need some sump pump basics

[greenbikemike]

We've had alot of rain[who wasn't] and need some info.I have done a search here and did some google'n,not sure what the hell to do. It's a 1/2 ,3200GPH at 10' with a 7' rise,2' pit but its only 16" in diameter and when the pump kicks on,it emptys the pit in 2-3 seconds and seems to fill up quickly and and it cycles on and off alot. The 1 1/2 discharge pipe goes out 20' and I put a ****** on it and attached a 25' garden hose to it to get the water as far away as I can [it does go down hill] The pump seems to run alot less now and for longer periods,6-10 seconds now.I'm thinking that the pit to small or the pump is to big or both. Also,I know the pump has to work a little harder because of it being necked down,but the sudden on for 2-3 seconds and then off again can't be good for it also.Right now I just have to live with it till it dries out around here,I do have a back up pump AND my old pump that still works,its just old and I didn't want to wait for it to go out.
Any and all info wanted,THANKS
Greenbikemike

BTW,what the hell is a "cubit" and has anyone got any Ark building plans?

 

[JohnK007]

You do have a check valve on the vertical rise from the pit, right? If not then water will flow back into the pit when the pump shuts off causing it to short cycle. Also, you might be restricting flow with the garden hose. I would suggest using 3 or 4 inch corrugated plastic pipe at the end of your PVC discharge pipe to get it away from the house. When things dry out you can just pull the corrugated pipe off the end and store it somewhere until the next time.

 

[greenbikemike]

Thanks for the reply,
I do I have check valve,seems to be working fine,still wondering about the pit size and size of the pump......I just picked up another 10' stick of 1 1/2 and 24' 1 1/2 flexable drainage hose......I'm doing what I can to stay on top of this......a little sun would'nt hurt either,
more info about the pit size and pump size wecome....thanks,
Greenbikemike

 

[Bondo]

Ayuh,.... A Bigger sump pit is pretty much Always a Good idea,...

I don't use the check-valve, due to freeze ups in the winter,...

 

[Ohio Auto]

Appears you replaced the pump? Did you have this problem before? If not I doubt it's the crock.

A pump with more horsepower than the old one might be the culprit. More horsepower is beneficial when having to overcome backpressure and long line runs. If you have a short run and little resistance the problem maybe you don't need that big of a pump.

 

[joes169]

Generally speaking, 20 seconds of run time used to be kind of an industry standard for effluent pumps (sewage grinder pumps) and has often been applied to sump pumps as well. It will help in getting the most life out of the pump as possible, as you're short-cycling it now. Your pit sounds relatively normal sized, but perhaps the float is set too low, allowing the pump to come on too quickly? Do you have the pump sitting directly on the floor of the basin? What is the high water mark (measure from top of floor) when the pump kicks in?

 

[kbs2244]

Return the 1 ½ pipe and get 2 inch instead.
When you hook it up leave it a sloppy connection so that air can get in.
It will not leak much water and the air getting in will stop any back siphon and allow the pipe to drain dry.

 

[Architorture]

smaller pump. I downsized my pump for this very reason. The original was a 1hp monster that would **** the pit dry in a few seconds and then turn on again not much later. I went down to a 1/3hp pump and now it runs for perhaps 5 minutes at a time much more infrequently.

 

[jkwilson]

You may be able to throttle the outlet down with a valve rather than swapping pumps. Just make sure nobody can close the valve by mistake.

A little restriction shouldn't hurt anything, but test it before you leave it unattended.

 

[greenbikemike]

Thanks for all the replies,as for the pump,same size [1/2]that I replaced,but the old pump kinda did the same thing,but this the most rain I've seen since living here on top of all the snow melt.The pump is sitting on the bottom,it comes on 12"[24" deep pit] from the top,goes down 4" and goes off,as for a restriction,when I necked it down it to the garden hose,it seemed to help and it does drain out,no back drain,its going down hill,but whats worse for the pump,working harder but not as offen with restriction or going on and off twice as much with no restriction? I'm thinking easiest thing would be trying a 1/3 and seeing how that works....thanks again and keep up the replies.....
Greenbikemike

 

[jkwilson]

Thanks for all the replies,as for the pump,same size [1/2]that I replaced,but the old pump kinda did the same thing,but this the most rain I've seen since living here on top of all the snow melt.The pump is sitting on the bottom,it comes on 12"[24" deep pit] from the top,goes down 4" and goes off,as for a restriction,when I necked it down it to the garden hose,it seemed to help and it does drain out,no back drain,its going down hill,but whats worse for the pump,working harder but not as offen with restriction or going on and off twice as much with no restriction? I'm thinking easiest thing would be trying a 1/3 and seeing how that works....thanks again and keep up the replies.....
Greenbikemike

Surprisingly, the pump has it easier with a little restriction.

