Community Forums

Homeby5 · 03-29-2023, 05:58 AM

For those of us that have installed an extra gate valve on the waste outlet, is there any drawback by leaving all of the gray water and black water valves open all the time? I understand that the tanks will back up into each other and equalize but I do that anyway to flush my black tank with gray water when dumping.
The reason I ask is because we all know the issues with the cables freezing up and looking to avoid an issue when on the road.

BillJinOR · 03-29-2023, 06:29 AM

I have done that when I needed more capacity for the grey tank. We had 2 , 75 gal waste tanks. The black never filled as quickly as the grey. It worked great to get an extra day or two. The negative is if it does overfill , waste water will come up the lowest point .. the shower drain. We have forgotten more than once and the grey smell in the shower is bad enough .. can you imagine the mixed tank smell ?? . When we use the grey to flush the black, the black is empty and the flow is into the black mostly not back to the grey.

JJH3rd · 03-29-2023, 08:08 AM

We have stayed in RV parks where flies have come into the MH via the sewer system if I left ether of the waste water valves open.

Country Road · 03-29-2023, 08:15 AM

Quote:

Originally Posted by JJH3rd

We have stayed in RV parks where flies have come into the MH via the sewer system if I left ether of the waste water valves open.

To avoid this possibility, I allow the drain tube to form a water filled trap before it gets to the sewer connection.

Argosy · 03-29-2023, 08:51 AM

It's nice to be able to flush the drain hose with what is essentially soapy water when I dump. I've never had a problem with tank odor but if I did I'd rather only deal with one tank. Same with sensors, it seem like problems are pretty much in the black tank, if I have problems I rather limit them to one tank.

**Camp CA** · 03-29-2023, 09:03 AM

Quote:

Originally Posted by Homeby5

For those of us that have installed an extra gate valve on the waste outlet..........we all know the issues with the cables freezing up......

Agree with the above posts keeping the valves closed until you are ready to dump. The extra gate valve at the sewer hose connection is a recommended upgrade to mitigate the risk of dumping waste on the ground when the sewer connection cap is removed in the event the black or gray tank valves leak. I was pleasantly pleased that our new 2022 Pinnacle fifth wheel trailer came with one factory installed. Only had one incident in 20 years on four fifth wheel trailers with a tank (black) cable freezing up......replaced it under my $0 deductible extended warranty.

DKRITTER · 03-29-2023, 09:17 AM

This question has been asked and asked and asked many, many times. I'd bet if you searched about leaving valves open or combining grey and black with an extra valve you'd get maybe a hundred responses.

One thing you'll see is, overwhelmingly the more posts you read you'll see is most everyone has a different opinion and reason why they feel the way they feel. Then after about a page of posts the posts will have little to nothing to do with the original post.

Figure out what works best for you.

tvt11tddb · 03-29-2023, 09:43 AM

I have seen to many Black tanks get plugged with the valve left open. They got a build up right under the toilet, some very hard to break up.

JohnBike · 03-29-2023, 09:54 AM

I don’t have a valve on the main outlet, but I did use a similar method as the OP once, but only as a temporary measure. A day before we were due to head out, the grey tank was showing full, but the black was only about half. I attached a clear elbow fitting and valve to the main outlet with the valve closed. Then I backflushed from grey into black to get a little more room in the grey and closed both grey and black valves.
Since the dump station was near the park exit, I left the dump fitting attached to avoid the need to deal with the waste between the tank valves and the temporary “main” valve. That stunt gave us room for showering and dishwashing until we could stop at the dump station.
Note emphasis on temporary.

Old-Biscuit · 03-29-2023, 10:00 AM

My last Trailer.........1980 vintage and my current 5th wheel ....2007 vintage
I added an extra dump valve on the common drain header.
With the 'extra' dump valve closed I opened black/grey (galley on 5vr) combining all WASTE tanks for increased capacity
The grey/galley WASTE can be as nasty as Black......and combining them with the Black creates a higher Liquid to Solid Ratio

Never had any issues with backing up/clogging or odors

Gary RVRoamer · 03-29-2023, 10:01 AM

Quote:

For those of us that have installed an extra gate valve on the waste outlet, is there any drawback by leaving all of the gray water and black water valves open all the time?

Read more carefully. He did not say leave all the valves open; he has installed a secondary valve which is presumably kept closed and asks about leaving the two primary valves open.

I see no problem with doing this. Some waste water is retained until ready to dump and no flies or aroma from the park sewer system.

US1 · 03-29-2023, 10:06 AM

Some see it as grey water going into the black tank for more capacity and to aid in flushing the black tank, I see it as black tank contents going into your grey water tank.

Old-Biscuit · 03-29-2023, 10:24 AM

Quote:

Originally Posted by US1

Some see it as grey water going into the black tank for more capacity and to aid in flushing the black tank, I see it as black tank contents going into your grey water tank.

It's all waste and combing them creates higher liquid to solid ratio........ending up with a slurry

Duster73 · 03-29-2023, 03:13 PM

Quote:

Originally Posted by US1

Some see it as grey water going into the black tank for more capacity and to aid in flushing the black tank, I see it as black tank contents going into your grey water tank.

This is how I look at it also, I deal with grey water alot more often then black water. Rather be able to let some grey water out on my property and not have to worry about a poop slurry.