Knowing that thr DHW load

hr

Is often the biggest energy user in most homes. My first choice would be to require a solar preheat panel on every new home. Next would be to generate this year 'round load as efficientlyas possible. With 125-130 degrees being the industry "safe" temperature for burn risk and legionella prevention :)a condensing heater makes the most sense from a sheer efficiency standpoint. I cannot see how running a boiler at 180-200 comes even close.

Now since the customer wants hi-efficiency everywhere This thermo siphon HX gives you the ability to add a small radiant zone or two. I'm hoping to see a 100-115 degree temperature an the B side. I have built a couple of these tube HXs and used them on my solar DHW. They seem to work fine in that application. I think they will work fine in the opposite mode. If not I have room for a circ pump.

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hr

Is often the biggest energy user in most homes. My first choice would be to require a solar preheat panel on every new home. Next would be to generate this year 'round load as efficiently as possible. With 125-130 degrees being the industry "safe" temperature for burn risk and legionella prevention :)a condensing heater makes the most sense from a sheer efficiency standpoint. I cannot see how running an 80% boiler at 180-200 for indirect tank use comes even close.

This tank has a 100,000 input and runs in the 90%s even at 130 from my testing. That should be plenty of power for most medium to large families.

Now since the customer wants hi-efficiency everywhere This thermo siphon HX gives you the ability to add a small radiant zone or two. I'm hoping to see a 100-115 degree temperature on the B side. I have built a couple of these tube HXs and used them on my solar DHW. They seem to work fine in that application. I think they will work fine in the opposite mode, especially with the 1" tappings on the tank. If not I have room for a circ pump.

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Floyd

Very interesting....

let us know how it works!!!!
It will be really interesting to see how fast the
thermo siphoning action starts once you
put a load on it after it has been setting for a while.
My gut feeling would be that you would want a circ.
especially if there was much of a load, otherwise the
delay would be too long.

Just thinking outloud, would love to experiment with that sucker!!

Floyd

kevin

a slight digression...

To help w/ reduce the cost of hot H2O would be one of the GFX heat extractors you put on the vert. drainage.I think ducette industries is making the now. i have put a couple in. HO cant't seem to run out of hot water now even w/ only a 50 gal top performer. Kevin

Dave Yates (PAH)

hot water - danger lurks

120 to 130 degree potable water is still within the legionella breeding range. 130 is getting closer to the 137 degree temperature where virtually all legionella growth is halted and the majotity (not all) of the legionella bacteria is killed. To be safe, all potable hot water systems should be held at a minimum of 140 degrees and only reduced to lower temperatures within 18" (or less) of the fixture. Recirculation should be required to maintain the supply piping at elevated temperatures.

Why maintain 140 degrees? Because safe levels of chlorine are ineffective against legionella bacteria, dissapates in water as it is heated (causes pitting of copper) and temporary hot water flushes to temps as high as 180 degrees have demonstrated they do not work beyond a few weeks until the system is recolinated.

Chemical treatment with chloramine or copper & silver ionization systems remain effective but expensive and best performed by those trained in their use.

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hr

The lesser of two evils??

I understand your concerns with bacteria, Dave. I have yet to hear of a plumber being sued for a DHW legionella bacteria problem, however. Have you heard of a plumber being involved in a domestic water legionella issue?

I do, however, know several plumbers that have been sued, and lost, soft tissue lawsuits, along with the heater manufacture, and the fuel utility.

The water heater manufactures are VERY clear about the dangers of changing the factory 120 degree setting on water heaters.

I'm not sure exactly how a plumber protects himself on these two issues. Personally I'll leave the tank at the factory setting, for liability reasons, or install a fail safe mix valve to keep the tap temperature within the limits if the tank is run hotter than 120, and notify the homeowner of this with the label provided with the mix valve.

I may reconsider if domestic hot water leigonella cases start hitting the news and courtrooms

hot rod

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Dave Yates (PAH)

All it will take

is one legionellosis lawsuit & the scalding suits will pale by comparison. 3 to 4,000 scalding cases occur each year in the US. CDC estimates 10 to 20,000 Legionellosis deaths per year in the US. Are lawsuits an unrealistic expectation/eventual outcome? Why wait? Other countries are a step ahead of US in this area by requiring a mix valve at the tank outlet that holds temps to within 3 degrees (did you know current water heater regs permit a 30 degree fluctuation from settings and an upper limit of 190 degrees?). Then the entire supply system is held to a minimum of 140 degrees until the final thermostatic and pressure balancing valve, which must be located within 18" of the faucet. So, everyone is off the hook & the lawyers go hungry(G). No scalding, no legionella, no worries!

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hr

Guess that takes

Mana-block, and other manifold hot water systems off the option list. What about kitchen faucets or other two handle type? I wonder how many of those 20,000 deaths are caused by plumbing systems, currently?

