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<pre>Hi Reuben,
Our tank is 70-litres in size which seems more than adequate for our modest needs.
For a good overview on the risks of legionella as it pertains to electric water heaters, see: <a class="moz-txt-link-freetext" href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2094925/">http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2094925/</a>
According to Hydro Quebec, "[e]ven at 60 °C – the setting on most electric water heaters – an estimated 25% of all water heaters are contaminated by legionella bacteria." They go on to report that "[i]n Québec, about 100 people a year are hospitalized for pneumonia caused by contaminated residential water heaters” (source: <a class="moz-txt-link-freetext" href="http://www.hydroquebec.com/advice_hot_water/index.html">http://www.hydroquebec.com/advice_hot_water/index.html</a>). I figure a dial setting of 75°C, knowing that the temperature at the bottom of the tank will be several degrees cooler, provides a greater measure of safety and this, at least to my mind, justifies the additional standby losses.
Cheers,
Paul
|On Sat, Aug 20, 2011 at 3:11 PM, Paul Eldridge <
<a href="http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org">|paul.eldridge at ns.sympatico.ca</a>> wrote:
|
|><i> ...To *minimize *the risk of legionella forming at the bottom of the tank,
</i>|><i> we keep the thermostat set at 170°F so our standby losses are a little
</i>|><i> higher than what they would be otherwise.
</i>|><i>
</i>|
|You think? Um, any particular reason for going that high?
|What is the size of your storage tank? At 170F I'd think you could get by
|with about 5 or may 10 gallons of storage.
|
|If at 170F you think you are but *minimizing *risk of legionella, what must
|the 99.3% rest of us with storage water heaters at lower thermostatic
|setpoints be?
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