65 gallon water heater for 28 units

Anyone ever see this type.
Plate says 327 gallon per hour recovery.

Will that be enough (units have spa tubs) ?

I haven’t personally seen one of these, but it appears to be a Rheem high-capacity commercial unit. To me it seems to be almost a “tankless” style heater and tank combination with recirculation pump. At 360,000 btu/hr. input it will heat a lot of water fast. According the the Rheem table it will raise 75 gallons of water 100 deg. in 5 minutes. By comparison, their residential tankless heater is only rated at 180,000 bth/hr and regular residential gas heaters are only 40-60,000 btu/hr. So, without trying to out-engineer the architect that likely selected the unit, I would probably not discredit it for that service.

They may need a clipboard installed in the hall with the designated shower times for each unit. :slight_smile:

Thanks Frank

Is that official wordage for my report.? :slight_smile:

Well, if you take the 327 Gallons per hour at its face value and do some simple math, you come up with a problem.

Lets say half of the 28 units all run their tub at the same time. At 5gpm (rough average spigot rate), times 14 units, times 5 minutes: you get 350gallons used. That leaves nothing for the tooth brushing, shaving, dishwashers, wash machines, etc. Now granted nobody runs a bath that is 100% hot valve only, but it’s not difficult to visualize a potential issue.


Do you really brush your teeth with warm water?

That’s a very high output unit.

Is it enough for 28 units? I don’t know but assuming 1/2 filling the tub at the same time is a bit high unless they all work the same shift at the same place. :wink:

Here’s something for individual calcs…

I am guessing it is fine but Suggested Plumber do sizing .

New rehab with 2002 unit.
Note serial number of 0202

Rheem has a Commercial Product Sizing Guide here.

Thanks, Mike

**edited, LOL I didn’t bother to fill out the form…

Turns out that one was Aussie only…I bet they have a US version though.

Does their water heat at a different rate:mrgreen:

“You know what they call a Quarter Pounder in Amsterdam?”

“Royale w/ cheese.”

…and do you know why that is?

The Metric System!

Thats right the metric system…

OK, try this one.

If I’ve got a sore tooth I do…

I know the example was over simplified to make the math easy to understand. The point is, even though that’s a lot of hot water in one hour, you’ve got a lot of people demanding it at a peak hour.

Change it up a bit if you want, make it 10 people each taking a 10 minute shower at 2.5 gpm. That’s 250 gallons alone. Stretch a few of those of 15 or 20 minutes, and you end up with cold water.

Who pays the utility bill?

I prefer Dusk till Dawn :roll:
Kill Bill was good, but what was in that glowing suitcase.

Fortunately for all of those tenants, load diversity calculations apply to plumbing systems in a manner similar to electrical systems. Also, I would imagine if a problems existed at that location, you would have heard about it already! In addition, we have to remember that we start out with 65 gallons of hot water in the tank + whatever number of gallons are in the circulating piping system - could be quite a lot!