[Kenswing]

Originally Posted by Toymeister

No doubt the reason it had the pump preinstalled is the cold sandwich effect Solutions To Cold Water Sandwich Effect. Not many people understand this. And it's not really applicable to a standard designer home. Unlike a conventional hot water heater with a tankless you can get, under certain situations, a hot, cold then hot water effect. It's not really a big deal. I would classify this as a first world problem.

Not to argue, but I disagree. The recirculation pump is so hot water can be always running through the system therefore illiminating the need to run cold water down the drain waiting for it to get hot. As your article states, the cold water sandwich effect is pretty well negated in gas fired units.

This is the unit we have. Maybe it's a little different than units you are familiar with. Tankless Water Heaters | Residential | Navien