Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

[reverse] indirect water heater as 2 pipe buffer tank?

ron Member Posts: 301
I watched some utube videos and I'm now an expert :) Have sort of a 3 part question:

are "reverse indirect" domestic water heaters still made/sold/used?
do they pose a benefit over the regular indirect since non-refilling oxygen depleted boiler water fills the tank instead... would the tank not rust out or build sediment and last much longer? How/when did the reverse indirect come to be or fall out of the spotlight?

scenario: small 3 bedroom single floor ranch with a 1 zone baseboard heat and a ~15 year old burnham ~0.9gph boiler in basement. New doors and windows put on house and I think the boiler is or will be oversized. A taco 007 on 1" pipe pumps into boiler. An old style taco air scoop cast iron air separator is on 1" pipe on the output side of boiler few feet away along with the expansion tank. Output of the air scoop has adapter to 3/4" copper which then runs around the house as the one zone coming back to the 007 circulator.

Are hydronic buffer tanks ever bad in terms of efficiency or trying to save on fuel costs? By that I mean is there a scenario where you add one and then say that should NEVER have been done ?
It seems like with a reasonably efficient and functioning boiler and within a reasonably insulated ~62°F basement space that an insulated buffer tank could only be a positive?

If one didn't want to blow $$ on a "hydronic buffer tank", can an indirect domestic hot water tank ( or reverse indirect ) be used in a 2-pipe buffer configuration to some benefit? Has that ever been done or proposed? Assuming ~160°F boiler water to do baseboard heating that would result in 160°F domestic hot water but then a mixing valve could mitigate the hot water temperature. Having such a hybrid'ish buffer could prevent [oversized] boiler short cycling and increase efficiency in the described scenario?