# water heater storage (residential)



## spudwrench (Sep 15, 2009)

Long story short-75 gal. gas, 75000 BTU. Installed an 80 gal soaking tub. Homeowner wants to provide adequate hot water after a tub fill for basic needs. The 75 served them well before the new install. Laing recirc. always on. If we install an 80 gal. elec. in series, with the constant pump, as a storage tank? What do you think? Forget tankless, not gonna happen. Power vent in parallel is a maybe, but for a once a week usage just seems to be an energy waster. The home is vacant 8+hrs. per day(m-f). The recirc. in my mind will provide the system with 80+80=160 gal. of hot water at any demand time plus the basic use. Checking with my Reps. on this kind of install, but looking for "been there,done that" responses from the PZ members. Read my post in full, and think about what I have said above. I think that it would work????


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## plbgbiz (Aug 27, 2010)

It doesn't take an 80 gallon water heater to fill an 80 gallon tub. Unless of course you have the water temperature set on the heater the same as you would take a bath in. Remember you are mixing that hot water with some cold water so you really don't need 80 gallons of "hot" water.

Adding an 80 gal electric to an existing money pit of a recirculating system would be my least favorite choice.

I'd recommend the programmable control module and mixing valve kit from Bradford White and retrofitting the existing 75K btu heater. According to BWC you can save 36% on the energy cost and increase the gallons of hot water by 50%. Many believe that the increased water temperature might decrease the life of the tank but that is still better than adding another 80 gallon unit tot he house for a once a week bath.

http://www.bradfordwhite.com/products/residential/accessories/accessory_module.asp

I have used mixing valves to increase hot water volume many times. Happens all the time in restaurants.


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## plbgbiz (Aug 27, 2010)

You can do it without Bradford's kit as well. Increase the temperature of the existing water heater and add a tempering valve to the outlet.

Without any added accessories, the BWC 75 gallon power vent will provide 140 gallons the first hour. It is probably off the charts if you add the accessory module and mixing valve kit.

http://www.bradfordwhite.com/images/shared/pdfs/specsheets/102-B.pdf

This seems to be a much simpler and more predictable solution than adding another tank or even a tankless.


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## CTs2p2 (Dec 6, 2011)

Yup just going to say that ^^^^ turn up the temp on the heater to make like 140 degree water and add a mixing valve. I would also add an expansion tank too.


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## JK949 (Mar 18, 2009)

Recirculate always on wastes energy and could lead to pin holes in bad water conditions. Get a timer or aqua stat on that thing, test for high chlorine in the water.

Adding a power vent where one hasn't been installed before my lead to noise complaints, I've experienced it. That being said, a properly installed A.O.Smith Vertex will make hot water all day long. 
I would go with the tempering valve idea first, but check the anode rod to see if the tank is still healthy.


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## plbgbiz (Aug 27, 2010)

+1 for checking the anode. Firing up a tank in bad shape might be the straw that breaks its back. Then everyone will wrongly accuse the hot water.


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## Joseph clegg (Nov 12, 2011)

Bradford white makes a water heater gx series the gx 55 gal will fill up that tub and still have enough hot water for another comes atmospheric and power vent models


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