How are you plumbing houses these day knowing all this is about to hit the fan Are you running a 140 degree recirc to within 18" of every tap? I would guess 1" insulation would be a must on a constant circ loop like that, as would copper pipe. The cost of plumbing will take a big jump when thermostatic faucets, and insulated constant recirc systems are code required. A profit center for plumbers or... ?

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Dave Yates (PAH)

well

block type manifold systems don't necessarily go away, they simply require some minor alterations.

Mixing devices that comply with regulations already exist for two handled faucets. Very easy & installer friendly. Refer back to previous paragraph!

I wonder too.

By informing the customer & letting them make the decision. mine runs at 145 degrees. If the codes are changed, this becomes a moot point & everyone gets to play on a level field. Right now, low baller gets the jobs (in new construction - a game I'm not playing since it's a no-win situation).

Insulation is already addressed in the current codes.

Costs go up? Profits increase? You betcha. But it's not the costs that concern me, especially considering the massive square footages and million dollar+ homes people are scarfing up. Hell, if they can afford to live in the lap of luxury, drive the newest model cars while all the time riding a knife edge of gambling on keeping healthy until that jumbo mortgage feels much more affordable, then they can afford safe plumbing. It's that phrase about the plumber protecting the health on the world that keeps popping up in my head.

Could be I take this stuff too seriously!

I toured a million dollar+ home a few weeks ago. The builder is marrying a classmate of Lois, so we were visiting & they wanted to show off the development. In the master baths, the tubs of choice are enameled steel! Don't you just love the sound of rain falling on a steel roof? They'll get that opportunity every day(G). Only the stuff that glitters matters.

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Duncan_2

80s vs. 90s, fifteen years vs. thirty.

Pretty spiff thermosiphoning HX, hot rod. And if the output isn't as expected, circs can always be added.

As for efficiencies in the 80 percents at 180 degrees coming close to efficiencies in the 90s at 130 degrees, I'd say it's within twelve percent or so. No question the 90 percenter is more efficient.

I'd say (from experience) people who are interested in solar are more likely to be interested in efficiency for the sake of conserving petro-resources than they are for realizing payback on investment. There is that market. It's likely to grow significantly, maybe explosively, in the years to come.

Most folks in my neck of the woods are interested in reliability: remote locations and some very cold winters. I'm not sure how well stainless welded tanks as heat sources hold up over the long haul compared to eighty percent efficient iron. I'm thinking of stainless welds in terms of water chemistry, service call expenses, and overall life expectancy vs. install cost.

To me, this lessens the attractiveness of SS tanks compared to the thirty year life expectancy of cast iron. Every type of installation has its advantages and disadvantages.

As far as Legionella, what kind of sediment is anticipated with stainless steel tank heaters? As an anchor for microbial growth, sediment is an aspect to compare and contrast indirects heaters with tank type. But I'll leave that aspect to Dave. [GRIN]

hr

Good points Dave and Duncan

Heat source reliability problems are generally electrical or electro mechanical problems. Gas valves, HSI, relays, aquastats, vent dampers, etc. So then the choice comes down to comfort level with materials. SS or cast for the long run? I am still waiting to see a 30 year old cast iron boiler connected to radiant! I am hope the latest O2 barriers and chemicals I have started using change my "cast iron life" experiences. The only 30 year old cast iron boilers I see are connected to copper baseboard!

I think SS has the upper hand for a long lasting material but the weak link has been the fab process. Viessmann seems to have it figured out in the weld arena.

Right now I'm more concerned about West Nile Virus than legionella from my faucets, seeing as I live in mosquito country. One health epidemic at a time or we will over load the shock jock newscasters

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Dave Yates (PAH)

Ah, my wild eyed brother from another mother!

you hit the nail in the sweet spot. Foil hats at dawn? Indeed, sediment and the lack of superheating thereof is a concern. Having said that however, gas fired beasties have tested positive too - just not at the same percentage rate - thereby lending credence to the theory that the little buggers enjoy a taste of amnesty in sediment uncooked.

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Dave Yates (PAH)

We're thinking too much alike!

just tonight I was discussing the very same issue with my bride & pondering why the WNV attracts so much attention for 88 infections, while issues such as legionella whither on the vine.

The bugs like to evolve! We're off to mosquito infested Chincoteague next week. Electric WH with sediment intact & tons of biting beasties - oh my!

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Dana Zaichkin_2

West Nile Virus

Lots of publicity and public resources on an infection that has pretty low morbidity/mortality - unless you are immunocompromised. Most people get flu-like symptoms and go undiagnosed. Now Rabies, Hantavirus and Hepatitis B,C & D - those are reasons to get scared. Stay away from bats, racoons, rodents and Tatoo parlors!

Cheers :-)

DZ

ScottMP

Another county heard from

Dave, 140 out of the tank ? Do you install tempering valves. I have no problem with the temperature, but more of a problem with the litigous customers who wait to spill coffee.

I understand the problem with Legionella and would love to put my customers health over their lawyers wallet, but I am scared of the enemy I know, more than the one I don't.

I have a personnal injury lawyer across the street and am reminded daily what they are like. His mind set scares me.

