Gas water heater setback...

[Goose66]

I have a program that puts the house into "Vacation" mode, including random interios lighting, thermostat setbacks, etc. The best thing about it is I can turn off vacation mode from MobiLinc on the way home and the house is cool by the time we get in. I would like to add a setback for our gas water heater. I am also in the market for a new gas water heater. Anyone know of 1) a gas water heater that has an electronically controlled setback or 2) know of a way to add a setback function to a gas water heater?

[Morris Hansen]

While I haven't tried this yet, it looks like it should work well. I am getting ready to replace both of my water heaters and will be ordering this soon.

 

It comes with a timer but my plan would be to hook it to my Elk and let it control the water heater just like I do my HVAC systems.

 

http://www.gaswaterheatertimer.com/index.php

[apostolakisl]

Keep in mind that Legionella grows in water tanks that are not hot enough. It might be better to shut it off completely than let it sit at an "incubating" temp. I would take care to research this before implementing.

[RickL66]

Legionella could possible occur if temped water was left in a water heater tank undisturbed for an extended period of time, a long period of time. Water heaters are always being refreshed with new cold water and any possibility of bacterial contamination is not likely. Many second home owners turn their water heaters off for weeks at a time. Water heater manufacturers have put settings for lower temperatures on their water heaters. If there were a chance of legionella they would change their design. Legionella is more likely to occur with cross contamination from boilers.

[apostolakisl]

Legionella could possible occur if temped water was left in a water heater tank undisturbed for an extended period of time, a long period of time. Water heaters are always being refreshed with new cold water and any possibility of bacterial contamination is not likely. Many second home owners turn their water heaters off for weeks at a time. Water heater manufacturers have put settings for lower temperatures on their water heaters. If there were a chance of legionella they would change their design. Legionella is more likely to occur with cross contamination from boilers.

 

That is not true!

 

Legionella will not grow in a tank that is too hot no matter how long it sits, the same is true for too cold. You should keep the tank at a minimum of 130 to prevent legionella growth but 140 is recommended. I do not know what the "too cool" temp is for legionella but turning the tank off would probably get you there in most climates, especially if you heated it back up before use to a "kill" temp. But you would not want to leave your tank say at 120, this would be prime growth opportunity. Flushing of the tank (either by regular use or purposeful flushing) is neither possible nor recommended for controlling Legionella. The bacteria grow on the walls and on deposits (calcium) in the tank. You could not flush your tank fast enough to "wash it out". If it is growing in there, you would only be able to remove it by getting the tank sufficiently hot for a sufficient amount of time to kill it.

 

Legionella would enter your system from the water supply. It is rare, but it is possible and many people have died. You don't save hardly any money turning your tank down into the danger range, and your risk a very expensive or even deadly infection.

[io_guy]

I agree with Lou, I would never lower my temperature.

 

Go tankless, bacteria worries and setback issues solved.

[sperok]

I agree with io_guy - we have installed tankless water heaters in 13 vacation and rental properties now and are very happy with them. Zero consumption when vacant, never a shortage of hot water. Several of the rental units have 6 full bathrooms.

[apostolakisl]

http://apnews.excite.com/article/201201 ... FHR80.html

 

Legionella happens.