Boiler combi mini series... Over the next couple of months, I will be sharing some Navien, Inc combi boiler install, maintenance and service tips. We start here by showing off the fire tube heat exhanger and how it functions. Fire tube heat exchangers can put less strain on pumps as we're not dealing with smaller passages that we see on water tube heat exhangers. If you'd like to watch the entire walk through, it's on the HVAC Know It All YouTube channel and added to my story. Or link in the com