Fresh water connection popping off toilet

[Hettinga]

1984 Bigfoot 17
Whenever I turn on my hot water tank, a few hours later the fresh water line pops off of the toilet. Every time this happens I need to remove the toilet to reconnect the fitting. I have even tried to epoxy the fitting.
I suspect that hot water is rising to this spot since it is higher above the tank. It is a cold water line but somehow it ends up having hot water in it. Could it be that the heat is rising in the system and then the heat softens the plastic leading to it popping off.
At this point I am not sure what to do. I don't want to replace the toilet, but I likely won't be able to find parts for it. Could it be that I am missing some sort of valve in my plumbing system? Any ideas welcome. I've attached picutres of the connector, the hot water bypass and the toilet.

[Denece]

Is it possible to put a hose clamp on it?


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[k corbin]

Rule number one for trouble shooting that I learned from the teacher in my computer A+ certification program....ALWAYS check the physical connection first. Meaning, make sure it is plugged in right. In your case it should be plugged into the cold water source but it seems likely they plugged it to the hot water source instead.

But if it is not that situation you might want to insulate that line if it immediately adjacent to a hot water source.

Toilet parts like that should be possible to find in a well stocked RV supply store. If not in stock they can likely help by ordering the right part.

[Casita Greg]

The same tubing is used in the trailer for both hot and cold runs, so that's probably not the culprit. But, also agree that it sounds like you have the flush water for the toilet coming from the hot side plumbing line. That in itself shouldn't be a problem, other than wasting hot water. Sounds like you may have a defective press-on PEX fitting (in your photo above) where your water line hooks to the toilet. I'd get a new replacement fitting with the correct threaded end to screw into the toilet valve, but one that uses a compression ring-type screw clamp instead of the press-on one.

[mszabo]

Try something like this, but in 1/2" get at local hardware or box store.
You didn't say if you were on pump or city water.
On city water and hot weather pressure builds up and this fitting always blows apart.
Just my observation for what it's worth.

https://smile.amazon.com/SharkBite-U...kbite+fittings

[Eddie Longest]

Make sure the center valve in the picture between the two lines is off during non-winterization operation. If currently on that is where you are mixing the hot and cold water.
Eddie

[Hettinga]

Originally Posted by mszabo

Try something like this, but in 1/2" get at local hardware or box store.
You didn't say if you were on pump or city water.
On city water and hot weather pressure builds up and this fitting always blows apart.
Just my observation for what it's worth.

https://smile.amazon.com/SharkBite-U...kbite+fittings

I think it must be my fitting. I most recently put a hose clamp on it and it still popped off. I like the idea of a high quality fitting like the one you suggested. I am rarely on city water. Mostly dry camping, but need to be able to use either. When on city water I use a pressure regulator.
I have put it back together and am going to test it out at home. I'm still scratching my head on the hot water.
Thx for the other comments.

[Hettinga]

My conclusion is that the hot water tank increases pressure in the whole system. The only way to release that pressure is to turn on a tap. Or in my case, a poor quality fitting pops if no taps are opened for a long time
In terms of the warm water coming out of the tube, it is likely because the hot and cold tubing is all run together. If the cold water is not run for a while it will naturally heat up. That of course will eventually trigger the hot water tank to go on again, increasing the heat and pressure.
There seem to be 2 things I need to do, first, deal with the lousy fitting, then insulate the hot water tubing.

[Borrego Dave]

Hi Justin, just a thought for you. Until you figure it all out, leave the water heater off until you need the hot water. It only takes about 10 minutes to heat enough for 2 showers and shut it off. I've been doing that way forever. Can't see just having the lines side by side being a problem. The hot water shouldn't be flowing out of the tank at all to heat up the cold line. Are you sure some OP didn't plumb the toilet to the hot line?

[Carol H]

Originally Posted by Hettinga

My conclusion is that the hot water tank increases pressure in the whole system. The only way to release that pressure is to turn on a tap. Or in my case, a poor quality fitting pops if no taps are opened for a long time
In terms of the warm water coming out of the tube, it is likely because the hot and cold tubing is all run together. If the cold water is not run for a while it will naturally heat up. That of course will eventually trigger the hot water tank to go on again, increasing the heat and pressure.
There seem to be 2 things I need to do, first, deal with the lousy fitting, then insulate the hot water tubing.

Not sure how the hot water would increase pressure in the whole system. Not had a trailer where that has happened as the cold system should be on a totally separate system and the piping does run around the outside of the trailer together.

I recently installed small sections of thin pipe insulation around any pipes I had room to fit it around and could actually get at (inside of hatches or cabinets) to quite down the vibration against walls etc. from my water system . It helped a bit. It would be a fast and easy way of separating the pipes where possible to test out your theory.

