Irrigation pump losing prime

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Dorlando13

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I have a shallow well with a one line suction. I was digging around the lines today, the shovel lifted the pump and pipes and I heard a loud crack, like pvc. The pump is now losing prime and a couple of times the pressure has gone in and out, meaning strong to weak on different zones.

If something cracked causing loss of prime would it only be on suction side and not on discharge side(after pump)? Could a crack on suction side cause pressure to weaken during a cycle , get weaker as cycle goes on? If there is a crack wound I see water coming out?

Also, check valve is installed about 1 foot from pump on suction side. Would a crack in suction line, before valve, cause the check valve to not close?

Thanks
 

WorthFlorida

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Suction side only. While the pump is running you're sucking air. When it's not running the cracked pipe loses water and allows air to enter. It is an easy fix. Just have to dig down deep enough. PVC gets brittle with time, even under ground. PVC is damaged by UV from the sun. I broke a few pipes myself.

How shallow is shallow?
What is your zip code. I'm 32828.
 
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Dorlando13

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Thank you. I am in 32807. Not sure how deep the well is. I have a vertical line that goes that around 18" and then there is a tee with horizonal lines going left and right. I am guessing those two lines lead to two well points down ever how many feet. I was able to dig down to the tee and replace everything from the tee to the pump. The pump tank is retaining water so i am guessing the check valve works, valve is about a foot before the pump. It would be very difficult to replace anything along the horizontal lines attached to the tee. But those weren't close to what I was working on. However, the tee and the horizontal lines attached to it slide back and forth, so whatever is on the other end of the horizontal lines is not fully glued. My pool guy broke these once and repaired so maybe he used a rubber boot that is allowing the pipes to slither a bit. This has probably always been like this so thinking it is not my issue

After my fix it is better but loses prime very slowly now. After 15 hours it takes 20 seconds to prime, after 8 hours 10 seconds. I do have a small water leak at the discharge port of the tank, but that is not suction side. I was thinking of redoing all of the threaded connections again, particularly the one before the check valve.

is it better to use teflon tape or pipe dope? I have read on plastic that tape may be better. I have read some people use both.
 

Valveman

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Teflon with pipe dope on top of that seems to be the most forgiving. You are going to keep having a priming issue until you fix the leak on the suction line, which is apparently prior to the check valve.
 

Reach4

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If the problem is more after you let the pump sit not used for a few hours, chances are you have a leak somewhere. One way to track that down is to slather shaving foam on every accessible joint that is downstream of the check valve. Turn on the pump, and look for shaving foam sucking in.
 

dorlando

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Agree. But it could be a threaded connection or something small, right? I may not see water leaking out, is that correct?
 

Jeff H Young

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inspect area where you heard a crack., the breaks are most common at fittings cant be that much going on how many suspected joints could there be?
 

Reach4

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Agree. But it could be a threaded connection or something small, right? I may not see water leaking out, is that correct?
Yes. Air goes thru much smaller cracks than water. Although water molecules are smaller than air molecules, the water is much more cohesive (stick together).
 

dorlando

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I replaced the threaded fittings and still no luck. However, it looks like my distribution valve is cracked and I don’t know if that is the crack I heard or if it happened later. Since that is on the discharge side, can that be causing my problem? I have a k rain cycle matic distribution valve.

Also, at this point it appears the check valve is working because the pump stays full. If the check valve wasn’t working would water get sucked out of the pump back down to the well?
 
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dorlando

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Well, after letting it sit for 14 hours, I think it is actually worse than before I repiped yesterday. The vertical pipe on top of the pump was mostly full, but now it is empty down to the suction line. I think the check valve is not perfectly level and slanted towards the pump but if the check valve isn’t fully closing, would it be sucking water from the pump when it is off?? This would explain why the pipe is empty and my water is being removed from the pump. I also have the leak in the distribution But that’s on the discharge side.
 
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