Sure, my emotions get the better of me all the time, but if Caduceus has actual information to share I'd like to see what it is. If that info isn't available on the internet fine, I have multiple medical professionals (one is a research MD/Phd) and multiple PHd biologists in my family, and can get second-hand access to published research that may not be readily via internet sources.
Without outlining the mechanism by which letting the tank stagnate to room temp it's hard to assign much credibility to a point of view. Simply asserting "you don't know what you're talking about" isn't very illuminating.
According to the CDC data the prevalence of legionella in the US is over 300,000 reported cases/year reported, which is more than 5x the risk of getting hit by lightning. It's a real public health problem, but the increased risk factors from potable water systems come from tepid-water stagnation, not room temp stagnation. If your normal storage temp is at a lethal level, I don't understand the mechanism by which letting it cool to room temp with no flow carries any significant elevation of risk. If water is stored at only 120F there is a theoretical elevation of risk by the few 10s of hours it spends in the high-growth temperature zone.
All ad hominem BS aside, I'd really like to know how this works.
Last edited by DonL; 10-18-2013 at 09:11 AM.
Nobody is disputing legionella exists, it's bad, it kills when inhaled...but it's not active in my water heater at 140F or at ambient.
Romeo and Atlanta, MI
Medicine kills also. I would rather have the problem, than the side affect of medication.
Doctors are always practicing. What do they know ?
First thing they ask is "What is wrong with you"
I pay them to know, not to kill me with their Fix All.
People are living to long and going Nuts, and we need to Purge...
If you go to your remote cabin, with your loved one and die from drinking bad water, Then more power to you both. It will not happen unless it is your time, You can not change that.
Not much hope for the world as we know it. Nothing is safe now a days.
That includes the GOV and what they say is good for You.
Last edited by DonL; 10-18-2013 at 10:09 AM.
In the absence of actual evidence that there is an increased risk when a tank normally run at 140F is allowed to stagnate at room temp for weeks/months providing a plausible narrative on how that risk might rise under those circumstances would be useful. The risk is never actually zero in almost ANY scenario (even storage at 140F) but in terms of the magnitude of risk, it varies a lot with the circumstances. The amount of legionella that could actually form over a few days as the temp decays through the active zone from a nearly-sterile 140F to an inactive room-temp would be quite limited- more than would happen were the tank maintained at 120F over the entire week/month/year of no-flow. But it doesn't seem plausible that it's anywhere near the risk of pointing the five-iron skyward on the backswing while taking a shot from in the middle of the par-4 fairway during an active lighting storm. If there were even a single case in the literature of detectable legionella from a potable storage that followed anything like the time-temp profile of letting a 140F tank drop to room temp and dwell there for a substantial length of time I might be convinced. But from the published information on how this stuff actually behaves in potable water systems, I'd be VERY surprised indeed.
Big vats that are rarely purged and maintained at danger-zone temps like hot-tubs become pretty serious legionella reservoirs. Be sure to hold your breath in the hot tub, eh? Seriously- if you can't smell the chlorine you may not want to soak in the hotel spa. Even though the risk is still small, it's probably several orders of magnitude higher than the room-temp hot water heater scenario.
I do not think the pilot on a heater will do much good to keep water warm.
It may keep water from freezing.
The differential on a gas valve can be as much as 20 degrees.
I think most electrical controls may be around 10 degrees.
So even in normal use you could die.
The new thermostats that I have seen will not let you crank the temp, or you may hurt yourself.
Just shoot me now.
Dana, I think your theory is good. It all depends on the water quality.
NASA may pay you to pee then drink your own urine. Astronauts do it.
How sick is that ???
Last edited by DonL; 10-18-2013 at 02:52 PM.
OK so this guy isn't a rocket scientist, he's an astrophysicist, but his hands-on lab measurements are no worse than the average HVAC pro. ;-)
"I could never recommend allowing a water heater to drop below the 120 deg.F. mark for any period of time. If you are gone for just a few days, what is the harm in leaving the tank stay as it is. It is unknown at any time how much legionella bacteria may exist in your public water system at any time. Typically there are low amounts of microrganisms depending on what type of chemicals are being used for water treatment and they have no affect on us because of the low concentration. But don't try to sell yourself into an idea that promotes a lack of safety, err on the side of caution.
Some may say that they have never gotten sick from their hot water, but may have and not realized it. The symptoms are the same as the flu and may take just as long after exposure to show the symptoms. Children and the elderly are especially susceptible to the health risks when exposed. Rarely is ingestion of contaminated water a cause, unless aspirated. It is when taking a shower that it is inhaled with the vapors and settles in the lungs.
The ideas that water sits in the pipes anyways and that temperatures drop in the tank when cold water is used are geared towards ignoring the core issue of safety with your water system.
Just flush the pipes when you walk in the door and keep your tank at the normal operating temperature and you won't have to worry about Pasteurizing your tank or chlorinating the piping. "
Or if you're having trouble with all of the letters and words...."Leave the tank on, it couldn't hurt". That was my reply before the barrage of smart-ass comments. To think you've been shooting your mouth off this whole time and didn't see my first post. You've really shown your arrogance many times in this thread...it's actually quite impressive. Now you can save your money from those ESP classes and spend it on charm school.
Last edited by Caduceus; 10-19-2013 at 06:16 AM.
I'm, at this very moment, having my septic tank pumped out.
Too bad I can't get this thread sucked out also.
Little did I realize, at the beginning when using the descriptive "inane", that this thread would evolve and descend into something suitable for a cesspool.
Very appropriate for a plumbing forum.
Last edited by Caduceus; 10-19-2013 at 08:51 AM.
Last edited by BobL43; 10-19-2013 at 09:12 AM.
I am definitely not a pro plumber, but I am a pro crastinator