Posted by Tarzan on July 10, 2001 at 16:35:34:
In Reply to: CB 800 LE Refractory Design, 4 pass dryback posted by Joe Mihalov on July 09, 2001 at 03:50:52:
: We've split 40 tubes in a 3 year old 150psi unit. The welded tube ends are splitting due to 'over heating.'
: The tubes have 1/16" scale deposits. Is the 2nd pass refractory too close to the tube ends causing localized overheating? Is there a design flaw in the refratory angle (baffle design)?
Scale will cause the metal of the tubes to overheat....get rid of the scale and take measures to prevent reformation....sounds also like you may be overfiring your boiler...is your boiler designed to cyle "On-off" or is it modulated?