boiler firing rates

steamfitter

What determines the firing rate of a boiler? Is it by design of the system? Is it something that's pre-determined by the boiler manufacturer? or is it strictly determined by controls like thermostats, aquastats and outdoor reset controls?

Tim McElwain

First of all what is on the

rating plate of the boiler for input, determined by the manufacturer. Then it would depend on a heat loss having been done and a measurement of radiation and also type of radiation. The equipment should be set up with a combustion tester and fired at the maximum design firing rate following manufacturers instructions for CO2, O2 etc.



From that point different controls can control modulation (outdoor reset)