Identifying a 110 or 220 Well Pump (What to Know) – WaterFiltersAdvisor

Determining the voltage of your well pump doesn’t take much effort if it’s practically new. What you particularly ought to probe into are the labels and the manual. These come in handy for people who tend to forget purchase details right away. The labels and the manual should be able to tell you all the pertinent details you need to know about your system. Problems arise when it’s already old.

At times, the pump labels aren’t readable anymore. And what if you recently bought a property with an old pump that has been there for ages? 

Here, we will be looking at a number of helpful practical steps to determine the voltage of your well pump. We’ll also look over some relevant matters we need to consider regarding well pumps.

How to Determine the Voltage of a Well Pump?

Determining your well pump’s proper voltage is essential. Running your system on the wrong voltage is not advisable. Your pump would perhaps refuse to operate. Moreover, you can damage it as you let it run on higher amps.

There is a most convenient and accurate way that you can know the voltage. This is possible by plainly utilizing a digital voltmeter. And you can now proceed with these below for a proper voltage reading for your pump.

First, you need to turn the power off to your pump. Next, you should find out if yours has a 2 or 3 wire configuration. Then, if it is a 3 wire configuration, do these further steps:

  • First, access the control box.
  • Second, remove the control box cover.
  • Then, use the digital voltmeter to check the voltage in Lines 1& 2.
  • At times, it does not give a proper voltage reading. In this case, check the pressure switch next.
  • After that, remove the pressure switch cover. Now, check the voltage reading.

240V pumps use pressure switches with 4 terminals. The 2 outer terminals are for the breaker box, while the 2 inner terminals connect to the control box.

Sometimes there is no control box. That means it’s a 2 wire configuration. You can do the following steps:

  • First, remove the pressure switch cover.
  • Next, check the voltage reading.

You should note that the 2 outer terminals are for the breaker box. Furthermore, the 2 inner terminals connect to the pump.

Can a 240v Well Pump Run on 120v?

Yes. A 240V well pump can run on 120V. 

If you run a 240V pump with a 120V current, either one or both of the following scenarios can happen:

  •  The pump can’t build enough pressure. Because the power output is considerably reduced. Moreover, the water supply won’t be as reliable. And it’s because of the weak water pressure.
  • Additionally, the pump can overheat and quickly burn up. Because it will be using double the amount of amperage as it would if it was running on its designated voltage.

Note that any motor, or device you operate should use its specified current voltage. By not doing so, you can substantially diminish its performance. Moreover, this can potentially result in costly damages and repairs.

Knowing If You Systems is a 110 or 220

determine voltage of well pump

Sometimes, the voltage details of your pump are inaccessible. Other times, the information is nowhere visible. Hence, here are a couple of thoughts to consider. These give you some ideas on voltage:

  • First, most old submersible pumps are 220V. This is particularly true for those that people install in deep wells.
  • Jet pumps, on the other hand, can be either 110 or 220.
  • Moreover, shallow well submersible pumps that have low horsepower may well be 120V.

Now, after these considerations, you can also figure out the voltage using a voltmeter. Check either in the control box or in the pressure switch.

Lastly, you may have access to the pump. If so, try to collect or make notations of information you can. You may also know the brand. If so, you can probably ask the manufacturer for details about your pump. Sometimes, the brand or manufacturer’s information is not available. In this case, try comparing all the details you gathered about the pump. Check it against other available pumps in a dealer shop. Also, make inquiries as to whether there’s a similar pump in the store.

110V vs 220V

A lot of people are mistaken regarding 110 vs 220. They think that they save on electricity using 220V. Because it uses half the amperage compared to 110V. However, they don’t understand one detail. A lower amperage in the 220V is possible because it basically uses twice the voltage. This means that both literally use the same amount of wattage. And wattage, of course, is what power companies charge to their consumers.

The difference between your 110V and your 220V is not on power consumption. This is because they both draw the same amount of power. That’s why it depends mainly on what they are used for.

In some cases, you’re drawing from a shallow well. This only requires less than a 100-foot wire to run. But getting a dual voltage well pump that can run on either 110V or 220V would be your best option. This is in case you eventually require more than a 100-foot wire to run your pump. When you switch it to 220V, you can go up to 400 feet with the wire connection.

In other cases, you’re drawing from a much deeper well. In this situation, you will need to use a larger pump. Large pumps use 220V. Because they require more voltage to start. And using a larger 220V well pump for a deep well will cost you a lot less eventually. The case is the same for situations that you have a much longer wire requirement. This is because the higher voltage allows the pump to run more smoothly. This is true even with heavier loads. It can last you longer than a 110V pump would.   

220V With a 110 Generator

As we mentioned earlier, it’s always advisable to run any motor or device on its designated voltage. You may think of running a 220V with a 110V generator. But the pressure will be substantially weaker. Not only that, it can overheat and burn up your pump motor as well. And not to mention the damage it might do to your generator too.

In unfortunate cases, you have zero recourse. You need to use a 110 generator for your 220V pump. Well, here are a few things you can do:

  • First, check to see if your system is dual voltage.
  • If it is, you can rewire it to 110. Do this through the touch of a switch. You can also adjust a wire and a screw inside the motor.
  •  If it is not, better get yourself a 110V to 240V step-up product transformer.


Knowing the differences between a 110 or 220 V can be very helpful. This is particularly useful if you end up owning an old, but excellent-conditioned, well pump. But there’s no information left on it. And knowing enough about using a 110V and a 220V pump might just save you. It spares you from the trouble of experimenting. And you won’t have to shoulder costly repairs.