HOLY SH**!! Is he on a mission to kill someone?? That "Field repaired" in his words, cracked heat exchanger is actually a "NOS Energy" drink can slathered with high temp sealant to block the crack. Look at the URL Frosty posted then look at this pic. Amazing. You can make out the words energy closer to the bottom of his HACK repair.
Seriously, after reading about this guy it kinda ruined my day at work. Knowing that his "clients" supposedly saving $ , not knowing their house could burn up or they could die of CO poisoning at anytime.