Galley Grey Tank

[campermama]

My galley tank is not draining. Valve is on long cable in insulated and enclosed underbelly so I can't see it but the handle doesn't feel any different, feels like it is working?
Water goes down the drain with no hesitation, could there still be a clog somewhere?
I am in the cold but have heat running everywhere and my other valves (black & another grey) work fine..the galley tank is furthest back under the trailer, could the pipe from tank valve to dump opening be frozen? But then it was 42 under the trailer yesterday and still no water coming out, not even a dribble!
This is driving me crazy....anybody have ideas I can try before I start cutting the underbelly??
Thanks!!

Wish I could attach picture of my plumbing for you here.

[campermama]

It shouldn't happen again, the main dump valve was frozen so I started using a hair dryer to thaw it, half way through I thought I would see if water would come through yet so I pulled the tank valve real fast open close. So pretty sure that is how water got in there. Temps are staying very cold here but I am heading south next week!

[MFL]

Thanks for the update! Glad you got it thawed out.

Is there something you can do different, to keep this from happening again? Don't know where you are at, but hopefully the extreme temps are not the norm.

Jerry

[campermama]

UPDATE!!!

I got a gallon of full strength antifreeze and poured it down the drain, opened tank valve and let sit all day, then opened main drain valve and the tank emptied!!!!

Thank you all so much for all the ideas/advice!!!!

[jdc1]

Force water in the opposite direction. You can do that using one of these;

https://www.amazon.com/Valterra-Degree-Reverse-Attachment-Trailer/dp/B008O9DV78/ref=sr_1_3?crid=Q988JVIA36TJ&keywords=rv+backflush+waste+attachments&qid=1641843453&sprefix=rv+backflush+waste+attachments%2Caps%2C141&sr=8-3

[Grit_dog]

Why not save the cutting first and shoot heat up the drain pipe?
Or run a snake up it and verify if/where a blockage is. Could probably verify operation of the valve as well like that if it's clear to the valve.

Assume it worked recently and now gotten colder?

[schlep1967]

If you're not getting even a trickle either the valve is not opening or the pipe is frozen. Construction debris will not stop all of the water. Get some heat in the belly above the coroplast. You can do a minimal 3 sided cut with just enough room to get a hair dryer nozzle up in the hole and cover the whole thing with a single piece of gorilla tape when done.

[campermama]

It has got down in the teens a some nights but mostly low to mid 20's all night and in the day upper 20's to mid 30's.
I think I might try putting a heater underneath to see....I really don't want to have to do "surgery" 😞

No food gunk down the drain, been living almost 2 yrs in it so don't think construction material, at least hope not!

[MFL]

^^Good question above! If temp only dropped to 28-30F, should not be frozen much, if at all. However, if temp in the mid teens, for hours, could freeze hard.

A few other possibilities, a piece cut out from tank install, may be inside tank, and moved to point of blockage. Most know not to put a lot of food scraps down the drain, that may build up over time.

Temp at coldest point, will help diagnose if frozen. Let us know if you managed to get it open to drain.

Jerry

[Grit_dog]

How cold has it been? You didn’t mention that.

Best of luck. Hope it’s just frozen and you don’t have to do surgery to fix the valve.

[campermama]

Yeah there are no markings or access areas underneath my trailer, all I can do is wing it according to the schematics 😞
That's why cutting is my last resort.
Still hoping maybe ice in the one pipe but not seeing even a dribble come out I'm losing faith. Maybe I can try a heater under there for a bit and see what happens.

[MFL]

My tank valves are enclosed and whole underbelly heated. Mine is described as 4-season capable (a bit of a stretch). If you look closely, or enlarge pic, you can see a cover over valve area. All my tank valves were made accessible from factory, by cutting 3 sided window. Mine came with additional coroplast covers screwed over the window. If you need, you can cut your own 3-sided window, and seal edges with gorilla tape.

Jerry

[campermama]

I do have a long pipe like that but its completely enclosed underneath
And I have not seen even a drip of water come out so far. If it is frozen I would think outside temp of 42 should start to thaw it?

[MFL]

Many times, with a long line running from trailer rear, all the way to front sewer exit, a small amount of residual water remains in lengthy pipe, that in Summer, may be enough to wet your shoes, when opening sewer cap. In cold temps, this could freeze, stopping flow. I had a galley tank vent on roof plug up from critter invasion (bugs) one time, that slowed the draining to a trickle.



Here is pic of mine, maybe similar to yours? You may even notice a slight rise in pipe middle area, on it's way to the main sewer outlet. This will cause residual water to stay in pipe, until towing, when it moves to exit cap, to give a surprise next dump.

Jerry