Ouch! black holding tank flush issue

[jkinglet]

Originally Posted by 73shark

My check valve was installed backwards and the dealer told me that it was located on the curbside and you had to remove the plastic cubby to access it.

Thanks. Cubby? Are you talking about the macerator access cover on the outside where the flush hose port lives? This coming Tuesday I have put aside time to search for this demon, wherever it might be hiding. By the extent of the flooding and damage shouldn't be too difficult to locate. This valve apparently has a long, checkered past of unreliability.

[73shark]

The cubby is on the curbside to the rear of the step.

[InterBlog]

Thank y'all for reminding me why I'm perfectly contented to have a lower-tech, older Interstate which includes, among other stone-aged implements, an almost fail-safe gravity-driven black tank. Anti-siphon whatchamacallit?! Good grief! As if the Dometic sink faucet wasn't posing enough of a flood hazard, now you've got to worry about that, too?

[73shark]

Judging from the number of problems you've encountered, the older version is not trouble-free.

[jkinglet]

Not to get off the anti-siphon valve subject. Speaking of sinks and floods. Peaked under the Dometic sink lid in a new GT at the dealer. You guessed it..same sink, same faucet handle, same problem and eventually same flood!

[73shark]

Wonder if anyone has ever written/talked to the mfg about this problem?

[scarletbison]

Originally Posted by 73shark

Wonder if anyone has ever written/talked to the mfg about this problem?

I happened to be talking to Airstream this morning, They called me to set up communication lines since I purchased back in November. I did tell them about this thread/issue. I also wasn't sure if I had the problem since I bought it winterized and haven't done spring prep yet, because we still have 20 degree nights here

The customer service person, Gretchen, I believe, said she was going to read the thread and look into it.

[jkinglet]

Originally Posted by 73shark

Wonder if anyone has ever written/talked to the mfg about this problem?

I emailed the AS head of AI service about it last year. Never heard back. Not even a, "hey, got yor email!".

[jkinglet]

Originally Posted by jkinglet

I emailed the AS head of AI service about it last year. Never heard back. Not even a, "hey, got yor email!".

..about the sink faucet issue..not the anti-siphon valve.

[InterBlog]

Originally Posted by 73shark

Judging from the number of problems you've encountered, the older version is not trouble-free.

VERY true, but I don't have THAT problem, and I never will. So my potential list just got shortened by at least one item.


The larger question is interesting: Where is the sweet spot of engineering such that you get maximum convenience and utility for minimum failure potential?

Airstream has added SO MUCH to the Interstate in the more recent models, but I wonder how much corresponding bellowing we're going to be hearing on this forum three to five years from now when a lot of that stuff commences its first failure cascade?

Every little plastic piece, every little rubber piece, every moving part - it'll all be in danger of letting go without warning. And at least with older Interstates, the most challenging issue is that there is ZERO systemic redundancy (not sure if this is equally true of the newer ones). Every friggin' component is essential to operation, no matter how small. Nothing substitutes for anything else.

Our Interstate being 8 years old, my husband and I are going through this "OK - time for stuff to start dying" process right now - ferreting out every weak link in every chain, hardening the vehicle so that we don't unexpectedly end up with dead batteries or black water spewing or gray water backing up through the shower or refrigerator draining into the interior of the vehicle instead of to the outdoors or turbo resonators that split open or electrical converter that cooks the coach battery or whatever (!). I wonder what everyone else's list is going to look like when THEIR Interstates get 5+ years old? Time will tell.

[73shark]

These things are just a house on wheels and will succumb to the same type of failures that happen to a house. Unfortunately quality is not job one in either instance.

Not sure what kind of redundancy you're looking for but it would add cost to an already expensive vehicle.

[jkinglet]

Pictured is the evil anti-siphon valve positioned not so conveniently behind the Microwave/Convection oven. I reached under with my smart phone with flash to get the picture. Notice the white end of the red tube is not connected to the anti-siphon valve fitting. The white tube capped with the anti-siphon valve comes from the outside black water flush hose connector to the left of the macerator. Sooooooo, when I hooked up the hose to the black water flush connector outside, the water pressure either blew off the fitting or the fitting had come loose, most likely from not being tightened properly in the first place. And guess where the anti-siphon valve opening was aimed? Directly at the furnace. Not very well thought out.
I wonder who at AS came up with the idea to put that anti-siphon valve in the worst possible spot in the coach -- positioned so it can do the most damage possible to the appliances if it fails like this one?
The good news. Dried out the furnace with a space heater and it fired back up without hesitation. Hats off to Attwood. To fix the situation, I laid on my back,reached up behind the oven and with the aid of a mirror and flashlight was able to loosen the nut on the plastic (pressure?) fitting on the anti-siphon valve and re-insert the tube and screw the nut back down, hand tight. Will test at next dump cycle.
Sent all of this information to both Airstream NW service facilities and scheduled an appointment for next month to hopefully either get this one fixed or have them add a much more substantial valve, especially if it needs to stay mounted where it is.
In conclusion, my humble recommendation, if you own an Interstate lounge model and plan to routinely use the black flush feature, remove the bottom drawer and check to see if that fitting is secure. Jeff (just another saga)

[Protagonist]

Originally Posted by jkinglet

Sooooooo, when I hooked up the hose to the black water flush connector outside, the water pressure either blew off the fitting or the fitting had come loose, most likely from not being tightened properly in the first place.

