Indirect DHW 60 Gallon - What brand offers the highest btu absorption?

[davideliarosenbloom]

Currently running a SS 60 gallon INDIRECT DHW supplied by 1.25" piping and a 15/58 circulator set on speed 1. Cannot get a 30 degree Delta T in system at any temp and wonder if its speed through the system being too fast.

Does anyone know what the best indirect DHW tank can perform at as far as BTU absorption>? Would it make sense to use the ball iso valves as restrictors and see if slowing the flow increased heat absorption? Could the heat exchanger tubing which is quite large be coated from 20 years of use? Is the latter more likely than not?

thanks,

Dave

 

[Phog]

What are you trying to do -- get more hot water out, improve recovery time? From a pure heat transfer standpoint, higher boiler loop flow is better, you will actually see slower hot water recovery time by restricting your circulator. To increase the hot water output performance you'd actually want to go in the opposite direction & increase the flow (this will negatively impact the energy efficiency though). Inlet/ outlet deltaT will decrease over time as the tank ages, as a result of the internal coil liming up, the scale deposits impede heat transfer.