Craftsman 390.2522 Professional "Hydroglass" convertible Deep Well Jet Pump

[ngregory94522]

I need someone to help me understand where I am going off the rails. I thought I knew what I was doing, but I'm stumped.

Let me describe the system...

I have a residential well/water system. The well has a pump down in the well, that pumps water from underground into a Captive Air tank, and thence into a ground-level 4000 gallon holding tank. I don't know the depth of the well, but it isn't relevant.

Water is drawn from the holding tank, through a two stage water filter, into a jet/pressure pump, then into another Captive Air tank, which then feeds the residential water system. The tank is pressured to 40 PSI, and operates at 40-65 PSI. All has worked very well for many years. Until the Jacuzzi brand pump failed.

Since much of the system here was Sears, including the Captive Air tanks, etc., I picked up a Sears 390.2522 Craftsman Professional "Hydroglass" convertible Deep Well Jet Pump, and inserted it in place of the Jacuzzi. It is rated at 40-60 PSI, and 1 HP, same as the Jacuzzi was.

Since the pump is drawing water from the ground-level tank instead of deep below ground, I did not connect the Jet system. I plugged the Jet output and connected the inlet and discharge lines, just as the Jacuzzi had been before it. It is installed essentially identical to the way the Jacuzzi had been, and I even used a new check valve on the inlet side, as the old one was leaking a bit, probably causing the old pump to run excessively, and perhaps even contributing to it's demise.

All is working fine except for one thing. The new pump will not make it's rated pressure. If I adjust the pressure switch for 25-40 PSI start/stop it works just fine, except that residential water pressure is too low. It is low enough that it is quite noticeable when taking a shower. It's workable, but not like it should be. I guess I could live with it, but it seems just too low to be normal. (I like a good, vigorous shower, and this just isn't up to snuff.)

Under full flow, the pressure hovers around 36-38 PSI instead of the 55-60 PSI the Jacuzzi delivered. If I adjust the pressure switch higher than about 42 PSI, the pump simply runs forever, never reaching a cut-off pressure.

I disassembled the pump housing to inspect the impeller and seals, and all looks perfect. But nonetheless, the pressure is low.

While I had the system down, I checked and adjusted the pressure in the Captive Air Tank to 40 PSI according to instructions. The tank was not completely flat, but had lost pressure no doubt due to years of neglect so I corrected it.

When I encountered problems I lowered the tank pressure to be more in line with that of the pump, (abt 30 PSI) and all seems fine, albeit at a lower pressure than I expect.

Perhaps the motor is running too slow (it is wired for 220V and served by a 220V feed) but it sounds normal. Possibly there is an internal leak within the pump and it just allows too much water get by the impeller. But when I inspected it, it seemed OK.

My only other thought is that somehow the pump wants the "feedback" of some output being fed back into the suction side via the "Jet" in order to produce full pressure. But the Jacuzzi did not have that, and I thought I understood that was only needed to bring water up from below ground. I thought I understood well how that all worked, and I didn't need it, since water flows into the pump easily from the ground-level tanks. Feeding water back into the pump via the Jet seems intuitively counter-productive.

Am I wrong? As I say, the Jacuzzi had the jet output plugged and easily made 65 PSI cutoff pressure, and it was rated identically to the Craftsman, in terms of flow, pressure, Horsepower and RPM rating.

I see from searching the forum that dkellogg3 posted he was using this pump at 62 PSI cutoff without problems, but mine won't exceed 42 PSI no matter what I try. I infer he is using the Jet feedback, but......

Any thoughts or suggestions from those here would be most welcome. In other words, H.E.L.P.......

Thanks,
Nathan

P.S. If this pump is just a POS and I should return it and put in a better one, what do the experts recommend?

[Pumpman]

You need to use the jet assembly to allow the Sears pump to reach higher pressures.
The Jacuzzi may have looked a little different, but I'm betting it had a jet assembly in it. Look at the left side of the pump head (standing behind the motor). You should see a plastic plug towards the bottom. If that plug is there, that is the jet assembly. A jet pump withouit the shallow well adapter (the jet) is merely a centrifugal pump, which isn't made for higher pressures. If the Jacuzzi wasn't a jet pump, it was at least a multistage pump, which will produce higher pressures.
A little known secret about Sears pumps: They are underrated, as far as capacities go. Sears pumps are made by Pentair, which manufacturers jet pumps under the Sta-rite name. While the Sta-rite pump and the Sears pump look alike, a Sta-rite 1hp pump has a higher capacity because the 1 hp Sears pump has a 3/4 hp impeller in it. In other words, the 1 hp Sears pump is the same as a 3/4 hp Sta-rite. Not all pumps are created equal. The Sears 1 hp pump will not have as high a capacity like the old 1 hp Jacuzzi.
After all of that, install the jet assembly on the Sears pump and it will help it reach higher pressures. Also, adjust the precharged pressure tank to 2 psi less than pump cutin pressure.
Ron

