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Sump pump operation

10K views 16 replies 9 participants last post by  MikeKy55 
#1 ·
First a little back ground: My sump pump failed a week or so ago. Since it was monsoon season the cycle time was about every 10 seconds. I was pouring a cup of coffee when I noticed I couldn't hear it running. So I went downstairs and found it not working. I reached in and pulled the float rod up and nothing. So I run to HD and bought a Flotech 1/2 HP submersable to replace the 1/3 HP submersible I had. When I got back with the pump, the water was within 2 inches of floor level. I pulled the old pump and when I went to move the discharge pipe to the new pump I discovered the outlet had a male connector rather than the female the old one had. So I mumble a few choice words and run to the local ma and pa hadware and got a fitting. When I got back home, I had about 1 inch of water in 80% of the basement. More choice words...I quickly assemble the piping and install the new pump. It works and the water runs back into the sump. I spend the next 4 hours with the wet or dry shop vac and clean up. Luckily I haven't gotten to floor coverings yet in the basement project.
Now to my quandry. The new pump takes about an hour to empty the basin enough for it to shut off. In my opinion, that is waaaaaaaay too long. My experience is a sump pump should empty the basin in seconds, not an hour. So since it IS pumping and holding the water level down to a safe level I leave it going. I stopped by HD and spoke with a fellow there that is a retired plumber and has never led me wrong. I gave him the back ground and he scratches his head and says 'It will be the first time I have seen it with Flotech, but it sounds like a bad pump'. So, I buy another pump like it and take it home and install it. Took the old 'new' one back for a refund. However, this pump does exactly the same thing. The discharge line is 1.5 inch and is about 8.5 feet vertical with a check valve midway, makes a 90º then thru the outside wall, back down the outside about 3 feet, makes another 90º and then travels underground away from the house about 20 feet and discharges onto the lawn.
In addition to trying a second new pump, I pulled the check valve and looked inside for something blocking it. Nothing there.
Also, there seems to be quite a bit of turbulence in the basin when the pump is running. I don't recall ever seeing the water in a basin churn like that.
My question is I guess, am I expecting too much from this pump? Is the Flotech an inferior pump?

Thanks in advance!
 
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#2 ·
Sump pumps are rated in GPM, gallons per minute or hour. It sounds like you got one that is too small for the job. If from a big box store, they will take anything back, But I would suggest getting one with more capacity, and using this one for a backup. Have it all piped up and ready to go if needed.
 
#3 ·
Is the discharge line pitched downwards from where it exits the building? If not, this could be putting a lot of back-pressure on pump. I can't imagine a 1/2 hp pump not clearing a sump pit in less than a few minutes unless you've got downspouts or other drainage into this pit.
 
#4 · (Edited)
Sounds like you have some sort of restriction in the piping downstream from the pump. The churning sounds like the pump is cavitating (google that term) http://en.wikipedia.org/wiki/Cavitation
and unable to literally pump. The restriction may have burnt out the original pump. On some of them you need to drill a relief hole (3/16") of an inch above the pump to allow the trapped water/head to drain on the off cycle. Should have that info along with the maximum feet of pipe it can pump against in the instructions it came with or check their website. Every elbow equals 5 feet of pipe I believe.
 
#6 ·
The 1/2 HP Flowtech pumps I looked at online show various flow rates but I would say the average is 55 GPM @ 10' of vertical lift in which your case the pump should be emptying your sump well much more quickly than stated.

A quick calculation of your sump capacity assuming 16" dia x 18" deep would mean that there is approximately 4 gallons of water in the pit resulting in a pump time of approximately 4 seconds.

That being said and the fact that you report "churning" in the pit indicates that there is an obstruction down the line somewhere, which is driving the discharge head and thus the pump off the operational curve.

If there is no obstuction in the piping I would replace the check valve as it is likely that it is not openning properly. As a rule, you should replace the check every time you replace the pump.


Mark
 
#7 ·
Thanks for all the replies. I did drill an 1/8 hole in the discharge line near the pump. I blasts water out. The feedback makes me question the line out side being obstructed. I will snake it from the outside end and see what I find. About 15 feet of the line is accessible, but the 12 feet or so nearest the house is under my deck which I I underpinned with 1X fence boards. So that won't be an easy fix. But I can do it. I screwed the underpinning to the stringers. I will report back with what I find. Thanks again.
 
#9 ·
Ditto the check valve suggestion. A 1/2 HP pump is plenty large enough, and while Flotech is not the top of the line, it is plenty good enough to drain the basin in a matter of less than a minute. I had a similar problem with my sump pump, I ended up removing the check valve entirely. This is not a problem unless the outlet pipe pitches upwards for a long way, in which case there would be a lot of water in the outlet pipe when the pump stops, and you can have pump stall problems starting up against the pressure of the water.

By drilling a 1/8 inch hole in the outlet pipe inside the pump pit, you allow any water remaining in the pipe to drain out when the pump shuts off. This reduces the chances of freezing in the winter, and also effectively eliminates hard startups for the pump since it never starts up against a head of water.

I know the books all say you need a check valve, but based on my personal experience of 20 years living in a house which absolutely needs a sump pump, I have found that removing my check valve was the best thing I ever did to improve performance of my system.
 
#11 ·
I will remove the valve tomorrow. The daughter has volleyball all weekend and it takes most of each day. I did snake the discharge line and there was nothing in it. In fact after the 1.5 pipe exits the house it steps up to 2 inch. Snake slid right in without so much as a drag.
 
#12 ·
Okay. Here's what I did. I was watching some youtube videos about 'proper sump pump operation'. As we discussed here, the check valve seemed to be restricting the flow. So I had a 2 inch valve sitting out in the garage from another project here. I bought a couple reducers for 1.5 to 2 inch PVC. I set up the 2 inch valve so that I could adapt it to the 1.5 inch pipe. When I pulled the 1.5 valve earlier to check it out, I noticed the valve opening couldn't have been much more than an inch in diameter. So that seemed like a dumb setup. One thing I did not mention in my earlier posts was the fact that the basin was half full of gravel. That put the perimeter drain system under water at all times. That too didn't make sense to me. So I removed the gravel and lowered the pump about 10 inches. That means when the pump kicks off, water from the drain system is running out of the pipes and 'down' into the basin.

Now, the pump empties the basin in average 45 seconds and kicks off. Granted, it kicks back on again in about 20 seconds. But given the amount of rain we have had, I think that would be normal.

One more benefit of this setup (in my mind) is the water table under the floor of the basement will be at least 10 to 12 inches lower.

Thanks to everyone for their suggestions and direction. I feel much better about the pump operation now.
 
#15 ·
Good catch. Likely what cost you the old sump pump was the constant running and the restriction.

I installed my sump pump when I bought my house. It had a chronic flooding problem and therefore was prone to severe seepage. Up until recently, the setup worked great (despite the sump "pit" not being quite deep enough for my liking) until I ran into some outside erosion issues and some gutter problems.
 
#13 · (Edited)
I keep a spare pump in my basement. With the amount of use that yours gets a spare is always a good idea. I also have a float switch tied into the house alarm (monitored) and they call me if the pump fails. Alarm company can help you with that and supply the float switch.
 
#14 ·
Adjust the pump so it comes on before half of any perimeter drain pipe as seen in the pit has become submerged. You can also try setting the pump to come on before 1/4'th of any drain pipe has become submerged and use that if the pump restarts are not too frequent.
 
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