Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.

If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
Need to contact us? Visit

Restaurant options for domestic.

SnowmeltSnowmelt Posts: 1,162Member
I service this one owner who has 3 steakhouses, he just recently inquired another restaurant.

He has an existing boiler with 6 zones valve. ( has 2 pumps in parallel, if one stops working he can isolate that pump and continue)
Piping and wiring looks like something from a taco training ( Webinar).

He also has a pretty decent flat plate HEX off the boiler for domestic water.
Also has a tm 50 from Takagi. To make the long story shorter the takagi and the HEX are by passing the storage tank and there using the storage tank water to mix the water down. ( it took me 1 1/2 hours to trace it in my head)
He wants to simplify everything. The Tankless is on its way out. I put a heat exchanger in for him to buy him time to think.
What do you think will get him more how water for money spent?

Option 1. Install two naviens and connect it properly to the storage tank. ( somehow use this flat plate hex exchanger in the equation since it exists.
Or maybe a navien boiler with an indirect feeding the storage tank at 150 degrees and mixing valve to 130 degree.
The other restaurant I put the navien in and he likes them .


  • Larry WeingartenLarry Weingarten Posts: 1,675Member
    Hi, If the boiler stays on year round, might that be a good heat source for the DHW?

    Yours, Larry
  • HVACNUTHVACNUT Posts: 2,850Member
    Reverse indirect(s) off a separate boiler.
  • SnowmeltSnowmelt Posts: 1,162Member
    Hvac nut that’s what I was thinking, but what do you mean by reverse indirect? Also since they have a flat plate hex, can I maybe use that some how.

    Maybe use that with the existing boiler and storage tank , and boiler, then but a navien boiler only with an indirect?
  • ZmanZman Posts: 5,532Member
    edited February 5
    Stop the madness! Start with the required storage and/or Btu's and do the math from there. Restaurant water requirements are often mandated by the health department. I would inquire there first. If you decide to use the existing boiler and a heat exchanger, you would have to consider the heating requirements of the building as well.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • mikeg2015mikeg2015 Posts: 1,125Member
    Tankless aren’t ideal Because the water temp requirements are so high and flow rates change constantly. But leak demands are manageable with storage. That’s my opinion at least. A boiler with indirects or reverse indirect (more flow, less pressure drop) is the way to go. Reverse indirect stores more total energy, which is the goal so you don’t need as big of a boiler or water temps as high, not storing lots of domestic water.

    Still need to Calculate peak Flow and the sustained flow. Normally bathrooms, and the wash sink and prep sinks are the bad load and you add the dishwasher Machine for peak loading.
Sign In or Register to comment.


It looks like you're new here. If you want to get involved, click one of these buttons!