The Ariston Horizontal Coaxial Kit + Vertical Starter (Part No. 3318074) is the standard dual-option flue bundle for Ariston HE condensing boilers, combining the 3318073 Horizontal Coaxial Kit (1000mm) and the 3318079 Vertical Starter in a single box. It is listed in Ariston's own range as the primary flue accessory for the E-Combi ONE, Clas ONE, Clas System ONE, Genus ONE, Alteas ONE, and Alteas ONE+ NET — the complete HE ONE Series. Buying the bundle gives the installer the horizontal terminal ready for immediate through-wall installation, while the vertical starter is available on the same job if the final flue route requires a vertical exit instead — without a second parts order. The Ø60/100 mm coaxial system handles both combustion gas exhaust and fresh combustion air intake in a single concentric pipe, in line with BS 5440-1:2008 for room-sealed appliances.
3318073
Horizontal Kit — Included
3318079
Vertical Starter — Included
1000 mm
Horizontal Kit Length
HE Range
Boiler Compatibility
⚠ Gas Safe Registered Installer Required: Flue installation must be carried out by a Gas Safe registered engineer in compliance with current Gas Safety Regulations, Building Regulations, and BS 5440-1:2008. All terminal positions must observe the required clearances from openings, gutters, and other obstructions as specified in the boiler installation manual.
⚠ Vertical Flue Terminal Kit Not Included: The 3318074 bundle includes the
vertical starter (3318079) but not the vertical flue terminal kit. For a vertical installation, the correct vertical flue terminal kit must also be purchased:
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3318080 — Vertical Flue with Black Terminal (125mm, domestic HE)
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3318081 — Vertical Flue with Red Terminal (125mm, domestic HE)
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3319235 — Vertical Flue with Black Terminal (100mm, leisure/caravan only)
ℹ What's Included in 3318074:
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Horizontal Coaxial Kit (3318073) — Ø60/100, 1000mm length, push-fit horizontal wall terminal with weather cap, clamp, and seals
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Vertical Starter (3318079) — boiler manifold clamp adaptor with push-fit Ø60/100 socket for vertical flue kits
Extensions, elbows, and vertical terminal kits are all available separately in the HE Ø60/100 accessory range.
Both Flue Routes in One Order
The 3318074 is particularly useful for installers working across multiple jobs — the horizontal kit covers the most common route while the vertical starter is available if needed without a return trip to the merchant. On multi-unit developments or managed holiday parks where some units route horizontally and others vertically, a single order covers both scenarios.
Official Ariston HE Standard Flue
Listed directly in Ariston's UK product range catalogue as the standard flue accessory for the entire HE ONE Series — E-Combi ONE, Clas ONE, Genus ONE, Alteas ONE. This is the Ariston-recommended starting point for any HE condensing boiler installation, used across Ariston's own authorised installer network.
Extendable with HE Accessories
The 1000mm horizontal kit accommodates most standard wall thicknesses and simple straight runs. For longer or more complex routes, the full HE Ø60/100 accessory range extends it: 3318077 (1m extension), 3318078 (500mm extension), 3318075 (90° elbow), 3318076 (45° bend pair). Maximum permissible run varies by boiler output — refer to the installation manual.
| Specifications — 3318074 Horizontal Coaxial Kit + Vertical Starter |
| Part Number |
3318074 |
| Contents |
Horizontal Coaxial Kit 3318073 (1000mm) + Vertical Starter 3318079 |
| Flue System |
HE Ø60/100 mm coaxial (not SE — see compatibility note) |
| Horizontal Kit Length |
1000 mm |
| Connection Type |
Push-fit with lip seal throughout — no clamps required on flue joints |
| Vertical Terminal Kit Included |
No — order 3318080 (125mm black), 3318081 (125mm red) or 3319235 (100mm leisure) separately |
| Compatible Boiler Ranges |
E-Combi ONE 24/30, Clas ONE 24/30/38, Clas System ONE, Genus ONE+ Wi-Fi, Alteas ONE, Alteas ONE+ NET, E-System ONE |
| Not Compatible With |
Next Evo X gas water heaters — use SE system kit 3319648 instead |
| HE Extension Accessories |
3318077 (1m), 3318078 (500mm), 3318075 (90° elbow), 3318076 (45° bend pair x2), 3318465 (2m) |
Frequently Asked Questions
What is the practical benefit of the 3318074 bundle over buying 3318073 and 3318079 separately?
Convenience and cost — the bundle prices both components together and ensures they arrive in the same delivery. For installers visiting a property where the final flue route hasn't been confirmed, having both the horizontal kit and the vertical starter avoids a wasted journey. The 3318074 is the product Ariston lists as the standard flue for this boiler range in their own literature.
Can I use the 3318073 horizontal kit from this bundle for a vertical installation?
No — the 3318073 horizontal kit is a horizontal-only through-wall terminal. For a vertical installation, the 3318079 Vertical Starter (also in this bundle) is used with one of the vertical flue terminal kits (3318080, 3318081, or 3319235). The horizontal kit remains unused in a vertical-only installation — in that case, ordering the 3318079 alone is more economical.
What is the maximum horizontal flue run for the E-Combi ONE 24 kW and 30 kW on Ø60/100?
Based on the Ariston flues data sheet: 8 metres for the 24 kW model and 7 metres for the 30 kW model. Each 90° elbow (3318075) and each pair of 45° bends (3318076) reduce this maximum — refer to the installation manual for the specific deductions. If the run exceeds these limits, upgrading to the Ø80/125 coaxial system (up to 33 m at 24 kW, 24 m at 30 kW) is the appropriate solution.
Is there a silver version to match the Alteas ONE+ NET?
Yes. For the Alteas ONE+ NET where visible flue pipework should match the boiler's silver aesthetic, the silver horizontal kit is Part No. 3319163 and the silver vertical starter is Part No. 3319167. These are mechanically identical to their grey counterparts; the difference is colour only. A silver bundle equivalent to the 3318074 is not listed separately — order 3319163 and 3319167 individually.
Does this bundle work with the Next Evo X gas water heater?
No. The 3318074 is an HE system bundle for Ariston condensing boilers only. The Next Evo X uses the SE flue system — the correct horizontal kit for those appliances is the 3319648. Do not fit HE flue accessories to SE appliances or vice versa.
