Gray tank does not drain through macerator

[buddy110]

Not sure why, but my gray tank will not drain through the macerator unless I run the pump. Bypass off, macerator valve open etc. All fluids will drain when I run the pump. Any ideas?

[sweetandsour]

Originally Posted by buddy110

Not sure why, but my gray tank will not drain through the macerator unless I run the pump. Bypass off, macerator valve open etc. All fluids will drain when I run the pump. Any ideas?

Mine will do that sometimes when I first setup. After I notice the tank is not draining I simply turn on the macerator pump for a few seconds then turn it off and gravity takes over. Its like it has to be primed to start. Then no problem after that.

[buddy110]

Originally Posted by sweetandsour

Mine will do that sometimes when I first setup. After I notice the tank is not draining I simply turn on the macerator pump for a few seconds then turn it off and gravity takes over. Its like it has to be primed to start. Then no problem after that.

I will try that

[Gary.Jones]

Buddy

I will acknowledge up front, I dont really know and am just guessing, BUT, my 19 Cornerstone gray tank will not passively drain through the macerator hose naturally all of the time. It does sometimes, but I would guess that 75% of the time, it does not and has to be pumped out.

Here are my assumed explanations. First, a macerator drain system is an active system and designed so that all gray and black must pass through the macerator pump, to be shredded and pressure applied to deliver the contents the distance out through the hose (some of which is actually vertical stand pipe before it gets to the hose. So, one should expect to always have to run the pump to pump out the tanks. If you want a gravity drain, then I would not use the macerator system and would connect up a stinky slinky type hose to the second set of connectors running downward from the wet bay and out through the cap and gravity from there. I have assumed that sometimes the macerator pump simply stops in a place where water can easily bypass the blades and pump itself and is able to drain, whereas other times, the pump blades stop in a position that virtually blocks any fluid from passing. As I say, sometimes my system drains through the sanicon hose and other times it does not. I have found that I like the sanicon hose system sufficiently that I no longer am willing to get down on the ground to run the stinky slinky and I would rather turn the macerator pump on and off to drain through the sanicon hose.

Possibly you mean that you are in fact using the old stinky slinky type hose and fitting and it is not draining through that hose. In that situation, I can only think that the valve directing water flow through the old stinky slinky type system is blocked with some debris or broken. I would try draining through the sanicon system and see how that works and then try the lower slinky system again and see if things have freed up.

Gary

[The Taj]

I discovered I had same problem and neither tank would drain even with macerator on.

Tried everything including rapping on side of macerator. Finally decided to take the end cap off the nozzle that I’d left on when I stuck the nozzle into the ground connection

[buddy110]

Originally Posted by Gary.Jones

Buddy

I will acknowledge up front, I dont really know and am just guessing, BUT, my 19 Cornerstone gray tank will not passively drain through the macerator hose naturally all of the time. It does sometimes, but I would guess that 75% of the time, it does not and has to be pumped out.

Here are my assumed explanations. First, a macerator drain system is an active system and designed so that all gray and black must pass through the macerator pump, to be shredded and pressure applied to deliver the contents the distance out through the hose (some of which is actually vertical stand pipe before it gets to the hose. So, one should expect to always have to run the pump to pump out the tanks. If you want a gravity drain, then I would not use the macerator system and would connect up a stinky slinky type hose to the second set of connectors running downward from the wet bay and out through the cap and gravity from there. I have assumed that sometimes the macerator pump simply stops in a place where water can easily bypass the blades and pump itself and is able to drain, whereas other times, the pump blades stop in a position that virtually blocks any fluid from passing. As I say, sometimes my system drains through the sanicon hose and other times it does not. I have found that I like the sanicon hose system sufficiently that I no longer am willing to get down on the ground to run the stinky slinky and I would rather turn the macerator pump on and off to drain through the sanicon hose.

Possibly you mean that you are in fact using the old stinky slinky type hose and fitting and it is not draining through that hose. In that situation, I can only think that the valve directing water flow through the old stinky slinky type system is blocked with some debris or broken. I would try draining through the sanicon system and see how that works and then try the lower slinky system again and see if things have freed up.

