sump pump relief hole

[Grinchiedog]

I have a sump pump at my house that pumps (roof gutter rain) water approximately 18" upwards through its discharge line and then turns 90 degrees to the piping (under the sidewalk) that drains the water about 10 feet to the street.

Currently, the float is set so it pumps the sump completely dry. I also have no check valve or weep hole.

The pump works 90% of the time but periodically I go out there and the pump is on and turning but it is not pumping the water out of the sump (the pump is submerged).

My thought is that I don't need a weep hole because I don't have a check valve and that possibly I need to raise the float setting so the pump is always in 2-3" of water rather than dry.

Any thoughts would be appreciated. Do I need a weephole or is my logic ok on raising the float level? Or a different version?

 

[Pik107]

Hello group, I'm from Illinois and it's now our rainy season when sump pumps run almost continuously. As for the weep hole discussion, O.M.G. you guys are giving me a headache. Between horsepower of pumps, depth of sump or circumference, or amps, I'm going nutty. I don't know anything about any of that. I do know that my original builders pump was installed when my house was built and I closed in Jan of 07. The darn thing has run almost constantly in our wet season, and I have a battery backup installed that has not run yet as far as I know. I'm curious to hear your opinions on my situation.
As I said I'm surprised my original pump hasn't burned out yet. I have two issues I'm curious about hearing your suggestions:
If I unplug my primary pump I watch the inlet fill the sump about 1/3 full, then it stops coming in. If I leave the pump plugged in, it runs, and shuts off. It quickly starts again, and after pumping it shuts off. As I said before, the sump doesn't fill up so I'm thinking the pump or float should be quite a bit higher. It appears it doesn't need to run (at least so often).
The other issue is if I unplug the primary pump, if I push the float on the backup pump it works, but it sprays like crazy since the weep hole is too big. Should I just replace a section of the discharge pipe for the hole, and drill a 3/16 or similar weep hole to correct this?
Please keep in mind my technical abilities are minimal so plain language is much better for me to follow your point of view. Thanks much
Also, per the weep hole discussion, I can't see how any pump would work properly without having the ability to expel the air. Just my uneducated opinion.

 

[larry4406]

...If I unplug my primary pump I watch the inlet fill the sump about 1/3 full, then it stops coming in. If I leave the pump plugged in, it runs, and shuts off.

Sounds to me like at the 1/3 elevation, your drainage system is finding a way to relieve itself elsewhere. So, you should use this knowledge to set your sump floats accordingly. Often this is done by simply raising the pump by setting it on bricks or a cinder block.

Many plumbers don't have knowledge of the static groundwater level and set the pumps too low. Then the pumps run and run forever and the discharge often creates a mess of the yard. Analogous to putting a pump at the bottom of a pond where it runs forever whereas if it were at the pond surface, it would only run when the pond level rises.

 

[engineer2]

The darn thing has run almost constantly in our wet season,

As larry said, the pump install height might need improvement. Your foundation perimeter drains are probably at about 1/3 up from the bottom and once the water in the pit gets higher than them, the flow slows down because the water fills up the perimeter drains. No problem with this as long as your foundation is well sealed.

Lots of builders and homeowners put in the smallest/cheapest pump they can find. You might look into a bigger pump if it is running constantly. I finally bought a Zoeller after fighting cheap **** for years. In any case, a larger pump is insurance if there is torrential rain.

In one house (built next to a swamp) I put in tandem pumps on a 2" discharge, so if one couldn't keep up, the second one, mounted 12" higher, would kick in. Worked like a charm and ended their flooding problems.

You also have to make sure the end of your outside discharge hose is far away from the foundation as possible. Otherwise you are just recirculating the same water.

A 3/16" weep hole seems big, but that is what manufacturers recommend. I made mine 1/8" on the backup pump since it is a much smaller pump, and it works fine.

Make sure you put your backup pump on it's own check valve. If you want to ensure against winter freeze-ups, put the backup on its own discharge line to the outside.

Previous posts mentioned check valve thunk and I fixed it by putting an air column above it, much like your home plumbing. Problem solved.

I hope Frank the Plumber chimes in. While most any Chicago DIYer grew up dealing with sump pumps, I would expect a licensed Chicago plumber to be a sump pump ninja.

 

[jepalan27]

Great thread. Love the highly-technical explanations of the need for the weep hole. It is as simple as this - think upside down glass shoved into a basin of water...

*If* the sump goes dry then the closed cavity that consists of the pump itself and the section of discharge between the pump and the check valve is like a sealed empty glass turned upside down in the well. When the well begins filling no water gets into the pump *inlet* and the pump never primes.

Think about sticking an upside-down glass into a basin filled with water. No water in the glass even if it is submerged. You need to drill a hole in the glass to break the air lock.

The weep hole can be anywhere in the discharge between pump and check valve to break the air lock - as long as the weep hole is above the level of the pump inlet and the impeller.

 

[pstnbly]

That makes no sense...then why even have a Check Valve if you bleed it off all the way to the waterline?

The check valve is there to keep the pump from spinning backwards as the water goes back through the pump. Spinning the pump backwards will destroy the motor on some pumps.

 

[pstnbly]

I've designed several sump systems for industrial use, and don't recall ever including relief holes or seeing them mentioned in the pump spec's. Maybe the pipe fitters took care of it themselves?

Most small sump pump are not capacitor start. They do not have start windings to overcome initial starting torque needs. Therefore the weep hole so the pump doesn't have to start against an 8' water column.