To fix the situation, I laid on my back,reached up behind the oven and with the aid of a mirror and flashlight was able to loosen the nut on the plastic (pressure?) fitting on the anti-siphon valve and re-insert the tube and screw the nut back down, hand tight. Will test at next dump cycle.

In conclusion, my humble recommendation, if you own an Interstate lounge model and plan to routinely use the black flush feature, remove the bottom drawer and check to see if that fitting is secure.

The municipal water intake has a built-in pressure regulator. I would hazard a guess the flush fitting doesn't have one— which is possibly why the water pressure was able to blow the hose of the valve. May want to consider getting an external pressure regulator to use with the flush fitting.

[jkinglet]

Originally Posted by Protagonist

The municipal water intake has a built-in pressure regulator. I would hazard a guess the flush fitting doesn't have one— which is possibly why the water pressure was able to blow the hose of the valve. May want to consider getting an external pressure regulator to use with the flush fitting.

Good thought. Not sure though if the water pressure blew it off or it just vibrated loose over the last year and finally nudged off by the water. It worked fine up until last Friday. I have a regular pressure reducer attached to the link of hose I used. Might need to get a better one if pressure was the issue. Is there a variable pressure regulator available for various pressure conditions at RV parks and state parks? Will plan to have that conversation when I take it to the dealer next month. BTW, plan to order the Aluma trailer tomorrow for the Smart toad. About 8 weeks out. Plenty of hitch weight left for a cargo container up front.

[jkinglet]

Thanks to everyone who contributed to this thread. Your contributions and advice saved me $$$ as well as time and energy. My black water flush problem is almost a memory (or is it a fading nightmare?). One of those. Enjoy the road. Wave!

[gmillerok1]

Since the valve is always "open" from the input side and the flow is not restricted, there is little or no chance excessive pressure could blow the valve. It goes straight into the black tank. It's only on the way back would the valve be closed, and that would never happen.

What is more than likely, is the guy at the production didn't tighten it down or even connect it at all in the 5 seconds he had to install it.

Add it to the list of things to check as the final (and probably only) inspection done after taking delivery.

Originally Posted by Protagonist

The municipal water intake has a built-in pressure regulator. I would hazard a guess the flush fitting doesn't have one— which is possibly why the water pressure was able to blow the hose of the valve. May want to consider getting an external pressure regulator to use with the flush fitting.

[73shark]

To paraphrase a famous movie line, "We don't need no stinking inspections."

[InterBlog]

Originally Posted by jkinglet

...

I wonder who at AS came up with the idea to put that anti-siphon valve in the worst possible spot in the coach -- positioned so it can do the most damage possible to the appliances if it fails like this one?
...

My money's on it being the same person who decided to keep sourcing the Dometic sink faucets that can do the most damage possible in the event of user error. Which is probably the same person who decided to position defective black water tank vents within inches of the electrical converter on older mid-bath models, so that when the vent fails and water starts sloshing out of the tank, the vehicle's entire electrical system is placed in jeopardy. One good flood deserves another. And another.

[jkinglet]

Originally Posted by InterBlog

My money's on it being the same person who decided to keep sourcing the Dometic sink faucets that can do the most damage possible in the event of user error. Which is probably the same person who decided to position defective black water tank vents within inches of the electrical converter on older mid-bath models, so that when the vent fails and water starts sloshing out of the tank, the vehicle's entire electrical system is placed in jeopardy. One good flood deserves another. And another.

..and as you're probably aware of, that "magic" faucet on the Dometic sink is still in play on the flashy, new GT and most likely on all the 2015 models. Can't wrap my brain around that one.

[Protagonist]

Originally Posted by jkinglet

..and as you're probably aware of, that "magic" faucet on the Dometic sink is still in play on the flashy, new GT and most likely on all the 2015 models. Can't wrap my brain around that one.

I can. They're made by Dometic, not Airstream, and Dometic has a virtual monopoly on the "RV sink with fold-down faucet and lid" market. You've got Dometic, and you've got SMEV, which is Dometic's Italian subsidiary. That's it. Regardless of the name on the lid, the sinks are identical.

Even if we complained en masse to Airstream, what can Airstream do about it? Without another supplier to choose from, and without enough market share to have any influence with Dometic/SMEV compared to other RV manufacturers, the chance of getting Dometic/SMEV to fix the problem is virtually nonexistent.