Fresh water drain plugged

wyocamper · 04-03-2021, 02:44 PM

Sometime last fall my fresh water tank drain stopped draining, I noticed it when I was winterizing last year but kind of forgot about it. Until this week when we returned from a short trip and I had to winterize again. I ran a metal rod up it just to see if some crawly thing had got in there but didn't feel any obstruction. So something might have got in the fresh water tank and is plugging the drain.

I've looked at the plumbing diagrams but can't see how I can get to the drain to try and clear it. I thought about using my compressor to blow through the drain line, but that would either leave what ever's plugging it in the tank, or possibly blow something from the line into the tank. Anyone know how to reach the drain? And can it be disconnected for clearing? I haven't looked under the bed yet, but I don't remember being able to see the side of the tank from in there either.

Morich · 04-03-2021, 04:02 PM

I did a look at the parts catalog for your RV and took a snip of the drain line.
It looks like that valve is a crimp style, so not likely to be easy to replace if PEX tools are not on hand, but it doesn't really say much more about the valve but I might expect it to be a form of ball valve.
My thoughts would leave several options to consider.

One is if it is a ball valve, make sure the handle is actually moving the ball to open and not come loose in some way? Broken, it likely requires replacement and not fun for PEX.

Two, if I felt the valve was actually getting opened when turning the handle, I might then assume something in the line and try to either run something up the drain , since it is a straight shot and try to move something laying on top of the valve around enough to drain. Probe kind of gentle if using wire so that you don't scratch a plastic ball to make it ooze?

Three and sounds kind of weird but pretty standard for clearing condensation tubes at times, is using bleach. Our Air conditioner is in the attic and runs kind of bad, so we need to bleach it once in a while to clear algae that collects.

Bleach is scary to some but it is sold in plastic bottles, so not likely to hurt the tank or drain, but if you can get the RV tilted with left side and front down and then pour a jug of cheap, no name bleach in the gravity fill port and leave it, you might be able to clear any organic stuff like algae, mold, etc. that has broken loose in the tank and stuck in the drain.

I turned the picture all wonky to get a better picture of the drain but it does put the drain near the front and left so tilting the RV in kind of the same way, will put the bleach more directly on the drain.

See if any of that makes sense?

Bones2003 · 04-03-2021, 05:58 PM

If I'm interpreting Richards picture correctly, it looks like the drain valve is directly behind your outdoor shower. Almost looks like you could reach up behind there and unscrew the drain fitting from the tank - of course you would have to remove the PEX from the fitting first. If the tank has a lot of water in it you would get a nice shower if it comes pouring out!

wyocamper · 04-03-2021, 06:18 PM

Thanks, I did look at that pic, and I can run a wire up past the valve so that's not it. I was referring to the fitting that connects to the tank. Number 72 in the drawing and labeled "fitting-spinweld". I looked under the bed, I think I can see where the drain tube connects but I'd have to be a 10 y/o with really long arms to even come close to reaching it.

We didn't notice any funny taste in the water this week like algae, but I'll try the bleach anyway.

Bones2003 · 04-03-2021, 06:35 PM

Does it drip at all when open or is it completely plugged? Another thing to try is to drive around with the drain valve open to see if the sloshing around loosens something up. It's also possible that when they punched out the holes for the fittings that one of the plastic disks ended up inside the tank. Not a good scenario.

Morich · 04-03-2021, 06:57 PM

Quote:

Originally Posted by Bones2003

Does it drip at all when open or is it completely plugged? Another thing to try is to drive around with the drain valve open to see if the sloshing around loosens something up. It's also possible that when they punched out the holes for the fittings that one of the plastic disks ended up inside the tank. Not a good scenario.

I've always thought about this happening but then on the other hand, I'm not sure I can see it really totally blocking the drain.

If we punched a 1/2-3/4 inch disk out of a hole, would it be likely to align and fit in exactly the right way and flat against the opening to totally block it . Seems it more likely to get jammed flat if getting into the hole and then maybe other stuff catching on it?

One of those things that we could never do if we planned it but then the gremlins CAN do things we can't !!!

wyocamper · 04-03-2021, 07:23 PM

Quote:

Originally Posted by Bones2003

Does it drip at all when open or is it completely plugged?

Nothing, even with a compressor hooked up and all the other faucets/drains closed.

Morich · 04-04-2021, 08:56 AM

Quote:

Originally Posted by wyocamper

Nothing, even with a compressor hooked up and all the other faucets/drains closed.

This is possibly due to the air going out the overflow???
Can you hold a finger over the overflow to tell if air is coming out there or to close it to build some pressure?

If no way to get air to go in the drain, I'm guessing it is the valve broken and the ball is simply not moving.

Then there is the nasty sounding question to ask if you are sure there is water in the tank, not something else, like a bad water level reading?

Sometimes I get so involved in chasing things that I miss where I've screwed up in the thinking!!!

wyocamper · 04-04-2021, 11:18 AM

I usually open the fresh water drain while I'm dumping the holding tanks on the way home. It always drained pretty fast, but then last fall I noticed that it was still drained for quite a while after I got home. Then the other day I noticed that it wasn't draining at all. I opened the drains at the pump and the water heater and ran the pump until the tank was as close to empty as I could get it.

