Low point drain line caps nightmare

Lemonhead78 wrote:

mobeewan wrote:
If the cap is a Flair-it cap and looks like the one in the link, there is no gasket. Those caps are used to cap Flair-it fitting where the PEX tubing has been removed. They seat against the Barb the PEX normally slips over before tightening the nut used to hold the PEX to the fitting. They will hold pressure up to the rating of the fitting, valve or PEX tubing without a gasket.

I have a couple I keep on hand in case I have a plumbing problem and have to disconnect a piece of PEX until I would have time to make a repair. I used one once to temporarily cap a tee I added where I was adding a new PEX line where I was installing a captive air tank. I still needed to use the trailers fresh water system before I had time to finish the tank install.

So what am I suppose to do. I checked hardware stores and the rv parts department where I bought trailer it and no one can help. I’m getting depressed over this. I called forest river and that was a joke.

Okay my understanding is that you have all three caps, but you believe the one cap is missing a gasket. if the one cap matches the picture that you found online no gasket is needed he just needs to be threaded back on. If there is a valve above where the cap was screwed on then you're fine as long as the valve is closed. You do not need to put the cap back on.

My freshwater tank drain has a Flair-it male pipe thread x PEX connector screwed into the tank. Then there is a short piece of PEX, then a Flair-it valve. I I think it might have came with a cap on the end of the valve. The valve doesn't need one and I didn't feel like crawling under the trailer just to remove the cap on a valve, so I left it off and the cap did not have or need a gasket just like the one in the link you posted.

If you have PEX tubing coming off the fresh water tank drain with no valves you will need to screw the cap back on. Otherwise the tank will drain through that fitting.

You say you have the cap and don't know if it needs a gasket. Can you take a couple pictures of the cap and post them other than just saying will it looks like this one and it looks like the gasket is missing.

There are so many different ways low point drains and tank drains can be configured. With valves and caps, with valves and without caps. With caps only, with valves inside the trailer at the floor that have open end tubing going through the floor to the underside of the trailer, etc, etc.

Can you get someone to crawl under the trailer and take a photograph of the freshwater tank drain and the 2 low point drains to see what the fittings on the end of the lines look like. There has to be a fitting or a valve because the cap was removed from something.