Adjust your combi boiler flow temperature for increased efficiency

Adjusting a combi boiler is much easier as you can simply set the lowest flow temperature that keeps the home warm. There are advance design calculations that can help determine the flow temperature, however for this technique we go to the flow temperature of 55 degrees, which virtually guarantees condensing savings. From there if you are not getting the home warm, you can increase by 1-2 degrees at a time, let the system run for a day and then repeat increasing as necessary. You may find that 55 degrees works for most of the year except very cold days. For this you find the temperature that works for the extremely cold days and use 55 for the remainder. A small amount of trial and error is necessary without heatloss calculations and testings, for determining the flow temp. See below for condensing boiler savings and videos below showing you how to adjust the flow temperature. *See disclaimer below.

Combi Boiler Condensing savings calculator

BrandModels / FamilyBoiler TypeVideo
MainHE, Eco HE, Eco, Eco EliteCombiVideo
IntergasRapid, HRE and ECO RFCombiVideo
VaillantEcotec Plus/ Exclusive Pre 2012CombiVideo
VaillantEcotec Plus/ Exclusive Post 2012CombiVideo
Disclaimer: Please make sure your boiler is in full working order, installed to manufacturer regulations as we cannot be held liable if your installation is not correctly installed and a problem such as frozen condensate arises as a result. See video below of a condensate that is unlikely to freeze as it is terminated internally or of appropriate size piping.

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