My toilet won't flush on city water

[godaddy64]

Hello collective brain trust!

I have many updates to post here regarding my '94 Excella, including some pics on the sewage system, but my briefcase got stolen this summer, and it set me back six months in terms of digital work.

But in short: I have a Ford F2504x4HD460 crew cab long bed tow beast now and a functioning black tank/sewage system. There's brand new pimpin' upholstery everywhere, and I've lived part-time in the trailer for work, using the fresh water tank and 12v pump for my water needs. Almost made it camping this year with the wife/kids.

Today was supposed to be the next frontier of greatness. I replaced the city water regulated inlet valve, plus the black tank/rinse plumbing. The earlier setup had many leaks, but this all seemed to seal beautifully for me. No drips on the inlet side. Inside the trailer, faucets and shower work great after a little sputtering.

Except...

Now I want to flush the toilet. The coop the grass. And there's no water.

I found no way to get the toilet to flush, except to turn off the city water and revert to the pump. This toilet is a replacement Thetford unit that I had installed successfully without leaks, and had worked well on the pump for over three months of use.

I checked the owner's manual but no luck yet. I've been all over the forum looking for a similar story, but no dice yet. Dear fellows, what in the world is causing this?

[Tinsel Loaf]

Is there a check valve for the head that may not be working or put on backwards? Black tanks should have a check valve. Look at the inlet pipes in the Airstream and see where the head pipe or hose is connected to, there may be a check valve put inline but backwards. Let us know the outcome please.

[godaddy64]

Mr Loaf, I finally had a chance to look around. This is what I found:



This is the plumbing under the bathroom cabinet. You see a gray valve there and right below it is some sort of copper plumbing in-line element on a loop around the gray valve. Could this be the defective check valve?

It looks to me like the line that feeds cold water to the w/c sink and shower also feeds the toilet. I get city water into the sink/shower, but no flush. Is it perhaps the wrong kind of valve on the replacement toilet?

Here's another murk picture with my no-flash phone and flashlight illumination:



Just left of the napkin box is some sort of valve/breather. This does not seem to be on the same line that feeds the sink, but rather comes up and down from the floor.

Thanks for your help.

H.A.

[Aage]

The tap you show in the first picture is in the "Off" position. Try turning it on...

The valve in the second photo is call a pop-off valve, and its purpose is to pop open if your water pressure regulator fails, and thus prevent higher than safe pressure from damaging your plumbing.

If I am right, the numbers "111" should be stamped into the cap. It will end in a piece of pipe that merely spills the overflow onto the ground outside your trailer. Look below the trailer for the pipe, if you want.

Hope this helps...

ps: when you said "coop the grass", did you really mean "coup de grâce"? They sound a lot alike.

[vswingfield]

Originally Posted by Aage

...

ps: when you said "coop the grass", did you really mean "coup de grâce"? They sound a lot alike.

Or since he can't flush, perhaps he really meant "poop the grass."

[godaddy64]

Originally Posted by Aage

ps: when you said "coop the grass", did you really mean "coup de grâce"? They sound a lot alike.

HA! I knew somebody would sooner or later catch on to my Looney Tunes reference. I believe it was Bugs Bunny who said it this way in an attempt to sound all suave and deboner...

Originally Posted by Aage

The tap you show in the first picture is in the "Off" position. Try turning it on...

Good point. But I forgot to mention in the original post that I tried everything possible with the valve in the open and then the closed position. It seemed to make no difference, whether on pump water or city water at various pressures.

I was the family "figure-outer" in the 70s and 80s. The vcr light actually told the time at our house. My dad was a machinist by trade, and we worked on 4x4s and my daily drivers together. Then in my 20s and 30s I fixed up a lot of Mopar hot rods. In my 40s I got into kart racing with my son and now it's mostly Home Improvement and this Airstream that I love so much to work on. So I've fixed a lot of different things and I'm still a pretty good troubleshooter with the trees of "if not this, then try that" kind of logic -which is a long-winded way to say that my Powers of Deduction match at least those of Inspector Clouseau.

That's why I feel like such a minnkee when confronted with this flushing confusion. My intuition is beginning to suspect cloggage at either the valve or the copper inline screw-in element. I guess replacing the inline copper element (below the valve in the upper picture) would be the next thing to do, non? I'd first need to study what that thing actually is.

Either that or remove the toilet and check pressure at the inlet. Could this be a defective toilet valve? I DID install it myself and it works fine on pump pressure. Strange.


Strange indeed.

[Splitrock]

Does everything else in the unit get city water both hot and cold with no problems? So it's JUST the toilet that doesn't get city water but gets pump water fine?

[godaddy64]

Originally Posted by Splitrock

Does everything else in the unit get city water both hot and cold with no problems? So it's JUST the toilet that doesn't get city water but gets pump water fine?

Yup. Just the toilet. Weird, ainnit?

[godaddy64]

Update: I went home on my lunch break, and fiddled around some more with Star Ship Excella. I discovered that with super, duper low pressure from the city water, I could actually get the toilet to flush. With the city valve barely open, it would be enough for a mild stream out of a fully open kitchen faucet (I'm guessing 1/3 of full flow with the 12v pump) and a weak flush out of the commode.

Then I increased the city water pressure bit by bit until there was good flow out of both, but soon the pressure would build up and the toilet wouldn't flush anymore. I'd open the sink faucet on full for a couple of moments to relieve system pressure, and voilá: It would flush again.

So either the newly replaced water inlet valve and pressure regulator puts out too much pressure into the AS/is defective, or the newly replaced toilet is rated for a lower pressure system/is defective. Or could it be that still-mysterious brass inline valve thingie? I'm about to dig into the owner manual's plumbing schematics tonight, but I'm always open for more clues from the collective brain trust.

[godaddy64]

Victory! Case closed.

I wound up calling the Thetford customer service 800 number. Within 30 seconds of my describing the problem the young man had it solved:

These new Thetfords apparently like pressure in the 40-50 psi range. The city water inlet regulator that I had just installed was rated at 65 psi.

By simply attaching a 50psi in-line pressure regulator, I had it licked quick:



I was anticipating a long, expensive campaign to get this fixed. But in the and all it took was a the right phone call and 5 minutes of work. If only the rest of the project were that easy...

[Splitrock]

So . . . you licked your toilet?

[Tinsel Loaf]

Good job and a interesting post. Some other members may need to refer to your fix.
Now go have some fun.

[godaddy64]

Why thanks for those kind words Mr. Loaf!

Without this forum I wouldn't have made it far. I am glad to contribute back to such a great knowledge base.