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cadillac08 · Feb 24, 2008, 08:21 AM

I have a problem with my basement sewage ejector system that has puzzled the first pluber and contractor I've brought in for help. The problem ultimately presents itself with a very violent water hammer sound when the pump shuts off, and along with that the pipe and rubber joint above the check valve speperating and releasing raw sewage into my basement mechanical room (this is very enjoyable). I had the septic tank emptied and verified when the ejector pump runs waste water does freely flow into the septic tank. Could this be a venting problem? (We live in Michigan and the temps have been below 20 degrees).

When I had the contractor and plumber in the first time, the theory was the hammer was moving the pipe so much that the rubber connection between the exit PVC pipe and check valve was working itself loose. Extra hose clamps were added and the exit PVC pipe was more firmly connected to the walls to minimize movement after the pump shuts off. This has worked OK for 2 months.

Last hint is we only use the basement on the weekends for the most part.

Thanks for any help

hkstroud · Feb 24, 2008, 10:20 AM

The water hammer noise comes after the ejector pump shuts off?

cadillac08 · Feb 24, 2008, 12:34 PM

Yes - the pump runs normally without a lot of noise, then when the pump shuts off the big hammer noise happens and the pipe jolts

speedball1 · Feb 24, 2008, 01:06 PM

Could this be a venting problem? (We live in Michigan and the temps have been below 20 degrees).

It would be simple to just blame it on frozen vents. If the pit ventwere blocked then

when the ejector pump runs waste water does freely flow into the septic tank.

that wouldn't happem. And if the fixture vent were blocked then the discharge from the fixtures would be impeded. High high is the lift and are there any bends in the line? Could it be that your "hammer" is the crap falling back from the main down to the check valve?
Let me know what you think, Tom

cadillac08 · Feb 24, 2008, 01:48 PM

The vent from the ejector tub goes directly through to the roof (up from basement to top of two story house). I'm not sure if the crap falling back to the check valve would make this much noise - also I've been careful since we've had the issues not to put solid waste into the system - liquids only. I'm assuming the liquid being pushed up from the pump would be a continuous column - not allowing a slamming effect? (I am guessing at that based on hydraulics but I'm not 100% sure how the system works).

cadillac08 · Feb 24, 2008, 01:51 PM

My theory on the pit vent is that it could be so long that with the infrequent use of the basement plumbing we could actually be drawing a vacuum down the vent pipe and compressing the air slightly, since it would compress before the fluid would (kind of a vacuum reservoir). Again, I don't understand the ejector system well enough to know if that is totally impossible

massplumber2008 · Feb 24, 2008, 04:15 PM

Cadillac.. I have seen this more than a few times... Like I think you already have done... the waste line from ejector needs a rigid hanger above and below the check valve.

That will help significantly.

Further, when the ejector was installed the manufacturer asks the installer to drill a 3/16" hole in the ejector pipe, just above pump, but still way in the ejector basin.

I must wonder if that hole got drilled in the pipe... read instructions left with the pump. Without the hole, the system can get air locked and may not pump properly.

So, three things... 1) hangers as stated, 2) replace check valve, 3) check for or drill 3/16" hole in pipe just above the pump... yucky, but I think this is important to all pump installations.

Also could be that this is just the noise you will hear whenever it shuts down....enough of a head of pressure can simply slam the check valve flapper back down...and may not be much you can do about it. Try the things I mentioned...

If this helped, please RATE THIS ANSWER. Thank you

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cadillac08 · Feb 24, 2008, 06:13 PM

That makes a lot of sense - do you think this could also have made the rubber joint above the check valve separate also? The noise doesn't bother as much as the rubber joint blowing off. I will check into the 3/16" hole - that is on the waste pipe right? Not the vent pipe?

massplumber2008 · Feb 24, 2008, 06:50 PM

Hey Cadillac:

What brand ejector system do you have?

Do not worry about the clamp blowing off anymore as long as hung above and below the check valve (and clamp tightened well, now ;) ) I use 2" galvanized F&M split rings and 3/8" galvanized f&M plates, and 3/8" threaded rod to anchor my ejector pipes to somthing real solid (foundation/stone wall..or nearest stud)...(see pics. below..sorry no pic of F&M plate).

hang that well....may even need to change out your check valve...some of them have cheap clamps that flex and clamp rubber poorly.

And yes, 3/16" hole is in waste line... not vent... check out this site Zoeller Pump Company ...manufacturer of submersible sump pumps for dewatering, effluent, sewage and grinder applications, home improvement products, and pump sizing software. Look for literature for your pump.

Keep us posted.

cadillac08 · Feb 25, 2008, 07:34 AM

It is a Sta-Rite pump - I looked at the literature left with the pump and it only details the pump assembly - not the installation. I noticed Saturday night when I had the latest "Big Bang" that sewage was seeping out of the check valve on the rubber. The joint was still in tact but where the two halves of the check valve bolt together the rubber was protruding, and sewage was dripping. Does this still fit the profile of needing the 3/16" hole? If so I will get after it

massplumber2008 · Feb 25, 2008, 07:42 AM

I believe all ejector pumps need to have this hole drilled... but more important.. change that check valve out to a good compression type check valve... (see pic)... ONLY FOUND at plumbing supply houses...OK? I bet that will fix all this noise and leaking. Let me know what you think.