Jet pump runs but wont build pressure HELP

Crazy 4 grass · Apr 23, 2021

3/4 horse 16gpm red lion jet pump

Worked fine for two seasons.

Was properly winterized last fall.
Now won't pump water nor build pressure.
Heres what I've done.
Plugged it in, motor runs fine. Impeller is spinning. Filled with water to prime, runs but won't build pressure and shut off. It also won't suck water through intake line. I tapped on check valve, it moves freely up and down. I then connected a garden hose to pump from another water source. Other water source filled it and got pressure up to 60psi. Plugged in the pump, it did not turn on. This is good because its a 30 50 pressure switch. Then let water out, as soon as it got down to 30psi the pump kicked on and runs and runs, but will not build pressure.

What am I missing here?

1idejim · Apr 23, 2021

Crazy 4 grass said:
3/4 horse 16gpm red lion jet pump

Worked fine for two seasons.

Was properly winterized last fall.
Now won't pump water nor build pressure.
Heres what I've done.
Plugged it in, motor runs fine. Impeller is spinning. Filled with water to prime, runs but won't build pressure and shut off. It also won't suck water through intake line. I tapped on check valve, it moves freely up and down. I then connected a garden hose to pump from another water source. Other water source filled it and got pressure up to 60psi. Plugged in the pump, it did not turn on. This is good because its a 30 50 pressure switch. Then let water out, as soon as it got down to 30psi the pump kicked on and runs and runs, but will not build pressure.

What am I missing here?

Hole in pipe

Crazy 4 grass · Apr 23, 2021

Thanks for the response.

I should have added this.

I already pulled the pump. I undid the unions and its currently sitting in my garage with the intake in a 5 gal bucket of water. So there really isnt any hole in pipe. Any other ideas?

I'll post pictures later if that helps.

Scott87 · Apr 23, 2021

Had the same problem once and it turned out one of the bolts holding the impeller in place broke.

Crazy 4 grass · Apr 23, 2021

I removed the four bolts that fasten the front on. I tried separating the two halves. I could not get the front part off. I reassembled it. I removed a plug on the front and inserted a wire gently while the motor was running. I could feel the impeller tap tap tapping on the wire. Thats how I know impeller is spinning.

I replaced pressure switch just in case. No change.

zr100 · Apr 23, 2021

Like Jim said, hole or leak on suction side.

Crazy 4 grass · Apr 23, 2021

Thank you for the reply this ought to be fairly easy to check seeing as it's only connected to about 2 ft of pipe right now

RhettMan · Apr 23, 2021

pump's life cost is currently under 10 bucks a month at $225 for two seasons

should be easy to pressure test?

what if its free wheeling? "spins if no hydraulic load"

Crazy 4 grass · Apr 23, 2021

RhettMan said:
pump life's cost were under 10 bucks a month at $225 for two seasons

should be easy to pressure test?

Yes the thought ran through my mind that I may have got my money's worth out of it.
I'm irrigating about an acre and a quarter.

I did the math once and I run it about 1500 hours 150000gal a season.

I really want to upgrade to the Gould 1 horsepower

Crazy 4 grass · Apr 23, 2021

Check pressure tank it's at exactly 28 PSI with no water

RhettMan · Apr 23, 2021

i mean the vessel itself.

you could put a guage on the outlet union and pressurize the inlet union.

any air escape especially on the inlet side would revert cause back to jims "hole in the pipe"

irritation · Apr 23, 2021

Could have had air in suction pipe. Sometimes takes several try's when priming.

RhettMan · Apr 23, 2021

credit to Jim for that one too, if i trace my memory to its origins.

Crazy 4 grass · Apr 23, 2021

Any idea in either hours or gallons what one of these pumps are rated for?

RhettMan · Apr 23, 2021

Im not very familiar with pump systems, but whatever you chose should be based on the demands and restrictions of the existing system.

you couldnt run a 300 sq ft drip line bed with a diesel centrifugal and a 5 gallon pressure tank...for example.

or, vise versa, a 150 ft hose reel impact with a solar powered pump (excluding govt funded projects/experiments/grants)...

You will be somewhere in between, but it depends entirely on its use. (to achieve maximum or even reasonable efficiency.

this of course if stuff you already knew, but came here to be re-assured, as we'd hoped.

some pump guys will chime in "momentarily"

1idejim · Apr 23, 2021

Or

zr100 · Apr 24, 2021

These numbers go from 5-25 Total Suction Lift(feet) in increments of 5.

Crazy 4 grass · Apr 24, 2021

Thank you. Im in water at 16ft. So I'm figuring With the 1hp I'd be at around 18gpm

Wet_Boots · Apr 24, 2021

On your pump install, is there a shut-off valve downstream of the pump?

Crazy 4 grass · Apr 24, 2021

Yes. There is a hose bib on top a hose bib on bottom for draining and a ball valve shutoff for the rest of the system

Crazy 4 grass · Apr 24, 2021

Crazy 4 grass · Apr 24, 2021

I usually prime it via a hose from the house water supply connected to the hose bib on top.

irritation · Apr 24, 2021

The bronze check valve may not be moving freely or spring tension is too strong. Impellers worn out.

