4 INCH SUBMERSIBLE PUMP FAQS
 

4 Inch Submersibles FAQs

 

4 inch Submersibles FAQs (Frequently Asked Questions)

View All Flotec 4" Submerisble Pumps

Q. How do I know what horsepower pump to buy?
A. There are two things to consider in choosing the horsepower: 1) What is your depth-to-water? And 2) How much water do you need in your household? Every pump is designed to work in a specific range of depth-to-water. You need to choose a pump that is designed to work at your particular depth-to-water. Too high a horsepower pump could cavitate or at minimum will draw too much power and run hot. Its life will be shortened in either case. If too low a horsepower pump is chosen, it simply might not get the water to the surface properly. The other consideration in horsepower is that higher horsepower pumps will move more water. The GPM flow rate will be greater. If you have a household with more people and more water-using facilities you need a higher horsepower pump so that you can get more water into the house. Remember – the more water your pump puts out, the bigger your pressure tank should be in order to prevent frequent cycling of the pump.

Q. Which is better, 2-wire or 3-wire?
A. A lot of this choice comes down to personal preference. The only difference between 2-wore and 3-wire pumps is where the motor starting components are located. In a 2-wire pump, all the motor starting components are located in the motor, down in the well. In a 3-wire pump, the motor’s starting components are in a “control box” that is located above ground in your well house or basement. The one possible advantage of a 3-wire system is that if anything ever needs to be tested because of a problem, it is easier to test (and replace, if needed) the starting components that are above ground in the control box.

Q. What is the actual diameter of a 4-inch well pump? Will it fit inside my 4” diameter well casing?
A. The 4” submersible well pumps have a diameter of about 3.875” (3- 7/8”). They really should NOT be put into a 4” diameter well casing. If the casing has any rust or bumps on the inside, or if it bends slightly, it would be possible for the pump to get stuck. Also, there simply isn’t enough room around the pump for the water to flow properly into the intake of the pump. This can cause the pump to perform badly and for the motor to overheat.

Q. What size well casing IS recommended for a 4” submersible?
A. For residential pumps, 4” submersibles should be used in 5” or 6” well casings. If your well casing is larger in diameter than 6”, then you should sleeve the pump so that it gets proper cooling.

Q. I only have a 4” diameter well casing. Is there any option for a submersible well pump in this well?
A. You can install a 3” submersible well pump in a well with a 4” casing.

Q. What does it mean to “sleeve” a submersible well pump?
A. To sleeve a pump, you put the pump into a piece of 6” diameter PVC pipe that is a little longer than the length of the pump. You put a 6” well seal on the top of the PVC pipe. In doing this, you are forcing the water to enter around the pump from the bottom. This forces the water to go up past the motor which cools the motor.

Q. Can I put a 4” submersible into a cistern to pump water from it?
A. You can, but you must sleeve the pump (see document “Sizing a Submersible Sleeve”)

Q. Can I put a 4” submersible into a lake to pump water out of it for my cabin or irrigation?
A. We recommend that a 4” submersible never be put into water where people or pets will swim. You are putting an electrical item into water. If a splice were to become exposed, or the electrical integrity of the motor were to fail, the water around the pump could be dangerously “charged” with electricity. It would be possible for someone to be injured or killed.

Q. I’m putting in one of your 3-wire pumps to replace my old one. Do I have to use a new control box?
A. The control box is matched to a specific motor. In most cases, you will need to put in the new control box to match the new motor.

Q. Do I need to put a check valve in the pipe down to my pump?
A. Our pumps are equipped with a check valve in the discharge of the pump. It is not a bad idea to add an additional check valve for every 100’ or so of drop pipe you use. This can help to break up the water column so that one check valve does not have to hold all the weight of the water.

Q. I have a low-producing well. How do I make sure that the pump won’t out-pump the well?
A. There are a couple different methods you can use to control the amount of water your pump will put out. If you know the rate at which water comes into your well (the recovery rate) then you can put a “dole valve” into the drop pipe. This will limit the amount of water that the pump is able to push out. Choose a dole valve that is the same as the recovery rate of the well and the water level in the well case won’t drop. The other method is to put a “pump protector” on the pump. These are usually designed to work with 3-wire pumps. They go into the wiring and sense the power draw of the pump. If the power draw indicates that the pump is not moving water, it will shut off the power to the pump in order to protect it.

Q. The pump I bought says it was in the “10 gallon-per-minute series” but it doesn’t seem to be doing that amount. Why?
A. The pumps that are in the “10 gallon-per-minute series” are designed to flow about 10 GPM in the middle of their performance curve. It is close to the highest efficiency operating point for that pump. If the depth-to-water in your well is not quite as deep, the pump is going to flow more than 10 GPM. If the depth-to-water is a little deeper, then the pump is not going to put out quite as much. As long as the actual performance of your pump is within the range we state for it, the pump is OK to run in your setup.

Q. I want to replace my pump myself. What kind of special tools are required?
A. Working with submersible well pumps is pretty much basic plumbing. The toughest part of replacing a submersible well pump is the actual lifting of the pump and pipe out of, and then back into, the well. A 4” submersible well pump is going to weigh as much as 35 lbs or so. Add to that the weight of the pipe, wire, etc. and it could easily be more than a person can lift. It is recommended that you have some kind of lifting equipment if you want to try to do this yourself.

Q. I’m putting in a new pump. Besides the pump, what other items do I need to have?
A. To work with the well itself (not the in-house items like tank, etc.) you will need the pipe and pipe fittings (enough to go down as far as you have figured out to be necessary), the wire (enough to go down to the pump and into the control box or pressure switch), some centering guides, a torque arrestor, and at least one check valve. If using PVC pipe you will need cleaner and glue for the connections. You may need to have. if the well driller did not install it for you, a pitless adapter to go into the well casing. Naturally, you will need an assortment of hand an power tools (hacksaw, pipe wrenches, electrical tools, etc.) You will also need lifting equipment to support the weight of the pump, pipe, etc. as you guide it into the well.

Q. How far down do I put the pump in the well?
A. The pump needs to be set at a depth that is a minimum of 5’ off the bottom of the well. If your well has a sandy bottom, in order to prevent the pump from picking up sand, it should be set more like 15’ to 20’ off the bottom.

Q. What kind of pipe do I use for a drop pipe to support the pump?
A. You can use 100 psi-rated polyethylene plastic pipe (poly pipe) for setting depths down to 100’. Use 160 psi rated poly polyethylene plastic pipe )poly pipe) for setting depths down to 220’. Use galvanized steel pipe for setting depths deeper than 220’. Schedule 80 PVC pipe can be used with threaded couplings at depths down to 500’. Use metal threaded couplings for setting depths below 300’. We recommend you never use regular Schedule 40 PVC

Q. How important is it to use a safety rope or cable?
A. We strongly recommend it. If one of the fittings in the drop pipe fails, or even if an installer gets slippery fingers, the safety rope or cable will be the only way to retrieve the pump from the bottom of the well. We recommend a good stainless steel cable rather than rope. Rope (even nylon rope) can degrade over time in the damp environment of a well.

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