I intend to turn off my main water supply to the house while on vacation. Do I also need to turn off my on demand tank-less water heater?

Since no water will pass through it during your absence most people would say to leave it on, not me. I would shut down the power to it just in case there were a malfunction in your absence. Is it gas fire?

Great advice from Bob. Are you the evening your house heated for you vacation or do you wish to winterize your home? Let us know if we can help. Good luck and have a great vacation. Tom

It is a propane supplied tankless. I am hoping it has a vacation setting somewhere on the controls. If not I assume I would need to turn off the propane. This heater is in a mountain home and we don't use the home that much in the winter. I am always concerned about a frozen water pipe if our heat malfunctions.

No vacation setting on tankless, just pull the plug out of the receptacle.

One more time. Are you heating your house heated for you vacation or do you wish to winterize your home? Back to you, Tom

What the plumbers are saying is that you need to do more than just turn off the water main. And more than just open faucets. Your comments are a confusing mix of true winterizing vs keeping the heat low.

We are not winterizing our mountain home and intend to use it throughout the winter when there is snow. We turn down the thermostat to 55F when we leave. My concern is that the heat will go out and pipes could freeze. I don't want to have the house flooded. Our tankless is propane gas not electric. I have heard that the gas has a low wattage heater that prevents any chance of freezing so maybe I don't need to do anything with the tankless?

Your tankless heater may be propane but it uses 120 vac for its controls, unplugging it shuts it down. Never heard of heaters having a low wattage heater in them but that would further support your heater is also using 120 vac. Does this home have a computer router?

We turn down the thermostat to 55F when we leave. My concern is that the heat will go out and pipes could freeze. this statement makes no sense. If you leave this thermostat set at 55° how can the pipes freeze? You may the tankless on or off. Since you can't drawing water the heater won't take on anyhow. Have a great vacation and enjoy the snow. Tom

I think he means if his furnace heat goes off the pipes would freeze. Not very clear though.

So you want to turn off the water main in case the heat source FAILS for some reason.

The concern is that just doing that and opening faucets doesn't drain all the water.

So the plumbers here want to know if you need to know all the steps to get water out of pipes (and maybe drains and toilets).

The trouble with that is that if you do use the place at times, you have to repeat all this each time you leave.

My suggestion is a computerized thermostat that calls you if your house falls below what you set it for, or it calls a local contractor.

http://www.talkingthermostats.com/freeze.shtml

There are plenty of others.

I was lucky to buy a house that has all the water going through inside walls only. I feel confident that I could set my thermostat to 45.

(I shut off an addition in the winter, turn off the zones, drain all water at the lowest spot in the cellar, flush/scoop out toilets, and fill all traps with antifreeze. Not something I want to reverse until spring.)

That's why I asked in post #9 if he has a router, home must have a router to make that stat work, some also work off phone land lines

Sorry missed that.