Crazy 4 grass · Apr 25, 2021

I had that same thought. I looked up the intake pipe and pushed on the center of the check valve. It springs up and down freely.

How do you remove or check for impeller wear?

RhettMan · Apr 24, 2021

and is the check proper direction? (probably is, but this is part of never assuming*)

i guess we would want to include outlet gate valve open in the checklist also*

Crazy 4 grass · Apr 25, 2021

Yes check is installed in proper direction. Suction would pull it open, then when suction stops it snaps down again.

Heres my usual priming method.

1 close all valves
2 attach hose from different water source to hose bib on top of jet pump.
3 open hose bib, allowing pump and pressure tank to fill. This usually puts the pressure gauge showing around 40psi.
4 shut hose bib on top
5 turn on pump, let it run for a few seconds
6 crack open hose bib on bottom slowly allowing water to go out. I watch psi, if it drops to 10 or so I shut off pump and repeat process.
7 usually 7 or 8 times doing this primes intake pipe and its pulling water from well.

I did this repeatedly with it connected to the well. Then pulled it out of the well pit to more easily access.

I've been doing this procedure repeatedly with the end of the intake submerged in water in a five gallon bucket, to no avail. I've stuck my hand in the bucket, with pump running and held my palm tight against intake opening. I had expected to feel suction against my hand but felt nothing. I need to try jims idea of pressuring from intake union side yet.

1idejim · Apr 24, 2021

Do you have a vacuum gauge?

Sprinkus · Apr 24, 2021

I've had some pumps where I had to choke down the outlet valve to get them to properly prime and get pumping.

Crazy 4 grass · Apr 25, 2021

Yes I usually shut outlet valve at first then slowly open it, while running, to coax pump to suck water.

RhettMan · Apr 26, 2021

what are the chances that the inlet pressure on the "bottom hose" is enough to pin the check valve down?

a hose here might have 100 psi static from muni.

What if you open both top and bottom hose bibs, and fill (hose connection to bottom bib) until water leaks out of the top bib, and then close both, and then power on the red lion.

1idejim · Apr 26, 2021

Take the check valve out of the equation.

With the information you’ve gathered the reasoning lends to the check valve, impeller or air leak.

Crazy 4 grass · Apr 26, 2021

Here's my process of elimination to do list as I see it. If one doesn't work try the next
1Prime pump via hose bib on bottom until water starts coming out hose bib on top.
2 pressurize system via intake to check for air leaks.
3 assuming no air leaks remove check valve and attempt to Prime
4 if none of these options are success then the only thing left is the impeller. Are the impellers replaceable on these units or is it time for a new pump at that point?

enorl76 · Apr 26, 2021

Crazy 4 grass said:
Here's my process of elimination to do list as I see it. If one doesn't work try the next
1Prime pump via hose bib on bottom until water starts coming out hose bib on top.
2 pressurize system via intake to check for air leaks.
3 assuming no air leaks remove check valve and attempt to Prime
4 if none of these options are success then the only thing left is the impeller. Are the impellers replaceable on these units or is it time for a new pump at that point?

Maybe the motor shaft is spinning backwards? Its possible with some 220V motors to get the leads reversed and spin backwards.

Can you mark the motor shaft and make sure its spinning clockwise with regard to the pump case facing you? When it's reversed It'll look like it's pumping but not great.

The quick fix is simply reverse the two 220V leads.

enorl76 · Apr 26, 2021

Wet_Boots said:
It may seem counter-intuitive to have to (nearly) close the pump output in order to get it to prime, but it may be the only way you will extract the final bit of air that lies between a pump spinning uselessly and a pump primed and working.

As long as you're not completely cutting off the output, like I see many do, then it somewhat works, but not the reason you're thinking. Centrifugal pumps are not positive displacement pumps, ie they allow for some flow-back, which also means the impeller can be spinning and no water can be moving.

Cutting down the output is creating an insufficient flow scenario in the pipes. Think feet per second here... With insufficient flow, the air bubbles in the suction line are able to more easily stay in their high voids and not get moved with the high velocity water flow through the pump case and out the output line.

Best way to prime a pump, is fill the case entirely with water, so that the air is forced entirely out of the pump case. Air coming from the suction line, then has a definite path out of the pump case and out of the system. Self priming pumps have the suction line intentionally below the impeller suction level, but this costs you efficiency due to turbulence in the flow when running. (I would always recommend self priming pumps for pretty much every setting until you get into high flow, high efficiency needed scenarios)

Wet_Boots · Apr 26, 2021

I'm forgetting something in my advice. Since I do work with well points, I have to accept that air is going to be in the suction line. For the folks that employ a foot valve, they have a chance to get rid of nearly every last bit of air in the suction line, which might help the priming process.

RhettMan · Apr 27, 2021

If removing check valve:

You might also hold hand under suction during filling, so it doesn't run back into bucket.

Remove hand and power on simultaneously.

Wet_Boots · Apr 27, 2021

Someone with a few gauges to spare (including vacuum) might set up a pump, and see what, if anything, is happening when the pump output gets choked down. There is no question that a wide-open output is not prime-friendly, regardless of how carefully the pump was filled with water before energizing it.

Jet pump runs but wont build pressure HELP

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