Golden_HVAC wrote:
Yep - they set them for 140F because you can mix about 6 gallons of incoming 55F water and still have 12 gallons of 100F water to shower or wash dishes.
If lowered to 120F, then you can only mix in about 3 gallons of cold water, and you will only have 9 total before running out hot water.
Another brand of water heater sets the thermostat even higher, like 160F. THen they MUST use a water mixing valve, so the output is limited to a max 120F, to prevent scalding, and basically the first gallon of hot water is mixed with nearly 1 gallon of cold water, so the 6 gallons last for about 12 output at 120F.
It gives a lot more hot water, and the mixing valve prevents the scalding.
My suggestion is to get a mixing valve. Then you can still have the full output, and not get scalded.
Fred.
That would be Atwood XT models.....6 gallon & 10 gallon sizes.
T-stat set for 160*F and mixing valve output set for 130*F which still requires mixing with cold at point of use.
Equivalent of 9 gallon (from 6 gallon size tank) and 12 gallon (from 10 gallon size tank)