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Vaillant ecoTEC Plus 637 System Boiler


The ecoTEC Plus 637 System Boiler is a capable unit ideal for large homes with high demand for central heating and domestic hot water. In this case, we’re referring to homes with more than 4 bedrooms and 2 bathrooms.

Indeed, its output rating is ground-shaking. It gets even better since it’s a system boiler with a hot water cylinder. That way, you’ll rarely suffer from hot water shortages.

Continue reading for more on the Vaillant ecoTEC 637 System Boiler.

Vaillant ecoTEC Plus 637 Key Features

  • It’s a premium condensing boiler.
  • It has a 94% efficiency rating.
  • It’s ErP A-rated for both central heating and domestic hot water production.
  • A stainless steel heat exchanger.
  • It has easy-to-use controls and a backlight display.
  • A sound pressure level of 50 dB (Quiet Marked).
  • It has a Flame Lift detection system for quiet and efficient combustion.
  • Hot water max output of 37.6kWs
  • Central heating max output of 37.6kWs
  • 130,000 BTU.
  • It can serve up to 20
  • Compatible with unvented systems.
  • It comes with a standard 5-year warranty extendable to 7 or 10 years.
  • The in-built filling loop makes re-pressurizing that much easier.
  • It’s fully compatible with mechanical and smart controls.
  • NOx Class 5 for low toxic emissions
  • It’s Boiler Plus compliant.
  • Compact dimensions of 270mm Height by 440mm Width by 338mm Depth.


The hand-built ecoTEC Plus 637 looks like any other Vaillant boiler—Simple, crisp, and complete. It only comes in white that blends with most home decor. As far as its surface is concerned, the quality finish will ensure its appearance ages well through time.

There is a facia board that neatly hides all the controls. Open it, and you’ll find a decent backlight display for temperature and status notification. Additionally, you’ll also see simple buttons for boiler configuration.

Its innards are also quality. The ecoTEC Plus 637 System Boiler comes with a hardworking stainless steel heat exchanger that will see you through the years. The rest of its components are low-count for stable operation with less frequent breakdowns. However, should it fail, you can always count on its 5-year standard warranty (Extendable to 7 or 10 years when fit by a Vaillant Advance Installer).

Finally, it’s compact enough to fit almost all kitchen cabinets.

Fuel and efficiency

Energy Saving endorsed the ecoTEC Plus 637 System Boiler because of its high 94% efficiency rating. On top of that, it’s also ErP A-rated for both central heating and domestic hot water production. Indeed, it’s a boiler that can save you a lot of money on heating bills.

To further boost your savings, we advise you to fit it with smart controls that will help you monitor your usage and reduce waste.

Power output rating

The overall output rating of 37.6kWs says it all for the ecoTEC Plus 637 System Boiler. It’s definitely among the strongest in the market that can comfortably supply heat to large homes with at least 4 bedrooms and 2 bathrooms.

If your house has fewer rooms and less demand for heating, consider its other variants. The ecoTEC Plus range has other system boilers offering different output ratings of 12kWs, 15kWs, 18kWs, 24kWs, and 30kWs.

Installation and servicing

The Vaillant ecoTEC Plus 637 System Boiler is easy to install and maintain. It weighs around 43kgs and will require, at most, 3 engineers to fit. Furthermore, it also comes with an inbuilt frost-protecting thermostat for installation in lofts and garages.

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