Gordon Claridge wrote:Something to think about is that 140degF is 60degC and is right on the borderline for preventing the development of Legionnaires Disease bacteria from breeding in your tank. If your planned operating max temp is going to be 140, this means that a lot of the time the T is likely to be below this, or conversely, there will be days when you do not reach this temp.
You need to look carefully at the longest recommended time a system can be without reaching 140 or above. In some jurisdictions it is a requirement that hot water systems stay above 140, in others 140 needs to be exceeded for a given time in any period of X days (X depends on the jurisdiction).
Tim Malacarne wrote:Yeah, me again... Jim, there's lots to read on thermosiphoning on the internet. I grew up in a 2 family flat in the city. We had a hot water system, was the most even heat ever. No pump, all thermosiphoning.