OT: Separate hot and cold valves on kitchen taps save energy.

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It doesn't sit in a largish tank at just the right temperature to grow things, though. ...one reason to not lower the temperature of the water heater.
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wrote:

Good point. 120F is the standard temperature for good reason, set it there and leave it. Not only does it kill off most nasties in the water, but it also gives a pretty decent run time when you fill the tub or take a shower.
Some fools turned my aunt's water heater way down, it was probably 80- 90F. Filling the tub meant there was no water for anything else, as you had to open the tap all the way to get warm water for the bath. If you wanted a hot shower, you couldn't get it. The whole system was grossly inefficient.
I was more concerned with the lack of hot water and didn't think about the nasties until later. WH's back up to standard, things are safer and working like they should.
Puckdropper
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On 1/31/2016 2:12 PM, Puckdropper wrote:

In my opinion, 120 is too low. You can prevent scalding with the proper shower valve though. I just turn it to full on and the temperature is fine.
http://www.cashacme.com/resources/hot-water-safety/ Legionella is an aquatic bacteria that thrives in warm water environments, and is the cause of Legionnaires Disease. It is commonly found in potable water supplies, hot tubs, cooling towers, fountains, swimming pools, etc. and multiplies in warm conditions especially between 68 – 122 °F. The Legionella bacteria can spread to humans when breathed in.
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Glad you mentioned this, one thing is consistent in what you described that is not true about HW heaters, that is that everything you described is open to the air. Most use the same chemicals for water treatment which some humans like myself are allergic to in the first place. Cooling tower chemicals have changed in most places to different chemicals to help eliminate the problem.
The only thing in a HW heater that might present a problem is a zinc anode, and many new HW heaters are glass coated to eliminate erosion and do not use Zinc.
105 deg HW is the safest for those who have diabetes and do not feel things as they should, 102 for infants to prevent burns and scalding's, 140 degrees F for dishwashers, so that their booster heaters can raise the temp high enough (180) to kill germs on dishes etc. So you can set it where you need it for your best interests, and if you need to for showers and tubs you can buy thermostatically controlled mixing valves but that brings up additional needs and retrofitting costs.
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Yet Legionella is found in closed water heating systems.

140F at the water heater does not mean 140F at the faucet.
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I have never heard that to be the case, if it was then the disease would be consistently high across the nation since you cannot treat it there.

Yes, if you have a recirc system or in the normal home if you let the water run unmixed, otherwise the Dishwasher would never see it. Usually the only time you see it is in restaurants for the kitchen area's. My home was set that way for years, but we had mixing valves at every sink. It is a real problem when one has two separate valves, one hot, the other cold and it has to mix in the sink. I don't know that it would ever be a viable option in that case.
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It is. Huh? It's easily treated. Turn up the damned temperature! ;-) It won't survive above 133F, IIRC.

Dishwashers have heaters. It's usually cheaper to let it boost the temperature.

You can mix before the hot faucet.
Our first house (banns second, for that matter) had a domestic water coil in the furnace ("boiler" that doesn't). Of course the furnace was set at 180F(+) and it backed right up to the kitchen and the bathrooms. No mixing valves. The water was *hot*.
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The link above is designed to sell ACME Mixing valves, in order for those to do their job properly all the HWS and HWR lines must be insulated along with that you need a recirc pump or you are just wasting money on the mixing valve.
You should also not that the disease was contracted via your lungs, not your stomach.
In many years of experience in the HVAC commercial and industrial industry I have yet to see any evidence of bacteria in a closed loop system, I have pulled down boilers, HW boosters, heat exchangers of all types and never was their any sign of any growth. Now, that said, once it hits the air and lingers all bets are off. I have seen growth in Hot tubs for general use in Hotels and Motels, Swimming pools, cooling towers of all types. Chlorine is often used to kill it, but especially in cooling towers there are spots where the water pools and flows very little. We also used algaecides or other types, plus they all require constant maintenance, tear down, clean up and repairs if necessary. This is done for a variety of reason, the least of which is any disease.
Think about it. Air? Where in your HW tanks is any air? Air stops water flow or lowers the flow depending on where the air is trapped and we used air bleed on lines to eliminate that.

Really? They are designed for say a 40 degree rise. While the thermostat could be set for 180 deg F and the High limit at 200 deg G, if the incoming water is only 120 deg F add 40 deg F and the best you will see is 160 and that is not enough to sterilize the dishes and pans. Most domestic dishwashers do not publish the deg rise, but the info is out there. Until people make a fuss it'll never be a big deal.

And it should be.

