More hot water....

Phil_6

with a 35 degree temp rise. Okay for Florida I suppose. I don't know exactly what the water temp is here on LI in the winter, but I'm pretty sure it's less than 70 degrees. I figure one of these will be about half of what he needs in the winter. Or should I say half of what he would like.
People see all these crazy shower systems in magazines and on TV and don't realize they need a nuclear reactor to make the hot water fast enough ;-)

Phil_6

more hot water needed

I have a customer who is looking to be able to have a pretty much unlimited amount of hot water available. Right now he has 2 75 gallon gas water heaters but he says it's not enough, and there's a new bathroom going in with a big shower with 6 body sprays, a shower head etc. There are also 4 or 5 other bathrooms. I haven't really checked, but I don't imagine his chiminey can handle another piece of equipment connected to it. There is a hot water boiler we could use for an indirect. It's around 200,000 btu or so. Could I pipe them all together and get the right results? I'm skeptical. We considered 2 tankless heaters piped together dedicated to his new shower but have location and venting issues to be resolved (never mind the cost)
What do you think?

Thanks, Phil

Bruce M.

Rinnai Continuum

This on demand gas hot water heater delivers 8-1/2 GL per minute. It can be mounted indoors or outside. Will probably save a lot of money. Here is the URL for their web site.

http://www.foreverhotwater.com/

Mike T., Swampeast MO

Are The Heaters Piped in a Parallel Arrangement

If so, put them in series with the first set a little below the second. I did that (plus fix the little problem of a thermostatic valve installed backwards by "the best plumber in town") a few years ago for a person with a multi-outlet shower and they no longer ran out of hot water.

If you pipe and valve as shown, you can run both or isolate either for service.

Phil_6

yes

they are piped in parallel. What you suggest is certainly worth a try. If it works out for the guy it's a pretty inexpensive fix. Thanks for the suggestion.

Bruce M.

Commercial Rinnai with a 60 degree rise =5.6 GPM

That is without the Rinnai Storage tank. The Rinnai can also be used in multiple units. With the storage tank and a second Rinnai it would be virtually impossible to run out of hot water.

Bruce M.

800 number for Rinnai

1-800-621-9419

hr

No free lunch

IF they really want that much hot water for that duration you need to A- store that much in insulated tanks. or B-create the HW as they flow the load(s)

First identify EXACTLY what they want then use the charts from the WH manufactures to size the tanks, or the instantanous size sheet for that route. To make a lot of hot water instantanously you need lots of BTUs. Period! Gasline, flue size, incoming water temperature are all important.

In this case I would put it all in writing! Spell out exactly how much hot water your system will provide.

Some people just never get enough

hot rod

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Bill Barrett

piping and showers

Hi Mike,
Was just at a AO Smith
meeting today, we talked about this very thing. He told us
TO pipe in parallel, In series the first unit will handle most of the load, and with high demand condensate will shorten life span of first W/H . We also talk about some of the showers and shower heads now, its nothing to see a 12 gal/min. hot water demand! Glad we have a energy shortage.
Bill

Phil_6

never get enough..

I am always amazed at the amount of money people will spend to be able to take a long, hot shower. When they tell me what they want..6 body sprays big grohe shower head..hmm pull out the restrictors and you can probably use way over 10 gal a min. I tell them to do the math, that that 75 gallon heater will be done in 5 minutes,and they get this look on their faces like "hmm...I never really looked at it that way." But I have to admit, this guy seems ready to spend the money. I kinda hinted in a rough way what two big tankless heaters would run and he wasn't really too put off. I just need a place to put them. Hopefully real close to the gas meter. The basement is all finished off nice so there's not much room.

Thanks for the help

Phil_6

I do like the idea

Actually the customer mentioned it before I could. But we need 2 for sure if we're going to do it at all, but I need a place to install them. Big giant house and not much room to spare. Venting considerations, gas pipe size, protection to the rest of the house from accidental leaking, freezing, distance from the bathroom. Each little nook and crannie we consider has a drawback so far. But there's still time to figure it out, we're just starting into the project.

Phil_6

But...

...the question to ask them really is "will it make more hot water or not??" If you pipe them like Mike shows above, and the first one lasts less time because of more condensation, the second one should maybe last longer from less condensation...lol And does the customer, or me for that matter, really care if we all know this up front, and they have plenty of hot water? Or maybe the water heater companies don't want to get any extra 10 year heaters replaced after 7 years since they could never know how they were piped at the job anyway. Just thinking out loud.

Phil

Larry Weingarten

I know...

it's been mentioned elsewhere, but the right model of GFX heat exchanger will recapture 60% of the heat going down the drain. Put that back into the shower and you can substantially downsize the heat making equipment. GFX and showers are a good match. Heck, the client will be forced to save money too!

Yours, Larry

Jack_21

First thing I guess is to ask what the load

is to be sized to. Is just feeding the shower, for sizing purposes, ok? With 6 (2.5gpm) body sprays and, what, a 7gpm shower head equaling a mere 22gpm you can do it with Rinnai Continuum's with or w/o storage. Hot Rod is spot on with the gas line sizing issue. These are on-demand units so when they call you have to be able to feed them. Also, I had a guy call me for these in this type shower and I asked what he had for a drain in the shower. Totally inadequate for the load. That took care of that.

Either the models 2532FFU or the 2520FFU will provide 4.5gpm at a 70f rise. You can run these with or without storage. Location and piping layout will of course depend upon the floor plan/recirc,etc. Once you get a bit better idea of what the customer is going to accept I can make some specific recommendations for you with the Continuums.

The advantage of multiple units is that if you had 5 Rinnai's in a line with the MSA controls installed. you would have a system set to run from .6gpm-5X5=25gpm depending upon temp rise again. The other plus is that with full modulation you can fire anywhere from 15,000btu up to 900,000btu. No energy is consumed unless there is a load. If only one of the other reasonable showers is running the system will fire only enough gas to satisfy that load. But the potential is there.

I am just amazed by people who give no consideration to the location of mechanical equipment. You tell them that you would prefer to not put the equipment down by the end of the driveway and it is like you slapped them. But then if they are not comfortable...look out!

When you get an actual design number I'll help with a sizing with Rinnais with and w/o storage. Just tell yor customer that this is like building race cars. "Speed costs money, how fast do you want to go?"