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CEO Speedwagon.
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Ok I have a house on city water. It had a 1/2 hp shallow well jet pump, and a 20 gallon pressure tank. The pump shot craps so I replaced it. The old pump never had a check valve before the pump, so I put in a dual check as per code before the pump. When main pressure drops at peak usage times the pump is just to be supplimental. The new pump is a 1/2 hp flynt and walling shallow jet pump with a 30/50 pressure switch. My tank is good and air is set at 28lbs. What is happening is when it drops below 30psi the pump kicks in and struggles to get to 50lbs, and when it does the pump kicks off and the pressure immediatly drops to right above 30 until a 3rd fixture is turned on. Then with the third fixture running it drops below 30lbs and kicks the pump on and acts like it is short cycling. I even tried a new pressure tank and checked pressure with 2 seperate gauges, and still the same problem. Pressure switch is new, I even tried it without the check valve, like it was originally just for kicks, same symptom. Anyone have any ideas, or need more info, I'm at a loss.
 

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I always used a 20/40 for a jet pump if I recall. 30/50 for a submersible. I used to have problems using the 30/50 on a jet pump as they always seemed to struggle to get the pressure up.
 

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Ok I have a house on city water. It had a 1/2 hp shallow well jet pump, and a 20 gallon pressure tank. The pump shot craps so I replaced it. The old pump never had a check valve before the pump, so I put in a dual check as per code before the pump. When main pressure drops at peak usage times the pump is just to be supplimental. The new pump is a 1/2 hp flynt and walling shallow jet pump with a 30/50 pressure switch. My tank is good and air is set at 28lbs. What is happening is when it drops below 30psi the pump kicks in and struggles to get to 50lbs, and when it does the pump kicks off and the pressure immediatly drops to right above 30 until a 3rd fixture is turned on. Then with the third fixture running it drops below 30lbs and kicks the pump on and acts like it is short cycling. I even tried a new pressure tank and checked pressure with 2 seperate gauges, and still the same problem. Pressure switch is new, I even tried it without the check valve, like it was originally just for kicks, same symptom. Anyone have any ideas, or need more info, I'm at a loss.

I live in the city where Flint and Walling pumps are made. :laughing:

I have rarely seen a shallow well pump used that way, but have seen them installed on many a well systems. If that problem were to occur on a well, I would say you have some sort of well issue, plugged screen, old well or something like that.

So following that same logic, it would seem to me that there is a supply issue, but....

I will wait however to see what others have to say as this problem intrigues me.

Call Flint and Walling their tech support is pretty good.
 

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Another thing is inside the pump there is a metering valve. One way is for deep well, another way is for shallow well applications. Cant recall, but if memory serves me right there is a bolt on top that you remove to get access to it.

damn I hate getting old. How they say, if you dont use it you lose it? Used to love working on jet pumps. I prefer them to the submersibles. Just been too many years since I fooled with them.
 

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Going on what Bill said, what model did you use? The ones I put in on well are the CPJO5SB, and do not have that adjustment screw.

I still say call tech support. 5 Minutes and you will have answers on that model. :thumbup:
 

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I am not a big pump guy so please excuse me if i am wrong. If you have a pressure switch set for turning off at 50 psi shouldn't the tank be set to 40ish psi not 28 psi? I can't remember what we did the last time we put in a designed pressure booster pack. And I understand what you are doing is different. I would make sure you don't have something plugging the inlet.
 

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The cut in pressure is always 2 lbs below the swithch's cut in pressure. hence a 20/40 would have 18 lbs of air and a 30/50 would have 28 lbs of air
Thanks. I don't get to see many pumps around here. the last one was a huge system designed for the 7 story building and it was all set we just plumbed it and they told us how much to charge it. The rep. did the startup as part of the package.
 

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I am not a big pump guy so please excuse me if i am wrong. If you have a pressure switch set for turning off at 50 psi shouldn't the tank be set to 40ish psi not 28 psi? I can't remember what we did the last time we put in a designed pressure booster pack. And I understand what you are doing is different. I would make sure you don't have something plugging the inlet.
The pressure in the tank needs to be at least 2PSI less than the "Cut-on" pressure. Otherwise the pump will spend unnecessary time trying to overcome the tank pressure, and thereby reduce the amount of water a tank holds.

2PSI ensures that a tank will be used to maximum capacity. It is also true that if you put the pressure to low, that volume will be reduced. Its all about maximizing tank capacity.
 

