is our hot water safe

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8 years 9 months ago #39916 by Farmersden
We had solar tubes installed for our hot water for both $ and eco reasons. We have found we can manage on just solar without topping up using the grid but currently tank temp varies between 35 and 50 degrees depending on weather. An article in dominion post is warning of legionnaire disease if hot water tanks don't get above 70 degrees. How do other solar users keep their water safe?

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8 years 9 months ago #509665 by Ronney
Replied by Ronney on topic is our hot water safe
I'm not able to answer your question but as I understand it, hot water cylinders are supposed to have a governor (is that the word?) on them to stop them getting over 65 degrees in the interests of safety. I don't personally consider that hot (or economical) and can hold my hands in water that hot.

So if legionnaires can occur in water under 70 degrees, we're all at risk!

Cheers,
Ronnie

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8 years 9 months ago #509667 by Stikkibeek
Replied by Stikkibeek on topic is our hot water safe
Just a thought, but if Legionnaires is caused by a bacteria, couldn't you shock the water pre house use with something antibacterial? otherwise the water temp needs to be 60 degrees.
Here's the Auckland regional health fact sheet www.arphs.govt.nz/Portals/0/Health%20Inf...is/legionellosis.pdf

Did you know, that what you thought I said, was not what I meant :S

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8 years 9 months ago #509671 by Hawai
Replied by Hawai on topic is our hot water safe
This article just popped up on the Stuff website tonight:

www.stuff.co.nz/national/health/70285141...sults-in-amputations

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8 years 9 months ago #509674 by muri
Replied by muri on topic is our hot water safe
The article says legionaires at below 60 degrees, not 70 degrees.
I would say that 35 for hot water is too low and would be looking at an alternative heating system if that is all your getting, for health reasons.
A gas caliphont is a cheap way of getting hot water and would remove some of the risks.
I would imagine that a number of other things might also survive well in warm rather than hot water

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8 years 9 months ago #509678 by wal89
Replied by wal89 on topic is our hot water safe
Wondering about ours now the wetback that is gets heated at night then gets to cool during day then heated back up at night however have been using it for past 6 years and no probs and only in winter as well.

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8 years 9 months ago #509681 by spoook
Replied by spoook on topic is our hot water safe
If you still have an electric hot water cylinder, turn it on once a week to heat to 65deg. This should solve your problem.
I would suggest you contact your doctor for advice to put your mind at rest.

There are no bad questions only those that are not asked.
"You are responsible, forever, for what you have tamed"

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8 years 9 months ago #509686 by Alan Gilbert
Replied by Alan Gilbert on topic is our hot water safe
AFAIK, the law requires that the water in the tank be kept above 60 degrees, so I simply leave the electric element switched on. It heats only the top half of the tank anyway, and the solar usually keeps the temperature in the whole tank well above 60, so the element is usually switched off by its thermostat, and hence costs little to run.
Ronney, the gadget you're thinking of is called a tempering valve, and it is fitted in the hot pipe immediately outside the tank. It mixes a small (and adjustable) amount of cold water in with the hot before the hot goes off to the taps, in order to prevent scalding. It is a compulsory fit.
The idea is that the temperature of the water in the tank should be high enough to kill the bacteria, but the temperature of the water that comes out of the tap should not be hot enough to scald. For once, it's a sensible regulation.
Ronney, have you ever accurately measured the temperature of the water you're holding your hands under? If you consider 60 degrees Celsius cool, you've got serious neurological problems! No offence, but 60 is bloody hot!

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8 years 9 months ago #509689 by LongRidge
Replied by LongRidge on topic is our hot water safe
The electrical element also has a thermostat which turns the electricity off when the temperature is up to what has been set. If the electrical element is not getting the water hot enough then adjust the thermostat.
35 to 50C is too low, so keep the element on and just use the sun to supplement the heat. Use hot water during the day as much as possible.

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8 years 9 months ago #509703 by Farmersden
Replied by Farmersden on topic is our hot water safe
Thanks for the feedback. We do have mains and have set it to come on for at least an hour a day n will adjust with the weather. It is a bit disappointing though as we were proudly managing on just solar n found anything over 40 deg was plenty for a good hot shower n washing machine but health comes first! Has made usr rethink going completely off grid.

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8 years 9 months ago #509706 by rhyso
Replied by rhyso on topic is our hot water safe

Alan Gilbert;516521 wrote: If you consider 60 degrees Celsius cool, you've got serious neurological problems! No offence, but 60 is bloody hot!

Anything above body temperature will feel hot so yeah 60 is probably not even bearable.

Thanks for the feedback. We do have mains and have set it to come on for at least an hour a day n will adjust with the weather.

An hour is probably not long enough... that is a lot of water to heat to 60, especially in a temperate climate. I guess that could be calculated if you know the output of the element/s.

As for the wetback thing a decent wetback should be heating to at least that anyway, so if people are turning their cylinder off beacuse the fire is on every day or so, then that is all good anyway, if not you need a plumber/new wetback.

...

Is this bacteria everywhere/something that is present even in rain water stored in tanks (maybe possums on the roof?).

Or is it something linked to main water supplies?

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8 years 9 months ago #509707 by Stikkibeek
Replied by Stikkibeek on topic is our hot water safe
It is present everywhere (a bacteria) but it doesn't usually give problems unless the conditions are right. With water, it is more frequently found in air conditioner cooling towers, where warm water is recirculated. Can also be found in potting mixes but nowadays manufacturers put warnings on the outside of the bag, Not all companies are diligent about this however and often the warning is in fine print on the back of a back instead of boldly on the front where people will see it.
I doubt we would have problems with our wetback. The fire only needs to be going for a few hours and the cylinder boils over.

Did you know, that what you thought I said, was not what I meant :S

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8 years 9 months ago #509709 by Ronney
Replied by Ronney on topic is our hot water safe

Alan Gilbert;516521 wrote: Ronney, have you ever accurately measured the temperature of the water you're holding your hands under? If you consider 60 degrees Celsius cool, you've got serious neurological problems! No offence, but 60 is bloody hot!

Alan, I didn't say that 60 degrees was cool, I said I could hold my hands in it. How accurate is a dairy thermometer? I've scalded 100's of pigs in my lifetime. The ambient temperature for scalding is 65 degrees. I put my hand into the bath, not hot enough. Pour more in, hand in again and it's good. Kevin puts the thermometer in and it's almost bang on. I can't hold my hands in 65 but as the temperature drops a bit, I can. Don't forget that some people have a much higher threshold than others.

I heard this on the radio news today but the kittens were destroying the place and the noise was such that I missed most of it. It did seem to be along the lines that anything under 60 is not good.

Cheers,
Ronnie

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8 years 9 months ago #509752 by AlanL
Replied by AlanL on topic is our hot water safe
So, to recap then. Legionella is present in a lot of places and likes to breed in warm and damp environments (like your lungs, air conditioning units). It cannot survive in high temperatures so hot water above 60º is good. However it is also present in compost and so it is important to wear appropriate protective clothing if you are at all susceptible (such as a compromised immune system).

en.wikipedia.org/wiki/Legionnaires%27_disease

I wondered if legionnaires might live in a heat pump and yes it can. A heat pump should have a function to increase temperature on a regular cycle of around 7 days.

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