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. This basically the temperature of the water running through your radiators, pipework and system. 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 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.
BrandModels / FamilyBoiler TypeVideo
MainHE, Eco HE, Eco, Eco EliteCombiVideo
IntergasRapid, HRE and ECO RFCombiVideo
VaillantEcotec Plus/ Exclusive Pre 2012CombiVideo
VaillantEcotec Plus/ Exclusive Post 2012CombiVideo
Worcester BoschGreenstar i ErpCombiVideo
DISCLAIMER: There is a note of caution, if your condensing pipe is terminating externally and has not been correctly installed or insulated properly, it may be more likely to freeze due to extra condensate produced by optimising the boiler for increased condensing mode. We cannot be held liable if your installation does not conform to latest regulations and your condense pipe freezes as a consequence of not being correctly installed or insulated.
Combi Boiler Condensing savings calculator

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