Baxi Platinum & Duo-Tec Combi Boilers

25 Apr. 2019

Written by Neil Marsh MCIPHE RP RHP EngTech


In this article, we will be discussing the latest Baxi Platinum and Duo-Tec Combi boilers, of which are pretty much the same boiler, except the Platinum has a 10-year warranty, whereas the Duo-Tec is 7-years …

Value For Money

Both of these boilers are much cheaper to buy than the premium Vaillant and Worcester Bosch versions, and neither in our opinion have build qualities that match the Platinum/Duo-Tec, especially any current Worcester Bosch products.

Neither the Platinum or Duo-Tec require additional components, such as filters, for the warranties they offer, unlike many other boilers which use this to rum up extra profit. 

Track Record

As of when this article is written, both of these boilers have been on the market for 14-years and with exception for a few minor changes, are pretty much the original design. Very few boilers on the market have anything near this length of the production run. Baxi made two excellent combi boilers!

Our Thoughts On The Overall Design

These are both one of the best-built combi boilers on the marketplace and arguably one of the best overall combi boilers ever made. Above is the inside of a Baxi Duo-Tec we were servicing, which is around four years old.

The layout of the boiler is very well thought out and it is easy to work on, which will help keep repair costs outside of the warranty lower due to reduced labour requirements where work is conducted on an hourly basis, or by an honest Gas Safe registered engineer who quotes fairly. 

The boiler has a stainless steel heat exchanger, of which we would strongly advise in all instances over aluminium. Above is the inside of the Duo-Tec/Platinum’s heat exchanger. 

For more information about issues with aluminium heat exchangers, click here!

The gasket used to seal the heat exchanger door is of a silicone variety, but we have never seen one deteriorate from heat damage and many of these boilers which are over 10-years still have the original seals, unlike some other boilers. 
The system water containing components are mostly brass and copper, of which the photo below shows. 

It is very easy to power flush with the boiler running.

More information about power flushing can be found by clicking here.

Criticisms: Build Quality Issues

We would have preferred a metal pump block instead of a plastic one. 

The wiring connection could be made better and the clips to hold the wires in place through the case can be flimsy. 

The heat exchanger is fused, as the outer part is made of plastic. Consideration needs to be given where the boiler is installed and could run dry briefly, such as being in a loft, as if the thermal fuse was to fail, then the main heat exchanger, which is a very expensive part, would need replacing. 


The boilers are on the larger side, so fitting into tight spaces is not always possible. Also, the off centre flue can make a straightforward combi swap more complicated, or even prevent its use in some instances.

The Boilers Life Expectancy

So long as the heat exchanger is kept free from overheating, sludge and limescale and is serviced periodically, there is no reason in our opinion why this boiler could not last 18+ years with some modest part replacements. There are a number now that are not far from that age. 

There are many of these boilers out there with long track records which are still going today. As it is still a boiler that is being produced, boiler spares are still on the lower end when compared to other boilers. 


In our opinion, the Platinum is the best value for money combi boiler product on the market. Although the Duo-Tec is equally exceptional, in most instances we would recommend that a home owner spends a little more for the Platinum and get the 10-year warranty. 

For all your Baxi Platinum and Duo-Tec boiler installations in Cheltenham, Gloucester, Tekesbury and the areas around, you will not go wrong when you contract Forthright.