 

[p_mori7]

You want ZERO restriction on the pump outlet. They are not designed to make pressure.

You need a bigger pit. Mine is 24" long x 18" wide x 24" deep. A bigger pit and the pump you have now will allow you to move the water more effeciently

A smaller pump would work too, as you've already stated it will simply run longer.

A large capacity pump is good, because you have less chance of having the system overwhelmed by a large influx of water.

 

[joes169]

Your pump float switch doesn't have enough range between on-off right now. Some are adjustable (like the tether bulb switched) while other aren't. Ideally, your pump would shut off at 1-2" left in the basin, and not turn on until there was 12" or so of water in the basin......

 

[gdh33]

Like stated you want to adjust your float, if possible, to turn on near the top of the pit and shut off near the bottom. 16" drop would be good. Secondly your pump is too large. Make sure to look at the pump curves to pick a suitable pump. Some pumps are designed for low flow and higher lift (30-40 ft) and others are high flow and lower lift (12 ft). I would just throttle or restrict the outlet of the pump, it is easier on the pump because it is doing less work. Replace it with a smaller one (less flow) when it dies in 10 yrs.

 

[WQ59B]

^ Make sure the "near the top" of the pit is still below the bottom of your slab; concrete likes to wick water.

 

[G_P]

If you chose to use a valve to throttle down the ouput, remove the handle. Otherwise someone will eventually turn it completely closed without thinking and you will end up with a flooded basement and a burned up pump.

 

[greenbikemike]

Thanks guys....great answers..

You want ZERO restriction on the pump outlet. They are not designed to make pressure.

You need a bigger pit. Mine is 24" long x 18" wide x 24" deep. A bigger pit and the pump you have now will allow you to move the water more effeciently

A smaller pump would work too, as you've already stated it will simply run longer.

A large capacity pump is good, because you have less chance of having the system overwhelmed by a large influx of water.

A bigger pit is probably the answer,but I'm leaning to smaller pump and see how it goes,the pit and 1/2 pump was put in by a basement waterproofing co. and when that pump got old[still working]I replaced it with the same size

Your pump float switch doesn't have enough range between on-off right now. Some are adjustable (like the tether bulb switched) while other aren't. Ideally, your pump would shut off at 1-2" left in the basin, and not turn on until there was 12" or so of water in the basin......

No adjustment on my switch,and I looked for a different one yesterday,no luck and with the main pump and back-up pump,no room for the tether bulb,but it would work a hell of alot better with more travel in the switch

Like stated you want to adjust your float, if possible, to turn on near the top of the pit and shut off near the bottom. 16" drop would be good. Secondly your pump is too large. Make sure to look at the pump curves to pick a suitable pump. Some pumps are designed for low flow and higher lift (30-40 ft) and others are high flow and lower lift (12 ft). I would just throttle or restrict the outlet of the pump, it is easier on the pump because it is doing less work. Replace it with a smaller one (less flow) when it dies in 10 yrs.

I'll have to look into pumps a little harder....but it does seem to work better with some restriction....runs longer.......
I've noticed that the water is not coming in from my drain tile...but from the weep holes in the bottom 10-12"of the pit,high water table here so I'm thinking that its ground water coming up and really nothing can be done to correct it besides the above fixes?

^ Make sure the "near the top" of the pit is still below the bottom of your slab; concrete likes to wick water.

never gets near the top.....damn pump works TOO good,cleans that baby out in no time....

Thanks everyone again...I just want to get this fixed so I can go back play'n with stuff I enjoy.....I have alot of irons in the fire.....a fireplace hearth,air compressor to put in,2 bikes to finish....and,I know yadrwork is here....
Greenbikemike

 

[greenbikemike]

Just an update,I replaced the 1/2 hp with a 1/3 hp and it made a big differance,
my back-up pump kicked on last week[rain gauge said 6 1/2" here,but at the airport,the "official" rain was 4.13,but who in the hell lives at the airport?J.C.]
I don't know if it was from the short cycling and getting weak or what,but after resetting it,the main pump worked again,but I ran out and found a 1/3 and put that in. I have 30' of 1 1/2" pipe and then necked down to 100' of 3/4" hose,the pump does run longer,but does not short cycle,it seems to be the ticket.
I've put in a couple of pumps lately for friends that never had water problems before and their pumps didn't come on,well,they were so damn rusty I can see
why! they've been sit'n for years.
A battery back-up pump saved me,you lose power or main pump quits=mess.
I now have 2 spare main pumps[used,but still work] and a new main,I'm good,now back to work on stuff I LIKE to do!

