Combined holding tank

SmokelessJoe · 12-30-2005, 06:01 PM

One of the Thompsons’ at Can Am RV told me yesterday that the 28’ models had a combined holding tank and advocated them.

According to the Airstream site, this is wrong. They have rather robust sizes of separate black and grey.

I’ve just noticed, in a 2004 brochure, that the 28 CCD and Safari did have a combined 70 gallon tank.

Does this mean that AIRSTREAM rather quickly learned that it was a mistake?

Can anyone shed some light on this?

We are installing new tanks now and I am curious.

Sergei

davidz71 · 12-30-2005, 06:21 PM

I would see it as a serious mistake and imagine that Airstream had enough comments from people who shied away from that type of combination. I may be wrong but that was my impression when I first heard about them.

lewster · 12-30-2005, 07:33 PM

Smokeless,

I've been in many a small RV park that have no sewer hook-up at the sight, just a central dump station. They DO allow you to drain your grey tank into a gravel area at your sight. A mono tank would prohibit this, either shortening your stay or requiring a few trips to dump out. It was probably a nice idea that AS found had some extreme limitations.

Silvertwinkie · 12-30-2005, 08:16 PM

The combined tanks were done a year of so ago for one model year on what I think was the model you are talking about. It is now two seperate tanks.

I would suggest going with a unit that has two seperate tanks if you go in remote locations without sewer hookups. It is far easier to drain the grey tank than a combined tank when boondocking.

davidz71 · 12-30-2005, 08:45 PM

Quote:

Originally Posted by davidz71

I would see it as a serious mistake and imagine that Airstream had enough comments from people who shied away from that type of combination. I may be wrong but that was my impression when I first heard about them.

The area I hunt in most of the season has a water source but no electricity. I rely on a 30 watt solar panel and another 5 watt panel to keep the battery charged up. I can fill the 30 gallon grey tank numerous times by doing dishwater and taking showers before I would come close to filling up the blackwater tank. Matter of fact, the blackwater tank could possibly not even be used on any of my 3 day weekend hunts by using the 20,000 acres I hunt in. That is another topic I don't intend to discuss; however, there is no problem draining the greywater tank onto the ground in the rustic area our hunting party parks their 5 trailers. How are you going to do that if you have a combination tank? If you always plan on staying at an RV park which has sewer then it will not be a problem but many of the parks I have stayed in have only a dump station, no sewer for each site. I admit that 70 gallons is a big tank but some of your flexibility is lost. In addition, if you have 2 tanks like my Sovereign, you could use one of the Blue Tote containers to dump the greywater which is not as bad as the blackwater contents. That's the way I see it.

SmokelessJoe · 12-30-2005, 09:23 PM

Craig, Lew, Silvertwinkie:

Actually, our plan to increase the tank capacities during the remodel of a 1976 Argosy has already been decided.

The discussion was on this thread should anyone be interested:

http://www.airforums.com/forum...nks-18634.html

We moved the existing 12 gallon grey forward about 24” to make room for a new under-the-floor 15 gallon black and added a separate 26 gallon grey (for the galley alone), located between the axles.

This brought the joint capacities up from 22 gallons to 54, around 2 1/2 times the original.

I was just curious as to why Can Am advocated the combined tank, which seemed impractical.

The theme of all of your replies shows why it is very impractical. As pointed out, Airstream probably realized this, and rather quickly too.

Sergei

Pick · 12-31-2005, 06:50 AM

I'd be thrilled to death with a 70 gallon combined tank, instead of the single 17 gallon black tank and NO grey tank my '72 has. I wonder if the single tank models have a grey water bypass drain? This would allow grey water to run on the ground or to a blue tank, instead of the on board tank. A combined tank would not be to bad if you could do this.

SmokelessJoe · 12-31-2005, 07:58 AM

Pick,

Yes, a by-pass would certainly make it more practical.

Can a 2004 /28-foot owner chime in, telling us about this?

Just curious.

70 gallons combined WOULD seem like a dream if you have a pre-grey Airstream - but only if you can mount it at the axles.

My bath is at the rear and this could get up to 700/800 lbs, tank and contents, if ever it had to reach full.

Allied subsidiary question: does anyone on the forum have experience with or advice or opinions on:

Macerators?

Tank Sensors?

Sergei

tphan · 12-31-2005, 08:10 AM

pick-I have a '72 also, and I did exactly what you mention: ran the kitchen sink graywater into a T-fitting with a valve, so I can let it run out like it used to OR divert it into the black tank, in case I'm parked in a wal-mart lot for the night. I don't have that possibility with the shower water, as it ties into the whole thing below decks, after aforementioned valve. I did this while involved in a total gut and re-do, so not sure how easy it would be otherwise. I just think valves and options are good, same in the supply lines. Good luck- tim

dieterdog · 12-31-2005, 03:04 PM

hi all, as an owner of a 2004 bambi ccd international,, i can tell you that combined tanks are one of the reasons for the purchase of a new to me trailer. you need to be tied to a dump station, or risk back up into the shower of a rather unpleasant mix......dieterdog

cosmotini · 12-31-2005, 03:12 PM

We have the 28' CCD. It has the 70 gallon combination tank. There is no bypass for the grey water to drain to ground. I never understood before why this was a problem but could see if you are staying at a place without sewer hookups how that could be inconvenient. It's not been a problem for us so far.

SmokelessJoe · 12-31-2005, 04:59 PM

Cosmotini, thanks for coming in on this.

Now we have confirmation that there is no bypass on the 28s of 2004.

For those that stay only in full service trailer parks the installation is probably acceptable and might even have some small advantage in clearing the tank.

To those that boon dock, stop wherever enroute or otherwise travel unconventionally, the arrangement is probably unacceptable or, at least, very, very limiting.

Sergei

davidz71 · 12-31-2005, 09:19 PM

Quote:

Originally Posted by SmokelessJoe

Craig, Lew, Silvertwinkie:

Actually, our plan to increase the tank capacities during the remodel of a 1976 Argosy has already been decided.

The discussion was on this thread should anyone be interested:

http://www.airforums.com/forum...nks-18634.html

We moved the existing 12 gallon grey forward about 24” to make room for a new under-the-floor 15 gallon black and added a separate 26 gallon grey (for the galley alone), located between the axles.

This brought the joint capacities up from 22 gallons to 54, around 2 1/2 times the original.

I was just curious as to why Can Am advocated the combined tank, which seemed impractical.

The theme of all of your replies shows why it is very impractical. As pointed out, Airstream probably realized this, and rather quickly too.

Sergei

Sergei,
Really good idea on the additional greywater tank for the galley. Keep us informed on how it works out.