tankless WH question

Randy B.

I have mega experience on this subject. You could use one Rinnai 2532 wich in a cold region like mine will give 4.7 gallons per min roughly @ 70f degree rise. In other words at a 50f degree incoming water temp you'll get 120f degree all day long out of 2.5 showers. or one shower and a washer and a dishwasher. Or fill a large tub with no problem. If you live in a power prone area it takes 75 watts to run them or you can do like your contractor proposed and have a storage tank.
But don't get a gas fired water heater. Use an electric and dont hook up the elements. Instead use the thermostat to control a pump that circulates through the Rinnai which heats the water in the tank.
A gas fired water heater is very inefficient (uninsulated metal tube through center venting heat all day) unless you use a power vent and it will still not be as efficient as Rinnai due to the modulating ability of the Rinnai. Electric water heaters are an efficient storage tank as long as you dont use the electric elements to heat them with(no metal tube through center to loose heat 24 hrs a day).

Timco

My wife and I have decided to go with a tankless in addition to our 40 gal rather than 2 40 gal's. (We can and will easily get a HO permit.) Question is does the tankless feed the 40 gal, or take over when the 40 gal is out of HW? Seems to make sense for it to take over after the 40 gal is out of HW. We want to keep the 40 gal for emergency water storage should we need it.

Thanks,

Tim

Larry Weingarten

Why...

...are you looking at two heaters? Is there a large tub that needs filling periodically, or lots of showering? Tankless is particularly appropriate for big tubs and if that's the need, I'd plumb the tankless after the tank type heater, but only to supply the tub. A little more info on your hot water needs would be helpful. Some 5 gallon jugs for emergency water storage would be less costly than a hot tank ;~)

Yours, Larry

Timco

We always run out of HW every morning from showering. Both of us enjot the long, hot shower. Just the two of us, and on occasion, a guest or family member in town. Maybe leave the tank heater on 'vacation' or off alltogether?

thanks,

T

Larry Weingarten

It sounds like...

...the ideal application for a GFX shower heat exchanger! You can reuse about 60% of the heat going down the drain. That would negate the need for a new 40 gallon or tankless heater and have a payback too.

Yours, Larry

Timco

Please tell me more about this devise!!! I have never heard of such a thing and we are very interested and intrigued. How does this thing work?

Tim

Jack_21

Drop the tanks

You don't need them. One Rinnai 2520 FFU will run your shower(s) all day. Having said that, measure the actual flow of your shower head(s) with a bucket and watch and repost the real flow rate.

Larry Weingarten

Here 'tis.

http://gfxtechnology.com/ It is a simple counterflow heat exchanger. Lots of research and testing has been done on it. The claims are backed up.

Yours, Larry

Timco

soo...I will measure the flow, it's one of those large pan-shaped 'sunflower' type heads with no limiting bushing. We love the effect of the 'warm rain' it gives. Has anyone on the wall used one of these heat exchangers? It feeds the waterheater and the cold side of the shower? Looks a bit hoakey to me, but also makes sense. Some expert opinions prior to spending 3-400 would be great! Also, how to know which model. I have CI drain pipes, and would re-route the shower drain to run vertically and drain into the combi that is half burried and serving as my washer drain, rather than horizontally into the side of the toilet arm as it does now.

Thanks,

T

Timco

Is this a tankless heater? Could it be used with the heat exchanger recommended?

T

Jack_21

Yes it can use the HX mentioned.

Post the flow info. time the fill into a 5 gal pail and post the results.

hutch

propane tankless at 8200' elevation

Does anyone have experience with tankless HW on propane at high elevations. I understand there are BTU losses for both. What could I expect? Also, brand recommendations and dependability, of course.

Mark Eatherton1

Count on...

losing about 4% per 1000 feet above sea level. That and the combustion efficiency will KILL ya in places like Leadville, Colorado, 12,000' ASL...

Then throw in 35 degree F incoming water temperaturesm and ya got yourself a LOAD.

Properly sized, they can be made to work. Improperly sized, and they get cussed at a lot.

ME

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Randy B.

adendem

keep in mind this is at 2000 ft or under allowances need to be made for high elevation as the prevois poster said.