[k corbin]

Hot water expands and the extra volume creates pressure. That pressure has to go somewhere for relief

Maybe the issue lies with the pressure and temperature relief valve on your hot water heater not letting excess pressure escape. But if you have water dripping out of the relief valve when the water in the tank is fully hot that indicates the relieve valve is working OK.

Also it could be you have the water temperature set too high, so try turning that lower.

Now you have some more trouble shooting information to act upon but at least it is easy stuff to look at and you don't have to buy anything to do the investigation.

[Casita Greg]

Originally Posted by k corbin

Hot water expands and the extra volume creates pressure. That pressure has to go somewhere for relief

Maybe the issue lies with the pressure and temperature relief valve on your hot water heater not letting excess pressure escape. But if you have water dripping out of the relief valve when the water in the tank is fully hot that indicates the relieve valve is working OK.

Also it could be you have the water temperature set too high, so try turning that lower.

Now you have some more trouble shooting information to act upon but at least it is easy stuff to look at and you don't have to buy anything to do the investigation.

Pressure in any closed system, (like in your trailer's hot and cold water system and associated plumbing lines,) will equalize and be at the same pressure at all points in the closed system (Boyle's Law). Why wouldn't all the other fittings and piping do likewise and pop off too? It sounds like a defective fitting to me. Have you considered installing an expansion tank in your system?

[Ben Barkley]

I live in a house that is about 45 years old that was plumbed with all copper. In the past 5 years I have made probably 6 repairs where the copper pipe developed pinholes. (We have our own well.) One was inside an internal wall in the bathroom. I had to replace the floor under the shower/tub. I replaced a portion of the copper pipe to that bathroom shower with CPVC. In the past 3 weeks, I have replaced the rest of the copper (approximately 220 feet) with PEX tubing. I am not a plumber by trade. I do Industrial Maintenance, which covers a lot of trades. PEX is fairly easy to work with if you follow the instructions and use the correct tools. And I am pleased to say we haven't seen any leaks. But in doing the research for my project and on several trips to two different hardware stores (Lowe's and Wally's Hardware) I heard folks looking for grey pipe fittings. From your picture, your pipe looks grey, so it looks like you don't have CPVC, PVC, or PEX. I found out is it called Polybutylene pipe and it has been outlawed in most states because the pipe and the fittings are subject to failure. Lowe's doesn't sell it anymore. Walley's doesn't sell the pipe but one can still get fittings there. If you can see a length of pipe anywhere in your trailer, see if it says polybutylene on it. If it does, you may want to consider replacing all the plumbing in there. I am including a link to an article about polybutylene. It is one of many. This may not be what you have in your camper and yours will be a simple fix. I hope so. Good Luck.
Ben

Take Another Look at Polybutylene Plumbing | The ASHI Reporter | Inspection News & Views from the American Society of Home Inspectors

[Carol H]

Originally Posted by k corbin

Hot water expands and the extra volume creates pressure. That pressure has to go somewhere for relief

Yes it sure does but if a trailer is plumbed correctly there is absolutely no connection between the hot water system and the cold water system which is what should be feeding the toilet.

If the OP is not opening the pressure relief valve when filling the hot water tank and waiting until the water pours out of it they will end up with lots of air in the hot water system. Result in a lot of pressure coming out of the taps when they first use the hot water at the sink which could well blow the connections apart at the sink, but again it would be very strange for the toilet connection to blow off due to air in the hot water tank.

[Paul O.]

If there is any air in the pipes or the water heater, the pressure will increase less when the heater is turned on, since air is compressible. If there is no air in the system, water will expand with temperature, but it is essentially non-compressible and the pressure will increase. The plastic plumbing in the system should allow for some expansion, being more elastic than copper pipes.

Circulating hot water in cold pipes might be possible if the shower is left on and only the hand held sprinkler is shut off at the end of the shower hose. Am I making sense?

[tractors1]

That gray poly tubing was discontinued many years ago; in my 85 rig the leaks got worse with age. I think the name on the tubing was Quest.

[k corbin]

New fitting for sure but one does wonder why the temperature increase at the toilet? Not that the temperature issue has be solved if a new fitting solves the issue of it popping off. It is just one of those odd curiosities of why?

[Paul O.]

Originally Posted by k corbin

New fitting for sure but one does wonder why the temperature increase at the toilet? Not that the temperature issue has be solved if a new fitting solves the issue of it popping off. It is just one of those odd curiosities of why?

Yes, that is what I was trying to suggest in my post, two or three above. The hot water will circulate by gravity, if there is an unrestricted loop in the piping, even if the elevation difference is just a few inches.