Plastic water drain valve

[Waterman]

In the course of draining my water system, I have somehow gotten a stuck (open) grey plastic/nylon? drain valve under my galley sink on my '89 Excella. The valve is a screw type with a small 't' handle. All of the other ones (there are three others) on the trailer opened and closed as they were supposed to.

Are these little buggers re-buildable? If so, how does one disassemble? I have tried relentlessly to get this valve to re-close, pushing down while turning but the handle just turns and the valve does not move. Anybody have similar experience and/or successful repair?

[j54mark]

You have the dreaded polybutylene plumbing (do a search on "polybutylene" for more than you want to know).

That particular valve is, I hope, no longer available. However, the Flair-it brand fittings will install as a direct replacement. They are available at some hardware stores, and many RV dealers.

Mark

[Waterman]

Thanks, Mark. I was hoping to avoid a repair because it means splicing into the plumbing and, because of the location under the galley, is a lot more work than I wanted to do.

Before I give up and give into replacement, I am going to try using compressed air from upstream and downstream of the valve to try and blow out whatever may be stuck in there. If that is unsuccessful, then I guess I'll be using some Flair-it to replace my 1st piece of polybutyl junk tubing. Sounds like I may as well start getting used to it now as it may be a matter of only a few seasons before there are more failures at valves and junctions.

[j54mark]

Except for the fact that you can't actually physically get to it, it is not a bad repair. The polybutylene tubing fits on the Flair-it connectors much more easily than does Pex. You need only cut the tubing on either side of the affected valve. You may as well invest the $10 in a plastic tubing cutter.

I did all that plumbing down in that well back in the early spring. The injuries have pretty well healed by now.

Good luck!

Mark

[Waterman]

I was able to get the valve to function properly again through sheer luck and a more than healthy level of compulsion. Figuring I had little to lose, I used a small hammer to pound on the top of the 't'. Apparently, in doing so, I dislodged whatever was holding the valve open. I was then able to twist it to the closed position -in other words it worked normally. I also re-opened and closed it several times to convince myself that my universe was once again in harmony. It is strange how anything wrong in that trailer eats at me relentlessly.

I am concerned about the eventual replacement of the tubing/valves in this area with the very difficult access. Can you get at it from below? I noticed an access opening on the bottom side of the trailer (on the water tank sheet metal) just next to where the two polybutylene drain pipes exit the body. I dread working in this tight space at some future time but at least everything is ok for now. From what I've read, the polybutylene tubes rarely go bad but elbows, 't's and other junctions seem to be the problem points.

[j54mark]

You are correct, it is the connectors that fail. The tubing is perfectly decent stuff. But I'd replace it all as it may frighten some future buyer and PEX tubing is inexpensive.

The access from below is via removing the pan that contains the holding tanks. You can do it from above, just pre-assemble everything and only make the final connections down in the hole.

Mark