Purging the water system for Serious winter camping

[Wallowa]

I thought I drained my system a few weeks ago. Turned on all the valves, including hot water drain. Opened the sink faucet. Drove around. Sat tilted towards my external water drain, it all stopped, I closed everything.

Few weeks later, I opened it all up again, and bunches of water poured out. Then I drove around for a couple hours, watching water trickle out behind me the entire time. Pulled into my driveway, and still a slow steady stream of water trickling out. It comes out this same faucet fast, when the system is full...

I cannot imagine where it is coming from!! Has to be gallons of water that is very slowly draining from somewhere. I had the camper apart a few weeks ago when I drained the system and could see the water tank was empty. So, I guess from the hot water heater.

Long story to a short question.. Is that normal? Does it take a while for the water to drain?

I had the same thing happen - thought I had everything drained and a couple months later was messing with things and a lot of water came out! I'm very curious about the vodka/grain alcohol option, but unsure how to implement it and if it really works. Don't really want to put antifreeze in the system, but would like to be a bit more confident that winter won't bring problems.

Thought about this...the hot water heater ['16 Hawk] always holds about 1 gallon even when "drained" into main tank and the main water tank in turn holds perhaps a gallon or less after normal "draining" of the entire system [line exiting the main tank is not at lowest point]....what could be happening is that the residual water in these two tanks does not drain even when drained on a slope but may put water into the main drain line as the vehicle is subsequently driven and the water in tanks sloshes out into the main drain line [line that exits the rear of the camper] as the truck leans and bumps up and down...a way to check if the hot water tank is contributing this water is to turn off the the hot water drain to the main tank, after doing the usual complete draining of system, close rear drain spigot, drive around over different road grades and surfaces, park with spigot downhill, then open spigot at rear of camper to see if water flows out....if yes, then the main tank is contributing this "new" water....repeat to see if more water is still in main tank....if no, then open drain from hot water heater to main tank [closing rear drain spigot] and repeat driving around and checking again at spigot for "new" water...if yes, then hot water tank is contributing this new water via the main tank and then main drain.

OK...a lot of messing around to find out where the "extra" water is coming from, BUT this does not resolve the questions of does this extra water threaten the water system lines if it freezes and, then of course, how do you eliminate this extra water if it is causing damage.

Whew...sorry, got wound up there!

Phil

 

[ckent323]

Water expands by about 9% when going from a liquid to frozen state.

So if a cointainer is mostly empty it should be fine with one caveat, the air in the continer will be compressed if it is sealed so it would be wise to have a way for the air to escape if the container cannot hold the slighly increased pressure (which depends on the volume of the tank and how much ice forms in it).

I think the hot water tank holds about 4 or 5 gallons. If only a gallon is left it should be fine. Most of the container volume (75% or so) will be occupied by air which can compress (water is incompressable). The tank is designed to hold pressure. The over pressure valve on most residential hot water tanks open around 150 psi.

It would be appropriate to understand the pop off pressure for the over pressure valve in the camper hot water tank. Presumably it is sized to protect the tank and the lines from bursting under excessive pressure. If much less than 100 pounds this probably requires more detailed evaluation.

All this written, the water lines should be well drained so that ice cannot form and expand in them.

Regards,

Craig

 

[McLofgren]

Hi Dafinga,

I don't know if this helps but FWC has put out a video on winterizing their campers. They have a video for Flatbed and one for Slide-in Models.

Here is the flatbed video

Hope this helps

 

[Wallowa]

Flatbed system plumbing is unique and not like my '16 Hawk slide-in but the steps and logic for draining the water out of either system remains the same....just the location of the tanks and valves differ...

My Atwood [?] hot water heater holds 6 gallons and only 5 can be drained into main water tank which holds 22 gallons...as I remember...

All true about expansion % and air compression but the source of "new" water that appears after we think we have drained the system was the object of my previous post....in passing, expansion of water in the hot water or main tank when drained should not lead to any damage [plenty of space for expansion] but not so in shower head/lines, faucets, filter bowl on pump or in the outside drain spigot/valve...there water may not have sufficient room to expansion before expansion pressure does damage.

But hey, I could be wrong..

Phil