Pressure drops about 10psi when pump shuts off

[kadidlehopper]

HERE IS WHAT I HAVE
CREEK PUMP SYSTEM used for irrigation only
Wayne 3/4hp convertible pump (CWS75) set up for deep well use.
Parts20 flotec jet assembly (FP4800) using #52 jet and #24 venturi
20gal Water Worker tank (HT20HB) set at 27psi
1-1/4" suction poly pipe
1" drive poly pipe
50' from water source (creek), 30 of which is up hill
The pressure switch is set for 30-50

I also have a well pump system that is interconnected to the creek pump system which allows me to open a valve and use it to prime or increase the psi for testing purposes of the creek pump system.

The creek pump system will not pressurize above 30psi and so will not shut off the pump. When I turn off the pump the pressure instanly drops to 20psi and will hold that pressure unless I open a faucit. When I turn the pump back on it quickly builds back up to 30psi but no higher. I can close the valve between the tank and the pump and still get the same results. The pump, tank, and jet assembly are new so I don't think they have a problem. If I use the well pump valve to pressureize the creek pump system to 50psi the pump turns off and holds the pressure. However when I open a faucet the pressure sloowly drops to 30psi and the pump starts but will not pump the system past 30psi. I have checked the system for leaks and have none. If I drain all the water out of the lines then reprime the pump the system will again pump up to 30psi and no higher, pump just keeps running, and again when I turn off the creek pump the pressure drops to 20psi. I cannot understand why the psi drops instantly to 20psi when the pump is shut off, or why it will not pump past 30psi. My pressure guage is sitting on a tee about 3" above the rest of the feed line to the tank, could that be holding air and causing the pressure to drop when the pump shuts off.

I am thinking about changing the jet and venturi but am not sure which ones to change them to. I have jets #51, 52, and 53, and venturis #18 and #24. Also because of my age (over 70) I find it very scarry to go down the embankment to the creek for the change so I am hoping someone might have another solution of suggestion. I cannot afford to call someone to fix it due to limited income and I lost my son about a year ago so I have no one else to help.

I also thought that perhaps the jet assembly kit I purchased might be the wrong one. Perhaps I should have ordered the one made by Wayne, the people that made the pump, but it was much more expensive.

I am at a loss for what to do next so I can get the system working correctly. Any help or suggestions would be welcomed.

kadidlehopper

 

[Valveman]

Either the nozzle in the jet assembly is clogged or you have the wrong nozzle. If you have 28 PSI air charge in the tank, it will drop to 20 PSI when shut off because the bladder in the tank hits the bottom as the check valve closes.

 

[Sponsor]

 

[kadidlehopper]

Either the nozzle in the jet assembly is clogged or you have the wrong nozzle. If you have 28 PSI air charge in the tank, it will drop to 20 PSI when shut off because the bladder in the tank hits the bottom as the check valve closes.

Thanks for the quick reply
I did make the trip down to the creek once and checked the nozzle and it was ok. I will try to figure out the correct nozzle and install it.

 

[Reach4]

Where is the pressure switch? Where is the tank. (should be same place.) Bottom of the hill after the pump, top of the hill, or what?

You should drop your precharge to 26 PSI with a 3o PSI turn-on on a jet pump. It will probably help with that pressure drop you are seeing even before you fix your pump.

 

[kadidlehopper]

Where is the pressure switch? Where is the tank. (should be same place.) Bottom of the hill after the pump, top of the hill, or what?

You should drop your precharge to 26 PSI with a 3o PSI turn-on on a jet pump. It will probably help with that pressure drop you are seeing even before you fix your pump.

The tank is at the top of the hill and about 10' away from the hill inside the garage. The pump is mounted to the top of the tank and the guage is located in the line between the tank and pump. There is also a ball valve between the guage and tank so I can isolate the pump from the tank. Closing the ball balve has no effect on the presurre droping, it drops from 30 to 20 when I shut off the pump with or without the valve closed. This leads me to think that the problem is in the pump or the jet assembly.

I will drop the tank precharge to 26psi in the am tomorrow.
I will also change the jet and venturi from #51 jet and #24 venturi to a #52 jet and a #18 venturi. I found a place in the manual where it states that the 52-18 combonation will give better pressure, and the 51-24 gives greater volume.

Thanks for the suggestion

kadidlehopper

 

[kadidlehopper]

The tank is at the top of the hill and about 10' away from the hill inside the garage. The pump is mounted to the top of the tank and the guage is located in the line between the tank and pump. There is also a ball valve between the guage and tank so I can isolate the pump from the tank. Closing the ball balve has no effect on the presurre droping, it drops from 30 to 20 when I shut off the pump with or without the valve closed. This leads me to think that the problem is in the pump or the jet assembly.

I will drop the tank precharge to 26psi in the am tomorrow.
I will also change the jet and venturi from #51 jet and #24 venturi to a #52 jet and a #18 venturi. I found a place in the manual where it states that the 52-18 combonation will give better pressure, and the 51-24 gives greater volume.

