Vaillant EcoTEC Plus 635 Boiler Instruction Manual

Manual Vaillant EcoTEC Plus 635 Boiler Instruction Manual

Vaillant EcoTEC Plus 635 Boiler Instruction Manual

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Vaillant EcoTEC Plus 635 Boiler

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Vaillant EcoTEC Plus 635 Boiler

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Vaillant EcoTEC Plus 635 Instructions

Here we offer the Vaillant EcoTEC Plus 635 Boiler manual completely free and in English. We have cataloged this manual in the Boilers section on Manualverse, and it has been rated by 1 users with an average rating of 5. If you have any specific questions about Vaillant EcoTEC Plus 635 Boiler, we suggest checking the Frequently Asked Questions (FAQs) section of this manual.


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Vaillant EcoTEC Plus 635 Boiler Specifications

Category Specification Value
General Designated Country GB, IE
Permitted Gas Boiler Category I2H
CE PIN 0063CU3910
UKCA PIN 0063CU3910
Gas Connection (Boiler Side) 15 mm
Flow/Return Heating Connections (Boiler Side) G 3/4 ″
Expansion Relief Valve Connection 15 mm
Condensate Discharge Hose Connection 19 mm
Air/Flue Pipe Connection 60/100 mm
Capacity of Heating Expansion Vessel 10 l
Pre-charge Pressure of Heating Expansion Vessel 70 kPa (700 mbar)
Min. Flue Gas Temperature 35 ℃
Max. Flue Gas Temperature 85 ℃
Approved Gas Boiler Types C13, C33, C43, C53
NOx Class 6
Weight with Packaging (incl. accessories) 41 kg
Empty Weight of Product 38 kg
Weight Ready for Operation (filled) 44 kg
Physical Dimensions Total Height (D) 720 mm
Width (B) 386 mm
Depth from Wall (A) 125 mm
Height to Bottom of Connections (C) 440 mm
G20 Natural Gas Performance Gas Connection Pressure, G20 2.0 kPa (20.0 mbar)
NOx Emission, Weighted, G20 27.30 mg/kWh
30% Efficiency, G20 109.4 %
Max. Gas Volume Flow (DHW generation) 4.32 m³/h
Nominal Heat Output Range (40/30 °C) 5.2 to 37.8 kW
Nominal Heat Output Range (50/30 °C) 5.0 to 37.7 kW
Nominal Heat Output Range (60/40 °C) 4.8 to 36.4 kW
Nominal Heat Output Range (80/60 °C) 4.5 to 34.9 kW
Nominal Heat Input Range for Heating (Hi) 4.8 to 35.7 kW
Nominal Heat Input Range for Heating (Hs) 5.3 to 39.6 kW
Min. Flue Gas Mass Flow Rate 2.22 g/s (7.99 kg/h)
Max. Flue Gas Mass Flow Rate 20.55 g/s (73.98 kg/h)
Max. Heat Output for Domestic Hot Water 45.3 kW
Nominal Heat Input for Domestic Hot Water (Hi) 40.8 kW
Nominal Heat Input for Domestic Hot Water (Hs) 45.3 kW
Heating Adjustment Range 4.8 to 35.7 kW
Heating System Max. Flow Temperature 85 ℃
Flow Temperature Adjustment Range (Factory: 75 °C) 30 to 80 ℃
Permissible Operating Pressure, Heating 0.25 MPa (2.50 bar)
Nominal Circulation Water Volume (ΔT = 20 K, 80/60 °C) 1,537 l/h
Approx. Condensate Rate (pH 3.5-4.0, 50/30 °C) 3.6 l/h
Remaining Pump Head at Nominal Circulation Water Volume 0.025 MPa (0.250 bar)
Electrics Rated Voltage 230 V~
Mains Frequency 50 Hz
Permissible Connected Voltage 190 to 253 V~
Built-in Fuse (Slow-blow) 4 A
Max. Power Consumption in Heating Mode 110.4 W
Max. Power Consumption in Domestic Hot Water Mode 134 W
Electrical Standby Energy Consumption < 2 W
IP Rating IPX5D

Vaillant EcoTEC Plus 635 Boiler Details

The Vaillant EcoTEC Plus 635 boiler features advanced Sitherm Pro™ technology for intelligent combustion optimization. This system dynamically adjusts the combustion process, making manual gas-air ratio adjustments unnecessary within the same gas family and ensuring highly efficient and reliable operation.

Equipped with a sophisticated digital display and intuitive controls, the boiler provides users with easy access to various functions. Dedicated buttons allow for activating standby mode, performing resets, setting desired temperatures, navigating menus, and accessing help functions.

The display utilizes a range of symbols to provide immediate visual feedback on the boiler's status. These include indicators for burner modulation, current system pressure, active heating and domestic hot water (DHW) modes, comfort mode, and alerts for maintenance or potential faults.

An intelligent operating concept underpins the user interface. Adjustable values and list entries are easily navigated and modified using a scrollbar, enhancing user experience. To conserve energy, the controls dim after a period of inactivity.

For added security and to prevent unintended alterations, the boiler offers a button lock function. This feature protects the control panel, requiring a specific code for access, thus safeguarding preferred settings.

The EcoTEC Plus 635 seamlessly integrates with the Vaillant sensoROOM pure (VRT 50/2) room temperature control. This allows for sophisticated scheduling of heating, including the configuration of daily or weekly time periods, and features a convenient time programme assistant.

When generating domestic hot water (DHW) through a connected cylinder, the boiler's Comfort mode can be activated. This mode maintains the hot water generation system in a ready state, significantly reducing wait times for hot water at the tap.

A crucial safety feature for systems with a shift-load cylinder is the automatic anti-Legionella function. If the water temperature in the cylinder drops below 50 °C for 24 hours, the boiler automatically heats it to 70 °C to prevent Legionella growth.

