Originally Posted by menzies
The house valve is in the garage and just for the house. My concern is the gas water heaters. Do I cause issues by turning off the water and heating those dry. Or can I turn off the gas without issue or are they designed to handle going dry?
Why would they go dry? Where's the water going to go if the faucets are all closed? Even if the faucets are open, likely the water heaters are low in the system, and unless there's pressure in, no flow out. The tank only stores a volume of water, it relies on system pressure to move water through the tank. The thermostat keeps the water at temperature, it doesn't know if the water is shut off. It may call for heat, so if you're gone for a long period of time, you may save a buck or two if you set the heaters to "vacation" or "pilot" if they have that setting. Heaters with electronic ignition can simply be switched off. If they're electric, you can shut the breaker off, you just may have to wait a bit for the water to heat upon your return.
So, short answer is you don't have to do anything special to the water heaters.
Same goes for the areas with hydronic heat. They're closed systems, and in normal operation, they don't actually require a constant source of pressure, they'll operate fine with the water shut off.