It will be the same temperature it was before I turned it off. On a Tankless system though the fan runs long after the burner shuts down to help cool the heat exchanger faster when the water stops flowing.
Any documantation of your theory? The water temperature will rise after the water flow stops!
Not really. You are starting from a hot water going to warm which is more an ideal growing temperature than cold water.
A tankless water heater does not store hot water. Cold and hot water pipes will equalize at room temperature, so they are both the same temperature when not in use. A tank water heater never cools down.
If you keep the tank hot enough like in the Bradford White model
GX-2-25S6BN Which stores the water at 180º and distributes it at the set temperature of 120º Yes it may be a small 25 gallon tank but it can provide 155 gallons of hot water in the first hour. Its big brother
GX-1-55S6BN which is a 55 gallon tank can give you 200 gallons of hot water in the first hour.
Don't you need a 3/4 inch gas feed for those? I would have to install a new vent also. You know, that looks to be as expensive as a tankless installation!
You also forgot about all the crap that settles in that a tank water heater. 180 degree water storage temperature makes things much worse. That temperature setting conflicts with this recommendation: "** Excessive lime scale formations can also be reduced by setting the water heater temperature control at the lowest possible temperature which will provide satisfactory hot water service. The usage of water softening equipment greatly reduces the hardness of the water. However, this equipment does not always remove all of the hardness (lime). For this reason it is recommended that a regular schedule for deliming be maintained."
http://www.hotwater.com/lit/training/4800r9.pdf
"The amount of calcium and magnesium carbonate (lime)
released from water is in direct proportion to water
temperature and usage, see chart. The higher the water
temperature or water usage, the more lime deposits are
dropped out of the water."
Well you are right and you are wrong. Yes a home will not have as long of a distance from the tankless units to the fixtures. But things still can grow in the lines after the tankless system. Also if you think about it lots of people only set their tankless to 115º to 120º which is the ideal temperatures for things to grow in it. Please do not be under a false sense of security that you or your family can not get sick just because you got rid of the tank.
Tankless heaters do not store water at 120 degrees. The water temperature in a tankless is room temperature the vast majority of the time. Hardly the "ideal" temperature for things to grow in. Same temperature as the hot and cold water pipes.
Peak use is all the fixtures turned on at once. If you do not believe me call your local plumbing inspector and ask them what they consider as peak flow per the code.
Oh and the minimum water pressure at all the fixtures during this peak flow is to be at least 8 p.s.i. per the code again. When you open more hot water taps in the home and if the tankless system is undersized it will restrict the flow rate so it can still deliver hot water. I have seen installs where when people opened 3 hot water taps I be lucky to see a trickle come out of the fixtures.
Adequate for the intended use if the general wording of the various codes here.
