Kitchen sink won't drain

[mrsbuzzardflats]

I've tried everything. Have opened and closed outside pull handles til and path.
It's 50 outside so not frozen.
Have used plunger until thought drain was clear. Ran water for 15 minutes it's backed up again. It does go down but not fast or just slow supper duty slow.
What is my next option. With the black water tank I just got one of those back flush valves.
Should I try to black flush???? Please I need help

[Daryles]

Does anything come out when you have the drain valve open?
If YES, I would pour boiling hot water down the drain. Watch the sewer pipe outside to verify it is coming out.

[rohrmann]

Have you operated the pull handle that might be located behind the tires on the drivers side? That is where our galley tank drain pull is located. Some have said they have theirs between the tires and maybe ahead of the tires.

[jimcol]

The profile shows it's a 3400RL. Can someone tell the OP exactly where the pull is for that model?

[steiny93]

Have you opened the trap under the sink?
Is the black tank full?

[DutchmenSport]

If the holding tank is dumping, and it's just slow draining from the sink, then your drain lines are clogged.

If grease and food particles have been dumped down the sink, then it's most likely clogged.

Using an Enzyme eater will clear the pipes of anything blocking them as long as it is bio degradable (food) and not plastic in the pipes.

Potato peelings and washing bacon grease down the drain in an RV is a disastrous clog waiting to happen. Before washing any dishes, especially greasy pots and pans, wipe them completely out with paper towel first and work dilligently hard to keep ANY food particles from going down the drain.

With all your best efforts, some food particles will go down. It's inevitable. And it does not take much to create a clog, especially when the camper is not being used and the crud in the drains dries hard, the next batch of food particles comes along, sticks to that, dries, get's hard, and repeats and repeats until the drain clogs completely.

Enzyme eaters for drains work great for your home pipes AND for your RV pipes. This is how high pipe and drain maintenance is done on high rise buildings and cruise ships. They use enzyme eaters down the drain.

Do not use Drano or any caustic drain opener. They really do not work and can actually cause more damage than good, especially to RV plumbing seals and such. Not to mention, the caustic effects on everything it touches, and the poisonous gasses those products create.

See my post on this thread: Click here.

[TK1]

Originally Posted by jimcol

The profile shows it's a 3400RL. Can someone tell the OP exactly where the pull is for that model?

On our 3400 RL the galley tank drain valve handle is/or was on the drivers side between the wheels. These handle had a habit of vibrating loose and falling out the road after replacing ours twice we just opened the valve and left the handle off. Adding a gate valve to the black and gray water outlet keeps you from having the galley tank drain out when you take the cap off.

[Jay & Bobbie]

First, do what DutchmenSport suggested. It is likely greese and slime buildup inside the pipes.
If that doesn't work, check the p- trap, then the air admittance valve under the sink. It could be stuck in the closed position.
Your drain valve handle for the kitchen sink grey water tank should be where TK1 said.
If the grey water tank valve is open and the drainage is still slow, it is possible the drain pipe in the belly from the tank to the main 3" drain pipe is clogged. That pipe (on my rig) is 1 1/2" and really should be 2".
Hate to say it, but it may require the expertise of a licensed plumber if these suggestions have not effect.