25 gallon water heater

[Frank Bombardiere]

I ran across this 25 gallon water heater today. It was in a nice new home about 2600 sq ft. Had approval stickers for plumbing approval. It had some type of re-circulating system on it. I have not ever seen a 25 gallon water heater set up this way. Any knowledge would be appreciated. Side note - the gas service was off so I could not run water to see how long the hot water would last.

[John Dirks Jr]

Was this re-circulating system plumbed with 1/4 copper tubing? I've heard they do this so that water is hot at the fixture as soon as you turn it on.

It is done in case where the source is far from the water heater. The system pumps just enough water through the lines to keep the hot supply heated up. When you turn the faucet on, you don't need to wait for hot water. It's right there waiting.

[Frank Bombardiere]

That is correct. I am familiar with re-circulating systems, but I have not ever seen a 25 gallon water heater that supplies an entire 2600 sq ft home with three baths. I don't see how the re-circulating system can make enough difference to supply enough hot water for a home like this.

[Ron Hasil]

I ran across this 25 gallon water heater today. It was in a nice new home about 2600 sq ft. Had approval stickers for plumbing approval. It had some type of re-circulating system on it. I have not ever seen a 25 gallon water heater set up this way. Any knowledge would be appreciated. Side note - the gas service was off so I could not run water to see how long the hot water would last.
That 25 gallon water heater provides more hot water in the first hour than a single 75 gallon water heater, which is 155 Gallons first hour delivery.. The temperature inside the tank is 180º F with a tempering valve on top reducing the outlet temperature to 120º F.

[Ron Hasil]

Here is the cut sheet for that heater. http://www.bradfordwhite.com/images/shared/pdfs/specsheets/119-B.pdf

[Jim Luttrall]

Did it have a thermal mixing valve on top?
I came across a 50 gallon unit designed for replacing twin 50s that one of our plumbing specialist clued me in on a few months back.

[Jim Luttrall]

Thanks Ron, you beat me to posting while I was looking up the photos from when you helped me with a similar issue.

[Ron Hasil]

Did it have a thermal mixing valve on top?
I came across a 50 gallon unit designed for replacing twin 50s that one of our plumbing specialist clued me in on a few months back.


Its a 55 Gallon unit by Bradford White model # GX-1-TW-55S6BN which gives 200 gallons of hot water in the first hour delivery.

[Ron Hasil]

Thanks Ron, you beat me to posting while I was looking up the photos from when you helped me with a similar issue.
So after you learned about these units and seen one first hand, what do you think of them?

[Frank Bombardiere]

Bingo. It did have the tempering valve. Makes sense now. Thanks

[Jim Luttrall]

So after you learned about these units and seen one first hand, what do you think of them?

The jury is still out for me since I have only seen one installation and have not heard back from the client, but the theory seems sound.
It definitely was a good replacement for the single lady living in a large house with 100 gallons on standby, but she may never test the capabilities fully.

[James Foy]

Seems to work similarly to the 'instant' hot water heaters in some ways: smaller capacity and higher BTU's, keeps a supply of hot water on standby, but doesn't use as much energy as keeping 40,50, or more gallons hot. Funny thing about the instant water heaters is that people tend to take much longer showers and saving no energy, and using more water. I'm sure someone at the EPA will require timers for them in the (near) future.

[Bob Harper]

Check that rating plate again. It states 78,000 BTU input. That's more than your typical 75 gallon tank. They figure on a rapid recovery but putting a flame thrower under it. I would be very concerned about gas pipe sizing and being able to deliver 78mbh with the house under full load. Otherwise, you could be under firing, which could result in lower recovery rate and poor combustion.

Any pics of the tank further back showing the venting and gas piping?
Bob

[Bob Harper]

Jim, that foam insulation on the mixing valve loop has to go. 6" clearance to combustibles from the draft hood.
Bob

[Jim Luttrall]

Bob, that is an old picture I recycled just for an example, but yes there were a multitude of issues with the installation. I basically told the client to find a competent plumber (Not the one who did the install) and have them start over since every area from the drain pan to the vent flashing on the roof was messed up to some degree.