Draining Waste Tanks

terawatt

Member
I just returned from a week and a half long stay in the Arizona mountains. I had full hookups and everything was working fine until I tried to drain the grey water 1 tank. It simply wouldn't drain. I pulled the lever and nothing. After pondering for while, I hooked up the water source to the black tank flush system and flushed out the black tank (grey water valves closed, of course). After that, the grey water 1 tank drained just fine (grey water 2 never had a problem draining). Maybe it was a fluke, so I tried it again a few days later and the same thing. It might be from the altitude (6500 - 7000 ft.). I did this three or four times on the trip with the same results. It didn't seem to matter how full the tank was. Has anyone else ever had this problem?
 

cdbMidland

Past Michigan Chapter Leader
Could the sewer line have been plugged from something that had drained from the black tank? Do you wait until the black tank is about 2/3 full before draining it?
 

terawatt

Member
I thought it might be plugged at first, as well. However, after I figured out how to make the grey 1 tank flush, I filled it back up again and had the same problem. I had just got all the tanks empty, then filled only the grey 1 tank and it would not drain until I ran water through the black tank flush system. Air bubble maybe? If I had a plunger, that might have worked. I guess it isn't a big deal as long as I have city water available when I need to flush.
 

phranc

Well-known member
Wow thats strange ,, I don't think there is any physical connection between the black tank and it's flush/rinse system and either of the grays.. Only thing I can think of is a plugged vent pipe in gray 1 that may be trying to vent from the black or other gray..
BTW is your gray1 , the bathroom or galley ??..
If It is the galley, do yoy have a vent under the counter with a vacuum breaker type of vent device ??
 

timk

Well-known member
terawatt,
I had something that sounded similar happen to me last week. We were at a full hookup site. When I pulled my grey, nothing happened. I was ready to cut up the underbelly to look for a broken valve, when my brain started working again. I had the grey valve open a bit and the tank was draining all along, all by itself. I had the grey one and two mixed up. So after that I got out the label machine.
Or it might just be a Tucson thing.
TimK
 

terawatt

Member
phranc,

The grey 1 tank, in my coach, is to the shower and the sink in the bedroom. Some type of clogged vent makes perfect sense. I am pretty sure there is a vent on the top of the tank, but I don't know if there is one somewhere else. Anybody???

timk,

I am possitive that the tank was full. The other grey water and the black water didn't have any problems draining. I did some testing and continued to fill up the grey 1 tank. It would never drain until I plugged the city water hose into the black flush system and flushed that tank out first. I vote for a clogged vent somewhere and the flow through the black water system broke the vacuum. That is the only thing that makes sense to me and even that theory is stretching it a little bit. I guess it isn't really that big of a deal.

I was pretty giddy to get out of the heat and up to 80 degree weather, so I might not have been thinking straight. The beer could have had something to do with it too. :)
 

phranc

Well-known member
Each tank would have a vent. But weather they are tied together into 1 stack that goes to daylight at the roof or have separate stacks , I'm not sure..If you could get to the roof ,maybe you could use a hose to flush any debris back down the vent stack..
Just grasping at straws here................
 
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