I have a sanibest which was just recently installed and it seems to work fine. But after flushing the macerating pump comes on and pumps out the water then shuts off. Then I hear a rushing of water which seems to be water coming back up into the discharge. Is this normal? Other than that it seems to work fine.

You're saying that after the pump stops that you hear the discharge draining back into the pit. Correct ?
As you can see by the image I've put up there's a check valve installed to prevent this from happening. I Think something's got under the flapper band is preventing it from closing. Clear the check valve and you'll be just fine. Good luck, Tom

My Sanibest doesn't look like your diagram. Is your and older version? I have attached a picture of what mine looks like. Are you saying that the check valve is in the part that the hand in the picture has hold of?
I put up a cutaway version of a ejector pit. They all pretty much work the same T

My installation is such that the discharge comes out of the discharge elbow, goes horizontal for about 8 inches,then using 2 45 degree elbows goes down about 1 foot to 2 more 45 degree elbows, then horizontal about 8" to 2 more 45 degree elbows, then straight down about 6 feet. Then it turns about 60 degrees and goes almost horizontal but in a downward slope about 50 feet to the soil sack. Does it sound like I need to install an anti-siphon valve? If so where in the run should I install it?

I have a sanibest which was just recently installed and it seems to work fine. But after flushing the macerating pump comes on and pumps out the water then shuts off. Then I hear a rushing of water which seems to be water coming back up into the discharge. Is this normal? Other than that it seems to work fine. Should the check valve prevent this and is it located in the discharge elbow?

My installation is such that the discharge comes out of the discharge elbow, goes horizontal for about 8 inches,then using 2 45 degree elbows goes down about 1 foot to 2 more 45 degree elbows, then horizontal about 8" to 2 more 45 degree elbows, then straight down about 6 feet. Then it turns about 60 degrees and goes almost horizontal but in a downward slope about 50 feet to the soil sack. Does it sound like I need to install an anti-siphon valve or should the check valve, which I think is inside the discharge elbow, prevent this from occurring? If so where in the run should I install it?

Hi Dgrodi...

If I remember these correctly, the check valve is under the first discharge elbow. The "check valve" in this case will just be a flapper... may be something caught in it (see image).

Be aware that any sewage above this check valve will fall back toward the unit when you loosen that elbow so have a bucket and gloves nearby to keep things clean, OK?

Once the check valve is free/clear you should not need any additional valves... as long as this was all piped according to instructions!

Mark

I appreciate your help with this. I am sure that is it. Fortunately this is a recent install and has only been used a few times, and no solid waste so far so it shouldn't be too difficult. Plus there is no verticle run. I'll let you know how it turns out.

I removed the discharge elbow and took a look at it. It has a small flapper valve that seems to be working fine. It's about 1/2 inch in diameter and seems to be made of rubberized plastic. I am sure it must be closing when water tries to flow back in. Maybe what I am hearing is water flowing out since the run takes about a 6 foot drop after leaving the macerator. Like I say, it flushes and seems to be working fine but the noise was sounding like water was flowing back in. I have never had one so I am not sure what it should sound like when the pump shuts off. I appreciate your help with this.

Just a thought: It is very possible there is piece of discharge wrapped around flopper inside check valve. Try to flush the toilet with CLEAN water several time to see if it clears... Back to you. Milo

So far I have not really used the toilet since the installation and so the water is very clean. I checked the valve when I had the discharge elbow removed and it seemed to move freely, was extremely clean, and had no obstructions.

Dgrodi...

I'm thinking you are all set here. In most applications, sewage is pumped up, but since yours is pumped down you may be getting a faster flushing through then in most cases.

If the toilet works and there are no leaks I say leave it alone for awhile and see if any issues pop up, OK?

Mark

That's what I was thinking. Like the old saying goes, "if it ain't broke, don't fix it". I was mostly being cautious and trying to avoid issues down the road that would require me to open it up after it's been used.