Unlimited hot water

mp1969

We have encountered several customers that have challenged us with the following.
I have encountered times when all hot water outlets (or most)are being used simultaneously and we still run out of water, I have a $12 million dollar house in Florida that I never run out of hot water. Why can't I have that here in River Hills, WI.?

Variables:

We know the owner is using on demand gas fired units such as Rinnai in Florida but the mechanical room space limitations in Wisconsin and the outside temperatures don't allow us to do a similar install.

I am leaning toward a low mass boiler with one or more indirect storage tanks, maintaining a temperature at around 140-150 with mixing valves engineered to various needs throughout this owners home.
My boss and another experienced mechanic want to use an AO Smith water heater with an adjacent storage tank.
I would think that a Munchkin or similar unit with the indirect(s) would be more efficient and every bit as reliable for this application ??
Would appreciate any input from the experts!

Thanks

Rich K.

hr

Think a condensing water heater

would make more sense than a boiler and indirect. IF you are only concerned with DHW. You lose some efficiency every time you pass through a HX.

Polaris, Voyager, AO Cyclone, Rheem, Bradford White, all offer condensing tanks in large volume, high output sizes. Couple it with storage if necessary.

If it were me, I would pin them down on exactly how much hot water they want.

Building a DHW system to an "unknown quantity" seems to always get the plumber in "hot water"

hot rod

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Jack_21

What makes you think you cannot use Rinnai's in WI

You tell me the flow requirenments and I can tell you what you need to make it work. You will need to use the FFU (direct vent, interior ) models.

When I say flow req,, I mean, incoming water temp, actual flow at the fixtures (5 gal bucket and watch works). I'm assuming this place is built.

Constantin

Talk to HTP or Triangle Tube

Both of them make models just for hot water heating. If it were me, I'd go with a VHW series Munchkin and a buffer tank. 400kBTU of heat gives you about 650 gallons per hour at 70 degree rise. Plus, they can be set up to cascade together, etc.

Weezbo

hello *~/:)

point of use has its advantages....

oil-2-4-6-gas

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Aerco

oil-2-4-6-gas

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Aerco

jerry scharf_2

Can you recover the heat?

Rich,

A rinnai has a limitaion on combined flow and temperature rise. You can bet the water coming to the house in Wisconson in the winter is a whole bunch colder than the same water in Florida. This means that the same unit will produce much lower flow up north.

Also, what are the water demands? It is is tubs, washing machines and dishwashers, then storage tanks help you out and you can pretty much work out the size. If it's showers, then take a look at the waste heat recovery units from gfxtechnology. For a few hundred dollars and no moving parts, they can recover up to 2/3rds of the heat going down the drain of the shower. I think these should be just about standard for those fancy showers with bunches of body jets.

jerry

Jack_21

Jerry, no question

that the output gpm would be less/unit with colder ground water temps. Simply design for it. Also, if you are using the recovery HX on the drain then use it to give a short boost to the cold water entering the Rinnai's to get the higher flow capabilities out of them. Also, they work very well with a storage tank. Indirect is not req'd

Paul Pollets

I'd be using

a Viessmann boiler (either the larger Vitodens) or Vitola (if oil is the fuel) combined with VitoCell 300 stainless indirects. The 120g indirect has amazing flow rates and can be twinned for additional capacity. They can be ordered in horizontal, and can be stacked 3 high. Lifetime warranty. I've seen no other indirects with a higher recovery rate,flow rates or a better warranty. Yes, they cost more.

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oil-2-4-6-gas

AERCO kC1000 1116 GPH 100* TEMP RISE --30 GPM max continuos water flow 30 gpm

Scott Gregg

Why Not a Noritz system

I'm kinda new here, but this one gets my atention.

If you have the space for anything, you should have the space for a Noritz system. They make tankless heaters like the Rennai but have a wider range of products including the biggest tankless on the market at 13.2GPM per unit. You can put up to 24 together for 317GPM or about 19,000GPH. Each heater weights 105# and wall mounts.

All you need to do is ensure combustion air which you will have to do with anything else anyway.

Other advatanges are the Noritz commercial units ARE commercial units with thicker heat exchangers and heavy duty construction. With a few of these on the wall in a multi-unit instalation you will have a lead/lag system with automatic redundancy and an extreamly efficient system that will modulate from 21,000btu on up to the max.

Contact them for sizing help www.noritzamerica.com