Lots of water heating

Good morning,

I inspected a large home - 7058 sqft. Two large gas fired water heaters with a small circulating pump. The heaters are plumbed one after the other in series.
My question is why are there two much smaller storage tanks located after these heaters?
Is this storage to prevent running out of hot water during peak usage? - 7 bathrooms.


Not clear in the basement utility room :smiley:



All appear to be functional hot water heaters to me.

Perhaps they have friends over who use a lot of hot water…

Just for storage no power to the little ones , they didn’t happen to heat the place with hot water did they?

The smaller two have No power source…hot water storage tanks.

All do equal a functional water heating system.

No power to the smaller units. Just acting as storage tanks. But why?

Unless there is a relatively constant usage where these tanks are replenished with hot water wouldn’t this just allow the smaller tanks to cool?

Heating is all gas forced air.

Where does the pipe in the right side of the picture with the two heaters go to? What about a snow melt system. With a house that big it’s a possibility?

Copper pipe at the right of the large heaters is connected to the circulating pump located near the floor.

That would be my guess, but I don’t understand why the two powered units are insulated and the two holding tanks are not. What is the total holding capacity when you add all 4?

Looks to me like a good argument for “on demand” water heating equipment.

The tanks are connected in series, it’s like one big tank. Cold water enters system at right tank, is heated, fed to small tank at far left, then to next small tank, then to large tank at left, heated again if necessary, then fed to house distribution system.

Not true if you follow the pipes. The photos do not make this clear but all of these heaters/tanks are connected in series with the two heated tanks first and then the two unheated tanks last. Makes no sense to me but I thought there may be a reason.

Thanks to all for your comments.