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Baxi 636 Combi Gas Boiler


Today we’ll be reviewing yet another member of the Baxi 600 series. We present to you the Baxi 636 Combi Boiler. It’s among the best in the series featuring impressively high output power ratings and even better features.

The Baxi 636 Combi Boiler is best suited for households with medium to high demand for hot water and central heating.

Continue reading to find out more about the Baxi 636 Combi Boiler.

 Baxi 636 Combi Gas Boiler Key Features

  • It’s a premium-level condensing boiler.
  • It has a 93% efficiency rating.
  • It’s ErP A-rated for both central heating and hot water production.
  • A stainless steel heat exchanger.
  • A brass hydraulics block.
  • It has easy-to-use controls and an LCD.
  • A sound pressure level of 48 dB.
  • Hot water max output of 36.8kW.
  • Central heating max output of 26.4kW.
  • A central heating range of 25 to 80 ℃.
  • A hot water heating range of 35 to 60 ℃.
  • It can serve up to 20 radiators.
  • It has a hot water flow rate of 15 litres per minute.
  • It comes with a standard 7-year warranty.
  • The in-built Easy-Fill filling link makes re-pressurizing that much easier.
  • It has a frost-protected thermostat.
  • It’s fully compatible with USense Smart Controls.
  • It’s Boiler Plus compliant.
  • It’s compatible with the In-Flue Outdoor Sensor (IFOS).
  • It offers extensive flue options of up to 20 meters.
  • Compact dimensions of 700mm Height by 390mm Width by 288mm Depth.


Despite its overwhelming power, the Baxi 636 Combi Boiler is still simple and compact. It will comfortably fit in a standard kitchen cabinet without interfering with the room’s overall decor.

Indeed, it only comes in white. Nonetheless, Its design is seamless. Specifically, we appreciate its embedded controls that give it a refined and tidy look.

As expected of Baxi, the boiler has a stainless steel heat exchanger and brass hydraulics block. With those materials, the unit is sure to last several years without serious complications.

As far as noise is concerned, the Baxi 636 Combi Boiler is among the stealthiest in the business. It’s a hardworking unit boasting noise pressure levels of 48dB.

Finally, we have the LCD interface. Although it’s not a touchscreen, it will be enough to help you identify fault codes, temperature readings, and the boiler’s overall status.

Fuel and efficiency

Like all other Baxi 600 Boilers, the 636 has a seasonal heating efficiency rating of 93%. Additionally, it’s also ErP A-rated for both central heating and hot water production. If you’re moving from an older boiler, you stand a chance of saving up to 310 pounds annually.

Besides this gas version, the Baxi 636 Combi Boiler also comes in an LPG variant of the same efficiency ratings. Even if your property is off the national gas grid, you’ll still be able to keep warm without spending much on fuel.

Finally, we are happy to announce that the unit also runs on a 20% hydrogen bond.

Power output rating

As mentioned earlier, the Baxi 636 Combi Boiler is among the best in its boiler range. When shopping for a suitable boiler for your household, there are two output ratings you should look out for—Central heating and hot water power ratings.

Fortunately, the 636 excels in both. It has an impressive central heating output rating of 26.4kWs and a domestic hot water rating of 36.8kWs. It can supply heat and hot water for homes with up to 20 radiators and 2 bathrooms.

Additionally, its reliable hot water flow rate of 15 litres per minute will make life much easier.

Installation and servicing

Baxi boilers are the easiest to install and service. Weighing only 30.2kgs, the 636 is relatively light and should only require only one certified engineer to install. Additionally, thanks to the unit’s extensive flue options, its installation is more flexible.

It’s even easier to service and maintain. The easy-fill permanent filling link enables you to pressurize the boiler without spending money on heating engineers.

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