Gray Tank Drainage - New Escape 21

[escape artist]

Originally Posted by wetzk

This would fix that problem.

Hi: wetzk... OUCH!!!
On another front... 1/2 of one of those will work to wedge open the dinette egress window. Alf
escape artist N.S. of Lake Erie

[Parker]

I seriously doubt that increasing the diameter of the gray tank drain line will make any difference. If I recall correctly, that mod on the Casita resulted in cutting the larger line into the side of the gray tank which had the effect of lowering the bottom of the drain line relative to the bottom of the tank.....maybe that would be an advantage here, but way too much trouble for me to want to mess with. The relatively low flow is so far below anything that would result in friction losses due to small diameters as to be un-measurable. I've done these calculations a gazillion times throughout my career. As it is, only a very small portion of the gray drain has liquid draining along the bottom of the pipe. Making the pipe bigger doesn't change that. What we have here is simply not much vertical drop (or head) to generate higher flows like we get from the black water tank that sits higher.

[Santiago]

Originally Posted by Parker

Making the pipe bigger doesn't change that. What we have here is simply not much vertical drop (or head) to generate higher flows like we get from the black water tank that sits higher.

I agree, you can make the outlet piping a straight 6 inch line if you like but as Parker said, lack of head is the real culprit. That's why tilting trailer helps as it slightly increases head. Now the bowed tank center does not help either.

[Steve Clark]

I'm still wincing at Alf's dribbling problem and wetzk' solution

[Parker]

I know....it is a bit distracting.

[tdf-texas]

Originally Posted by Parker

If I recall correctly, that mod on the Casita resulted in cutting the larger line into the side of the gray tank which had the effect of lowering the bottom of the drain line relative to the bottom of the tank.

The drain on the Casita grey tank is a 2" pipe connection - Casita inserted a 1 1/2" pipe into it restricting the flow. Also, they ran the piping uphill to the sewer drain connection reducing the hydraulic head.

The Escape 21' has some of the same problems. The drain from the grey tank enters the sewer drain at about 1/3 height in the tank. (see attachment) That means that 1/3 of the grey tank will not drain unless the trailer is tilted ( and it would have to be tilted a LOT) Also, even though the drain connection on the grey tank is a 1 1/2" threaded connection, using 2" pipe will increase the initial flow rate and reduce the drain times.

The second picture show the valves/piping I intend to install on my Escape. The grey tank connection to the sewer drain will be at the bottom of the piping giving it the max head that I can get reasonably and allowing more of the tank to drain. The flex connection on the 3" side will allow me to straighten the pipe run so that the valves are only as low as needed.

[Parker]

Okay, makes perfect sense in terms of getting everything connected as low as possible on the gray tank (and keeping it that low as much as possible).

[richardr]

We find it is quick and easy to tilt the trailer using an Anderson leveler at the dump station. This way the gray tank drains in relative short order.

[rbryan4]

Originally Posted by richardr

We find it is quick and easy to tilt the trailer using an Anderson leveler at the dump station. This way the gray tank drains in relative short order.

That's an excellent idea. Since the tank outlet isn't on the bottom of the gray tank but on the side near the bottom, that will help alot.

[tdf-texas]

I finally got around to installing the "fast" grey mod on my 21'.

I cut off the 1 1/2" pipe coming out of the grey tank leaving just enough to fit into a 1 1/2" to 2" adapter. (see pic below) When I cut off the pipe, I found about a 1/4" of glue collected at the bottom of the pipe creating a water dam - as if the drainage wasn't bad enough already! I got out a 1 1/2" hole saw, ran it up and down the hole a few times to get rid of the excess glue and all is good now.

Notice that the bottom of the drain fitting is now even with the ground connection for the tank monitor.

[tdf-texas]

Next I installed the 2" pipe with street 90 and the valterra assembly. Notice that the 2" pipe slopes downward and is below the bottom of the grey tank.

[tdf-texas]

Here is a pic of the finished drain assembly. I used a 3" rubber coupling to straighten out the black drain pipe connection to the black valve and allow the black and grey valve inlets to be level.

[tdf-texas]

Why was this necessary?

The first pic show the old assembly. Notice the long line showing the slope of the grey connection to the valves - the connection goes up hill. The two short lines indicate how much of the grey tank would not drain when parked level.

