Check Valve


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Old 09-28-08, 03:55 PM
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Question Check Valve

I have 2 basic questions.
Where should a check valve be installed?
1 Near the pump
2 Near the water

What is the proper procedure to prime the line?

I ask because it usually takes me 1/2 a day or more to prime
the system after I do some work on the line.
This time a boat broke the line just before the check valve.
I fixed that but a day later, no prime.

A friend, not a pro told me that the check valve should be located near the pump the other way arround.

Anyway, I get the water from a canal in the back of the house, about 50 yards away from the pump. the canal is 15ft lower than the pump.

I have already confirmed that the check valve opens and closes without problem. (about a year old, bronze looking)
I have cleaned the filter and flush the line.

I basically fill the line with water and fire the pump. I goes for a while but then it looses it's prime. I then use a manual pump to remove the air from the line but it still not getting a proper prime.

This time around I would like to fix this issue. I have had 2 pros come and look at it the last time I had the problem priming. One did nothing and the other worked 4hours with me but could not get it going either. I ended up fixing it myself.

There has to be an easier way.

Any leads would be greatly appreciated.

Thanks,
Michele
 
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Old 09-28-08, 04:39 PM
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My opinion is the BEST thing is a foot valve. A foot valve is a check valve that is put right at the intake. A foot valve holds water up near the pump so that the pumps doesn't have to work very hard to get the water.

A check valve, on the other hand maintains a suction. I think it is harder for a check valve to hold a suction than for it to hold water. It just so much easier to get a suction leak.

Now, let's talk about priming. First thing is that there MUST be some sort of steady incline between the water and the pump. The piping MUST NOT go up and down, else an air bubble develops in the pipe and will not let water past, or just a little.

Next, water must fill the pump and go all the way back to the check valve. A good way of doing this is to have a union right by the intake of the pump. Then you can fill the pipe and close the union by screwing it shut, then fill the pump before you turn it on.

Suctions leaks can be detected by using shaving cream. You slather it on around the joints, then when the pump is on and trying to prime, you look for pinholes in the shaving cream. See one and that's a leak.

Also, I have seen worn out pumps that will not pump any air at all. A good pump must be able to pump some air while priming. If you put your hand or fingers over a pump that is trying to prime and feel zero air pressure, then it isn't a very good pump.

That said, pumps don't pump air VERY WELL. So you don't want to make them do it very long since that will hurt the seal. It gets overheated and get too much water past it. If you see water coming out the backend while you are trying to prime or while you are pumping, then water is getting past the seal. The pump can be rebuilt, the seal replaced, it isn't necessary to buy a new pump.
 
  #3  
Old 09-29-08, 09:11 AM
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Check Valve2

Vey,
Thanks for your quick and detailed reply.
I am going to begin by looking for possible leaks in the system.
I did wanted to confirm my understanding of what you said about the "check valve".

You say "A foot valve is a check valve that is put right at the intake." In my case there is about 15 ft between the "foot valve" and the waterline. Is that ok?

See pics here.

Thanks,
Michele
 
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Old 09-29-08, 10:07 AM
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Foot valves in a pond or lake are usually inside a basket or screened so that trash doesn't get in. You should make sure that the screen isn't clogged up with algae or something. Also it shouldn't be in the bottom since it can suck up sand.

15 feet from the waterline is fine, provided that the foot valve is pretty deep. Remember what I said about the hose inclining to the pump? If it goes up, then down, then up again, a bubble forms at the high spot and very little water can get past that bubble.
 
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Old 09-29-08, 10:18 AM
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No expert, but learning as I read.

Vey, I couldn't see the pics, but the way I read it, the valve is 15ft past the water line up on dry land, not 15ft below the waterline. I think that would be like trying to suck a big slug of air up the pipe wouldn't it?

Maybe I'm just reading it differently.
 
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Old 09-29-08, 10:53 AM
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"Maybe I'm just reading it differently."

