Odd Water Heater Piping

[Jerry Simon]

Why would one tie the two bleed valves together, with a ball-valve in the middle of the pipe?  (No signs of a *looped* system.)

[Erby]

Is the supply plumbed series or parallel?

[Jerry Simon]

Series

[Charlie R]

That does tie the two tanks together and the cut-off allows you to stop that flow. Certainly unorthodox way of doing this.

[Marc]

Doesn't make any sense.  That tie in doesn't let you drain both tanks.  You still need to open each bib at the bottom to do that.

I doubt the manufacturer intended these two tanks to be installed in series. That HWH design doesn't lend well to a series connection.  Expect hot water pressure regulation issues.

[Jerry Simon]

7 hours ago, Marc said:

I doubt the manufacturer intended these two tanks to be installed in series. 

Not that it makes a difference (or does it?), but I erred when I said in-series.  The heaters are piped in-parallel.

[Jim Katen]

2 hours ago, Jerry Simon said:

Not that it makes a difference (or does it?), but I erred when I said in-series.  The heaters are piped in-parallel.

If they're in parallel, then someone might have been trying to equalize the pressure between the two tanks so that they'd get equal flow from both. I'm not sure it would work, but that might be what they were trying to do.