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Tankless with recirc and possibly storage
I am involved in a project at the tail end. Job consists of a Takagi TK-3 unit unit for dhw. The homeowner is complaining about the extended time it takes to get hot water 85-90 ft away to the furthest fixture. BTW, no return line was installed and all the walls are now closed.
Can I install a "comfort valve" (tee fitting) at the furthest fixture and recirc pump at the unit? I do realize I must size the recirc pump to overcome the pressure drop of the tankless if I dont have a buffer/storage.
Furthermore, after determining peak demand, the Takagi wont be able to keep up so storage must be added.
Any ideas on the best vessel to accomplish this: storage tank or electric water heater (venting of another gas appliance is a challenge here)? Also, can I install a simple "comfort system" recirc system where it only sees the headloss/pressure drop of the electric water heater and not have to overcome the pressure drop of the tankless (i.e. check valves strategically placed on tankless hw discharge)?
I checked out Rinnai's site and got a few ideas from their installation diagrams. Thanks for any/all input