Vaillant ecoFit pure
The Vaillant ecoFit pure is the brand's more affordable range, aimed at straightforward combi and system replacements.
At a glance
- Configurations: Combi, System
- Best suited to: Cost-conscious combi and system replacements in small to medium homes
- Fuel: Mains natural gas (some variants are LPG-convertible, check the manufacturer’s data).
Specifications
Match the badge in front of you to a row before you use any of this. Every figure below was read from the Vaillant literature listed under Sources at the foot of this page, checked 6 September 2026. Outputs, variants and part numbers change by year, so the appliance data plate is still the last word.
| Variant | Output | Hot water flow rate | GC number |
|---|---|---|---|
| ecoFit pure 825 combi (VUW 256/6-3) | 25kW | 10.4 l/min at a 35 K rise | 47-044-68 |
| ecoFit pure 830 combi (VUW 306/6-3) | 30kW | 12.2 l/min at a 35 K rise | 47-044-74 |
| ecoFit pure 835 combi (VUW 356/6-3) | 35kW | 14.1 l/min at a 35 K rise | 47-044-70 |
| ecoFit pure 612 system (VU 126/6-3) | 41-694-03 | ||
| ecoFit pure 615 system (VU 156/6-3) | 41-694-04 | ||
| ecoFit pure 618 system (VU 186/6-3) | 41-694-05 | ||
| ecoFit pure 625 system (VU 256/6-3) | 41-694-06 | ||
| ecoFit pure 630 system (VU 306/6-3) | 41-694-07 |
Case size: 700 x 390 x 295 mm (combi). Weight: 32 to 33 kg dry (combi).
- Vaillant also quotes a specific flow rate at a 30 K rise, which is the headline number on the brochures: 12.1, 14.2 and 16.5 l/min for the 825, 830 and 835.
- The factory flow limiter is set to 8.0 l/min on the 825, 10.0 on the 830 and 12.0 on the 835, so that is nearer what a tap will give than the brochure figure.
- Vaillant does not publish combi outputs alongside the ecoFit pure system boilers, so take the kW for a 612 to 630 from the plate rather than the model number.
- Guarantee is 2 years as standard, up to 10 through a myREWARDS installer with a protection kit.
Where the data plate is
Data plate on the underside of the boiler, which is where the GC number is printed as GC no. The serial number is on a plastic plate at the bottom of the front casing.
Reading the plate
Worth knowing on site
- Positioned below the ecoTEC plus as a value option.
- Confirm the configuration and output from the data plate before quoting a swap.
On the tools
Because it is positioned as Vaillant's value option, the ecoFit pure is commonly specified where a straightforward, cost-conscious replacement is the priority over the smart controls of the ecoTEC family. Engineers often meet it on simple combi-for-combi or system-for-system swaps.
Variants and configuration
It is offered in combi and system form only, without the regular option available on the ecoTEC plus, so the ecoFit pure covers a narrower slice of installation types. Confirm the exact configuration and output from the data plate before quoting a swap.
Where it sits in the range
The ecoFit pure sits below the ecoTEC plus in Vaillant's current UK line-up, giving the brand an entry point for customers prioritising price over the smart-control features found higher up the range. It is commonly the range fitted when a straightforward budget swap, rather than a system upgrade, is what's been asked for.
Finding the manual and the data plate
For the exact outputs, gas rate, dimensions and commissioning figures, work from the appliance’s data plate and the manufacturer’s installation and servicing instructions. The GC (Gas Council) number and serial are on the data plate, usually behind the front panel or on the underside. Vaillantpublishes its manuals and support at Vaillant support.
Frequently asked
Useful while you’re on the tools
More from Vaillant
Manifold is not affiliated with or endorsed by Vaillant. Brand and model names are used only to help engineers find the right resources. Specifications and available variants change by year and model, so always work from the appliance’s data plate and the manufacturer’s own installation and servicing manual. Gas work must be carried out by an appropriately Gas Safe registered engineer.