[Pumpman]

As I reread the question, I noticed that you said that there were filters installed between the holding tank and the pump. While it may have worked that way, there shouldn't ever be anything installed between the water source (in this case, the holding tank) and the pump except a checkvalve.
Filter impede the suction flow of the pump.
Ron

[ngregory94522]

Originally Posted by Pumpman

As I reread the question, I noticed that you said that there were filters installed between the holding tank and the pump. While it may have worked that way, there shouldn't ever be anything installed between the water source (in this case, the holding tank) and the pump except a checkvalve.
Filter impede the suction flow of the pump.
Ron

There is no impediment to the flow. In fact, the pressure from the tank, from gravity alone is quite strong. The Jacuzzi had no trouble at all reaching 60 PSI, with a flow volume that was quite generous..

I do not think the filters are a factor.

Update: While considering your advice and looking things over again, I realize I erred. The filters are NOT between the tanks and the pump. Too many pipes in too small an area, and I simply didn't look too closely at that particular spot. The filters are indeed between the pressure pump and the feed to the house. So that solves that question.

Thanks,
Nathan

[ngregory94522]

Originally Posted by Pumpman

You need to use the jet assembly to allow the Sears pump to reach higher pressures.
The Jacuzzi may have looked a little different, but I'm betting it had a jet assembly in it. Look at the left side of the pump head (standing behind the motor). You should see a plastic plug towards the bottom. If that plug is there, that is the jet assembly. A jet pump withouit the shallow well adapter (the jet) is merely a centrifugal pump, which isn't made for higher pressures. If the Jacuzzi wasn't a jet pump, it was at least a multistage pump, which will produce higher pressures.
A little known secret about Sears pumps: They are underrated, as far as capacities go. Sears pumps are made by Pentair, which manufacturers jet pumps under the Sta-rite name. While the Sta-rite pump and the Sears pump look alike, a Sta-rite 1hp pump has a higher capacity because the 1 hp Sears pump has a 3/4 hp impeller in it. In other words, the 1 hp Sears pump is the same as a 3/4 hp Sta-rite. Not all pumps are created equal. The Sears 1 hp pump will not have as high a capacity like the old 1 hp Jacuzzi.
After all of that, install the jet assembly on the Sears pump and it will help it reach higher pressures. Also, adjust the precharged pressure tank to 2 psi less than pump cutin pressure.
Ron

Much thanks for the response. At least you are zeroing me in on the Jet issue as the culprit. But I do not understand quite what you are saying. I am looking at the Jacuzzi, and it has nothing but an inlet, and an outlet. It has a second outlet for a "Jet" on the front, but it is plugged. If I take the plugs out and look into it, all I see is an ordinary centrifugal impeller.

There is nothing anywhere that appears to qualify as a jet, or maybe I just need to take it apart in the daylight....

As I understand it, the Jet is just pressure from the output fed back into the input. I understand that when you are pumping water up from deep underground, this helps lift the water out of the ground, by providing a positive pressure to assist the suction. That is clear and obvious. Or at least I thought it was, but maybe I don't understand it as well as I thought I did... But when the water source is at ground level, or even above the pump level, as when drawing from a ground level tank, it seems counter-intuitive that this would in any way boost the pressure. If anything, I would expect it to do the opposite, as it would act as a "leak" between input and output, reducing pump efficiency.

I guess it is my day to learn something new

Are you saying that if I install a loop from the output side back to the input, this will cause it to make more pressure? I am not quite understanding something. Is there some piece of the puzzle I am missing here?

Sounds like I need to purchase a shallow-well jet. Is this something I can make myself from plumbing parts, or is there some bit of magic in it that is not obvious? From all I can tell about the Sears diagrams, it appears to be nothing more than a 'Y' connector with a 1" pipe and a 1.25" pipe joining, and the small valve on the top of the pump acting to adjust the output of the 1" pipe. The check valve sits between the point where the pipes join and the tank, preventing any of the output from the 1" pipe making it's way back to the tank. So any given drop of water may make it's way thru the pump twice. Is that right?

