Patent ID: 8428449

Claim:
A method of operating a flow-through heating system comprising at least two heating elements in heat-transferring contact with one segment of a flow tube of a flow-through heating system, each individual heating element having a power rating, the method comprising the step of: operating said heating system at a required power less than the power capacity of said heating system by operating precisely one of said at least two heating elements at reduced power (i.e. between zero power and full power) while the remaining heating elements of said at least two are either operated at full power or at zero power, wherein said heating system has a power capacity Ptot, wherein the total number of heating elements is equal to two, wherein a first heating element has a power rating P 1 =α·Ptot and a second heating element has a power rating P 2 =(1α)·Ptot, with 0<α<1, and wherein said heating system is operated at a required power (Pr) between zero and α·Ptot by operating said first heating element at reduced power at least during a certain first time interval having a predetermined length, while said second heating element is operated at zero power.