Blowing out the lines unproductive!

[Tbos]

On my 2014 238ML I opened all the faucets, the low point drains, the water heater plug, etc... Drained everything then closed everything. Connected the air compressor and started blowing out lines. Everything seemed to be going well until I heard water in the lines at the water heater. I was able to pressurize the system and get some additional water out of the hot faucet in the tub. Now all I get is air but I can still hear water bubbling in the HW tank. Didn't matter if I had the bypass on or off. Does anyone know how to get all the water out of the system?

[hankpage]

You have to remove the WH drain plug to empty it. You can't blow it out.

[Festus2]

Try this:
1) Open low point drains.
2) Unscrew plug in HW heater. Allow to drain.
3) Apply air pressure with compressor (about 30 psi). Allow to drain.
4) Close low point drains.
5) Screw drain plug back in.
6) Apply air and turn on nearest faucet. Go to next nearest faucet. Continue with all faucets.
7) Open low point drains and take out drain plug/anode.

After you have completed winterizing using this air method, you can add RV antifreeze to the lines if you wish.

[Tbos]

Hankpage, Festus2, I have done all of the above but there seems to be some residual water in the supply line to the HW tank. Each time I remove either the HW plug or the red (hot) low point drain I get more water. Its just drips now but I can still hear the water in the supply line. Should I leave the HW plug out when I'm finally satisfied the lines are all clear?

[Festus2]

I would leave the HW drain plug/anode out and if you are not using RV antifreeze, leave your low point drains open. Have you pulled out the HW pressure relief valve? Try doing that and see if you get rid of any more residual water.

I am assuming that you have also taken care of the black tank flush and any outside taps such as an outdoor kitchen or shower.

The black tank flush system/lines has to be blown out separately from your city water lines.

[Tbos]

Festus2, No black water flush on my TT. I did flush the outside shower and pull the HW relief valve too. What do you use to keep the critters out of the low point drains and HW plug. Thanks.

[Festus2]

I use RV antifreeze so my low point drains are capped and closed. As far as the HW tank anode/plug, the access door to the outside of the tank would prevent any critters from finding their way into the tank.

If you are sure that you have adequately cleared your lines of water, I can't see any harm being done by closing your low point drains. If they are like mine, they have a screw-on cap which could be screwed on just enough to keep them on but also loose enough to allow any residual water to drain out.

As far as critters are concerned, I am more concerned about any mice finding their way inside the RV.

[Tbos]

Not sure how to handle the mice. I've heard fabric softener sheets. Thanks.

[koko]

Do a search. There have been several discussions about mice. The best one I learned about on this forum is Fresh Cab. It's balsam oil, and the strong scent repels mice. Four pouches in a box, about $13. Each pouch is supposed to last about three months. Got mine at a Murdock's. Very non-offensive and best of all not a poison or a trap.

[jsmith948]

If you intend to leave your FW tank drain and your low point drains open, you could wrap some fiberglass fly screen fabric around the drains and secure it with zip ties. we do that to keep the bugs/critters out.

[JRTJH]

Originally Posted by jsmith948

If you intend to leave your FW tank drain and your low point drains open, you could wrap some fiberglass fly screen fabric around the drains and secure it with zip ties. we do that to keep the bugs/critters out.

Another option is to put a ziplock sandwich bag over the end of the drain and secure it with a wire tie from a bread wrapper. Any water would flow into the baggie and freeze outside the RV. There shouldn't be but a couple of ounces of water drip out during the entire winter.

[jkohler70]

It occurs to me that one would have to have a significant amount of water remaining in the lines to actually cause damage. The expansion of water as it freezes is the culprit. The water will expand in the direction of least resistance. "Residual water" water will expand within the plumbing, and be unable to create the necessary pressure to cause damage. I wouldn't test it on an expensive RV, but I would bet you could leave your lines with 20% residue without damage. Water expands only 9% - 10% when it freezes.

[JRTJH]

Originally Posted by jkohler70

It occurs to me that one would have to have a significant amount of water remaining in the lines to actually cause damage. The expansion of water as it freezes is the culprit. The water will expand in the direction of least resistance. "Residual water" water will expand within the plumbing, and be unable to create the necessary pressure to cause damage. I wouldn't test it on an expensive RV, but I would bet you could leave your lines with 20% residue without damage. Water expands only 9% - 10% when it freezes.

