Question: I have a 2008 Eagle camper by Jayco. The kitchen sink is clogged. I took off the P-trap and problem is not there. Need help.
Answer: First, make sure that the gray water tank has been drained so there is a place for the water to drain into. This may be obvious, but worth checking as it would be an easy solution!
Next make sure that kitchen sink down-pipe before the p-trap drains. Place a catch basin under the down-pipe and remove the p-trap. If water drains into the catch basin from the drain pipe then you know that the down-pipe and anything else associated with the sink is draining fine. If water does not drain, then you have a problem at the sink and down-pipe in the sink. There is usually a metal cross bar that always catches stuff. You can clear that away with tweezers or a very slim bladed knife to cut away the clog.
Next look down the drain past the p-trap. Is there standing water in the pipe? If so then your next option will be to snake the drain pipe or use a chemical agent (see caution below). You could do this your self or have a professional do it. It all depends on your level of comfort and expertise using these methods.
Just be aware that your RV drain pipes are made of plastic and you need to exercise caution while using a snake or a chemical agent. You do not want to break a pipe that goes somewhere between the floor and the holding tank. These pipes are usually buried in places that are very difficult to get at and to repair. If you use a chemical agent use one that is approved for plastic drain pipes and that you flush your holding tanks as quickly as you can after you unclog the drain.
Another word of caution is not to use one of those CO2 capsules, high pressure air, or high pressure water through the system. If you do, you could rupture the joints or pipes.
Caution on the use of chemicals: Many RV parks do not like you to use chemicals because of there detrimental effects on their septic systems. Also, chemicals may have detrimental effects on the longevity of rubber seals in your holding tank and drain valves. So use chemicals as a last resort.
To keep your drains clean and flowing freely try using baking soda (about 2 tables spoons in each drain) then add vinegar (a cup) let stand for an hour and flush with lots of boiling water (4 cups should do it). Do this on a monthly basis and will take care of clogs and keeps it smelling nice.