I'm supposed to winterize a nice home for friends from out-of-state, and it has a propane gas-fired instant water heater in the basement. I've never touched one before, so how do I go about it? I know how to do all but that.
It's over in another county, so I don't know the make yet.
My guess would be to just shut off its ignition breaker, turn off the propane gas, and drain it down with eveything else?
You seem to have it right. There should be some caps on the bottom of the tankless that you can open and get all the water out of the system (after the water is turned off).
When your friend starts up the system in the spring he will get a lot of faults till the pipes get full of water and force the air out. Just let it run and it will eventually start up. He will have to reset the unit several times till it gets going.
My idea of a perfect day: No where to go and all day to get there.