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Author Topic: Storage tank for tankless  (Read 276 times)

Offline walker

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Storage tank for tankless
« on: March 08, 2017, 01:42:34 PM »
I'm looking to add a holding/storage tank for domestic re-circulation to my Bosch tankless water heater to have hot water more readily available, maybe something small like 20-30 gallon, anyone know who makes such a thing, I've seen them out there before but I couldn't remember what brand they were.

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Re: Indirect Storage tank
« Reply #1 on: March 08, 2017, 02:36:26 PM »
The tankless should produce constant hot water as long as the hot tap is open.  What problems are you having?

Keep in mind an indirect storage tank is something you use with a boiler to provide domestic hot water and would have a heat exchanger.  These are not cheap.

Noble Trade sells AO Smith and Viessmann and Boone sells Amtrol storage tanks, but they all seem to be larger 80g models.

Your cheapest option is probably to use a conventional vent or electric water heater.  Just connect the plumbing and nothing else.

But now when the hot tap opens the tankless starts feeding hot water into the storage tank then to the hot tap.  If anything you will lose efficiency.  But I'm trying to think of any benifits.  What am I missing here?

Offline walker

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Re: Storage tank for tankless
« Reply #2 on: March 08, 2017, 02:41:09 PM »
I found this.

http://www.johnwoodwaterheaters.com/en/products/residential/5-Flow_THRU_Storage_Tanks/12-Flow_THRU_Storage_Tanks


The problem I'm having with mine is it takes too long to get hot, I'm thinking if I have more readily available hot water, it will be faster.  Now I'm wasting lots of water waiting for it to get hot, and the water ain't cheap out here in Guelph. I'm waiting sometimes 30-45 seconds for the water to get hot up stairs, where before I put the tankless in, it was only 5-15 seconds, I understand that it takes longer when there's a bunch of cold water sitting in the lines, but sometimes its ridiculous how long it takes to get upstairs. 

Offline walker

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Re: Storage tank for tankless
« Reply #3 on: March 08, 2017, 02:45:01 PM »
I seen these used a lot in the stacked townhomes where they use a combi tankless/boiler,  it has a separete loop that feeds to a storage tank with hot water and whenever the hot water in the tank gets cold it circulates the water through the boiler to get hot again, that's sort of what I'm looking to do with one of these.

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Re: Storage tank for tankless
« Reply #4 on: March 11, 2017, 07:23:33 AM »
I think you can reduce the wait time for hot water without installing a storage tank.  Download the Bosch Service Bulletin AP-03

Quote
The following information and illustration can be used as a guideline for supplying instant hot water to desired taps when recirculating directly through the water heater.
By use of a circulator, aquastat and/or timer, a loop of hot water is kept constantly hot and ready to use. This limits wait time for hot water delivery to the tap and excessive waste of water.

Offline Viperi

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Re: Storage tank for tankless
« Reply #5 on: March 11, 2017, 09:35:39 AM »
I believe Bosch makes one. Saw it at a authorized distributor wear house

Offline walker

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Re: Storage tank for tankless
« Reply #6 on: March 11, 2017, 07:40:46 PM »
The recirculation circuit looks like an option.  What kind of timer would I be after and what parameters would I look to set it at?