Alternative Technology Assn Forums

1. 

   tullera182
   Member

   We have recently had a solar hot water system installed. It is, despite many days of no sunshine, doing what it is supposed to.

   As far as hand washing and showers are concerned the temperature is wonderful. However, I have never in my life before started washing up with water which is 50°C. This temperature rapidly drops as cutlery and crockery are added. By the time you get to saucepans the water is at best tepid (28°C).

   As human pathogens thrive in temperatures between 28°C and 60°C I have always commenced my washing up with quite hot water, in the area of 60°C.

   I believe it is law that 50°C be the output. But this seems absurd and while nobody is going to get scalded we might all end up with nasty infections.

   I could of course drain my sink every few minutes and put a new lot of water in but this is contrary to my water conservative ways and also uses extra detergents.

   Posted Sunday 2 Jan 2011 @ 8:46:26 pm from IP #
2. 

   sun2steam
   Member

   Dish washing is not meant to kill bacteria by temperature. Just washing the dishes clean and drying it will get rid of most of the bugs. This is fully sufficient.

   We are adopted to bacteria and can easily handle tiny amounts of them. Also the trend to use antiseptic detergents and cleaning agents is an overkill only helps the producers of of these chemicals. The increase of immune diseases in western countries has been related to our ever increasing move to 'clean' living.

   Only sick, elderly and very young people need to protect themselves more from bacterial infections.

   Posted Sunday 2 Jan 2011 @ 11:08:08 pm from IP #
3. 

   dymonite69
   Member

   Temp of 50-60 is required to prevent legionella thriving in the tank - effectively sterilising it. It takes a while for the germs to proliferate - not in the time to wash dishes. According to the Vic health dept there have been no instances of domestic systems causing Legionellosis.

   Posted Sunday 2 Jan 2011 @ 11:18:50 pm from IP #
4. 

   dymonite69
   Member

   and that is why untreated greywater left for 24 hours is a health issue and must be disposed of in appropriate safe manner. It's not a government conspiracy theory to stop greywater use.

   Posted Sunday 2 Jan 2011 @ 11:20:05 pm from IP #
5. 

   Garry
   Member

   I am with Tullera but for a different reason. I have recently installed a Hills evacuated tube solar hot water system but the temperature has been set I guess at 50 but I find it annoyingly low and not hot enough for my liking for dishwashing so end up using a dishwasher that heats its own water.

   I have contacted the supplier but been told that there is no way they will change the factory set thermoset. I would, if I knew how. Can it be done?
   Garry

   Posted Monday 3 Jan 2011 @ 6:13:17 am from IP #
6. 

   dymonite69
   Member

   I thought they set the thermostat to 60 but legislation requires a tempering valve that bring the water to 55 at the tap.

   Posted Monday 3 Jan 2011 @ 8:01:48 am from IP #
7. 

   Solgen
   Member

   Because SHWS can have water temperatures above 70 deg it is mandatory to have a tempering valve installed on the outlet which mixes some cold with the tank water so that the resulting temperature is around 50 deg. I adjusted mine with the little tool provided and it now goes to 53deg.
   It took so getting used to but now don't have any problem with it.
   We do all our dishwashing by hand and have found the temperature adequate and we certainly have not had any health issues in the 2 years we have had SHWS.

   Posted Monday 3 Jan 2011 @ 10:19:24 am from IP #
8. 

   sun2steam
   Member

   Hot water to the kitchen is theoretically no problem. Legally only the water to the bathrooms and showers has to be kept at a maximum of 50 degrees. You can connect the hot water from the hot water tank directly to the kitchen. This may require a clever plumber and will cost a bit more because the hot water lines must be adjusted accordingly.

   Posted Monday 3 Jan 2011 @ 11:16:30 am from IP #
9. 

   tullera182
   Member

   @ dymonite69 - no problem with the temp in the tank, its plenty hot enough to kill legionella. Its the tempering valve at the outlet to my kitchen and bathroom which is the problem.

   @ sun2steam - thanks - that looks like the way to go. I have no problem with 50°C in the bathroom but really like my washing up to be, look and feel clean. Fat/oil just doesn't dissolve at 50°C unless I use harsh detergents or lots of detergent. Neither of which suit me for a whole host of reasons.

   Posted Monday 3 Jan 2011 @ 11:12:38 pm from IP #

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