If a house has a water heater for hot water, and a burner for heat (natural gas, baseboard heating). When one goes on vacation in winter and turn off water supply to avoid frozen pipes, should they leave the burner and heater ON? Won't that damage both because there's no water to the burner and heater anymore?

  • What does "turn off the water supply" mean? Are you draining down the system? Because just closing the valve doesn't protect against freezing, and if the system is empty you absolutely should not be heating any of it.
    – isherwood
    Jan 7, 2021 at 14:55
  • Please revise your post to make that more clear and tell us more about the hardware.
    – isherwood
    Jan 7, 2021 at 14:58
  • You mention and don't appear to differentiate between a water heater and a boiler. It is unclear if you have two separate items or one that does both. It's also unclear if you are draining the heating loop and turning off the heat, or merely turning off the water suply to limit the size of a flood in case of the loss of heating (where heating is left on, but problems may occur when unattended.) Please edit to clarify.
    – Ecnerwal
    Jan 7, 2021 at 15:14

1 Answer 1


With the water turned off to standing pilot gas water heaters, I suggest leaving the controller in pilot; that way it can not turn on the burner and damage the tank. This also keeps the pilot running and those pesky little spiders that love to build nests in the tubing away; then, when you return, just turn it to the proper temp: no hassle having to relight the pilot. But you need to drain the pipes as no heat and water in the pipes can damage them.

If you have electronic ignition turn the control to off.

Since this is a recirculating heating system, though, I would suggest leaving the water in the system and turning it down. That will keep the pipes warm so breakage is not a problem unless your vacation is extended (a month or more, then draining makes more sense).

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