Like you, I wouldn't want to test it on an expensive RV (for me, my Cougar is expensive, others may not think so). The problem, as I see it, is that water in the lines will typically flow (or gravitate) to the lowest point. The low point drains and the terminal end of the holding tanks is usually the lowest point. So, as condensation, movement of the RV from wind and walking in it (to check throughout the winter), that slight rocking motion could (not always, but risky enough to use caution) cause water in the lines and tanks to flow toward that lowest point.

So, assuming there's a quarter cup of water in the horizontal part of the water line (hot, cold or both), as it flows to the low point drain, it can easily fill that 3" downward pointed half inch tube. Once that tube is full of water, if it freezes, there's no expansion space available (since it's only 1/2" wide and capped at the end). As it freezes, there is no 9 or 10% room for expansion, so there's a likely chance that it would split the fitting, cap and possibly the PEX line. Since that PEX line is attached to a Tee on the cold water or hot water line, once it splits, the underbelly has to come down to access the area to replace/repair the low point drain.

In the holding tanks, if you've ever emptied your tanks at the dump station, then towed it home and pulled the T-handle, you know that there's always a couple of cups of "fluid" remaining in the tank. It always finds its way to the valve. If it freezes in the valve, it can (and usually does) damage the rubber seals. Depending on how the valve is positioned along the tank plumbing, it could be full of water, or could have expansion room.

As you said, it's not worth the risk to test it with my RV, so I leave my valves open to make sure there's always room for expansion. I use antifreeze in my lines, so there's no need to leave the low point drain caps off, but if I didn't use antifreeze, I'd be inclined to be sure there's no cap on the terminal ends so they wouldn't fill with water, freeze and possibly damage the fittings. Early spring is not a good time to be under an RV trying to find a leak above the coroplast !!!

[jkohler70]

Good points. I'm not interested in conducting experiments on my RV!

[gkainz]

How many who blow out their water systems have oil/water separators or filters on their air lines?

[Javi]

Originally Posted by gkainz

How many who blow out their water systems have oil/water separators or filters on their air lines?

I use an oil less compressor, but I also drink out of garden hoses...

[JRTJH]

Originally Posted by gkainz

How many who blow out their water systems have oil/water separators or filters on their air lines?

Not me, I also drink from the water hose, eat fish out of "natural lakes" and don't wear a respirator or ear plugs when I walk outside to mow the lawn. Heck, I even start my diesel tractor inside the pole barn and breathe the fumes rather than push it outside before starting it. I'm sure there's probably "stuff' that gets introduced into the camper's plumbing by the compressor. That's a great argument for using bleach at the beginning of the camping season "next spring".

Maybe I'm living "too much on the edge", but for me, I can only protect against "so much", then I think you have to start using "compromises" to get things done. I suppose, IMHO, it's a matter of which makes more sense: Using my compressor "as is" and adding 25 cents of Clorox next spring or buying a $35 "add-on" for my compressor and still adding the bleach next spring anyway.....

I don't suppose there's a "down side" to using an oil/water separator or even a filter, but I've never noticed the need.

[Festus2]

For those who are afraid of drinking water from a garden hose and inhaling lawnmower exhaust, you can always use a good bicycle tire pump rather than a compressor to blow out your lines. No fumes, no oil, and you get a cardio workout at the same time.

Now how healthy is that!!

[gkainz]

lol ... wasn't expecting those responses!

I'm also of the generation that "drank out of garden hoses (probably real rubber), eat stuff freshly caught/shot/picked, rode bikes and horses without helmets" ... and even after spending years on Navy aircraft carriers drinking Navy coffee with the pretty multicolored sheen of JP-5 floating on top of every cup, I still would rather not introduce oily air into my fresh water lines .... mostly because my dear wife has a very sensitive nose ... and I'd rather not deal with "This STINKS!"

[outwest]

Originally Posted by Festus2

For those who are afraid of drinking water from a garden hose and inhaling lawnmower exhaust, you can always use a good bicycle tire pump rather than a compressor to blow out your lines. No fumes, no oil, and you get a cardio workout at the same time.

Now how healthy is that!!

But but but, the rubber in the manual pump will be outgassing petroleum products