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Vaillant ecoTEC Plus 838 Combi Gas Boiler


The Vaillant ecoTEC Plus 838 Combi Gas Boiler is a powerhouse. Not only does it come with impressive output ratings, but it’s also updated with some of the best boiler features. Indeed, there aren’t many boilers that offer what the 838 brings to the table.

It’s ideal for medium-sized and large homes with high demand for central heating and domestic hot water. We’re talking about homes with at least two bathrooms and four bedrooms.

Vaillant ecoTEC Plus 838 Key Features

  • It’s a premium condensing boiler.
  • It has an 3% efficiency rating.
  • It’s ErP A-rated for both central heating and domestic hot water production.
  • A stainless steel heat exchanger.
  • It’s compatible with the Airothem air-to-water heat pump hybrid system.
  • It has easy-to-use controls and an LCD.
  • A sound pressure level of 46 dB (Quiet Marked).
  • It has a Flame Lift detection system for quiet and efficient combustion.
  • Hot water max output of 38.7kWs.
  • Central heating max output of 30kWs.
  • It can serve up to 20.
  • It has a hot water flow rate of 15.9 litres per minute.
  • 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.
  • Dimensions of 720mm Height by 440mm Width by 400mm Depth.


As expected of any premium-level boiler, the 838’s design and build are simple but quality. Its out casing has a smooth and scratch-resistant finish that will ensure the boiler maintains its beauty through the years.

We also like how its controls are neatly hidden behind a facia board. Open the flap cover you’ll find simple push buttons and a large enough LCD for temperature and status notification.

On the inside, you’ll find a hardworking stainless steel heat exchange that will deliver its best through the years. Nonetheless, should anything go wrong, you can count on the boiler’s standard 5-year warranty (Extendable to 7 or 10 years if installed by a Vaillant Advanced Installer).

Fuel and efficiency

The Vaillant ecoTEC Plus 838 Combi Boiler can save you a lot of money on heating costs, thanks to its 89.3% efficiency rating. On top of that, it’s also ErP A-rated for both central heating and domestic hot water production.

If your property is off the national gas grid, consider the LPG dedicated model that shares the same features besides fuel type.

Power output rating

As mentioned earlier, the Vaillant ecoTEC Plus 838 Combi Boiler is a powerhouse. There aren’t many combi boilers offering central and domestic hot water output ratings of 30kWs and 38.7kWs, respectively. Its flow rate of 15.9 litres per minute further complements its raw power.

Ideally, you’ll want this boiler if your household has a considerable high demand for hot water and central heating. It’s perfect for homes with around 2 bathrooms and 4 bedrooms.

If it’s too much for your household, consider the less powerful variants offering max outputs of 20.4kWs, 25.7kWs, 30.9kWs, and 32.2kWs.

Installation and servicing

The Vaillant ecoTEC Plus 838 Combi Gas Boiler is easy to install and maintain. Indeed, weighing 43kgs, it’s heavier than most boilers and will require at least 3 engineers to install. However, it makes up for its weight by offering extensive flue options.

Furthermore, the ecoTEC Plus 838 has a 2-stage inbuilt frost-protecting thermostat for installation in lofts and garages.

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