I am installing a in-concrete pad pex radiant system for a family room. Looking at Taco mixing blocks with a water heater. They have two models, the XPB and the RMB. Does anyone know the difference between these models. After looking at their site and also calling them, I still don't have an answer. Appreciate anyone's help....

Water heater should be low enough temp to just have a pump.....Send the $750 I just saved you to [email protected]....

Some will say you need a heat ex-changer to protect from stagnant water but there is a loop you can do where....whenever you use water in your house the new water runs through your floor first. It is a very cool loop and have used it in both my houses. Plumbing it this way also cools the floor in the summer and preheats the water in the winter for longer showers. I have run both houses off a 70k water heater in Michigan with extra hot water and no problems. Old house is 3500 sqft and new house is 7000 sqft. This option has been in and out of the code book. I believe it is allowed now.

Let me know if you want for info.