The second pic show the new drain assembly. The grey tank now drains at a downward slope and the outlet is slightly below the bottom of the grey tank. This is as good as I can make it and it drains a LOT better!

[Sowen23]

Does a 19’ unit have the same problems?

[tdf-texas]

Originally Posted by Sowen23

Does a 19’ unit have the same problems?

Each Escape trailer is handcrafted and unique in it's own way. I have looked at other 21' that didn't have the upward slope that my drain had. So I would say that you would have to look at your 19' when you get it and decide.

The 2" pipe, offset valve inlet, and 3 x 3 valve assembly does improve the drainage but it may not be worth the effort for some.

Why did I do it? (read my signature)

[Ron in BC]

Originally Posted by Sowen23

Does a 19’ unit have the same problems?

On my 19 the slow draining issue isn't caused by the pipe slope or the diameter. It's caused by the fact that the drain is side mounted rather than bottom mounted. Bottom mounted would drain much more quickly but road clearance would be an issue.

The problem with the side drain is that the cross-sectional area of the drain decreases once the fluid level reaches the mid-point ( x ) of the drain. After that the rate slows to an increasing agonizing level. We usually say "good enough" at some point or, if we want a really empty tank, like maybe for storage, we use blocks to tilt the tank.

My drain looks a little different from other classic 19's because I retrofitted a front pull grey tank drain.

Ron

[rubicon327]

Originally Posted by tdf-texas

Here is a pic of the finished drain assembly. I used a 3" rubber coupling to straighten out the black drain pipe connection to the black valve and allow the black and grey valve inlets to be level.

Nice work. I wonder if you had the spray foam how difficult the job would have been and would you have been able to diagnose the issue as easily?

[tdf-texas]

Originally Posted by rubicon327

I wonder if you had the spray foam how difficult the job would have been and would you have been able to diagnose the issue as easily?

I don't know as I have not seen a 21' with spray foam - not many people order the option here in Texas. As far as difficulty doing the mod with foam, you could use the pics I posted to find out where to cut the piping through the foam and install the upgrade plumbing. It would be messy but doable.

As to the troubleshooting - since all the 21' are pretty much piped the same, all the 21's are going to have most of the issues my trailer had if not all of them. All the 21's will have 1 1/2" piping coming out of the grey tank and will not have a downward slope to the drain. The 3" x 1 1/2" ell valves has the grey tank piping coming into the 1 1/2" valve in the center - the 3" x 3" ell valves with the 3" to 2" offset has the piping coming into the bottom of the valve and allows a slope from the grey to the drain without lowering the height of the ell valve assembly.

So foam or not, if you are unhappy with how long it takes for the grey to drain, the mod is something to consider. The factory drain system works - just not that well.

[currinh]

We have an older '19 with a slow gray drain. I believe it is 1 1/2" piping. It comes straight into the 3" black drain at the 3" elbow. The kind with the awkward side pull valve. But it is a straight shot from the drain cap to the gray tank. I like this.

The gray tank drains slowly. As such it doesn't flush the tank well when emptied, even when full. So it tends to get a build up of soap and kitchen scraps. I found this can mess with our see-level tank monitor.

I built, since I couldn't find one to buy, an angled squirty head that fits on the end of a 1/2" PVC pipe. The other end of the 6' pipe had a fitting for a garden hose. I can open the gray tank drain valve and push the pipe/washer through into the gray tank. Turn on the water and move it around awhile. No cap on the drain, since the washer pipe goes though there, so all the water put in comes right back out. It brings with it a lot of the soap scum and crud trapped in the tank. I've done this once and it straightened out he see-level sensor. A mess but solved my problem.

So, I'll leave the gray water piping, with its awkward valve, so I can clean the tank out. If there are elbows in the line a cleaner/pipe can't reach the tank.

One reason to keep the original piping.

[tdf-texas]

Originally Posted by currinh

We have an older '19 with a slow gray drain. I believe it is 1 1/2" piping. It comes straight into the 3" black drain at the 3" elbow. The kind with the awkward side pull valve. But it is a straight shot from the drain cap to the gray tank. I like this.

I had to get a pic to get it into my head. (below) That would make clean out a lot easier!

I guess I could have obtained the same results if I had used a tee with a cap instead of a 90 for the grey pipe.