shower drain always flooding even with empty tank

[dedalus]

I just bought an 1969 Caravel 18' (only very small combined tank ~11gallons). What's most troubling me is that the shower drain will always back up and flood, with minimal kitchen/lavatory sink/toilet usage, even when the tank has just been dumped empty. Thus I can't even take a shower when boondocking and not connected to sewage outlet

1. could a blocked up tank vent on the roof cause this?

2. or is this the way it was designed? according to the manual the shower drain is even lower than the tank, it seems this will always happen. Are we supposed to have the drain blocked up whenever not connected to the campsite?

[overlander63]

Originally Posted by dedalus

I just bought an 1969 Caravel 18' (only very small combined tank ~11gallons). What's most troubling me is that the shower drain will always back up and flood, with minimal kitchen/lavatory sink/toilet usage, even when the tank has just been dumped empty. Thus I can't even take a shower when boondocking and not connected to sewage outlet

1. could a blocked up tank vent on the roof cause this?

2. or is this the way it was designed? according to the manual the shower drain is even lower than the tank, it seems this will always happen. Are we supposed to have the drain blocked up whenever not connected to the campsite?

Attachment 378884

If you read the text in the diagram, and look at the diagram, you will see the answer.
There is no grey tank, only a toilet tank. There were no grey tanks before 1973.

[ROBERT CROSS]

Our '63 Safari was plumed the same way, no grey tank.
The tank had a valve, with the valve closed and the cap off the grey water would drain into a large plastic dish pan.
At our primitive camp in the Adirondacks we drilled holes in the pan, lined it with cheese cloth, dug a shallow hole and let it sieve into the sandy soil. When we broke camp we just threw the cloth in the dumpster.

We also found a drain plug that fit the shower drain just in case.

Bob
🇺🇸

[Acheron2010]

Frustrating to click on such an important topic, only to discover it is happening on the African Queen and not late model Airstreams....js. Perhaps lead with year and model of the rig with the issue?

[ROBERT CROSS]

^
?

Originally Posted by dedalus

I just bought an 1969 Caravel 18' (only very small combined tank ~11gallons).
Attachment 378884

Just like the OP did in post #1?

Bob
🇺🇸

[batman]

Originally Posted by Acheron2010

Frustrating to click on such an important topic, only to discover it is happening on the African Queen and not late model Airstreams....js. Perhaps lead with year and model of the rig with the issue?

WOW! This is not the way. Perhaps some one should read before posting! Also, Why would you call names and try to belittle someone else's dream?

-Dennis

[PA BAMBI II]

You don't have a combined gray/black tank. You have a black water tank. Clearly, from the posted diagram, the gray outlet valve is plumbed AFTER the tank. With the older trailers, it was common practice to let the gray water drain out through a garden hose, away from the trailer, into the surrounding soil.

Gray tanks were added in 1973 as mentioned in an earlier response post. It is very possible to plumb in below-floor gray water tanks to make your trailer more suitably self-contained. I did so on my 1964 Bambi II with good results. We never have a drain backup...unless the tank happens to fill!

I also replaced the p-traps with Hepvo sanitary waste valves and I am very pleased with the change. It is sometimes good to have modern technology in an older trailer!

Enjoy your Caravel!

[PA BAMBI II]

Originally Posted by batman

WOW! This is not the way. Perhaps some one should read before posting! Also, Why would you call names and try to belittle someone else's dream?

-Dennis

Agree with this. Read and post helpful tips for the OP or just go on your way. This is a hobby, after all. There is no room for this.

[Fraser Field]

Originally Posted by Acheron2010

Frustrating to click on such an important topic, only to discover it is happening on the African Queen and not late model Airstreams....js. Perhaps lead with year and model of the rig with the issue?

I have a 1973 and added a gray water tank, small but it works. I have a 1973 because I tow it with my 1948 Chev panel. A lot more fun than my 2018 GMC. Maybe people like the old stuff because it has style. I know I wouldn't trade up.

[David F]

My solution for gray tank on my '67 Caravel was to add a loop of 4" PVC piping below the shower/sub floor. The sinks and shower feed into the loop and loop is connected to the dump valve. I eliminated the low point shower p-trap by using a one way waste valve. This allows the above floor plumbing lines to act as additional storage, but at that point, the shower will not drain. If I am at a campground with not sewer hookups, and cannot let gray simply drain out, then I take along a Blue Boy. I removed the black tank and use a waterless toilet, so I only ever have to worry about grey water...usually never a concern even with small amount of storage.

I have been known to dump the gray tank in the middle of the night (when not allowed) a time or two...

[M.Riley]

My 68' Caravel does the same. It doesn't take long to fill up an 11 gal. tank. Unless you are connected to sewer or you do a modification you will have to adapt to it.

[M.Riley]

I have a 68' model and it does the same. It doesn't take long to fill up an 11 gallon tank.