Greenbikemike

FWI......1 cubit=18" inches

so that would be 450'L X 75'W x 45'H

thats alotta wood

 

[G McKay]

smaller pump. I downsized my pump for this very reason. The original was a 1hp monster that would **** the pit dry in a few seconds and then turn on again not much later. I went down to a 1/3hp pump and now it runs for perhaps 5 minutes at a time much more infrequently.

The size of the pump has nothing to do with how frequently the pump runs. The thing that makes the pump run more often is the speed that water is running into the pit. When it doesn't rain for a few days, the pit will fill up less of often because the ground outside isn't so wet. So, less water is running into the pit.
A 1/3 HP pump is going to run as often as a 1 HP pump if the pit is filling up at the same speed with both pumps. The larger pump will just empty the pit faster. It won't make the pit fill up any faster. Right?
I would also be sure that the discharge pipe is at least as big or bigger as the one coming up out of the base of the pump. So, I would get that garden hose off of there ASAP. You could damage the pump.
I would also keep the old pump for a spare if it still works. You might need it some day in case the other one fails.

 

[gdh33]

First paragraph, thinking is correct. But for example the 1HP pump will pump 3x as much volume as in a given time vs. 1/3HP. If the pumps turn on every 10 minutes and the 1 HP pumps the pit out in 1 minute and 1/3 HP takes 3 minutes, then the 1 HP will cycle every 11 minutes and the 1/3 HP will cycle every 13 minutes. Pumps like to run longer and less frequent. The 1/3 HP runs longer, so would be a better choice.

Pumps have performance curves, you want to be with in this curve or you will damage the pump. Throttling or reducing the size of the discharge piping may place you on a better part of the curve and may increase the life of your pump.

I didn't read it all but should answer some questions.

http://abe-research.illinois.edu/pubs/factsheets/SumpPumps.pdf

 

[kozeehezheya]

I would just throttle or restrict the outlet of the pump, it is easier on the pump because it is doing less work.

 

[Architorture]

The size of the pump has nothing to do with how frequently the pump runs. The thing that makes the pump run more often is the speed that water is running into the pit. When it doesn't rain for a few days, the pit will fill up less of often because the ground outside isn't so wet. So, less water is running into the pit.
A 1/3 HP pump is going to run as often as a 1 HP pump if the pit is filling up at the same speed with both pumps. The larger pump will just empty the pit faster. It won't make the pit fill up any faster. Right?
I would also be sure that the discharge pipe is at least as big or bigger as the one coming up out of the base of the pump. So, I would get that garden hose off of there ASAP. You could damage the pump.
I would also keep the old pump for a spare if it still works. You might need it some day in case the other one fails.

it has everything to do with it...assuming you have the same pit conditions for both pumps the more powerful pump will clear the pit in less time regardless of the rate of water entering the pit.

the perfect situation would be to have a pump that is pumping water out of the pit only slightly faster than water is filling the pit. if your pump is able to far outpace the incoming water to the pit it is going to short cycle like crazy. therefore, slowly filling pit equals less powerful pump...quickly filling pit equals more powerful pump.

i still have the 1hp pump i replaced...and its a good thing, because earlier this week we had a huge downpour and the pit filled faster than the 1/3hp could pump out. so i dropped the 1hp in and everything was fine.

 

[jimindm]

I think the OP question would have many different answers. Everyone has there own sump pump needs, by how much water is getting into their pit.

Look at how the average sump basin is designed. Water comes in, and is pumped out. It does not just come on full flow at once, and shuts off. Usually it starts with just a trickle of water, sometimes all the way to full running lateral lines. As the ground dries out it eventually comes back to a trickle, and does not run any more.

You could make the case of longer or shorter running times are better for the pumps, but by that logic you should have several different sizes, ready to install as the need arises. I just do not think pump manufacturers would want the consumer changing out pumps as needed.

You can put what ever size pump in today, and as the water table moves tomorrow it maybe to big or to small.

I think you size the pump for the need that you have the most. Maybe a little bigger.

IMO you have a float adjustment problem. You should be able to adjust the float for more movement than that. You said that you couldn't because of two pumps in then hole. If one of those is a battery powered back-up pump, get it out of there and install a water back up if you can.

I can say, I would use a larger pump. I would take short cycles over not enough capacity any day. You may never know when you will need the capacity.

 

[greenbikemike]

I've had the new pump in for a couple of weeks and all I know is it seems to work better with the 1/3 hp.FWIW,but thanks for the the replies.
Greenbikemike