[jkburden1]

I recently purchased a cabin that has well water and a hot water heater that is run off the oil furnace. I shut off the well tank when I left but forgot to shut off the hot water heater. Does anyone know if I can damage the heater by having the main water shut off and leaving the water heater on?

[progunr]

Depending on how well the system is sealed, you will start losing water from the water heater fairly quickly.

Without that water being replaced, I would think eventually, you would run dry, but still be heating the empty tank.

Can't be good for it, I guess the bigger question would be, how long before you plan to turn the water back on?

If it's going to be a while, I think the hot water heater should be shut off as well.

[ballengerb1]

Two types of damage can occur and like progunr mentioned, it depends on how tight your system is sealed. If you have a check valve or backflow preventer pressure can build in the heater itself as the hot wayer expands. No back flow valve then you are OK. I don't really picture the tank running dry so I would not worry about that issue. I would worry about a hit water pipe bursting from the increased pressure. I have a cabin and shut all water and fuel use off when I will be gone for more than 2 or 3 days. I can now also control my heating and ac via a telephone linked thermostat, I call the cabin and punch in afew codes and the place is comfortable when we return.