Vaillant Ecofit Pure 425 Boiler Instruction Manual
Vaillant Ecofit Pure 425 Boiler
Vaillant Ecofit Pure 425 Boiler Instructions
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Vaillant Ecofit Pure 425 Boiler Specifications
| Category | Specification | Value |
|---|---|---|
| Heating Data | ||
| Max. Flow Temperature Adj. Range | Default: 75 °C | 10 … 80 ℃ |
| Maximum Permissible Pressure | 0.3 MPa (3.0 bar) | |
| Nominal Water Flow (ΔT = 20 K) | 1,094 l/h | |
| Nominal Water Flow (ΔT = 30 K) | 729 l/h | |
| Approx. Condensate Volume (50/30 °C) | pH value between 3.5 and 4.0 | 2.55 l/h |
| G20 Power/Loading Data | ||
| Maximum Heat Output (P) | 25 kW | |
| Effective Output Range (P) at 40/30 °C | 6.5 … 27.0 kW | |
| Effective Output Range (P) at 50/30 °C | 6.4 … 26.5 kW | |
| Effective Output Range (P) at 80/60 °C | 6.1 … 25.4 kW | |
| Domestic Hot Water Heat Output (P) | 6.0 … 30.0 kW | |
| Maximum Heat Input – Heating (Q max.) | 25.5 kW | |
| Minimum Heat Input – Heating (Q min.) | 6.1 kW | |
| Maximum Heat Input – Hot Water (Q max.) | 30.6 kW | |
| Minimum Heat Input – Hot Water (Q min.) | 6.1 kW | |
| General Data | ||
| Gas Category | I2H | |
| Gas Pipe Diameter | 1/2 inch | |
| Heating Connections Diameter | 3/4 inch | |
| Expansion Relief Valve Connector (min.) | 15 mm | |
| Condensate Drain Pipework (min.) | 21.5 mm | |
| G20 Gas Supply Pressure | 2.0 kPa (20.0 mbar) | |
| Gas Flow at P max. – Hot Water (G20) | 3.2 m³/h | |
| Gas Flow at P max. – Heating Mode (G20) | 2.7 m³/h | |
| Gas Flow at P min. (G20) | 0.648 m³/h | |
| CE Number (PIN) | CE-0063CP3646 | |
| Flue Gas Mass Rate (Heating Mode, P min.) | 2.81 g/s | |
| Flue Gas Mass Rate (Heating Mode, P max.) | 11.5 g/s | |
| Flue Gas Mass Rate (Hot Water, P max.) | 13.8 g/s | |
| Flue Gas Temperature (80/60 °C, P max.) | 77 °C | |
| Flue Gas Temperature (80/60 °C, P min.) | 55 °C | |
| Flue Gas Temperature (50/30 °C, P max.) | 62 °C | |
| Flue Gas Temperature (50/30 °C, P min.) | 35 °C | |
| Flue Gas Temperature (Hot Water Mode) | 68 °C | |
| Flue Gas Temperature (Overheating) | 95 °C | |
| Released System Types | C13, C33, C43, C53 | |
| Nominal Efficiency at 80/60 °C | 98.8 % | |
| Nominal Efficiency at 50/30 °C | 104.0 % | |
| Nominal Efficiency at 40/30 °C | 106.0 % | |
| Nominal Efficiency (Partial Load 30%) at 40/30 °C | 109.7 % | |
| NOx Class | 5 | |
| Product Dimensions (Width x Depth x Height) | 375 mm x 295 mm x 602 mm | |
| Net Weight | 22 kg | |
| Weight when filled with water | 26 kg | |
| Electrical Data | ||
| Electric Connection | 230 V / 50 Hz | |
| Built-in Fuse (Slow-Blow) | T2/2A, 250V | |
| Max. Electrical Power Consumption | 35 W | |
| Standby Electrical Power Consumption | 2 W | |
| Level of Protection | IPX4D | |
Vaillant Ecofit Pure 425 Boiler Details
The Vaillant Ecofit Pure 425 Boiler is engineered as a highly efficient heat generator, designed for closed heating installations and hot water generation. It bears the CE label, confirming compliance with essential directives, and is a licensed member of the Benchmark Scheme. This scheme ensures that products are correctly installed, commissioned, and serviced by competent persons according to manufacturer instructions and building regulations.
Unlike some boilers, the Ecofit Pure 425 does not require compartment ventilation. This is due to its high efficiency, resulting in very low heat loss from the casing during operation. The boiler is exclusively certified and fitted with a concentric flue system, ensuring a sealed combustion process and preventing flue gases from entering the room air.
Installation necessitates careful attention to several factors. Minimum clearances are crucial: 150mm at the top (or 75mm for rear flue), 150mm at the bottom, 5mm at the sides (70mm if side sections are removed), and 600mm at the front. These clearances ensure safe operation and accessibility for maintenance. The product must be transported by at least two people due to its weight, emphasizing safe lifting techniques.
The boiler features a user-friendly operating concept, with controls described in the operating instructions. For installers, a dedicated "installer level" provides access to advanced diagnostics and setting options. This level allows for fine-tuning system parameters, viewing live status codes, and accessing check programmes for purging, maximum/minimum load, and filling modes.
Heating water quality is paramount for the Ecofit Pure 425. It is critical to ensure that the water has a pH value between 6.5 and 8.5 (at 25°C) and that hardness levels meet specified guidelines. The use of unsuitable additives, such as certain frost or corrosion protection agents, biocides, or sealants, can lead to material damage, component changes, and operational issues, potentially voiding warranties.
The condensate discharge pipework must be installed with a continuous fall of 45mm per metre, be made of suitable materials like PVC, and be well-insulated to prevent freezing, especially if routed externally. Electrical installation requires a fixed connection with a contact opening of at least 3mm and a common 230 V, 50 Hz, ≤3 A fused supply for the boiler and its controller, strictly performed by qualified electricians.
Maintenance is essential for the longevity and efficiency of the Vaillant Ecofit Pure 425. Annual inspections are recommended, including checking the CO₂ content, gas flow rate, and overall condition of components like the heat exchanger and burner seals. A comprehensive service record should be maintained, as outlined in the Benchmark commissioning checklist, to track all inspection and maintenance activities.
Troubleshooting is facilitated by a system of fault codes (F.xx) that appear on the display, signaling specific issues. The boiler stores the last 10 fault messages in its memory, accessible via the installer level. In case of persistent faults or issues, the use of only original spare parts is strongly recommended to maintain product conformity and safe operation.
Frequently Asked Questions (FAQs)
Can't find the answer you need? Here are some frequently asked questions about the Vaillant Ecofit Pure 425 Boiler, and we answer them below.










