Design-build hot water washdown

M Lane

Hey guys- I have been asked to DB a washdown area for a restaurant equipment supplier who re-sells old equipment.. They've been using a 200MBH Hotsy outside (2.2 GPM), but want to move operations indoors. I want to give them @ 2 -3 GPM @ 160 under street pressure, which is 70 psi. I am thinking a water heating ng boiler with a 30-40 gallon storage tank. Want to stay under 200 MBH to avoid ASME. Anyone done something similar and have specific units they'd recommend? I don't think tankless could keep up with a 100 degree temp. rise in the middle of winter. I also don't see an advantage in using a side arm.

Rich_49

These might work

http://www.htproducts.com/phoenixplusdocuments.html



http://www.htproducts.com/phoenix-sanitizer.html

Mark Eatherton

Run the numbers first….

Doesn't sound like you need much storage, if any at all.



2.5 GPM (flow) X 8.33 (lbs/gallon) X 120 (160-40) X 60 (minutes/hour) = 149,940



Take that number and divide it by the combustion efficiency and that will tell you how many BTUH input are needed to get that output.



Assuming an 85% efficient appliance, 149,940 / .85 = 176,400. You are below the line as it pertains to the ASME requirements, which for the record are an input over 199,999 btuH, OR a storage tank greater than 120 gallons, OR an operating temperature in excess of 180 degrees F. Exceed any one of those parameters and you will need an ASME configuration.



If it were me, I'd use a reverse indirect capable of transferring those kinds of btu's per hour. Turbomax works great for me.



http://www.thermo2000.com/pdf/en-US/specs/specifications_turbomax.pdf The 23 gallon unit would work great.



Really, a major quantity of storage is a waste if the flow will always be at 2.5 GPM.



I also think I'd go with a modcon boiler, but that will add to the cost of the job.



ME

HDE_2

A condensing tankless would work

Say you use a 199,000, .95 EF, 96% thermal efficiency condensing tankless

Even at a 110 degree rise:



199,000 / 8.33 / 60 / 110 * .96 = 3.474 continuous GPM @ 110 degree rise

M Lane

Thanks

Great info so far. Much better than guessing.

What do ya'll think about a commercial Noritz, since a strong condensing tankless might work?

bob eck

A O Smith tankless gas water heater

Take a look at the A O Smith ATI540H tankless gas water heater www.hotwater.com it is a high efficiency condensing TGWH with 10 year heat exchanger warranty on commercial jobs 15 years HE warranty on residential jobs 199,900 BTU input.



40* F incoming water temp 160* out going water temp 3.1 GMP



check it out.

Steamfitter66

Darn near perfect application.

Norritz or Rinnai. No need for a boiler etc. Watch your venting and gas line sizing, have a good digital or slac tube manometer If its your first get trained a read the installation manual a couple of times.