Scott

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Dave Yates (PAH)

Scott

Nothing will change unless the codes get changed. It'll be business as usual; lawyers will continue to get rich; scalding cases will continue and legionella will continue to be invited to survive & grow in unprotected systems.

If we (as plumbing contractors) were required to install certified theremostatic devices at the hot water storage tank that were set for 140 degrees F (plus or minus three degrees) and a thermostatic or pressure and thermostatic device at the point of use that can be set for delivery temps of choice (again holding within a few degrees of set point), then everyone benefits. No scalding cases, no legionella (not to mention cryptosporidium or other nasty bugs) and no legions of lawyers getting fat from million dollar settlements. Gets the water heater and storage tank folks off the hook too. Then the liability would rest with the manufacturers of the mixing devices. At least one of them is ready to take on that liability.

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hr

Mixing devices

atr every h/c faucet will be a huge maintenance problem. My experience with thermostatic mixing valves (used onj every Combi Cor I installed) shows that these valves even under the best of water conditions need constant cleaning to operate properly. The thought of these scattered throughout the house...oh my aching back

What about RO units, water softners, point of use water filters, DHW expansion tanks, etc. Seems these are also breeding grounds for bacteria. Where does a plumber draw the line on protecting the entire nation against this?

hot rod

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Dave Yates (PAH)

the times, they are a changing

new thermostatic valve technology will allay your fears. You'll be seeing news on these in the near future. Untreated well water will require the treatment it should have had anyway - there's more work(G).

Flow through thermal expansion tanks offer no hiding places for bugs or stagnation.

Upstream or downstream of RO units?

UV filtration for softeners. Kill em before they ever get a foothold. BTW, this is doing quite the job for systems in public environs when initiated prior to placing them into service. Tough for the little buggers to gain a foothold if there's a bouncer at the only door(G).

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Duncan_2

Reducing the risks

I also have to wonder what the chances of getting Legionella actually are.

There's a couple of things going on here: the level of risk, and biasing the odds in your favor.

Legionella occurs naturally in almost every body of open water, but poses no risk to healthy adults. I think that gives most of us a pretty good chance of staying healthy.

There might be a ten million to one chance of being killed by a shark, but is it reasonable to assume jumping into the middle of a school of sharks keeps those odds?

Legionella-wise, are the odds going to lessen as more shared-water systems are installed?

Also, doesn't the CDC record only OUTBREAKS of legionella? Matt Frieje points out that there may be more undocumented cases than we're aware of. Single cases here and there are probably largely undocumented.

You know... sometimes this stuff hits closer to home than expected. I think of my brother who's taking drugs for leukemia. At one point, he had to take immune system supression drugs (which put him in an at-risk category). That put things in a different perspective for me, made it more real. Also, I had a severe case of bacterial pneumonia this winter (legionella is also a bacteria that infects the lungs), and it was no picnic, I was hospitalized six days.
On the other hand, 140 degree water can take your skin off.

I think it's about being prudent and minimizing risks the best we can.

Dana Zaichkin

UV Systems

Dave,
Do you have any good resources/references on residential uv whole house systems. We've been considering one for our house - out on a rural community water system where we dont really feel like being the "canary" for any water system problem. One I looked at combined a sediment, carbon block and uv chamber - I have no idea what the pressure drop is like across these either.

Best Regards

DZ

Dave Yates (PAH)

UV

Dana, Lots of options for combination filter units, but the UV portion does not affect pressures. What you'll need to know, is peak flow rate to accurately size the unit. We design ours for GPM rates in excess of actual flow.
If you want asssurance above & beyond, add a solenoid valve that fails closed during a power loss. That way no water gets to sneak past when the bulb is out from power loss.

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Dan Foley1

CI Boilers

Come to my neck of the woods, Hot Rod. I will show you plenty of old cast iron boilers hooked to radiant (copper, wrought iron and even threaded steel), radiators, cast iron baseboard, and fin tube. I work on one old radiant system that still has the Sarcotherm mixing valve controlled by a cap tube outdoor sensor. Maybe it is because these old boilers had a large water content - sort of like a built in buffer tank. -DF

Dana Zaichkin_2

Any preferred units?

That you have had experience with?
Thanks

Dana

hr

Cast iron

boilers connected to rubber or PB or Pex is what I meant to say. Mostly because those tube products were introduced to radiant here in the mid 80s so it will be a few years before we get to the 30 year mark.

As we all know much or the early plastic and rubber was non barrier, this will haunt us for a few more years I suspect, possibly manifesting itself in plugged and corroded boilers in systems that are not cleaned or treated properly on the water side, especially. It seems to present itself in copper tube boilers in the 10-15 year range in my experience.

I agree with your findings the old iron an copper radiant jobs seem to run until the tube rusts or corrodes or shears away, not the boiler. I have seen a fair share of 50 and 60 vintage Am. Std. boilers still cooking away in this area. That's old for this area of the country, hydronically speaking.

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