Temper domestic water or separate two systems?? 1

[PuckDrop]

I have some housing buildings that I manage that have one heat source for domestic water temps and a hydronic floor heat system. When the floor heat needs more than 120 degrees F I can't turn up my heat source or I have risk of scalding with domestic water temps over 120 degrees F.
I have 2 solutions. One: separate the two systems and set domestic water at 120 , and can then set floor temps higher. Two: install tempering valves on the domestic water to keep the domestic water at 120 degrees F. I can actually separate them fairly easily but wanted to see if anyone has had this issue or dealt with tempering valves in domestic water situations and what issues may come with that decision.??
Thank you.

 

[MiketheEngineer]

Tempering valves can always fail - I would go with two separate systems. Of course - that sensor could also fail.....

 

[willard3]

Separating by different pumped circuits makes it easier to fix as pumps are easier to replace than mixing valves when they fail.

 

[sspeare]

Perhaps this question really belongs in the HVAC/R part of the forum. Any way .....

I am concerned that you are at 120 Degrees F for the in-floor radiant piping, and that you want to go even higher. You can design in-floor jobs using 115 degrees max. - have to use proper tube specing, flow rates, etc.

Do you have a primary/secondary piping arrangement?

Can you upload a schematic?