defining a boiler short cycle

hot_rod

any thoughts on what is a short cycle. I feel a 10 minute on, 10 off would be a min. level.



We know the large mass cast boilers need time to get up beyond condensing mode, as I recall a survey a number of years back in the trade mags found 10- 15 minute was the majority opinion on cycling.



With mod con equipment the temperatures are not the issue, just component wear from short, successive cycles?



it would be nice for buffer tank sizing to get an industry agreed on definition of short cycling.



hr

CMadatMe

Burner

My take would be any time the burner lacks the run time to provide its rated AFUE. AFUE is really the only mark and standard testing we have to base it on.

eluv8

My vote

I like to see no more than 3-4 cycles per hour or no less than 15-20 min on any boiler regardless of manufacture or design.

rich pickering

Patterson Kelly white paper

This is a good paper on shortcycling, but there is no defined time.  I think each situation is different.

http://harscopk.qa.jplhosting.net/uploads/files/harsco%20industrial%20patterson-kelley/publications/4bf77cff8bc8411bb00c67e962d0ef7d.pdf

IIRC, IBC boilers had a definition for shortcycling, but I can't find it right  now.