A 100 gal water heater replaced with like-kind, along with A new circulation pump. Both were exact
replacement of the old parts. This system provides hot water 24/7 to a 9 unit, 3 story, condo with
72 fixtures throughout the building and is housed on the roof which amounts to a 4 floor.
We are experiencing inconsistent flow of hot water to some units, perfect hot water to others, delayed
delivery time for hot water on demand and even more troubling the same variation of
warm water and hot water in the same unit. Prior to changing the heater and pump we had hot water
to all units. Any thoughts or suggestions would be appreciated. At a loss here .... jw

just guessing but it does sound like a problem with the check valve in the recirculating system.

Thank you for the suggestion, we are looking at everything at this point.

[cdn.globalimageserver.com]

this is a really good explanation of cross-over and how to test for it.

quote.." Prior to changing the heater and pump we had hot water
to all units. "

this would make me think it is not a crossover problem.

One hundred for 9 units?

6 of them are cold water flats.

This volume of hot water has been plenty for our building for over 40 years.
We replaced heater and pump with like-kind and as mentioned had hot water to
all units prior to replacement.