Thanks for the suggestion

kadidlehopper

Well I lowered the tank pressure to 26psi and I replaced the jet and venturi with the one that says it gives the best pressure. I did pick up some pressure from 30psi to 35psi but the pump still will not pump past 35psi so it can shut off and 35psi is not enough for the sprinkler system. When it does get to 35psi the water pressure is good but when I turn on a faucit it drops down after a couple of min. to 25psi and will not recover back to 35psi with the faucit open. I am about to give up and take the new pump apart and check it out. Before I do that I though I would check in and see if there are any other ideas. Also I may just take the darn pump back for return rather then mess with it and void any warranty.

 

[kadidlehopper]

It may be less then 30', probley closser to 25'. It has about 10' of lines at the bottom of the hill to the place where the deep water is, and another 10' at the top of the hill to the pump/tank. The pump is advertized has pumping up from 0-90' in depth and 216 gph at 30' when set up has a deep well pump. If it will not pump up over 35psi of pressure at 25-30' then there would be no pressure at the 90' advertized so it would be unuseable. I called Wayne pump and was advised that the it should pump 50psi at that depth and the problem was a air leak in the suction line. Although that sounds resonable there is no leaks. When I pressure the lines to 60psi of water it will hold that psi for days. After talking to Wayne again, they said that the jet assembly has to be a Wayne jet Assembly and since I am using a Votek Parts20 fp4800 jet assembly that is most likely the problem. I will purchase and install the Wayne jet assembly and see if that makes any differance.

psi and lift = gallons per hour
Performance
PSI 0' 5' 10' 15' 20' 25' 30' 40' 50' 60' 70' 80' 90'
30 990 960 906 840 774 690 630 510 408 306 246 186 54
40 780 690 630 570 510 462 408 306 246 186 114 54 -
50 462 408 330 306 270 246 216 156 90 - - - -

 

[kadidlehopper]

It can only give you 30psi at 90ft, the pump falls off at 60ft for 50psi. You should make 3.6gpm, what kind of irrigation?

Then I should be OK at 25-30'. I will be using it to water a lawn and scrubs, maybe two to three sprinklers per station with about three stations. If that is two many sprinklers per station I can add more stations.
I called Wayne pump again and this time I talked to a person who stated that the Fotec jet assembly I am using will not work and that I need to use a Wayne jet assembly. He said that he has never found another jet assembly that works right on the Wayne pump. He gave me the part number and I ordered it. When it arrives we sill see if that solves the problem, I hope so. I will get back and post results later, it will take about 5 days to get the part.

 

[Reach4]

I have a Rain Bird 25PJDA-C sprinkler that the packaging says draws 2.4 GPM at 25 PSI, 3.8 GPM at 30 PSI, 4.4 GPM at 40 PSI.

 

[kadidlehopper]

It may be less then 30', probley closser to 25'. It has about 10' of lines at the bottom of the hill to the place where the deep water is, and another 10' at the top of the hill to the pump/tank. The pump is advertized has pumping up from 0-90' in depth and 216 gph at 30' when set up has a deep well pump. If it will not pump up over 35psi of pressure at 25-30' then there would be no pressure at the 90' advertized so it would be unuseable. I called Wayne pump and was advised that the it should pump 50psi at that depth and the problem was a air leak in the suction line. Although that sounds resonable there is no leaks. When I pressure the lines to 60psi of water it will hold that psi for days. After talking to Wayne again, they said that the jet assembly has to be a Wayne jet Assembly and since I am using a Votek Parts20 fp4800 jet assembly that is most likely the problem. I will purchase and install the Wayne jet assembly and see if that makes any difference.

psi and lift = gallons per hour
Performance
PSI 0' 5' 10' 15' 20' 25' 30' 40' 50' 60' 70' 80' 90'
30 990 960 906 840 774 690 630 510 408 306 246 186 54
40 780 690 630 570 510 462 408 306 246 186 114 54 -
50 462 408 330 306 270 246 216 156 90 - - - -

Well I changed out the jet assembly for the one make by Wayne per their suggestion {Wayne 55465) and it made no difference. Still can't get psi over 35psi. I called Wayne back and they now say that I have a suction leak and it is pulling in air. I have checked and can not find one. If there is one it must be very small. I am going to pull the two hoses up to the top of the bank where I can check them better. I have one question if I turn on the valve from my home well which is connected to the creek pump system it will presureize the creek system to 60psi of water. If I do that will I see water comming out of any leaks. What I mean is if the system is sucking air through a very small hole should it not push out water if presuseized to 60psi of water. I mean if the air suction leak is that small how could it affect the pump that much and would not water come out in a suction air leak that small or can air be sucked in at 35psi and still not let water leak out when presurized to 60psi. If I cannot find any leaks I will be forced to build an enclosure and move the pump from the garage down to the creek and try pushing water up then hope it does not get stolen.
kadidlehopper

ps: Wayne did say that I should have no problem pulling water up the 30' of bank and getting 50psi.

