sump pump problem

I bought a Dayton Stainless submersible sump with A float. I tested it outside with a 7 foot x 1-1/2 pvc attached and it pumps and shuts off as it is designed to do.

I put it in the basement in the crock and when the water fills up the pump starts, but does not pump anything.
I do have a weep hole drilled below the check valve (installed with arrow up) The discharge pipe is all new with no obstructions anywhere.
sometimes i can unplug it and plug it back in and it will pump. put most times this does not work .
The pump is sitting on a flat surface with no sand or mud getting into it.

This was a $500 (when new) pump I purchased on eBay used, it appears to have never been used.
I took intake screen off and it is clean with no clogging.

what would cause this erratic behavior ?

have yo checked to see if your check valve is opening?????

yes the check valve is working, it tried it outside in the yard with the pump in container and it works fine

Not sure what a "7 foot x 1 inch x 1/2 pvc attached" is.
What do you have on the discharge line in the basement?
How high are you trying to pump?
Is there a chance that you are trying to pump higher than what the pump was designed for?
Do you have the specs on the pump?
Mfr?
Model no.?
Horsepower?

dayton stainless
model 3yu75a
1/2 horse
only lifting 55 inches
my discharge is pvc , 1 - 1/2 inch schedule 40

thanks for looking into this

Hmmm!
Can you tell if there is water squirting out that weep hole.

Just re-read your comment, "sometimes i can unplug it and plug it back in and it will pump. put most times this does not work ." Sounds like an electrical problem. Like a bad spot on the motor, as one possibility.

yes is is squirting out of the weep hole

but the motor is running full time once the float goes up. just no water is being pumped, although is is flowing out of the weep hole good. almost seems like a air lock problem, but when the pump is out side hooked up , it never fails. very hard to figure out

Any convenient spot in the discharge line where you could disassemble it? Like maybe at the check valve?

Where/how does the discharge line terminate?

yes , i can unhook it at the check valve, and see what happens

i removed the check valve and it works good now. the only trouble is i get quite a bit of water rush back in the pit from the line. The pump may not be strong enough to open the check valve with the weight of the water holding it shut, not sure.

What type of check valve is it

just a cheap green Zoeller

would you suggest another check valve?

wildfig said:

i removed the check valve and it works good now. the only trouble is i get quite a bit of water rush back in the pit from the line. The pump may not be strong enough to open the check valve with the weight of the water holding it shut, not sure.

Click to expand...

NO! The 55" of head on the check valve would not be enough to hold back a pump that is rated up to a head of "23.5 ft". Something's messed up with that check valve. Although you did say that you had it on when testing it outside. ??

You never answered my 2nd question..."Where/how does the discharge line terminate?"

the discharge goes 10 feet outside the house onto the lawn.( downhill) The check valve seems to open and close ok, although i filled it with water in the sink and it does not even hold water. so why won't the dam valve open to let me discharge the water? I did have the valve installed while i tested it outside on the lawn.