Shutting off water to prevent frozen pipes: what do I do with my tankless (Navien NPE-240a2)

[capybara]

I live in a cold/snowy area, and we have typically shut off our house water supply if we leave for a few days in the winter. Otherwise you risk: blizzard -> power outage -> frozen pipes.

What should I do with my new Navien NPE-240A2? (1) unplug it, (2) unplug it, shut the water to the unit, and drain the water from the unit, (3) power it off from the main screen. My plumber told me to just unplug it, but Navien says to do #2 (and shut off the gas to the unit as well).

 

[bingow]

"New" = on warranty? Best follow the manual, which is standard procedure anyway for water-using appliances subject to freezing.

 

[Sponsor]

 

[Breplum]

(2) for sure...Draining water from Navien tankless is a bit of a messy job to do it fully, so hopefully you have the wherewithal to do a thorough job.
Fully draining includes (but not limited to), removing the cold and hot filters (just below the case), removing the small plug under the pump (also just below the case).