Assess First. Recommend Second.
Six regular-boiler output labels with a separate cylinder and external system components.
Six regular-boiler output labels with a separate cylinder and external system components.
CH means central heating; DHW means domestic hot water. Heating ratings use flow/return water temperatures, not a whole-house sizing formula. Natural-gas figures are shown; no LPG rating is inferred. A cylinder-reheat rating is not instantaneous hot-water delivery.
| Model / label | CH min–max at 80/60°C | CH max at 50/30°C | Cylinder-reheat maximum | DHW flow at 35°C rise |
|---|---|---|---|---|
| ecoFIT pure Open Vent 412 · 12 kW | 4.5–12.2 kW | 12.8 kW | Not separately specified | Separate cylinder; no instantaneous rating |
| ecoFIT pure Open Vent 415 · 15 kW | 4.5–15.2 kW | 15.9 kW | Not separately specified | Separate cylinder; no instantaneous rating |
| ecoFIT pure Open Vent 418 · 18 kW | 5–18.3 kW | 19.1 kW | Not separately specified | Separate cylinder; no instantaneous rating |
| ecoFIT pure Open Vent 425 · 25 kW | 6.1–25.4 kW | 26.5 kW | Not separately specified | Separate cylinder; no instantaneous rating |
| ecoFIT pure Open Vent 430 · 30 kW | 7.1–30.2 kW | 31.8 kW | Not separately specified | Separate cylinder; no instantaneous rating |
| ecoFIT pure Open Vent 435 · 35 kW | 7.2–34.8 kW | 35.8 kW | Not separately specified | Separate cylinder; no instantaneous rating |
The shorter heat-only casing and aluminium heat exchanger distinguish this configuration from the ecoFIT pure combi and system versions. Top/rear flue options help with assessed siting.
Do not confuse the pure 425 / 25 kW with the ecoTEC plus 424 / 24 kW. Each belongs to a different family with its own ratings.
2-year standard guarantee; up to 10 years for an eligible myREWARDS installation registered with the Boiler Protection Kit or Advanced Boiler Protection Kit. Registration within the manufacturer deadline, correct commissioning, system-water preparation and annual servicing are required. Installer status, eligible protection kit/filter and current manufacturer terms must be confirmed in your written quotation; maximum cover is not automatic. SwiftHeat accreditation is not asserted here.
Keep commissioning, registration and annual-service records. Any extension or paid upgrade is confirmed before purchase and remains subject to current manufacturer terms.
Manufacturer guarantee information for this rangeVaillant offers eBUS controls and connected-control options. The exact boiler generation, control, gateway, wiring and system accessories must be checked together during assessment; no universal thermostat compatibility is promised.
Manufacturer casing dimensions: 602 × 375 × 295 mm (H × W × D). Working and service clearances are additional.
SwiftHeat assesses fuel, heat loss, hot-water demand, system condition, flue and condensate routing, controls and access before confirming suitability. Assess First. Recommend Second.
The table separates the manufacturer model label from heating output at 80/60°C, the condensing heating maximum at 50/30°C and any verified DHW or cylinder-reheat rating. Missing figures remain unverified; labels are not substituted for technical ratings.
2-year standard guarantee; up to 10 years for an eligible myREWARDS installation registered with the Boiler Protection Kit or Advanced Boiler Protection Kit. Registration within the manufacturer deadline, correct commissioning, system-water preparation and annual servicing are required. Installer status, eligible protection kit/filter and current manufacturer terms must be confirmed in your written quotation; maximum cover is not automatic. SwiftHeat accreditation is not asserted here.
Do not confuse the pure 425 / 25 kW with the ecoTEC plus 424 / 24 kW. Each belongs to a different family with its own ratings. Suitability depends on the property’s calculated heating and hot-water requirements and must be confirmed following assessment.
Checked 2 October 2026. Product generation, availability and terms are reconfirmed when preparing your quotation.
The installed price for your selected boiler is confirmed after assessment. The quotation covers the appliance, controls, flue, system preparation and any required pipework. A conversion or relocation can have a different scope from a straightforward replacement.
New boiler installations from £1,790 inc. VAT apply to a qualifying standard, straightforward replacement: one bathroom, fewer than 10 radiators and a standard horizontal flue, subject to survey. Specification and warranty selection affect the final cost. This is a general starting offer and is not a price for every model in this catalogue.
Read the starting-package conditions0% options over 3, 6, 9 or 12 months through Humm Group Limited, subject to application, affordability, eligibility, approval and provider terms. Any applicable deposit, fees and repayment conditions are confirmed during your enquiry/application. Acceptance is not guaranteed.
Finance terms and chargesTwo free annual services and a Hive Mini are available on qualifying installations only. Every model is considered under the qualification rules; inclusion in this catalogue does not confirm eligibility. Ask us to confirm the offer in your quotation.
Ask about Care+ eligibilityPlan the maintenance your appliance requires and keep its service records. If you are considering replacement because of a fault, diagnosis can help establish whether repair is a suitable option first.
Boiler servicing · Repair advicePrice confirmed following assessment for this configuration. The general New boiler installations from £1,790 inc. VAT offer does not apply to every model or property.
From or indicative prices remain provisional. SwiftHeat issues a written fixed quotation for the agreed scope after the appropriate property and installation assessment, technical checks and warranty-package verification. Remote information gathering may be suitable initially; a home survey is required where the necessary checks cannot be completed remotely.
We assess heat loss, heating and hot-water requirements, water supply, controls and installation access before recommending an appliance. Bedroom count or a catalogue model number alone cannot establish the right boiler.
Gas Safe registration 978273 · Serving Cardiff, South Wales and across the UK.
Understand suitable boiler types · Start the Boiler Finder · Our installation assessment · Areas we cover
