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trumpetguy · 10-14-2018, 03:32 PM

We are new owners of a 2007 Classic Limited 31 rear twin and have sold our 2007 International Ccd28.

The International bathroom sink drained into the black tank. Is it the same with the Classic? I ask because I emptied both black and gray tanks in preparation for a trip. We have a septic tank. The external black tank flush is apparently stopped up because no water comes into the black tank when a hose is connected and turned on. So to flush the black tank I turned on the bathroom sink and let it run a long time. There was sufficient water in the black tank to get a good rinse.

So now the mystery. My wife came into the house and said the shower has two inches of water in it and the gray tank light is red. She was not running any water. So I go out and pull the gray slide and it dumps...a full tank of high volume water.

I am mystified. Could the flush inlet for the black tank be somehow tied in to the gray tank.

Does the bathroom sink drain into the gray tank or the black tank.

The owners manual is not at all helpful.

Thanks in advance for some answers.

DaveP · 10-14-2018, 03:54 PM

Hi David,

In my 2004 Classic, the bathroom sink drains into the gray tank. Sounds like yours does to.

DaveP

sb55 · 10-14-2018, 04:10 PM

Apparently, some are plumbed differently. I have a 2018 FC30. My bathroom sink goes into the black. I’m OK with that, as it usually takes longer to fill the black and a little extra water can’t be bad. In my 2004 Safari 25, all sinks went to gray.

DaveP · 10-14-2018, 07:10 PM

One thing you can count on with Airstream, lots of things are different!

trumpetguy · 10-16-2018, 06:34 AM

I have confirmed the bathroom sink drains into the gray tank.

trumpetguy · 11-21-2018, 12:19 PM

I am following up on this with another question. When I attach a water hose to the Black tank flush inlet no water gets into the tank. I removed the check valve and tested to make sure it was working and water flows in the direction it is supposed to and does not flow out. The valve is easy to access as it is just in line with the hose fitting.

I have also flushed the take three times after using one of those cleaning wands down the toilet . I’m thinking the piping into the tank must be plugged up and that’s a job I am not prepared to undertake.

Any ideas?

DaveP · 11-22-2018, 08:14 AM

Mine does not work either, but I don't think I need it since we drive around so much which helps keep things from "gumming up". I have read other posts on the topic. Probably damage by freezing weather or installed backwards.

Take a look at this link: http://www.airforums.com/forums/f163...er-141373.html for some suggestions.

trumpetguy · 11-25-2018, 07:36 AM

It would sure be convenient to add water to the Black tank using the inlet fitting provided. At least my sewer drain cap has a hose fitting built in so I can attach a garden hose, open the drain valve and add some flushing water. I like to keep at least three gallons in the tank at all times. When at home I fill the tank and let it soak.

polarlyse · 11-25-2018, 08:02 AM

There are 2 easy solutions that will allow you to quickly backflush and fill your black tank in the case of no tank flush system OR a non-functioning one. My former '85 AS did not have a tank flush. I purchased a "Flush-King" unit. It's nothing but a gate valve with a hose connection that attaches to your waste discharge. It has a clear section so you can even "ENJOY" the show. After a regular dump you can close the valve (leaving the trailer black tank valve OPEN) and turn the water on and it will quickly fill your black tank to allow a high volume discharge. Don't get distracted or walk away during this filling process. Do this multiple times for a really good flush.

Solution #2. On the forum here you can search for Sewer Solution or just google it. It also has an outside hose connection and will allow rapid backfill and flush.

They both work well.