Baxi Duo-tec

The Baxi Duo-tec Combi boiler is a firm favourite with installers and householders because it is straightforward to install and simple to use. It is an Energy Saving Trust endorsed product, so you can be sure it meets the highest standards of energy efficiency. 

We are so confident in the reliability of the Baxi Duo-tec Combi that we are offering a 7-year warranty as standard on all Baxi Duo-tec boilers installed before 31st December 2015*.

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  • Seven year parts and labour warranty for added peace of mind
  • Class leading hot water flow rates for increased comfort and convenience
  • User friendly controls with clear, easy to read display
  • A wide range of outputs to suit all heating and hot water requirements
  • Dedicated LPG 28kW model available, so households in off mains gas areas can enjoy the benefits of the Baxi Duo-tec Combi
  • Energy Saving Trust endorsed product
  • Aftersales services provided by Baxi Customer Support

*Terms and Conditions apply

Please note: warranty and purchasing information on this site applies to the UK only. For information on how to buy these products in the Republic of Ireland, please visit Baxi Potterton Myson.

Duo-tec clearance

A: Boiler width = 450mm

B: Boiler height = 780mm

C: Boiler depth = 345mm

D: Side clearance = 5mm

E: Upper clearance = 200mm

F: Lower clearance = 150mm

G: Front clearance = 5mm in operation, 450mm for servicing

  • Pre-plumbing jig, complete with pre-formed copper pipe tails, built in filling loop and 1 metre mains cable to save the installer time and money during installation
  • Built in frost thermostat, making it easier to site in garages and lofts
  • Compatible with Multifit flue kits, which provide an industry leading choice of lengths, bends and accessories, allowing for versatile siting
  • Free of charge Baxi product training throughout the UK 
  • Free Gas Safe notification and warranty registration online, saving you time and money on any Baxi boiler you install through the works loyalty scheme 
Duo-tec Combi 24  Duo-tec Combi 28 Duo-tec Combi 33  Duo-tec Combi 40 
Heat Output Central Heating (CH) (70°C Mean) kW (Max) 20 24 28 33
kW (Min) 6.8 8.7 9.4 9.6
Heat Output DHW Output - kW (Max) 24 28 33 40
Maximum DHW Flow Rate (Delta T @ 35°Max) l/min 9.8 11.5 13.5 16
Minimum DHW Flow Rate Required* l/min 2 2 2 2
Minimum Operating DHW Pressure Required bar 0.15 0.15 0.15 0.15
SEDBUK 2005 Seasonal Efficiency NG % 91.1 91.1 91.1 91.1
SEDBUK 2009 Seasonal Efficiency NG % 89 89 88.9 88.9
NOx Class (5 being lowest) 1 - 5 5 5 5 5
Mechanical & Hydraulic Connections
CH Flow/Return Pipe Size (mm) 22 22 22 22
DHW Flow/Inlet/PRV Size (mm) 15 15 15 15



Multifit GasSaver

A Multifit GasSaver can be installed with the boiler and could contribute additional annual gas savings on domestic hot water of up to 37%** - meaning even more savings on your fuel bills and greater benefit for the environment.

**Test conducted by independent scientific test house, TNO. Calculation based on an average household's consumption of 100 litres of hot water per day. Results were based on a comparison of a SEDBUK 2005 (> 90%) rated high efficiency boiler versus a high efficiency boiler and GasSaver.

Read more about the Baxi Duo-tec Combi by taking a look at our product literature, whether looking for instructions on what to do when changing a boiler part, or finding out about the benefits of using a Baxi.

  • Baxi Platinum, Duo-tec and Megaflo ErP range guide (PDF 2.42MB, 01/10/2015)
  • Baxi Duo-tec Combi ErP installation and servicing manual (PDF 5.41MB, 28/10/2015)
  • Baxi Duo-tec Combi ErP user guide (PDF 1.60MB, 01/10/2015)
  • We don't sell our products directly to consumers which is why our prices aren't on our website.

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    For more information about this type of boiler, please use the links below:

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    How combi works

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    Compatible products and accessories

    Brochures & guides

    Download documents about the Baxi Duo-tec Combi, from installation information, to brochures and user guides.