The Ariston E-Combi ONE 24 kW Condensing Combi Gas Boiler (Part No. 3301131) with 5 Years Warranty paired with the 100mm Vertical Flue Kit (Part No. 3319235) and Vertical Starter (Part No. 3318079) is the correct installation pack for static caravans, holiday lodges, park homes, and leisure accommodation where the boiler must flue vertically through the roof. The 3319235 is not the standard domestic Ariston vertical flue kit — it uses a 100mm-diameter terminal specifically sized to fit the smaller roof penetrations and existing 100mm flashings already fitted for older Morco and Worcester Bosch boilers, making it the ideal drop-in replacement in the leisure sector without disturbing the roof structure. The boiler itself delivers 94% seasonal efficiency, a 1:7 modulation ratio, and Ariston's patented XtraTech™ stainless steel heat exchanger — proven technology in a lightweight 29.3 kg package well suited to the space constraints of holiday home plant rooms.
1240 mm
Total Flue Kit Length
575 mm
Usable Flue Length
⚠ 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, current Building Regulations, and BS 5440-1:2008. This applies equally to holiday homes, park homes, and leisure properties as to permanent dwellings.
⚠ Not the Standard Domestic Flue Kit — 100mm Terminal Only: The 3319235 uses a 100mm-diameter roof terminal, compared to the 125mm terminal on the standard Ariston domestic vertical flue kits (3318080 / 3318081). These are not interchangeable. If your installation uses a standard domestic 125mm flashing or a full-sized pitched-roof plate, you need the 3318080 or 3318081 kit instead. The 3319235 is correct only where a 100mm terminal opening is already present or where a compact 100mm flashing will be fitted.
ℹ What's Included in This Pack:
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Ariston E-Combi ONE 24 kW Combi Boiler — Part No. 3301131
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Vertical Starter — Part No. 3318079 (clamps to boiler exhaust manifold; push-fit to flue kit above)
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Vertical Flue Kit — 100mm Black Terminal — Part No. 3319235 (Ø60/100 concentric, 1240 mm total, 575 mm usable)
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LPG Conversion Kit — included as standard (essential for bottled-gas holiday home sites)
Not included: Roof flashing / terminal cowl (must suit your existing 100mm roof penetration), flue support brackets (3318015 recommended per extension), and any additional extension pipes if the ceiling height requires them.
⚠ Flashing Compatibility — Measure Before Ordering: This kit is designed to pass through an existing 100mm-diameter roof flashing — the type commonly found on static caravans previously fitted with Morco or Worcester Bosch boilers. If your site has a larger aperture, or no flashing is currently fitted, a suitable 100mm cowl or flashing must be sourced separately. Do not attempt to fit this terminal into a 125mm flashing — the smaller terminal will not seal correctly in the larger opening.
100mm Terminal — Legacy Flashing Compatible
The 3319235 uses a 100mm-diameter terminal — specifically designed for the leisure boiler market where older Morco and Worcester Bosch installations left 100mm roof penetrations. Replacing a failed leisure boiler with this pack avoids any roof or ceiling work, making changeover significantly faster and lower-cost on a managed holiday park.
XtraTech™ Stainless Steel Heat Exchanger
Ariston's patented single-coil XtraTech™ stainless steel heat exchanger features wider waterways than conventional copper alternatives, resisting limescale accumulation and improving long-term reliability — important in holiday home applications where boilers may sit dormant for extended periods between letting seasons.
LPG Ready — Bottled Gas Site Compatible
An LPG conversion kit is included as standard in every E-Combi ONE box. Most holiday parks and static caravan sites operate on bottled LPG (propane / G31) rather than mains natural gas — the conversion is carried out at commissioning by the Gas Safe engineer, with no additional parts required.
AUTO Function — Efficiency Without User Input
The AUTO function continuously monitors system behaviour and automatically adjusts boiler output and pump speed to match actual heating demand. In holiday home use, where occupancy patterns vary from full-time residence, this prevents energy waste during partial-occupancy periods without requiring guests or owners to manually adjust settings.
Compact & Lightweight — 29.3 kg, 315 mm Deep
At 29.3 kg and only 315 mm deep, the E-Combi ONE fits comfortably in the restricted plant spaces typical of static caravans, park home utility cupboards, and lodge boiler housings. All connection points match previous Ariston models for straightforward like-for-like replacement without re-routing pipework.