The boiler provides useful energy consumption data, including gas and electrical power usage for both heating and domestic hot water. These approximate values, extrapolated through internal algorithms, can be viewed for periods like today, yesterday, last month, or annually, offering insights into energy efficiency (though not suitable for precise billing).

Multiple safety devices are integrated to ensure reliable operation. These include automatic shutdowns for electrical supply failures, robust overheating protection, and built-in frost protection that intelligently activates the pump and burner at low temperatures to prevent freezing.

A dedicated condensate drain blockage safety feature automatically halts boiler operation if the condensate drain becomes obstructed. In freezing conditions, blockages can often be resolved by applying warm cloths to the external pipe, followed by a simple boiler reset.

Designed for optimal safety and performance, the EcoTEC Plus 635 is intended for room-sealed installation (Unit types C13, C33, C43, C53). This configuration ensures that combustion air is drawn exclusively from outside the building, maintaining indoor air quality.

To ensure long-term reliability and efficiency, the boiler requires an annual inspection and maintenance by a competent person. The system provides digital maintenance messages to alert users when servicing is due.

The product is backed by a two-year parts and labour guarantee. To validate this warranty, the boiler must be serviced annually by a qualified professional, and registration with Vaillant is required within 30 days of installation.

Despite its primary setup for natural gas (G20), the Vaillant EcoTEC Plus 635 boiler is convertible to operate with Liquefied Petroleum Gas (LPG). This flexibility requires a specific conversion set and adherence to dedicated installation instructions.

Frequently Asked Questions (FAQs)

Can't find the answer you need? Here are some frequently asked questions about the Vaillant EcoTEC Plus 635 Boiler, and we answer them below.


How do I turn the boiler on/off or put it in standby mode?
You can put the boiler in standby mode by pressing the on/off button briefly. For a complete shutdown (if there's no risk of frost), you should switch off the boiler at the switched fused spur box.

What should I do if I smell gas in my property?
If you smell gas, immediately avoid the room, open windows and doors for ventilation, do not use naked flames or electrical switches, close the emergency control valve, warn other occupants, leave the building, and contact the gas supply company and emergency services from outside.

How often should my Vaillant EcoTEC Plus 635 boiler be serviced?
An annual inspection and maintenance carried out by a qualified competent person is essential to ensure the boiler's permanent readiness, safe and reliable operation, and a long working life.

How do I check the heating system's water pressure?
You can check the heating system's filling pressure on the basic display, shown as a numerical value or a five-stage bar symbol. Alternatively, access it via the `MENU` under `INFORMATION` -> `Water pressure`. The recommended pressure is at least 1 bar (0.1 MPa).

What does the 'Maintenance required' symbol (wrench icon) on the display signify?
This symbol indicates that the product requires maintenance work. The boiler is not in a fault mode and continues to operate, but it is recommended to contact a competent person to schedule the necessary service.

Can I perform cleaning and user maintenance on the boiler myself?
You may clean the external casing with a damp cloth and a little solvent-free soap, avoiding sprays, scouring agents, detergents, solvents, or chlorine-containing cleaners. However, all internal maintenance and complex cleaning tasks must be performed by a competent person.

How does the boiler's built-in frost protection system work?
With the gas and electrical supplies connected, the frost protection system activates the pump if the boiler water temperature drops below 12°C. The burner will then switch on if the temperature does not reach 15°C after 30 minutes, or at any time if it drops to 5°C, switching off once 35°C is reached.

What happens if the condensate drain pipe becomes blocked?
As a safety feature, the boiler will stop operating if the condensate drain becomes blocked. If the blockage is due to ice in freezing conditions, you can often clear it by applying warm cloths to the external pipe. After clearing, press the reset button to restart the boiler.

What is the purpose of the 'Comfort mode' for domestic hot water generation?
Comfort mode is designed to keep the domestic hot water generation system ready. This ensures that hot water is supplied at the desired temperature almost instantly, eliminating waiting times typically associated with heating water from cold.

Can I use an external room thermostat or smart control system with this boiler?
Yes, the Vaillant EcoTEC Plus 635 boiler is compatible with various room controls. This includes Vaillant eBUS room controls such as the sensoROOM pure (VRT 50/2), as well as traditional 24V or 230V room thermostats. Integration with smart home solutions is also possible via a Vaillant gateway.

What is the warranty period for the Vaillant EcoTEC Plus 635 boiler?
The boiler comes with a two-year parts and labour guarantee against manufacturing defects from the installation date. To validate this warranty, annual servicing by a competent person and registration with Vaillant within 30 days of installation are required.

Where can I locate the serial number on my boiler?
The serial numbers for the Vaillant EcoTEC Plus 635 boiler are conveniently located in two places: on the underside of the front panel and on the main data plate of the unit.

Why are the energy consumption figures displayed by the boiler approximate rather than precise?
The boiler, its system control, and associated apps provide approximate energy consumption values. These are derived from calculation algorithms and can be influenced by installation specifics, user habits, seasonal weather, and component tolerances, making them unsuitable for exact energy billing.

How does the boiler manage its combustion process for optimal efficiency?
The EcoTEC Plus 635 utilizes **Sitherm Pro™ technology**, an intelligent combustion regulation system. This technology adaptively optimizes the combustion process, automatically adjusting for efficiency without the need for manual gas-air ratio settings within a given gas family.

Is it possible to convert this natural gas boiler to run on Liquefied Petroleum Gas (LPG)?
Yes, despite its default configuration for natural gas (G20), the Vaillant EcoTEC Plus 635 boiler can be converted to operate using Liquefied Petroleum Gas (LPG). This conversion requires a specific conversion set and adherence to dedicated installation instructions provided by the manufacturer.

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