I have a 2 hp submersible pump that draws about 10 amps when running. Last month my water bill for electricity was for 410 kwh Pump voltage is 230 VAC

How can I figure out approx how many hours the pump has actually run?

I suspect a leak somewhere possibly if it is running all the time especially if it is running at night when sprinklers are on.

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Originally Posted by Bowler

I have a 2 hp submersible pump that draws about 10 amps when running. Last month my water bill for electricity was for 410 kwh Pump voltage is 230 VAC

How can I figure out approx how many hours the pump has actually run?

I suspect a leak somewhere possibly if it is running all the time especially if it is running at night when sprinklers are on.

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Greetings,

As your question is written, it is impossible to answer. To the best of my knowledge, PoCos do not isolate the electricity used by a location.

PoCos stop at the meter which measures the total load consumed by the location. The only way to get such a statement would be to have a separate meter for the water circuit, also not done, at least as far as I know.

How did you arrive at the 410kWH? Also, what is the billing rate, per kWH for your account? What is on the electrical circuit, besides the pump, such as a water purifier, hot water heater, pressure pump?

We honestly need more information.

Depending on how much time and money you want to put into getting the info your seeking, you can get an 230 volt rated hour meter and connect to the circuit to measure and record the hours of operation of this motor.

Hour Meter, LCD, 80-265 VAC - Hour Meters - Counters and Hour Meters - 16T958 : Grainger Industrial Supply

Not sure what that will help with.

If you measure the hours of operation AND the wattage while in operation, then you can determine the actual kilo-watthours.

What exactly are you trying to accomplish?

We suspect a leak underground because of the excessive cost of the 410kwh used by this pump only which is the only thing on that meter. My hunch is that it will be around 165 hours of running by itself which is a huge amount for a well pump for 30 days. I am not sure of my calculations though. Using the 410 kwh and the 230 volts and 10 amps, there has to be a way to find out approx how many hours of run time on the pump motor. A 2 HP pump is rated at 2500 watts or
2.3 kwh If the pump has used 410 kwh, and I divide the 410 by 2.3 and I come up with 178 hours. I know there is some other factors to figure in such as power factor but I was just looking for an approx number of hours the pump actually ran.

It would be simple to just check and see if the pump runs a lot, but most of the sprinkler lines run at night and during the day all of the sprinkler valves are off and pressure gauge doesn't bleed off.

Trying to calculate the actual wattage of an AC motor is complicated, due to the losses of a motor, efficiency rating, power factor, and starting currents, etc.

Keep in mind, the motor nameplate may list 230 volts, but your supply voltage, if located in the USA usually is 240 volts.

The AC motor formula:

I = HP x 746
E X Eff x PF

Or, a simpler calculation:

Watts = I x E x pf

Assuming 10 amps x 230 volt and .95 pF = 2185 watts

For your purpose let's round off to 2200 watts. Close to your calculation.

This is the running load, starting currents will be much higher, but for much shorter times, but still add the to total wattage the meter records.

Since: P(W)=1000 × E(kWh) / t(hr), then 410 kWh / 2200 watts = 186 hours, seems your calculation is about as close as possible.

Since your attempting to know exactly the hours the motor runs, an hour meter is the most accurate method.

Once you know or assume running hours, how does that help you? Since this pump is for a sprinkler system, how can running hours help learn if there is a leak?

If each sprinkler head was able to be closed, then , if the pump continued to run, that would indicate a leak.

What controls this pump? A timer? I am not sure we can help you with determining a leak using electrical calculations, seems there would be a mechanical issue. Need to know more about what this pumps serves and how is it controlled.

The calculations you came up with confirm my calculations. I just couldn't believe that many hours of actual run time on the pump. I know there are other factors such as power factor, start up current etc. that affect the calculations but an approx value is what I was looking for. The last billing was for only 18 kwh and then this big jump. Even far more than last years billing for the same month. How does this help me? Sprinklers are controlled by a RainBird controller. The pump running all the time or more than normal tells me that there is a leak somewhere for this to happen. I can't seem to see any water running or wet ground. Pump shouldn't be running that much. Yes, there is a large bladder tank to help keep the pump from starting excessively. I thank you for your answers.

Suggestion.

Start by observing what the maximum pressure reading is.
Remove pressure switch cover and see if the switch points are closed. If points are closed and pressure gage is at the maximum that you have observed, you have a leak in the well pipe and the pump cannot provide enough pressure to open the pressure switch and the pump is running continiously.

If pressure switch points are open, turn off breaker and close the main valve between the tank and the well. Observe pressure gauge for a period. Do not use any water anywhere. If pressure drops you have a leak in the house side piping. If pressure does not drop, open main valve on piping from well. If pressure drops you have leak in piping from well, or in well piping itself or a leaking foot or check valve. If leak is in piping between well head and house you should see visible signs. Given your estimated hours that the pump is running and a 5 gallon per minute rate for the well/pump, you should be pumping about 50,000 gallons per month. A leak of that size in the piping between the well and the house should have visible signs. Same is true if you have a leak in the sprinkler piping.

If you have a leak in the foot valve, each time the pump shuts off water in the tank will flow back down the piping to the well. That would be indicated by a drop in pressure when no water is being used. Closing the main valve between the tank and the well would stop that drop in pressure. Remedy for that is to install a check valve in the well pipe at the tank.
If the pump will not produce enough pressure to open the points of the switch you will have to pull the pump and repair the well pipe or replace the pump.

Most likely the problem is a substantial leak in the pipe going down the well, but the pump could be worn to the point where it can not longer provide the necessary pressure.