I'd bet. There's a lot of missing info about that system, was it for HW heating, forced air? A recirc pump between the coil and a storage tank, and so on. Whatever, I'd bet that it was an old house and done properly.
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On 2/1/2016 3:05 PM, OFWW wrote:

Then sanitize, not sterilize. The temperature, coupled with the caustic detergents do a good job. My KitchenAid goes to 155 degrees.
A dishwasher that has a sanitizing feature uses an extended hot-water rinse to kill germs. The National Sanitation Foundation has set a standard named NSF/ANSI Standard 184, which means that dishwashers bearing this certification kill 99.99 percent of bacteria when operated on the "sanitize" setting. In order to be certified, they also must reach 150 degrees Fahrenheit during final rinse. Dishwashers that don't have this certification most likely don't reach temperatures high enough to sterilize items.
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Commercial Dishwashers (NSF/ANSI 3)
• Must achieve a minimum 99.999 percent or 5-log reduction of bacteria • Must reach a final rinse temperature of 165°F for stationary rack dishwashers and180º F for all other commercial style dishwashers
You might have noticed that for domestic dishwashers I did not set a min temp setting, ("say")
However, they did not speak to a specified temp rise on the HT booster temp, which I imagine is that electric coil in the bottom pan.
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HW heating. The "domestic coil" is a loop inside the boiler used take off hot water from the boiler. When the boiler isn't in use, the water first coming out of the coil is at the boiler temperature, with is 180F +/-19F, IIRC. That house was built in '72, IIRC. Our second (same issue but the boiler further from the points of use) was built in '86.
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On 2/1/2016 8:39 PM, krw wrote:

Had the same system in my house. Terribly inefficient. On a hot August night you'd hear the burner fire up to keep that poorly insulated coil hot. Replaced the boiler with a more efficient system with an insulated tank indirect heated and got a 40% decrease in oil use.
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The advantage is that it keeps the boiler operating in the summer so it doesn't rust. When oil was cheap, it was cheap insurance. Of course I wouldn't have oil heat these days.
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On 2/1/2016 9:40 PM, krw wrote:

That cheap insurance would have cost me over $1000 at last years prices. New boiler saves me about 350 gallons a year. I put in an Energy Kinetics System 2000.
I'd switch from oil if I had a good alternative. Gas is too far away, propane is no better.
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Understood. When I owned the house, oil was less than $1/gal. The "insurance" was something like $50/yr.

Our second house (in Vermont), we had switched from oil to natural gas, not because of cost. Our houses since have been electric/heat pump. Our current system will probably have to be replaced in the next few years. :-(
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When I read that I see boilers that are quite a bit larger than a domestic types, but they are high maintenance unless you had a good water softener or naturally soft water, due to calcium build up in the coils.
I would have set the set point @ 140 during the summer season to save a lot on fuel, unless you live in a cold area of the country.
Due to efficiency requirements in Calif, there has been a lot of changes in all types of heating systems.
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NO, they're used for even small homes, too (~100KBTU). Yes. You bet!

That's the usual recommendation. I can't remember why we didn't do it. There was something screwy with the temperature controls on the thing but I don't remember the details.

Retroactive? Yeah there is a lot of difference between $.79 oil and $4.50 oil, too. Of course the price is down, now, but it's still worth some work to save.
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Yes, retroactive mods. Because of new state laws, and pricing regulations, since the state sets certain limits of fuel prices for heating etc. boilers over one million BTU's had higher energy costs, so we wherever possible re rated the boilers by modifying them, or replacing them with high efficiency boilers and the state, feds, and gas company's would pay a portion of the costs if they qualified and that with the reduced operating costs would ROI in 2 years or less.
We don't have many oil fired systems out here for smaller bldg's. But there were a lot of gas/oil fired boilers for large bldgs, and if those were replaced and oil firing done away with, there was a lot of savings there as well.
When I read of the fluctuating oil prices for the oil used in home heating in the east, I am real happy to be out here, plus the thought of a snow storm shutting off the supply, }}}
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More than 1M BTU isn't a residential system. That's a little different but it's still amazing they were forced upgrades.

Were they #2 oil systems or #6? Bunker?

A snow storm wouldn't do anything, other than perhaps taking out the electricity, which would affect any sort of central system. Worst case, 275 gallons of oil lasted three weeks.
In Vermont we had wood backup. In NY, we got cold (out three days once). The best solution was moving South, though. ;-) Though we were out 30 hours during Snowmageddon (2") two years ago.
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I know that, and most of my work was with commercial industrial HVAC, plus shopping centers, Gov't centers and the like. However, there was a lot or retrofit programs for both residential and commercial users.
Sad part is that a lot of residential users were never informed, nor took a look at the Utility companies web sites about it.

I remember #2 oil systems, but not much else. It has been decades since my last oil conversion job, and or service on them.

Well, I wish you the best this winter. Cold is never fun except for short periods, when planned.
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