Peak Rating of a Boiler

The Peak Rating of a boiler is the extra evaporation which the boiler can deliver for a specified period such as 2 to 4 hour a day.

In some cases, the boiler will be required to operate above the Maximum Continous Rating (MCR) for short period of time.  The efficiency during this temporary overloaded operation will be marginally lower.

The Peak Rating is usually about 110 percent of the normal operating capacity for about 4 hours a day.  Any further increase in the Peak Rating will need redesign of the boiler.

While the Peak Rating can be used in a contingency, it is best avoided.  This is because operating the boiler at peak rating will result in premature aging of the boiler.  It will also result in issues such as slagging, fouling, erosion, etc.