Pumping Black/Grey Water Tanks

Greetings:

I have an '06 Marathon conversion. I will be in a situation this summer where I will have to have my tanks pumped out rather than dumping in the usual manner. I have heard stories of people have had their tanks collapse during the pumping process. I was told that the key to to make sure that your "toilet" valve is open during the pumping. Not sure if this is even necessary or how to "hold the toilet valve open".

I am looking for advice on the proper way to pump the tanks.

Thanks in advance.

John Emmett

Hi John,

We were faced with that last year at the Balloon Fiesta - I talked to a few people who said " You should be ok " then talked to Leon at Marathon who HIGHLY advised Against it.

Looks like the issue is if it is not done 100 % correctly by someone who knows what they are doing you will have a situation you do not want to deal with.

I choose the safe route - did not let them pump it out - had to go into " conservation mode " the last day but as it turned out we had plenty of space left at the end of the event.

Jamie

Do not let anyone talk you into pumping your tanks if you have a Marathon conversion. If some one with the expertise of Leon at Marathon says NO that's enough for me.

One thing I have seen is dumping into a kids swimming pool then the honey wagon pumps from that pool.

Someone holding the toilet valve open is total nonsense. Another point ....if you have a Tecma toilet worth $2K and all electric operation, that's another problem.

Thanks to all. You have confirmed my suspicions.

John Emmett

I'm very curious how this could be.

3 questions come to mind.

Shouldn't the vent prevent this? What is the correct way to pump out? Very slowly?? and what is the explication for the phenomenon? Vent is only big enough to release vapors?

Al I couldn't in a million years imagine a prevo in a site next to me pumping a holding tank into a kids swimming pool. Not something I'd expect to see the average Prevo owners do. What of the pool when you're done, burn it? Yikes.

I saw so many coaches being pumped at the balloon fiesta. This is a valid concern given the discharge is so much larger than the roof vent for the black tank. The gray tank should not be a concern given the number of sinks and roof vent should be enough venting.

A fix would be easy. Make a T with the same size PVC pipe as your sewer hose connection. 2 ends will have standard hose connections. The other will be open and 3 feet long or so. Connect the coach and the pumper truck to the T. Leave the open end pointed straight up. Turn on the pumper and then the storage tanks. This would be an easy solution that guarantees the tanks won't be harmed.

Gill u r a knuckhead sometimes.

If you know you're going to be out boonien get a macerator.

Couldn't u just pump it to the honey wagon with a macerator? Which poses the next question all you Marathon guys.

Don't marathon's have macerator pumps? Does this mean every time I go boondocking and I get next to a guy with a marathon I run the risk of him pumping his holding tank into a kids swimming pool every evening around cocktail time???

Al,

No problem pumping out Marathon’s, remember the Rally in Quebec, Leon supervised the sucker truck and pumped out about 30 Marathon’s with no issue.

Joe - Most Marathon’s, mine included, don’t have macerator’s, I use a portable that works great.

Joe, I've had a macerator before. No thanks, don't want or need one. They are good for pumping uphill, that's about it.

I saw this online somewhere years ago and copied it it works really good and it was $69 or something plus Hardware. Everything that you can buy that's preordained macerator is a lot more dough than that and these have just slightly more powerfull bigger motors.

Attachment 15052

Attachment 15053

Big end waste tank little end hose.



I can run a garden hose from in front of my house through a basement window and shove the end of the hose not just in the toilet bowl but shove the end of the hose all the way down into the closet flange in the bottom of the bowl and you can pump into your toilet that way and it won't stink up the house. It's always worked good. Just beware if you allow it to accumulate in the bowl you're going to smell it. Run clean water through for rinse.

It's quick too, not slow.

Now I am worried about attending the FMCA rally in Gillette, Wyoming in July. We will go into "conservation mode" but what if we need a pump out? If I am understanding correctly, gray water should not be a problem due to all the vents. I am assuming the pump truck will create a larger vacuum than the vent can handle on the black tank? Is there some way to force the toilet flapper valve to stay open? Can't the pump truck throttle back to idle? Surely other Marathon owners have crossed this bridge. Why couldn't I stand by the toilet and continuously flush it to relieve the vacuum? Sure would appreciate other Marathon owners to give us their advice and experience.

Philip,

Just open black and gray tanks at the same time.

GIL, after posting , I wondered why it would not be the best solution to just open both tank valves. Surely the pump truck couldn't overwhelm both tank vents or can it? But you are the first one to come up with this solution, after discussing macerators, swimming pools and so on. Wonder why only Marathon? I would still like to hear if anyone doesn't think this is the correct answer.