I didn't think to check the overflow tube for air, but I didn't hear anything either.

IOS 3 · 04-04-2021, 12:46 PM

If you haven't already you might try connecting the compressor to the bottom of the drain line, below the valve, and then rotate the valve back and forth while under some pressure. The fact that it was draining slow, then slower, then nothing sounds like you might have something trapped just above that valve. If you have a pex crimper you could also remove the short pex line above the valve that goes to the fresh water tank. Then you could inspect the lines and the valve... Hope it ends up being simple.

wyocamper · 04-04-2021, 03:36 PM

I hooked the air up again today and closed all valves and faucets and did not get any air out of the drain line. I was able to hear air from the overflow tube, though. Not at all sure what I was thinking when I posted that I was looking for the fitting on the tank, it's right there in the water compartment. Anyway, I was trying things and found that when I turned the tank valve to "tank fill" I get air out of the drain tube. Is there a one-way valve somewhere that I'm not taking into account?

I don't remember in the past having to turn the valve to tank fill to drain it, but maybe I'm just forgetting? Hopefully that's all it is and I can chalk it up to another Homer DOH! moment.

Morich · 04-04-2021, 06:09 PM

If you were looking at a tank and it might not have any other openings, we could say it "might" have something of a vacuum that would not let the water come out fast but in this case, you have several things that won't let that idea fly.
One is that you have the overflow almost next to the drain only from the top instead of near the bottom but then you also have the gravity fill port which is pretty much just an open tube running into the top, so no vacuum allowed??

What I see is there are four openings on the front/near? end of the tank. The gravity fill at the right top which is a big opening and hard to stopper up, the overflow drain at top left, which you might get a thumb over to stopper air, and then there is the tank fill route which I marked in purple that lets water in at the input and goes up and into the tank on top if the fill valve is set that way.
But if the fill valve is left in the normal way, water comes in the port, can't go to the tank due to the valve cutting that route, so goes along the green line to the other end of the tank to the pump and all the inside lines to faucets, etc.

I don't see anything that I would expect to cause trouble draining the tank but there are a couple valves and openings to be aware of for thinking/checking.

One is the pump line from the tank, which comes out and then has the valves for choice of normal flow or sucking anti-freeze and that might do something weird, so maybe worth a check??? And then there is low point drain there, too.

Neither are things I would expect to cause any trouble draining, though.

But there are not many honest folks on here who do not know about the DUH! part of RV'ing!!
If I can find a DUH to fix my problems---I'm good with that as it costs hardly anything!

IOS 3 · 04-04-2021, 06:59 PM

Wyocamper - I have your same rig as you know, and your memory is not fading. I've never had to move the freshwater valve to "tank fill" to get the tank to drain. Something must be pulling a vacuum and not letting that tank drain... At least you now know the valve itself (and the line to the tank) isn't the problem. It's "upstream"....

Wyatt · 04-04-2021, 08:57 PM

Random thought...water can’t exit the tank, unless air can replace the water. What if the fill check valve is faulty? And I’m not sure how that happens exactly. Can you open the gravity fill cap and then see if water will drains out the drain tube? Sorry, late to the party, but had to chime in, just in case...

Morich · 04-04-2021, 09:13 PM

Overflow would also have to be fully plugged to create vacuum? Hard to see both the overflow and gravity fill both totally airtight for very long and then it really is hard to keep air from sneaking in past water trying to fall out of the drain, especially if things are moved around a bit. Think of what it takes to hold a glass of water upside down in a pool and actually keep the water from sneaking out?

Upinsmoke · 04-08-2021, 02:16 AM

Morich, wanted to let you know that both things you mentioned (plastic plug & "thinking" a tank has something in it) can happen.

I had a plastic tank plug from the hall bath go into the macerator pump and bind it up (had to replace it) and, ahem, I may know someone who was working on a tank valve because the tank wouldn't drain. Turns out the tank was already empty.

Not saying either of those are the case here, but they do happen.

wyocamper · 06-26-2022, 09:06 AM

Update: I finally got around to revisiting this issue. I removed the pinch-clamp and pulled the hose from the drain plug. The drain itself is a plastic elbow that screws into the spin-weld fitting in the tank. When I unscrewed it I found a piece of something that was blocking it. Not sure what it was but I think maybe a bit of silicone or similar sealant that had peeled off from somewhere in the tank. It was very thin, like sealant that had been spread. I was going to save it and take a pic but the wind disappeared it.

I thought this was going to be a difficult fix for some reason, but it turned out to be very simple. I used a hose clamp on the drain line so it will be easier to repeat if it happens again.

Morich · 06-26-2022, 10:24 AM

I used to work where we often found small bits of junk causing big problems when they got in just the wrong spot.

We often had trouble we blamed on gremlins, so those small bits became known as "gremlin droppings" but looser terms if you know what I mean?

wyocamper · 06-26-2022, 10:51 AM

LOL I like that one.

Gremlin "stuff" happens.