[Trowbridge]

In our 1964 Sovereign, we have the same problem...even though we installed new black and new grey water tanks. We have a rear door on the trailer which allows us to view under the floor. The grey water drain under the shower (shower drain tube is 1 1/4" below floor of shower) connects to the overall grey water drain tube, which then rises by 1 1/4" before flowing to the tank. So the 'downstream' part of the drain tube is exactly the same height as the floor of the shower. Not a brilliant design by Airstream.

We've made it workable by...

1. making sure the trailer is never tilted towards the shower side or forward. This minimizes back flow to the shower. We can cheat by angling the trailer toward the grey tank by 2 to 3 degrees.

2. especially to make sure nothing gurgles back while trailering, we bought a marine drain plug which expands via a lever to stay locked in place. Here's an example through NAPA...but make sure you get something similar sized for your particular shower drain (https://www.napaonline.com/en/p/BK_7...UaAkEOEALw_wcB)

[Hikingsolo]

My dad did the same to his ‘61 Overlander as David F, added as much 4” PVC under the floor to act as a grey water tank. If I remember right he ran several lengths back and forth and affixed a drain valve for the grey water. I’m not sure if he tied it into the black water connection, but that would be what I would try. In any case the trailer made easily it through an Alaska Highway trip before they paved the road.

[InsideOut]

I think some of you folks with pre-'73 trailers are missing the point that PA BAM II made:

Originally Posted by PA BAMBI II

You don't have a combined gray/black tank. You have a black water tank.

The reason your shower is filling with gray water quickly when showering is that your total capacity for grey water is only a gallon or so in the drainage piping itself. These older trailers were intended to drain onto the ground or into a 'gopher-hole' (it was okay 'back then'), be in a campsite with full hook-ups or capture your gray water into an external Blue Boy tank (today), unless a gray tank has been added.

We had a Blue Boy tank for years with our first '64 trailer - it worked fine. We retrofit gray tanks into our current '56 trailer under the floor & that works fine too with the added benefit of one less thing to carry.

Originally Posted by David F

My solution for gray tank on my '67 Caravel was to add a loop of 4" PVC piping below the shower/sub floor. The sinks and shower feed into the loop and loop is connected to the dump valve.

This is a good solution too, if you don't want to tear up the entire floor > longer pipes = more capacity.

If you have a grey tank & it's still backing up - check the vents. If there is no place for the air to go, the water can't fill the tank.

Shari

[bibbs]

My 71 has a retrofit grey tank below the belly pan just behind the axil. I think 27 gal

[suncoasteng]

You could re-direct the shower/sink drains and create a new gray water drain, then purchase a Camco portable tank to drain into when you boondock.

[Acheron2010]

First time I have received hate mail on any forum in my lifetime.

My sincere apologies to anyone who may have been offended.

This was my reasoning. (The apology still stands).

Let us imagine we are all members of a laundry forum.
Someone posts a message that is titled,
"Laundry soap turned my clothes green"

Well, EVERYONE who does laundry is going to click on that to see if their laundry could be affected, right?

But, if they titled the post, "My 1969 box of Boraxo laundry detergent turned my clothes green" we could click on it for mild interest, but most likely pass it by because 99.98 percent of the laundry forum does not own a box of 1969 Boraxo and it is not relevant.

I am simply suggesting that someone posting about shower drains clogging modify the title to, "My 69 Caravele shower drain is backing up."
I would then know the issue is not relevant to me, and I can proceed to the next post on the list of new topics.

Again, sorry if anyone was offended.

[Vitaver]

I had the same problem, called Service and Customer Support at AS and drove everyone crazy. Dropped 3 bottles of drank, put a snake through it, pumped with plunger, etc. The problem was my RV was not level and the water will just not go to the drain... Trying to help you save the embarrassment in case you did the same...

[ROBERT CROSS]

Originally Posted by Acheron2010

First time I have received hate mail on any forum in my lifetime.

My sincere apologies to anyone who may have been offended.

This was my reasoning. (The apology still stands).

Let us imagine we are all members of a laundry forum.
Someone posts a message that is titled,
"Laundry soap turned my clothes green"

Well, EVERYONE who does laundry is going to click on that to see if their laundry could be affected, right?

But, if they titled the post, "My 1969 box of Boraxo laundry detergent turned my clothes green" we could click on it for mild interest, but most likely pass it by because 99.98 percent of the laundry forum does not own a box of 1969 Boraxo and it is not relevant.

I am simply suggesting that someone posting about shower drains clogging modify the title to, "My 69 Caravele shower drain is backing up."
I would then know the issue is not relevant to me, and I can proceed to the next post on the list of new topics.

Again, sorry if anyone was offended.

Or look at the title and read the question.
I suggest getting some Airforums thin skin lotion.😂

Bob
🇺🇸