The Baxi MainEco Compact System 18 is the higher-output version of Baxi’s cupboard-fit system boiler: 18kW to the heating circuit for larger homes running a hot water cylinder. Front access to every component, a central top flue and a pipes-behind facility in the 700 × 390 × 285mm casing, at a 28kg lift weight.
Main is now Main by Baxi. Same boiler, same sales code (7714606), now sold under the Baxi brand.
18kW system boilerErP A-ratedNOx class 6Cupboard fitFront access5-year warranty
51 dB(A)
Sound power level
5 years
Parts & labour warranty*
Applications & suitability
Where it goes
A medium to larger home on mains gas with two or more bathrooms, feeding a hot water cylinder on a sealed system.
Typical job
Replacing a system boiler on an existing cylinder installation where the 15kW would run short on radiator load.
Works with / replaces
Runs unvented or vented hot water cylinders and accepts the Baxi Multifit pre-plumb jig; the pipes-behind facility tidies swaps where pipework rises behind the boiler.
When not to choose this
No cylinder, no hot water — this boiler does not produce hot water on its own. For a one-bathroom home without cylinder space, the MainEco Compact Combi is the better fit.
Key specifications
| Identity |
| Brand |
Baxi |
| Model |
MainEco Compact System 18 |
| Boiler type |
System |
| Fuel |
Natural gas |
| Performance |
| Output (central heating) |
18 kW |
| Seasonal space heating energy efficiency |
93% |
| NOx class |
6 |
| Sound power level |
51 dB(A) |
| Physical |
| Dimensions (H × W × D) |
700 × 390 × 285 mm |
| Weight |
28 kg |
| Flue type |
Concentric 60/100 mm |
| Hydraulic & electrical |
| Integral expansion vessel |
7 litres |
| Electrical supply |
230 V / 50 Hz |
| Warranty |
5 years (registration required) |
Installation & compatibility
This is a gas appliance: installation, commissioning and servicing must be carried out by a Gas Safe registered engineer. A hot water cylinder and system controls are required and are not supplied. *The 5-year parts and labour warranty applies subject to registration with Baxi after installation.
Related products
Baxi MainEco Compact System 15
The 15kW output for smaller homes with lower heat loss.
View 15kW System
Baxi MainEco Compact 30kW Combi
Heating and instant hot water from one unit, no cylinder.
View 30kW Combi
Ideal for
Larger multi-bathroom homes on a cylinder system, and installers who want front access and pipes-behind flexibility on the swap. Next-day delivery nationwide or click & collect from our Reading trade counter.
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