Historically, air preheater repair decisions were based on the boiler approaching operational limitations and inspection results. When administratively imposed performance tests were budgeted, these tests were based on industry practices recommended by the American Society of Mechanical Engineers (ASME). The financial environment for funding these tests has changed considerably in the past 10 to 15 years.
This article addresses some of the drawbacks of applying conventional testing as well as a common-sense approach that can be applied. The alternative air preheater evaluation results can be compared to the ASME testing for both rotary and tubular air preheaters. The primary focus of the article is on tubular-type air preheaters because they are more common, except for larger coal-fired units.