Replaced check valve, now no real flow.

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Yar02169

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23' deep, water 7' below ground. Goulds GT15 pump.
Replaced box store bronze check valve (1 1/2") with an Apolo SS ball check valve of the same size. Used goopy thread sealer instead of Teflon tape, hoping to eliminate any leaks.
Assembled, primed and hit go. After a bit, some flow comes out the outside hose bib, but pressure remains zero and no flow increases.
The CV is cold, the PVC from the well is more half-cold; the bottom half.
I used a better sealing technique, so I would like to eliminate an intake leak. Is it possible that the new check-valve closing spring is to strong? I did activate both with my finger, and the new did feel a touch stronger, but I'm rethinking it's strength.
Should I let the pump run for a while so it can pull the air slowly out of the supply side? Once full of water, the pump would pull what's needed, correct?
 

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A heavy spring on a check valve in the suction line will make the pump think the water is deeper than 7'. But the pump should still pull it open. I think your problem is the PVC union. The o-ring in that union will hold pressure just fine, but it doesn't like to hold a vacuum. My guess is a suction leak either at the union or the plug on top of the tee.
 

Yar02169

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Thanks for the quick reply.
I put water on top of the tee, if that was the leak it would be sucked in. It wasn't.
Like you, I was suspicious of the union. I was thinking about coating the o-ring with the thread sealer. When I just unscrewed it, there was a point that I could hear the seal 'break', so it seems that it's fine.
My plan is to re-install the original check-valve. If it works, then I can see about swapping the springs between the two valves.
 

Texas Wellman

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I noticed that part of the suction pipe looked like DWV, which is not rated for pressure (or vacuum). Are you sure it's not leaking?
 

Yar02169

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I noticed that part of the suction pipe looked like DWV, which is not rated for pressure (or vacuum). Are you sure it's not leaking?
It's all Sch 40 minimum. What is DWV? Somewhere there is a vacuum leak, but no fluid drip.
 
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Yar02169

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I went back to the old bronze CV, wores results - not even getting the 1 GPM now.
The can of shaving cream from the Dollar Store didn't show anything special. How long does it take to see the leak? My guess is not long.
Everything worked nicely prior to this, so I'm baffled and getting frustrated (typical pump life). Going to replace the Union, see what happens.
 

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Lubricant doesn't help with o-rings. Pressure pushes the o-ring into the crack between two fittings, and seals the leak. There is no way for the o-ring to get pushed into a crack when it is in a suction line. I am still thinking a suction leak at the union, but it could also be a bad impeller.
 

Texas Wellman

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I've done lots of these through the years. I doubt it's the union.

I would install a shutoff valve between the pump and tank. Put a gauge on the pump side. Start up with this valve shut. If the pump does not build pressure then the inside of the pump is damaged. There is an impeller and a synthetic rubber divider in the pump. There is also a plastic cover over the impeller. There should also be a Venturi and jet nozzle.

I've seen these pumps run hot before. Most likely the impeller and nozzle are fine. My bet is that the large rubber piece has a hole in it. There are 4 bolts holding the pump together. Pretty easy to take apart and look.
 

Texas Wellman

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Ps there is a 1/4" plug on the back of the pump that can be removed. Run a length of wire or coat hanger in to see if the jet is plugged.
 

Yar02169

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The guts look normal. The one thing I noticed is the off-set wear of the race on the impeller cover. I'm guessing that's not the cause.
I don't know about the jet nozzle and Venturi, but I'm going to check out the jet
.
 

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Yar02169

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The manual mentions nothing about any jet or venturi. Probably because it's not a jet pump.
 

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Valveman

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Those Gator pumps are straight centrifugal pumps, not jet pumps. The critical part is how tight the impeller fits in the wear ring. It looks like there is some wear on the impeller hub and wear ring. This maybe enough tolerance between the two to keep the pump from building pressure.
 

Pump Doctor

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You are correct. It is not a jet pump, it is a straight centrifugal pump. Designed to move larger volumes of water, but at a lower pressure.
Some suggestions for you to think about. 1. The fewer fittings from the well to the suction of the pump, the better. 2. The fewer fittings on the well head itself, also, the better. 3. It is possible, (sometimes), to insert the pipe nipple coming out of the check valve toward the pump in too far. This will block the cv plunger from opening very far (hitting the end of the nipple). 4. On the suction side of a pump, you must have near perfect joints in the fittings and piping, all the way to the water. 5. When priming the pump, you must allow air out at the pump, to allow water take its place in the pump.
I hope some of this will help you. You have a good pump to work with.
 

Yar02169

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http://www.lockewell.com/pdf/goulds/GT_IRRIGATOR.pdf is a datasheet for this single-stage centrifugal pump. I would think the pressure switch might be set to 20/40 PSI or maybe 25/45. But yar02169 seems to have a flow problem rather than a pressure problem.
It's more of a lack of flow. It was fine prior to the check valve change, all was good.
I did install a new Union and still have no flow. Prior to that,when the system would start, it needed to re-prime, that was one reason for the new ball check valve. It would prime in less than two minutes, and then run fine, until it would need to prime the next time. I would power down in between runs so it wouldn't cycle, or run dry.
Tried to get it to run all by itself, and things are worse.
 
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