The Ariston E-Combi ONE Condensing Combi Gas Boiler is available in 24 kW (Part No. 3301131) and 30 kW (Part No. 3301132) outputs, supplied here as boiler only — no flue kit included. This option is intended for replacement installations where the existing flue system is in serviceable condition and will be reused, or for new builds where the flue is supplied and specified separately by the main contractor. Both models share Ariston's patented XtraTech™ stainless steel heat exchanger, 94% seasonal efficiency, A/A ErP energy rating, and 1:7 modulation ratio. LPG conversion kits and wall brackets are included as standard in both boxes. The E-Combi ONE range is compatible with Ariston's full HE Ø60/100 and Ø80/125 coaxial flue accessory range and with Ariston NET smart controls.
LPG Kit
Included as Standard
29.3 / 31.9 kg
Weight 24 kW / 30 kW
⚠ Gas Safe Registered Installer Required: This boiler must be installed and commissioned by a Gas Safe registered engineer in accordance with the Gas Safety (Installation and Use) Regulations 1998 and current Building Regulations. A compliant flue must be fitted — this listing does not include one.
⚠ Flue Not Included — Must Be Ordered Separately: This boiler cannot operate without a correctly specified flue system. The E-Combi ONE uses the
Ariston HE Ø60/100 coaxial flue range. Standard options:
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Horizontal through-wall: 3318073 Horizontal Coaxial Kit (1000mm)
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Horizontal + vertical option for installer: 3318074 Horizontal Kit + Vertical Starter bundle
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Vertical domestic (125mm terminal): 3318079 Starter + 3318080 (black) or 3318081 (red) flue kit
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Vertical leisure/caravan (100mm terminal): 3318079 Starter + 3319235 flue kit
ℹ What's in the Box — Both Models: LPG conversion kit, wall mounting bracket, tap kit (filling loop), installation manual, and Benchmark commissioning checklist. No flue components are included.
XtraTech™ Stainless Steel Heat Exchanger
Ariston's patented single-coil XtraTech™ stainless steel heat exchanger uses wider waterways than conventional copper alternatives to resist limescale build-up and improve thermal transfer over the boiler's service life. Performance independently certified by TÜV Rheinland.
AUTO Function — Intelligent Efficiency
The AUTO function continuously analyses system thermal behaviour and automatically adjusts boiler output and pump speed to match real demand — reducing short-cycling and preventing energy waste during mild weather, without requiring the householder to intervene.
1:7 Modulation — Low Minimum Output
A 1:7 modulation ratio lets the boiler throttle back to approximately 3.1 kW (24 kW) or 4.3 kW (30 kW) minimum output. This avoids the short-cycling and associated heat exchanger stress that fixed-output boilers produce in well-insulated smaller properties.
Ariston NET Compatible
Although neither model includes built-in Wi-Fi, both are Ariston NET compatible. Adding the Cube S Net wired thermostat (3319126) or the Cube RF wireless controller enables full remote control and scheduling via the Ariston NET app without any hardware changes to the boiler.
Compact & Lightweight — Easy Retrofit
The 24 kW weighs just 29.3 kg at 315 mm deep; the 30 kW 31.9 kg at 385 mm deep. Pipework connections align with previous Ariston models, minimising re-routing time on like-for-like replacements where the existing flue is being retained.
LPG Ready Out of the Box
An LPG conversion kit is included as standard in both models. The Gas Safe engineer converts to propane (G31) at commissioning with no additional parts. This makes both models equally suitable for off-grid and rural properties on bottled or bulk LPG.
| Parameter |
E-Combi ONE 24 kW |
E-Combi ONE 30 kW |
| Part Number |
3301131 |
3301132 |
| ErP Rating |
A / A (Heating / DHW) |
| Seasonal Space Heating Efficiency |
94% |
| SAP 2009/2012 Efficiency |
89.4% |
| CH Heat Output (Max) |
22 kW |
28 kW |
| DHW Heat Output (Max) |
26 kW |
30 kW |
| DHW Flow Rate ΔT 35°C |
10.4 l/min |
12.5 l/min |
| CH Temperature Range (High) |
35 – 82°C |
| CH Temperature Range (Low / UFH) |
20 – 45°C |
| DHW Temperature Range |
36 – 60°C |
| Modulation Ratio |
1:7 |
| DHW Pressure Min / Max |
0.2 / 7.0 bar |
| Built-in Expansion Vessel |
8 litres |
| Noise Level |
49 dB / Band XL |
51 dB / Band XL |
| NOx Emissions |
53 mg/kWh |
51 mg/kWh |
| Weight |
29.3 kg |
31.9 kg |
| Dimensions H × W × D |
745 × 400 × 315 mm |
745 × 400 × 385 mm |
| Servicing Clearances T / F / Bo |
300 / 450 / 250 mm |
| Servicing Clearances L / R |
5 / 5 mm |
| Electrical Supply |
230 V / 50 Hz |
| IP Rating |
IPX5D |
| Gas Types |
Natural gas G20 and LPG propane G31 (conversion kit included) |
| Max Vertical Flue Run (Ø60/100) |
8 m |
7 m |
Frequently Asked Questions
Which flue kit do I need for the E-Combi ONE?
The E-Combi ONE uses the Ariston HE Ø60/100 coaxial flue system. The standard horizontal kit is 3318073 (1000mm); for vertical installations you need the 3318079 Vertical Starter plus one of: 3318080 (125mm black terminal), 3318081 (125mm red terminal), or 3319235 (100mm leisure/caravan terminal). The SE flue accessories (3318003–3318006, 3319648) are not compatible — these are for the Next Evo X water heater range only.
Can I reuse my existing flue on a like-for-like swap?
In many cases yes — this is the primary reason to order the boiler only. If the existing flue uses the Ariston HE Ø60/100 coaxial system, and the Gas Safe engineer inspects it as undamaged and correctly routed, it can typically be reused with the E-Combi ONE. If the previous boiler was a different brand or used a different flue diameter or type, a new flue must be specified and ordered separately.
Which output should I choose — 24 kW or 30 kW?
The practical difference is DHW flow rate: 10.4 l/min at 24 kW versus 12.5 l/min at 30 kW. For a single-bathroom property with up to 10 radiators, the 24 kW is appropriate. For properties with two bathrooms or higher simultaneous hot water demand, the 30 kW is the better choice. A heat loss calculation by the Gas Safe engineer is the only reliable method for confirming the correct output for a specific property.
Is a Boiler Plus-compliant control required?
Yes. For new boiler installations in England, Boiler Plus (Building Regulations Part L) requires a time and temperature zone control plus at least one of: a weather or load compensator, smart thermostat with automation, or flue gas heat recovery. The E-Combi ONE does not include controls in the box — a compatible thermostat such as the Cube S Net (3319126) or Cube RF must be specified to satisfy Boiler Plus. Neither is included in this listing.
Does the boiler come with anything to fulfil the hot water circuit connection?
Yes — a tap kit (filling loop) and wall mounting bracket are included in the box along with the LPG conversion kit. Compression fittings for the 22mm CH flow and return and 15mm gas inlet are required but not supplied — these are standard site materials.