As far as volume goes, I believe it will be quite adequate, if I can get the pressure up to where it should be.

Can you enlighten me further?

Much appreciated,
Nathan

[Pumpman]

Go to the Sears website and look up: "shallow well jet package". You will find a device that attaches to the front of the pump you have. Once it's attached, you'll have a 1 1/4" inlet and a 1" outlet.
A jet assembly only has two main parts: a nozzle and a venturi tube. We can talk all day about how it works, but I'll try to keep it simple.
After the water leaves the impeller, some of it is directed back to the jet assembly, under pressure. As this water passes through the nozzle and then the venturi tube, it's velocity is increased, which increases the pressure entering the impeller. If you increase the pressure of the water entering an impeller, the impeller is able to add that much more pressure to the output.
This is why adding the jet assembly to your pump, will increase your discharge pressure to the house.
Jet assemblies are engineered for each pump, so you'll need to buy the one that's designed for your pump.
Ron

[ngregory94522]

Originally Posted by Pumpman

Go to the Sears website and look up: "shallow well jet package". You will find a device that attaches to the front of the pump you have. Once it's attached, you'll have a 1 1/4" inlet and a 1" outlet.
A jet assembly only has two main parts: a nozzle and a venturi tube. We can talk all day about how it works, but I'll try to keep it simple.
After the water leaves the impeller, some of it is directed back to the jet assembly, under pressure. As this water passes through the nozzle and then the venturi tube, it's velocity is increased, which increases the pressure entering the impeller. If you increase the pressure of the water entering an impeller, the impeller is able to add that much more pressure to the output.
This is why adding the jet assembly to your pump, will increase your discharge pressure to the house.
Jet assemblies are engineered for each pump, so you'll need to buy the one that's designed for your pump.
Ron

Much thanks. It seems counterintuitive, that all it would do is keep the check valve closed, or else cause it to pulse.

But I trust you know what you're talking about. I will order one from Sears ASAP and install it.

My primary field is electronics, and we sometimes use something called Positive Feedback, which works in principle much the same way. I well understand the value and uses of positive feedback in certain electronics applications, so I guess the water-based analog works as well. Avoiding the pulsing, or oscillation in electronics depends on precise control of the amount of feedback. I guess the venturi in the jet allows for the plumbing equivalent of fine control of feedback.

Thanks again. I will report back when I have installed the Jet and let you know how it works.

Nathan

[Vey]

"that all it would do is keep the check valve closed, or else cause it to pulse.

I think you are over analyzing this. When I joined the Navy and they sent me to BEE, the plumbing/water pressure/volume analysis eventually failed me and I had to toss it out and just believe.

The normal reason for a check valve on the intake of a pump is to keep water up, so when the pump is turned off, it doesn't lose prime.

Also, please believe pumpman when he says no filter should be on the intake of a pump. You want me to cite countless sources that say they same thing? They tend to be more assertive than he is. They all say "NO FILTERS SHOULD BE ON THE PUMP INTAKE." If you you demand links, I can provide them.

Just follow the directions and you will be okay.

[ngregory94522]

Originally Posted by Vey

"that all it would do is keep the check valve closed, or else cause it to pulse.

I think you are over analyzing this. When I joined the Navy and they sent me to BEE, the plumbing/water pressure/volume analysis eventually failed me and I had to toss it out and just believe.

The normal reason for a check valve on the intake of a pump is to keep water up, so when the pump is turned off, it doesn't lose prime.

Also, please believe pumpman when he says no filter should be on the intake of a pump. You want me to cite countless sources that say they same thing? They tend to be more assertive than he is. They all say "NO FILTERS SHOULD BE ON THE PUMP INTAKE." If you you demand links, I can provide them.

Just follow the directions and you will be okay.

Gotcha. No filters on the intake......

Did you actually read my post?



I am trying to order, locate the Jet. Unfortunately they don't stock it here. When I get one, we shall see how it works...

Much thanks,
Nathan

[h2o4u]

If it was a jacuzzi "C" series, then it was a convertible jet and the jet assy is installed (as previously noted) in the side of the head. Look in the 1 1/4 suction part of the pump and you can see the nozzle. If it had the d/w bypass plug you would see nothing but casting.
Lastly, what is controlling the sub in the well, besides the pressure tank? Seen so many subs destroyed by this kind of system that has no run dry protection. Franklins Pumptec (for franklin motors only) or Centipro's Pumpsaver could save you 1000's of dollars.