Black/Gray water tanks

[PTgirl]

I have an IMAGINE 2800BH travel trailer. It takes a very long time to empty the black and gray water tanks. Anyone else have this issue? If so, how was it remedied?

[howson]

I have an IMAGINE 2800BH travel trailer. It takes a very long time to empty the black and gray water tanks. Anyone else have this issue? If so, how was it remedied?

Welcome to the forum. Please check out the letter to new members here: https://gdrvowners.com/forum/main-fo...to-new-members It should help you get the most from your time here on the forum.

There are a number of possible issues related to the problem. How old is your camper?

To do your own research, enter slow black tank drain site:gdrvowners.com into your favorite search engine (Google, DuckDuckGo, etc) and the list that returns will keep you busy reading for quite awhile.

Howard

[StephenO]

I have an IMAGINE 2800BH travel trailer. It takes a very long time to empty the black and gray water tanks. Anyone else have this issue? If so, how was it remedied?

I think the 2800 has the same tank and drain pipe configuration as my 2400, and I can say the kitchen and bathroom tanks can be slow to drain depending on the slope of the pavement at the dump station, especially the kitchen since it has that long drain pipe front to back. If the ground is sloped, even a little, so the trailer is nose down or towards the door side (away from the drain pipe), I know I will be there for awhile. Over the few years of ownership I have made a list of dump stations in my head with good ground slope (slight nose high and tilt towards the drain pipe) that will quickly drain the tanks.

[NoPeeking]

the kitchen and bathroom tanks can be slow to drain depending on the slope of the pavement at the dump station, especially the kitchen since it has that long drain pipe front to back. If the ground is sloped, even a little, so the trailer is nose down or towards the door side (away from the drain pipe), I know I will be there for awhile.

I have the same 2400 and experience likewise when draining the tanks... slope matters. My black tank does, however, empty with vigour regardless.

Mike

[mboehk]

I have a 2800BH and find the front grey tank takes the longest, the back grey is actually pretty quick. I think it's because the front has to drain down that long pipe that runs under the length of the trailer rather than the back one that is straight across. So the front one is definitely affected more by slope than any of the others.

What I do is start draining the front immediately then I go through the black and finally the back grey to flush out the black stuff.

The first thing I do is shut off the front grey tank because it will continue to drip for a long time after shutting it off. I figure if there is a half gallon or so left in the front grey it's not a big deal anyway. Then I finish the black and back grey and cap it all off.

Try a few scenarios, but I bet you'll find that front grey tank is your problem child - especially if the slope along the trailler isn't cooperating!

Mike

[JBill9694]

I'm wondering if this is a venting issue with the grey tank. It would be interesting to find out if the grey tanks are vented through the roof or depend on Air Admittance Valves (AAV) that may be faulty.

[howson]

I'm wondering if this is a venting issue with the grey tank. It would be interesting to find out if the grey tanks are vented through the roof or depend on Air Admittance Valves (AAV) that may be faulty.

Diagram could be wrong, but all three tanks show they have independent vents directly to the roof.

If there's an intrepid 2800BH owner willing to crawl up on their roof and take a picture...we'd know for sure the number of vents.

[Cate&Rob]

All holding tanks have to vent through the roof, because air has to go both ways. An AAV would let air in while draining the tank but would not let air out while filling the tank.

Rob

[JBill9694]

If each tank has a separate roof vent, then it could still be a ventilation problem with the front grey tank stack.

[Cate&Rob]

Long runs of drain pipe are usually plumbed with 1.5" diameter ABS for clearance and slope reasons. Short runs are often plumbed with 3" ABS. Since a 1.5" gate valve has about 25% of the cross sectional area of a 3" gate valve when open . . . flow rate is going to be much less. If you are comparing a tank with a 3" gate to a tank with a 1.5" gate . . . this could be the reason for the difference and everything is functioning as designed. You can tell the size of the gate valve by how far the handle pulls out.

Rob

[JBill9694]

Cate&Rob, then there would be a transition towards the downstream end of the 1.5" abs for the 3" sewer coupling?

[Cate&Rob]

Cate&Rob, then there would be a transition towards the downstream end of the 1.5" abs for the 3" sewer coupling?

My Reflection 303 has a 1 1/2" gate valve on the Galley grey tank. In the attached picture, you can see the 1 1/2" line and the transition to the 3" manifold. The shower grey and black tanks have 3" gate valves. (to the right in the picture)

Rob