What would you do?

JackFre

You could go on-demand. Dump the petri-dish tank, reduce the temperature of the hot water, reduce heat loss, reduce energy consumption. Endless hot water when you want it. Get rid of dhw load on the boiler and you can buy a smaller boiler.

adambuild

What would you do?

Given the choice of a 60 gallon indirect kept at 145* with a mixing valve or an 80 gallon indirect kept at 125*, which would you choose and why? We just bought a home with a 60 gallon Superstor connected to a natural-draft boiler. I'm going to put an Ultra in anyway and was curious as to the opinions of my fellow Wallies regarding the indirect.

Thanks in advance, Adam

Steamhead (in transit)

Use the 60 with mixer

it will help prevent Legionella in the tank.

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Mitch_6

If you go with the Ultra

use the plus tank with it for best recovery.

Definitely jack up the tank temp and mix it down.

Mitch S.

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adambuild

Reason.............

Aside from Legionella issue, what is the reason to keep hotter and mix down? More efficient?

Thanks in advance, Adam

J.C.A._3

The big questions....

How many people and how many baths? How far are the baths and kitchen away from the water heater?(is a circ.line an option?)

I'm going with the rest, heat it up and mix it down. It's like having the 80 gallon tanks capacity @125°, but no worry about Leigionaires disease. Chris

JackEnnisMartin

legionellia

Hello
I would take issue with the bacteria scare --- in residental applications the tank is flushed out constantly and the chance for a pathagen to be allowed to grow is very low.If you had a 600 gallon tank such as the ones we used to take care of in the hospital--- you would and should worry about illness. We heated the tanks up to 190 F. once a month to sterilize the tanks -- all the water tests that were done before and after the test were always negative.All the best and a wonderful 2007
Jack Ennis Martin

Dave_4

A different big question

I would love to know the standby losses of a larger tank at lower temp verses a smaller tank at higher temps with both yielding the same amount of mixed hot water. Higher surface area losses at a lower delta T vs lower surface area losses at a higher T. If they are close, then by virtue of those standby losses normally only being true losses in non-heating seasons then a smaller tank may be more efficient. Unfortunately, it would be very tough to do this accurately outside of a lab.

Chris_82

Arrgghhh

I wouldn't need worry too much about the disease thing period. Legonella or whatever needs fresh air and almost tropical temps to spread, not to warm not too cold. Hospitals don't as a rule worry about sterilizing potable water period,most h20 in copper is very antibacterial to begin with, it is one of the endearing things about copper as compared with PEX. we as plumbers do worry about dead ends in piping because sitting water tends to grow mold and other naturally occuring stuff as a rule this only affects the elderly, sick, and our children, but as I frequently point out who listens to our kids when they are sick anyways...dead ends in piping are a much greater concern than legonairs disease. and open heating systems because of other stuff in the water. I can not begin to describe the number of new homes i have inspected and the Hot shot local plumber hasent bothered to dump some clorox bleach for an hour or two as most codes require or reccomend! Lower temps do save money on larger tanks but as already mentioned, recovery is longer esp with setback systems as in the ultra and others. I always reccomend larger tanks because of the idea it is better to have than to wait. And there is nothing wrong with higher temps and mixing valves...YOU should have a anti-SCALD valve in ther anyways even if it is just a precaution!

[Deleted User]

Allow me to disagree with both of you regarding Legionella...

It IS an issue, and people ARE dying from it daily.

Take it from someone who damn near died from it, this is SERIOUS stuff, and if you choose to ignore it, you will eventually lose.

Google Legionella pneumophila and see what the US Center for Disease control has to say about this problem.

It is THE most commonly MIS-DIAGNOSED disease in the WORLD.

Just because you haven't caught it does not mean it doesn't exist. It is omnipresent.

The only good thing about contracting this deadly disease is that if you do survive, there are no known cases of anyone ever having had caught it a second time. So, you either build an immunity to the disease, or, maybe you die outright the second time...

It is NOT to be taken lightly.

Mark Eatherton

(Confirmed survivor of legionairres disease.)

Brian

Code

You may also want to check local building codes on water heaters.Here in balmy Ontario all new water heater installations must be set at least 140F with a mixing valve set at 120F.Either way go small and temper the water.

Good Luck
Dobber

Mike T., Swampeast MO

If the existing indirect is suited to DHW priority with the new boiler why replace?

Chris_82

if people are dieing daily,...

Then do something about it?

Plumdog_2

hot shot local plumbers

You inspect new homes? Where? Etheopia? Your advice about legionaires and mold growing in pipes and copper preventing bacteria is way misdirected and uninformed.

ALH_4

Legionella

From Wikipedia:

158 to 176 °F - Disinfection range


At 151 °F - Legionellae die within 2 minutes


At 140 °F - Legionellae die within 32 minutes


At 131 °F - Legionellae die within 5 to 6 hours


122 to 131 °F - They can survive but do not multiply


68 to 122 °F- Legionellae growth range


95 to 115 °F - Ideal growth range


Below 68 °F - Legionellae can survive but are dormant


------


Based on that, I would keep the tank at around 135 and feel pretty safe.