Sudden Low Pressure from Submersible Pump

[Liam DuBoise]

Describe the well casing. Diameter? Depth if you know?

Look down the hole. In the day, direct the sun's light down the well with a mirror. At night, shine a bright light down. Do you see a restriction of some sort? It might be that could be cleaned off.

You should not put a full size 3.9 inch "4 inch" pump down steel casing. There are slimline/trimline 4 inch pumps that are a tad smaller. I have a trimline pump down my 4 inch steel casing. I think I would go to a 3-inch (SQ) pump if I get my pump replaced.

Depending on the restriction, a 3 inch pump may be worth considering despite having bought a new 4 inch pump.

The casing is 4" steel, with some surface corrosion inside and outside. Depth to the water is about 35'. Depth to the bottom is 65'. The old pump was set at 63'. I'm in Florida, so no pitless adapter. There is a dark patch on the inside of the casing at about the depth where it snagged, but I don't really see anything else. When I pulled the old pump out it snagged slightly at about the same spot.

 

[Reach4]

The casing is 4" steel, with some surface corrosion inside and outside. Depth to the water is about 35'. Depth to the bottom is 65'. The old pump was set at 63'. I'm in Florida, so no pitless adapter. There is a dark patch on the inside of the casing at about the depth where it snagged, but I don't really see anything else. When I pulled the old pump out it snagged slightly at about the same spot.

I am not a pro. Perhaps you could fabricate a scraper to knock the rust, or whatever off of that spot. It would be a shame if your tool got stuck there, however.

I am thinking of a disk of material strong enough to do some mechanical action, but weak enough to bend if the force became strong.

 

[Sponsor]

 

[Liam DuBoise]

Well I am now paranoid at the idea of having a stuck pump - that would be an incredible disaster. Are there any downsides to a smaller diameter pump?

 

[Reach4]

Well I am now paranoid at the idea of having a stuck pump - that would be an incredible disaster. Are there any downsides to a smaller diameter pump?

I was concerned that they run at a high (>10000) RPM, but people have reported good experience with the Grundfos SQ pumps.

There are different choices appropriate for different head and gpm, as there are with other pumps.

10SQ07-200 looks good to me for your use, but do your own study.

 

[LLigetfa]

You could try mechanical means to scrape it off the buildup.

 

[Valveman]

When 4" steel casing rust up like that it can make a really tight fit for a 3.75" pump. An SQ pump is less likely to get stuck. However. if the casing is rusted up top it will probably be rusted at the screen or perf. It will usually get to the point where water cannot get into the casing. A 65' well shouldn't be that expensive to replace and use 5" PVC casing next time.

 

[Fitter30]

Since you don't know how deep the well is might consider getting well pump service company to look at it. My pump is 290' down and 3/4" galvanized pipe. You are lifting all the pipe, wiring and the pump. Pipe is in 21' lengths and have to uncouple every length while holding everything. My pump guy with his special truck diagnosed, pulled all the pipe, replaced the pump, 6 lengths of pipe and control box in 6 hours. Pump was 18 years old and still ran fine. Wasn't going to have it pulled without replacing it just because of age. Your well head is so rusty those 4 bolts will probably snap off. Start soaking them with penetrating oil.

 

[LLigetfa]

Since you don't know how deep the well is...

Either you didn't read the whole thread or you are posting to the wrong thread. OP knows the depth and has already pulled the pump.

 

[Liam DuBoise]

I was worried that even if I got the 4" pump down the well, some rust would eventually chip off the casing above the pump and make it impossible to get the pump back out if I needed to. So, I went with the posted advice and ordered a 3" pump. It arrived yesterday, and today it went down that casing nice and easy. I used the 200# blue PE drop pipe, and that also went down easy. Took some practice to get the heating right to get those extra long brass barbs on, but I'm happy with the result, and I'm pretty sure that PE pipe is never coming off of those barbs. So it's a 3" 1 HP pump, a 1-1/4" brass nipple, a 1-1/4" brass check valve, extra long brass barb, @ 62' of 200# blue PE drop pipe. I went with the ABS sanitary seal, because I hated life while trying to get that 23-year old rusty split seal off.

Also, I went with a replacement bladder in the 85-gallon pressure tank, because the tank looked to be in great shape inside and out. I just rolled the new bladder as tight as possible (great forearm workout), and it slipped right in the tank. The bladder was about half the price of a whole new unit. It's held 38# of air for a full week, so I think that's going to work.

I got everything put together and wired up today in about 6 hours. Water is now running to the house successfully with 55 psi. I ran out of sunlight and the Florida mosquitoes came out, so I'll have to make all adjustments and check for leaks tomorrow... and I'll put some pics up.

Couldn't have done it without y'all! You have no idea the level of my gratitude!

 

[Valveman]

Good job! You have a good system now except for the pressure tank. Any tank with a replaceable bladder is not good. They are replaceable for a reason as they need replacing often. Get a good diaphragm style tank that doesn't have a replaceable bladder and you will be much better off. You would also have much better pressure in the house and the pump would last longer if you added a Cycle Stop Valve. And with a CSV you would only need a 4.5 gallon size tank.

 

[LLigetfa]

Get a good diaphragm style tank that doesn't have a replaceable bladder and you will be much better off.

I agree. Replaceable bladders are a poor design. They collapse under normal use in a way that creates creases that repeated over time, stresses it to the point of failure. A diaphragm on the other hand can be made thicker as it has a smooth rolling action with no sharp creasing.