 

[Reach4]

I doubt that an underwater suction leak would hurt you for this purpose. So I would give my attention to above-water joints.

Air will pass more readily through a small hole than will water. If you kept water pressure for a while, you still might see water leaking eventually.

So if you can wet suspect joints while sucking, you may be able to see a rise in pressure. I expect you would need a helper for this -- one to read the gauge, and one to apply water to joints. I know this method works when using a vacuum pump, so it seems it should work with your jet pump drawing a vacuum.

My comments are not based on experience.

 

[kadidlehopper]

I doubt that an underwater suction leak would hurt you for this purpose. So I would give my attention to above-water joints.

Air will pass more readily through a small hole than will water. If you kept water pressure for a while, you still might see water leaking eventually.

So if you can wet suspect joints while sucking, you may be able to see a rise in pressure. I expect you would need a helper for this -- one to read the gauge, and one to apply water to joints. I know this method works when using a vacuum pump, so it seems it should work with your jet pump drawing a vacuum.

My comments are not based on experience.

Thanks for the reply. I too think it would have to be a above water air like. I will try your ideas about finding the leaks. By the way I do notice that when the pressure is at 35psi and I turn off the pump the pressure instantly drops to about 20psi. Since water does not compress I would think it must be air.
kadidlehopper

 

[Reach4]

By the way I do notice that when the pressure is at 35psi and I turn off the pump the pressure instantly drops to about 20psi. Since water does not compress I would think it must be air.

Makes sense. A delay in the foot valve closing could do it too, but you would not expect that to be so predictable.

 

[Valveman]

A suction leak is nearly always right where the suction pipe screws into the pump.

 

[kadidlehopper]

A suction leak is nearly always right where the suction pipe screws into the pump.

You are most lickly right. The only place where there is a joint is at the pump. I have solid new poly pipes from the pump to the jet assembly so unless there is a hole in the new poly pipes. that is where it would be. I have checked the connections for leaks, no water leaking and when I sparied water on the joints per Reach4's suggestion I see no change in the psi. I am going to try today changing the connections at the pump to see if it helps. Thanks for the input.
kadidlehopper

 

[kadidlehopper]

Well I checked the connections to the pump very close and did find a small leak. It was so small the water would evaporate before it could make a drip.
I do have short pipes running out of the garage where the pump is at and connecting to the pipes from the creek. That is where the small leak was at. I replaced both the poly pipes coming from the pump to the outside poly pipe from the creek and my psi has now improved to 40psi. There must be a leak somewhere else but I don't know it could be, the only other connections are at the jet assembly which is under water. I am begining to think that the new pump is bad but Wayne tells me that if it pumps water then it is good???. I do notice that there is a control valve on the front of the pump. It is a 1/2" plastic screew. When it is closed it produces 40psi and when I start to open it the presure drops about 15psi then when I get to about 1/4 turn open it picks back up to 40psi. Opening the valve further repeats the same thing over and over again, presure goes down then up again at about 1/2 turn an so on. Could someone explain to me the purpose ot the valve.
kadidlehopper

 

[kadidlehopper]

Well I decited to open up the pump and see if I could find anything bad, and I did. There is supposed to be a rubber seal between the defuser and the volute (pump case). Guess what it was not there so I called the Wayne teck again and he said he was supprised that I got that much psi. He is sending me one by Fed-Ex. I hope that solves the problem. Will get back with the results when I get the part and put it back togeather. Thanks for all the help.
kadidlehopper

 

[kadidlehopper]

So I received the new seal to replace the one that was not there, installed it and now the system will pump up to the set 50 psi. What I have noticed is that if I have a faucet or sprinkler on more then just a little the pump will not shut off. Seems that it cannot pump water fast enough to replace the water being used. according to the Wayne pump specs the pump should pump 675 gallons per hour or 10.25 gallons per min. I find it hard to believe that a faucet wide open can use that much water per min.

Thanks for those who gave me suggestions that helped me get to this point.

kadidlehopper

 

[Reach4]

Wayne pump specs the pump should pump 675 gallons per hour or 10.25 gallons per min.

The chart at the bottom of https://www.waynepumps.com/product-selector/well-pumps-convertible-well-jet/cws75 and your reply #7 on this thread say 216 GPH (3.6 GPM) with a 30 ft rise and 50 PSI, and that would, I presume, be with everything else optimum.

If the pressure stays adequate during use, having the pump not shut off during use is not bad. So if the pressure dropped to say 35 while filling the tub, and only went as high as 45 PSI while you are using the kitchen faucet full on, that would be a fine system I think.

If you redo your system, a suitable 1/2 HP submersible pump would give you a lot more pressure and water. There is no priming problem with a submersible. The downside is that you would need to run power to the pump.

 

[PumpMd]

So it was all that the pump could produce because of a rubber seal. I was close enough, I dont know jet pumps enough to take them apart, to know what goes bad in them or in your case just missing all together. They are old school around here, very few left out in my area.