No Flow Sewage Pump

[Mike547]

I have a sewage grinder pump that won’t pump the water, it runs but no flow. There are several holes drilled in the discharge pipe but there is no flow out of them. Last week I pulled the pump and checked to make sure the intake was clear. I put the pump in a barrel of water to test and it pumps fine. It’s as if the air holes in the discharge are all plugged but they aren’t. I checked out the discharge at the same time, it was clear. Does anybody have any ideas?

 

[breplum]

Shutoff valve open?
Check valve clear?
Is there a plate on the bottom of the pump that can be removed?
Is the plate still there? I've seen pumps run but not flow well when the bottom plate pops off the impeller pump zone. An inexperienced lay person might not know there is supposed to be a plate on the bottom.
Or stuff trapped in the impeller causing impaired flow.
We also use clear check valves to allow visual inspection for cases like this.

 

[Twowaxhack]

The pump may not be able to overcome the head pressure while connected to the sewer. Or you may have an obstruction like a bad check valve or gate valve.


Does this grinder pump into a forced main or a gravity main at the city connection ? There’s usually a check valve at the street along with a ball valve if it’s a forced main.

 

[Mike547]

Thanks breplum for the answer The shut off valve is okay, the check valve is clear. Yes, there is a plate on the bottom, and I pulled the pump this morning and checked the pump intake and discharge, all were clean. It's not that the pump is weak in any way, it just will refuse to pump sometimes when it's switched on and other times pumps right away, shuts off, and works well. You just can't depend on it in the slightest. As soon as you get water flowing out of the little vent holes of the discharge pipe I know the pump is running good and headed to the field. This morning, I had to call a vacuum truck when I couldn't get the pump to pump anything. I went into the house to unplug the pump. When I came back out the driver told me water was starting to blast out of the vent holes until I unplugged the pump. It's just particularly annoying it had to pick that time to prime. Clear check valves, great idea!

 

[Mike547]

The pump may not be able to overcome the head pressure while connected to the sewer. Or you may have an obstruction like a bad check valve or gate valve.


Does this grinder pump into a forced main or a gravity main at the city connection ? There’s usually a check valve at the street along with a ball valve if it’s a forced main.

I guess I didn't clarify very well it's a septic system grey water pump.

 

[Twowaxhack]

If the pump is set to pump down below the top of the pump you may be loosing your prime. Don’t let it pump down lower than 6” above the pump.

It’s not good to use a grinder pump to pump septic to the drain field.

 

[Mike547]

Thanks for your reply. I decided to order a new pump, now without a grinder, just a sewage one. Why shouldn't a grinder pump be used in a septic field? The grinder was installed by professionals who said it was necessary, I don't think it was. It did run trouble free for 7 years, but now it is a constant problem. With the cost of a vacuum truck running $200+ 2 or 3 times a month it won't take long for the pump to pay for itself. Thanks for the information.

 

[Twowaxhack]

It grinds and stirs up solids. Plus they’re more expensive that just a 2” sewage pump

 

[RS]

If it's only a grey water pump it doesn't need to be a grinder, if it's before the septic tank and pumping raw sewage it should be.

 

[Twowaxhack]

If it's only a grey water pump it doesn't need to be a grinder, if it's before the septic tank and pumping raw sewage it should be.

That’s not true......

The only time you need a grinder is when you’re pumping into a forced sewer main. That means a pressurized public sewer main.

There are special circumstances where a grinder may be desired for other applications but it’s not typical.

 

[SHEPLMBR]

Could be your control panel?