Most units use vertical finned-tube coils embedded in perimeter entry walls to connect to the suction side of a forced-draft (FD) fan or fan room —the source of combustion air.

Colmac Coil’s 7/8-inch plate fin heat pipe features: larger cross sectional tube area, allowing longer overall heat pipe length; greater secondary surface than finned tube heat pipes; center divider ...

Microchannel coils were long used in the automotive industry before they crossed over to HVAC equipment in the mid-2000s. Since then, they’ve become increasingly popular, particularly in residential ...