wkearney99 said:What?
What do you think is coming into the tank when hot water gets used from a tap? COLD water. How would that be any different than water being recirculated? If anything the in-wall water would likely be a bit warmer than what's coming in from underground. So, no, there's no more risk of thermal shock than present during normal operation.
That and when circulating there's no changes in pressure involved. The water is already in the system and it's all operating at the same pressure. As it pumps water out, it's pulling water in. The same pressure out, the same pressure in. Water recirculating systems like this have been around for decades.
Not quite. There is a pressure differential in the pipe proportional to the pipe's length and the flow velocity, and it increases with the number of fittings and bends. The pump's performance will depend on the plumbing configuration used. I know we have a few elbows on the recirc line, and it also runs up in the attic, while the pump is in the house. I could probably upgrade the pump, but the next model up is too pricey to justify the change. I use automation rules instead and the water is ready most of the time.