Could be. I don't know. I couldn't see any photos either. If you are right and the check valve is 15 feet above the water line, it could still work IF the pump is in good condition.
 
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Old 09-29-08, 11:03 AM
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Guess we'll see when the OP gets back.

I could just see the pump pulling on the water in the line, opening the valve, letting water drain back into the rest of the line as the air leaks by. And if the pump is a bit worn as you said, it can't lift it that far.

Man, I must be running out of projects if I'm following a pump thread...no bodies of water near me, thats for sure, unless I'm in the tub.
 
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Old 09-29-08, 12:39 PM
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well you could always do some reloading if your bored. it fills the time quite nicely

life begins when the kids leave home and the dog dies
 
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Old 09-29-08, 03:14 PM
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Anybody: why would any system NOT have a foot valve?
 
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Old 09-29-08, 03:35 PM
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Originally Posted by Bruce 01 View Post
Anybody: why would any system NOT have a foot valve?
A shallow well might not have a foot valve.

I made my well that way. It has 1 1/4" PVC screen and pipe down there. No casing. I had a choice when I did that. Either put the check valve right on top of the well, so it closes better since it faces down and gravity helps pop the seal shut tight.

Or attach it right to the pump which makes things easier if I am pulling from a well field, but makes it harder to prime.

Either way, it's the pump that makes the diff. If the valve is working right, it can hold the suction.
 
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Old 09-29-08, 07:23 PM
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Vey, what part of the country are you located in?
by the way i appreciate reading your posts, you are very knowledgeable and articulate.

life begins when the kids leave home and the dog dies
 
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Old 09-30-08, 08:32 AM
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No casing.
That's not the right way to say it. I should say that there is no drop pipe in this shallow well. There is just one pipe with a screen on the bottom and I pull from that pipe.

I'm in Florida.
 
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Old 09-30-08, 08:06 PM
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that is what i guessed from reading that post.
around here we never see a well smaller than 4" dia, unless it is for ground water monitoring,
have one house well south of norman about 70miles that the well is 6 ft x 10 ft concrete tiles set down to a sand layer water level is at 28 ft bgs. it makes several hundred gpm. i pumped it once at 40gpm and the water level rose 0.4ft. over about 10 min. but most of the state you have to work to get good ground water.

life begins when the kids leave home and the dog dies
 
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Old 10-03-08, 07:09 AM
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Check Valve Update

Ok guys, here is an update.
(not sure why the pics did not stick?)

I removed the check valve that was 15 feet away from the
filter and installed a new one in the canal next to the filter.

Unfortunately, no go. I still cannot prime so far.
When I fill up the pipe at night and try to add water in the morning, it does not take any more water. It seems the system
is air tight.

I have decided as a next step to use a hand pump I have to
attempt to remove any air trapped in the system, that is the only thing I can think of right now.

Thanks everyone for your input.
Will try again to add some pics a bit later.

Michele
 
  #15  
Old 10-03-08, 12:00 PM
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Check Valve final update

Primed up at last!
Alright guys, let me tell you what I did.

First I filled up the line with water, with the sprinkler valve closed of course.

Then I slowly opened a valve that is located on top of the pump, on top of this valve is a hand pump. As I open that valve some water under pressure came out of the hand pump as one would expect.

I then used the hand pump to pump out any air in the line. I
could actually feel when I hit an air pocket. I continued until
a solid stream of water came out. (more or less 10min time)

After that I closed the valve on top of the pump and turned on the actual pump. I then slowly opened the sprinkler valve 1/2 way and let it run a few minutes until I could see that I had lost pressure, at that point I would turn off the pump and add water in the line.

I repeated those steps a couple more time until I finally had normal pressure.

I have to assume at this point that the root of the problem may be the underground line. It must not be set on a slope therefore air pockets form.

I hope I was not too confusing and perhaps this will help someone. Above all, thank everyone for the useful tips.
Some of you a real experts, but more importantly you are willing to share that knowledge with others.

Until next time.
Michele
 
 

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