1:7 Modulation — Quiet, Efficient Part-Load
A 1:7 modulation ratio lets the boiler throttle back to around 3.1 kW minimum output, avoiding the short-cycling and noise that on/off boilers produce in smaller, well-insulated spaces. At 49 dB (Band XL), it is one of the quieter options in its class — a meaningful benefit in thin-walled leisure accommodation where mechanical noise carries easily.
| Technical Specifications — E-Combi ONE 24 kW (3301131) |
| Parameter |
Value |
| Boiler Part Number |
3301131 |
| ErP Energy Rating |
A / A (Heating / DHW) |
| Seasonal Space Heating Efficiency |
94% |
| Water Heating Energy Efficiency |
83% |
| SAP 2009/2012 Efficiency |
89.4% |
| CH Heat Output (Max) |
22 kW |
| DHW Heat Output (Max) |
26 kW |
| DHW Flow Rate ΔT 35°C |
10.4 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 |
| Min DHW Flow Rate |
2 l/min |
| DHW Pressure Min / Max |
0.2 / 7.0 bar |
| Built-in Expansion Vessel |
8 litres |
| Noise Level |
49 dB / Band XL |
| NOx Emissions |
53 mg/kWh |
| Boiler Weight |
29.3 kg |
| Dimensions H × W × D |
745 × 400 × 315 mm |
| Servicing Clearances — Top / Front / Bottom |
300 / 450 / 250 mm |
| Servicing Clearances — Left / Right |
5 / 5 mm |
| Electrical Supply |
230 V / 50 Hz |
| IP Rating |
IPX5D |
| Gas Types Supported |
Natural gas (G20) and LPG propane (G31) — LPG kit included |
| 100mm Vertical Flue Kit Specifications (3319235 + 3318079) |
| Flue Terminal Part No. |
3319235 — 100mm Black Terminal (Caravan & Leisure) |
| Vertical Starter Part No. |
3318079 |
| Flue Pipe Diameter |
Ø60/100 mm coaxial (concentric exhaust / air intake) |
| Terminal Diameter |
100 mm — fits existing Morco & Worcester Bosch legacy flashings |
| Total Flue Kit Length |
1240 mm |
| Usable Flue Length |
575 mm (varies with flashing type fitted) |
| Max Vertical Flue Run — 24 kW on Ø60/100 |
8 metres total (see installation manual for elbow deductions) |
| Connection Type |
Push-fit with lip seal throughout — no clamps required on flue joints |
| Standard Domestic Equivalent |
3318080 (black, 125mm terminal) / 3318081 (red, 125mm terminal) — not this kit
|
| Roof Flashing |
Not included — must suit existing 100mm roof penetration; do not use 125mm domestic flashings |
Frequently Asked Questions
Why is the 3319235 different from the standard Ariston vertical flue kit?
The standard Ariston domestic vertical flue kits — 3318080 (black terminal) and 3318081 (red terminal) — both use a 125mm-diameter terminal designed for conventional domestic roof flashings. The 3319235 uses a 100mm terminal specifically for the leisure and holiday home market, where boilers are typically installed in static caravans and park homes that were previously fitted with Morco or Worcester Bosch boilers using 100mm roof penetrations. Swapping to this kit avoids disturbing the existing roof flashing — a significant practical and cost advantage on managed holiday parks where minimal structural disruption per unit is essential.
Does the 3319235 kit include the Vertical Starter (3318079)?
The 3318079 Vertical Starter is included in this pack. It is a mandatory component — without it the flue terminal cannot connect to the boiler's exhaust manifold. The starter clamps to the boiler and provides the push-fit socket into which the 3319235 flue kit inserts above.
Can I use this kit if there is no existing flashing — for example in a new-build lodge?
Yes, provided you fit a suitable 100mm roof cowl or flashing appropriate to your roof construction and pitch. Because the 3319235 uses a non-standard 100mm terminal, standard Ariston domestic pitched-roof flashings (3318009 / 3318010) will not seal correctly — these are sized for the 125mm terminal. Source a 100mm cowl or flashing compatible with your roof material from a leisure/caravan specialist or roofing supplier. Always ensure the penetration is fully weatherproofed before commissioning.
Can I extend the vertical run if the kit is too short for my ceiling height?
Yes. Standard Ariston Ø60/100 coaxial extension pipes — 500mm (3318078) or 1000mm (3318077) — can be inserted between the vertical starter and the 3319235 flue kit to increase the total height. The maximum permissible vertical run for the E-Combi ONE 24 kW on Ø60/100 is 8 metres. Each 90° elbow (3318075) deducts from this maximum — check the installation manual for exact deduction figures. Do not cut the 3319235 terminal kit itself.
Does the boiler work on LPG for sites without mains gas?
Yes. An LPG conversion kit is included as standard in the E-Combi ONE box. The conversion to LPG propane (G31) is carried out at commissioning by the Gas Safe engineer — no additional parts need to be purchased. This makes the pack directly suitable for holiday parks and caravan sites supplied by bulk LPG tanks or cylinder manifolds.
Is the E-Combi ONE suitable for frost protection during the off-season?
The E-Combi ONE includes an integrated anti-frost device that activates the burner and pump automatically if the boiler's internal temperature drops to a critical level. However, this only protects the boiler itself — it does not protect external pipework, the wider heating system, or unheated spaces within the property. For holiday homes left unoccupied in winter, full system drain-down or a dedicated site-wide frost protection strategy is still recommended.
