Does water heater have a check valve?

[RedOrGreen]

I was just wondering if the cold water intake to the water heater (Atwood) has a check valve. The water heater manual talks of draining the heater by removing the drain plug on the outside, but the camper has low-point drains on both the hot and cold lines just behind the heater, so I'm wondering if I open these, if they would drain the water heater. The only thing that would prevent from happening would be a check valve entering the water heater.

I don't have the trailer here to look at, but I also seem to recall thinking that it would be difficult if not impossible to get a wrench on the water heater drain plug (if I can't get it off with hand pressure) because a pipe or something passed in front of it.

[kcconawa]

I don't know if it has a check valve or not but I drain my heater through the low point drains. I open the outside shower and all inside faucets, both hot and cold sides plus the water heater relief valve and leave them all open, including low point drains, all winter.

After draining the water lines and supply tank, I turn on the pump for 10-15 seconds to pump any residual water out of it. I also put a broom handle in the toilet because the water vlave will hold water and freeze and burst. I also pour a small amount of anti-freeze in the sink and shower drains.

We approach 10 degrees and often reach 15 here and I have not experienced any froozen pipes.