19 Vaillant ecoTec - powerflush or replace?

beckstar1975

Well BG have quoted £5.5k for a replacement Vaillant ecoTec 30 as the flue is vertical and we'd need scaffolding. Heatable is £3.5 excluding scaffolding, if the scaffolding isn't too much and they can arrange it it looks like it's Heatable all the way

FreeBear

beckstar1975 said:

Well BG have quoted £5.5k for a replacement Vaillant ecoTec 30

Heat output to central heating is 6.9-25.7kW at 50°C flow, 30°C. With 80°C flow, 60°C return, heat output is 8-24.7kW (and efficiency drops off considerably). Not the best modulation range, and unless you have a lot of large radiators, your heating requirement is likely to be less than 8kW. Standard warranty is 2 years, or if registered, 7 years. This can be extended to 10 years for an extra £150.

Not the best performing boiler on the market, and the choice of smart thermostats is very limited. So you'd be restricted to one supplied by Vaillant or stuck with crude on/off control.

I'd suggest researching your options and look for a boiler that can modulate down to 3-3.5kW and is OpenTherm compatible. Having a real low output will mean that your boiler isn't short cycling (less wear & tear, and better efficiency). Also consider doing a proper heat loss calculation on each room (the Stelrad one gives reasonable results) and increase the size of some of the radiators - Even better if you adjust the mean water temperature down to 50°C from the default 70°C. With bigger radiators, you can run at a lower flow temperature which helps to reduce gas consumption and still allows the house to heat up at a reasonable rate.