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So I have a question, maybe a little off base but you have city water and a well... are these connected? I couldn't tell from the OP...
Second why would the check valve be before the pump? Would seem the pump would be working harder to pump through rather than push through. My service area don't see too many pumps so I probably shouldn't be posting, rather reading more...
 

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Discussion Starter · #11 ·
I always used a 20/40 for a jet pump if I recall. 30/50 for a submersible. I used to have problems using the 30/50 on a jet pump as they always seemed to struggle to get the pressure up.
I think I may try dropping to a 20/40. I just can't figure why once it hits 50 it shuts off and the pressure instantly drops to right above thirty, with or without a check.
 

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I think I may try dropping to a 20/40. I just can't figure why once it hits 50 it shuts off and the pressure instantly drops to right above thirty, with or without a check.
I cant right now either. I do think you will have better luck with the 20/40 though.
 

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I have a ton of questions. If the gauge is good and the pump shuts off yet registers 32 lbs what is the domestic water pressure normally? Does the domestic water pressure increase as peak use of the main drops? I do not understand why the pressure would drop unless the check valve is not working and the main is at a constant 32 lbs. Is the check valve a swing or spring check? Could there be debris in the check valve?

He is using the shallow well pump as a booster pump. The pump you purchased how many gpm? How fast does it build up and shut off with no fixtures running? My bet is it does not have enough water volume and osculates in the pump and that is what is giving you the short cycling until it builds to 50 lbs. If the pump is required to pump 7 gallons a minute and it only has 3 gallons a minute it will struggle until water is shut off or slowed considerably. You may want to increase pressure ,that will drop the gpm of the pump.

Check your water heater relief valve and make sure it is not running. We are required to run the relief to the outside. You would never know if it is running unless you went out and checked it. No floor drains here. New pump may have set off a weak relief valve along with a closed system. No other leaks in or outside the home?

You did say shallow well. I hope they did not give you a deep well with a shallow well package on it. May be dirt in the venturi ,forgive spelling.
 

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Probably won't be anything mechanical or anything you did wrong, it probably has to do with the performance curve of the pump you installed.


There should be flow and capacity charts on the pump you bought, showing indication of how the curve moves in relation to pressure/rpms/volume of water.


I'd start there since everything you installed is not showing indication of failure.
 

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I have a ton of questions. If the gauge is good and the pump shuts off yet registers 32 lbs what is the domestic water pressure normally? Does the domestic water pressure increase as peak use of the main drops? I do not understand why the pressure would drop unless the check valve is not working and the main is at a constant 32 lbs. Is the check valve a swing or spring check? Could there be debris in the check valve?

He is using the shallow well pump as a booster pump. The pump you purchased how many gpm? How fast does it build up and shut off with no fixtures running? My bet is it does not have enough water volume and osculates in the pump and that is what is giving you the short cycling until it builds to 50 lbs. If the pump is required to pump 7 gallons a minute and it only has 3 gallons a minute it will struggle until water is shut off or slowed considerably. You may want to increase pressure ,that will drop the gpm of the pump.

Check your water heater relief valve and make sure it is not running. We are required to run the relief to the outside. You would never know if it is running unless you went out and checked it. No floor drains here. New pump may have set off a weak relief valve along with a closed system. No other leaks in or outside the home?

You did say shallow well. I hope they did not give you a deep well with a shallow well package on it. May be dirt in the venturi ,forgive spelling.





Excellent diagnosis. I would check that as well. If this is the case, replacing the T&P relief valve will remedy the problem.
 

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So I have a question, maybe a little off base but you have city water and a well... are these connected? I couldn't tell from the OP...
Second why would the check valve be before the pump? Would seem the pump would be working harder to pump through rather than push through. My service area don't see too many pumps so I probably shouldn't be posting, rather reading more...
He's using it as a booster for the city water connection.
 

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Ok required by code. I can read. But WHY? Just saying because its code and knowing why its code are two different things.

Having looked up shallow jet pumps on their site I'm unable to see the mfg instructions, but I don't understand why a double check would be required for an appliance that boosts pressure, but has nothing that may jeopardize public water, like with an ice machine or a commercial dishwasher...

So first, wouldn't the jet pump pulling through a double spring check have a definite restriction of flow and stress on the system? Would you use a double check on a recirc line? By your code, without knowing an explanation, yes

Second why use a jet pump to begin with? Most of the models that I looked at wouldn't suffice in any way as a booster. Why not just use one of there booster pumps designed for that purpose?
 
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