Of all the equipment selected and specified in today's HVAC designs, the Variable Frequency Drive (or VFD for short) has to be the single most overly specified piece of equipment of all!!
Ever see a product that has a much better marketing campaign than it does an educational campaign? It seems to happen a lot in the HVAC industry and condensing boilers is one of those products.
The evolution of the water source source heat pump has now lead us to hybrid designs that save energy and improve reliability. As a bonus, we're now afforded remarkable system design flexibility.