Just curious, what temp does everyone set their water heater at. I have a 40 gallon superstor, and I've played around with 160*, but generally stay 130.
Indirect DHW temps.
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I wouldn't recommend a water tank temp below 135F. The lower the DHW temp the more chance of breeding the legionella bacteria. That bacteria thrives on temps between 90 and 120F. I keep mine at 140.
Legionella is old, old news - if anyone thinks it is an issue in home dwh systems, please cite the confirmed cases of legionella contracted from a home dhw system. I'm not sure there are any. There is a much greater risk of getting hit by lightning, crashing on an airplane, or falling off a cliff then contracting legionnaires disease from a dhw system (my opinion only to dramatize the nonsense of the legionella phobia).
It is an issue in institutions, nursing homes, hospitals, etc. affecting the old, infirm, and immune deficient individuals.
From respected medical websites to govt conservation sites, none recommend dhw at the temps to kill legionella.
It is an issue in institutions, nursing homes, hospitals, etc. affecting the old, infirm, and immune deficient individuals.
From respected medical websites to govt conservation sites, none recommend dhw at the temps to kill legionella.
I'll trust my master plumber with over 20 years of experience, thank you very much.
Sting, thanks for that link and that's exactly how my house is set up. 140+ degree water is fed to the DHW and there is a mixing valve that goes out to the faucets that is adjusted to a temp that is hot enough for our liking.
Sting, thanks for that link and that's exactly how my house is set up. 140+ degree water is fed to the DHW and there is a mixing valve that goes out to the faucets that is adjusted to a temp that is hot enough for our liking.
Higher temperatures will provide more DHW drawdown. Be sure to use a top quality, listed thermostatic valve, 1070 is the most recent standard.
There seems to be a lot of caution about maintaining 60C (140F) temperature throughout Europe. Solar controllers are all preset at 140F.
More and more we see small capacity "hygenic" tanks installed inside the larger storage tank to deal with bacteria potential issues. Or stainless steel preheat coils feeding instantanous DHW heaters.
I'm not sure how great the risk of legionella really is. But running elevated temperatures is a simple way to avoid the potential.
hr
There seems to be a lot of caution about maintaining 60C (140F) temperature throughout Europe. Solar controllers are all preset at 140F.
More and more we see small capacity "hygenic" tanks installed inside the larger storage tank to deal with bacteria potential issues. Or stainless steel preheat coils feeding instantanous DHW heaters.
I'm not sure how great the risk of legionella really is. But running elevated temperatures is a simple way to avoid the potential.
hr
When I'm not calling for heat in the house I have the boiler water circulating through my Superstor. So the water can get as hot as my boiler setpoint of 185 F. I feed the DHW through a mixing valve set at 130 F. I've only had this setup installed for about 2 months but it seems to work great.
When I get the rest of my storage added next month I may need to change things to use the aquastat on the superstor.
When I get the rest of my storage added next month I may need to change things to use the aquastat on the superstor.
Kgryder, what is the reasoning of having the boiler water constantly circulate through your superstor?
Chuck:
On the Econoburn when the water temp is above 155 F the loop pump is on. Since I don't have any storage online my only choices when there is no call for heat is to just circulate through the boiler or through the superstor. Seems like a better choice to make as much dhw as I can. When I get my storage added I can see just heating the dhw to a set point and then switching to the tanks.
On the Econoburn when the water temp is above 155 F the loop pump is on. Since I don't have any storage online my only choices when there is no call for heat is to just circulate through the boiler or through the superstor. Seems like a better choice to make as much dhw as I can. When I get my storage added I can see just heating the dhw to a set point and then switching to the tanks.
Here's a link over at houseneeds.com that talks about legionaire's disease. (broken link removed)
They say 8,000 to 18,000 people a year contract it. My gut feeling tells me that in my dealings with larger potable distribution systems you have the potential for stagnation thus bacteria growth. I just think that with smaller domestic tanks they tend to get flushed out enough from daily use so the potential for growth has to be low. Just to be on the safe side keeping your tank at 140 isn't going to be that much of an energy waster.
Mike
They say 8,000 to 18,000 people a year contract it. My gut feeling tells me that in my dealings with larger potable distribution systems you have the potential for stagnation thus bacteria growth. I just think that with smaller domestic tanks they tend to get flushed out enough from daily use so the potential for growth has to be low. Just to be on the safe side keeping your tank at 140 isn't going to be that much of an energy waster.
Mike
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