat Output Max (DHW) | 26 kW |
| Modulation | Yes — with AUTO function |
| Heating | |
| Flow Temp Range (High Temp) | 35°C – 82°C |
| Flow Temp Range (Low Temp / UFH) | 20°C – 45°C |
| Domestic Hot Water | |
| DHW Flow Rate (ΔT 35°C) | 10.4 L/min |
| DHW Temp Range | 36°C – 60°C |
| DHW Pressure Min/Max | 0.2 / 7 bar |
| DHW Min Flow Rate | 2 L/min |
| Physical and Electrical | |
| Dimensions (H×W×D) | 735 × 400 × 299 mm (approx.) |
| Dry Weight | 29.3 kg |
| Electrical Supply | 230V / 50Hz |
| Electrical Protection | IPX5D |
| Flue and Gas | |
| Flue System | Balanced flue (room-sealed), 60/100mm coaxial |
| Flue Kit | Standard horizontal kit included (3318073) |
| Gas Types | Natural gas G20 / LPG (conversion kit included) |
| NOx Emissions | 53 mg/kWh |
| System | |
| Expansion Vessel | 8L built-in |
| Min Ambient Temp | 5°C |
| Servicing Clearances (top/front/bottom) | 300 / 450 / 250 mm |
| Servicing Clearances (left/right) | 5 / 5 mm |
| Included in Package | |
| Boiler | Ariston E-Combi ONE 24kW (3301131) |
| Flue Kit | Standard horizontal flue kit (3318073) |
| LPG Conversion Kit | Included as standard |
| Warranty | |
| Standard Warranty | 2 years |
| Extended Warranty | 5 years on registration within 30 days (via Ariston) |
| Installation Requirement | Gas Safe registered engineer |
| Manufacturer | Ariston Thermo UK Ltd, Milton Keynes |
Frequently Asked Questions
Related Products
Ariston E-Combi ONE 30kW with Horizontal Flue
Higher-output combi for larger homes and multiple bathrooms
