As late as 2001, the boiler code trip diagram clearly indicates a low air flow trip at < 25% full-load air flow in Figure 4.9.3(b) Boiler Trip Logic. However, the 2004 and current 2007 code is much less clear about this issue stating “low combustion air flow below the permitted limits shall...
To: davefitz
Thanks for the 25% MCR posting. Can you provide more information concerning this 1961 incident? Are you suggesting that this incident was the basis for the addition of 25% MCR minimum air flow to NFPA 85? If so, why wouldn't maximum air flow during the purge cycle clear the...