what is the maximum turndown ratio

[pesy]

what is the maximum turndown ratio avaliable on a fully modulating natural gas burner? If you have an answer, do you know of a source (document) that states this?

 

[Khaled200]

As far as I am concerned, Maximum turndown ration is the ratio between the full load output of for example, a burner of a boiler or a furance, and its lowest available part load output. Typical values can vary from 1:2 turndown ratio up to 1:8 depending on the size of the boiler and its inherent design characteristics.