Gary

Thanks, Gary. I'm not sure either. Nate's will gravity drain, but that could be because he has modified his outlet. I'm thinking it'a simply air locked. I wonder if it would be possible to wire a macerator switch inside the coach? That would be convenient

[Magic-carpet]

Originally Posted by buddy110

Thanks, Gary. I'm not sure either. Nate's will gravity drain, but that could be because he has modified his outlet. I'm thinking it'a simply air locked. I wonder if it would be possible to wire a macerator switch inside the coach? That would be convenient

Yes, its possible to put switches for the macerator and the tanks in the coach. I had someone do it for me this winter. I only had them put a switch in for the gray tank and a momentary switch for the macerator. That allows me to leave the gray tank open for doing laundry and if its airlocked I can hit the macerator switch for a few seconds and it starts the draining process and there is no risk of me walking away and leaving the macerator running dry.

[buddy110]

Originally Posted by Magic-carpet

Yes, its possible to put switches for the macerator and the tanks in the coach. I had someone do it for me this winter. I only had them put a switch in for the gray tank and a momentary switch for the macerator. That allows me to leave the gray tank open for doing laundry and if its airlocked I can hit the macerator switch for a few seconds and it starts the draining process and there is no risk of me walking away and leaving the macerator running dry.

Nice.

[LWBAZ]

Originally Posted by The Taj

I discovered I had same problem and neither tank would drain even with macerator on.

Tried everything including rapping on side of macerator. Finally decided to take the end cap off the nozzle that I’d left on when I stuck the nozzle into the ground connection.

I thought I'd made every mistake an RV owner can make. I'll have to add this one to my to-do list.

[Balladeer]

When we first had our Anthem I noticed that the gray tank would not gravity drain through the macerator hose until the tank was about 75-80% full. Came to realize that with the hose running from the macerator up through the little side door and then down to the discharge the flow would not happen until the water level of the gray tank was even with the edge of the hose at the door. Once it started it would empty until the siphon action was broken.
I eliminated this by modifying my macerator hose connection lower (they did this for a while on some coaches in 2017 and then stopped and went back to routing it through the storage compartment.
Attached is the modification I made and since then have no trouble allowing gravity drain of the gray tank. The cam-lock fittings also make connect disconnect very easy. Once I acquired the parts the mode only took about 1 hour to accomplish.

[Magic-carpet]

Originally Posted by Balladeer

When we first had our Anthem I noticed that the gray tank would not gravity drain through the macerator hose until the tank was about 75-80% full. Came to realize that with the hose running from the macerator up through the little side door and then down to the discharge the flow would not happen until the water level of the gray tank was even with the edge of the hose at the door. Once it started it would empty until the siphon action was broken.
I eliminated this by modifying my macerator hose connection lower (they did this for a while on some coaches in 2017 and then stopped and went back to routing it through the storage compartment.
Attached is the modification I made and since then have no trouble allowing gravity drain of the gray tank. The cam-lock fittings also make connect disconnect very easy. Once I acquired the parts the mode only took about 1 hour to accomplish.

I wonder why they stopped doing it with the pipe below the wet bay? Were they worried about it getting ripped off from road hazards?

[jobobjet]

Originally Posted by sweetandsour

Mine will do that sometimes when I first setup. After I notice the tank is not draining I simply turn on the macerator pump for a few seconds then turn it off and gravity takes over. Its like it has to be primed to start. Then no problem after that.

Yup. This is exactly what I do.

[Tom78418]

Initially I had issues with the gray tank draining without the pump until I worked with it a while. The light bulb went on after a few times initially arriving and setting up at a new location. What I found is the connecting an empty hose (Macerator hose) to the park’s sewer was not enough. First, the water in the gray tank had to travel up hill (hum) and then back down hill through the hose. Laws of hydrodynamics is against you at this point.

The solution was to let the gray tank fill a bit after arriving and connecting the hose. Then I’d go out, switch the pump on, but not let the tank fully empty. That’s it. Draining work fine albeit slowly due to the pump’s small internal pass through pipe. My take is the small amount of siphoning pressure with water in the hose is all that was needed.

[Matt D]

Gregg is the winner.. compare the top of the holding tanks with the pipe elevation inside the small macerator hose door.

You aren’t going to be able to drain much via gravity until you’re quite full.

The below deck drain is the solution, works great.

-Matt