I installed a new pool pump motor. It runs for a while, sometimes longer, then the breaker pops. The only thing
I have done different snce replacing the motor is that I installed a tankless water heater and had to get a bigger breaker because it rund 240amps. The tankless heater only runs when water is running. In the past hour the pool breaker has been reset 3 tims and I don't get it!:mad:

Need to know:

Size of pump watts or amps
Size or water heater watts or amps
Voltage rating of both
Are both on same circuit?
What size breaker?
2 pole 240 volt breaker?

When you changed the breaker, what's size is the original and what size new?

Did you change any wiring when you changed the breaker? What size wire?

Without most of the info above, it can be anyone's guess what the problem is.

Your pump motor and your water heater can not run at the same time on the same breaker without upgrading the load requirements. If you answer the questions that TK asked then we could give you information on your situation

The pool pump is a 1hp. On the motor there is only low voltage or high voltage. It is set to low voltage. The pump runs 110 not 240 and the breakers is 2 20 amp poles. I believe it only needs 32 amps to start then runs on 16 or 18. I verified the wiring on the pool motor and all wires are inplace and secured. I think the breaker may be bad. I shut the water heater breaker off and it still tripped the pool breaker.

Well I tried, at least got one piece of valid information, you have 1 HP motor running at 120 volts, but on 2 pole breaker?


A 120 volt motor does not need a 2 pole breaker, so not sure why you have :


The pump runs 110 not 240 and the breakers is 2 20 amp poles.

This motor needs #10 wire and a 30 amp breaker, and will need to run alone on the circuit. A 20 amp circuit is not large enough even for the motor, let alone the water heater.

If you changed the motor, sounds like you went to a larger motor than original, and did not size the circuit properly, tried to use the existing circuit, which is too small.

Just to piggy back on TK's response:

This statement:“The pump runs 110 not 240 and the breakers is 2 20 amp poles.” suggests to me that you have line supply of 240 VAC being supplied to your pump. This is a standard configuration for 240 VAC breaker. By the way, most motors will run more efficiently when using the 240 VAC setting.

A simple verification test can be made at the pump motor. If you have a Multi Meter, set the AC voltage setting on the meter to a voltage higher then 240 VAC. Place the black meter probe on the Black wire. Then place the red probe on the red lead if there is one or the second black wire on the pump. Please tell us what the voltage reading is.

A picture of the pump wiring would really help us.

This statement: “I think the breaker may be bad. I shut the water heater breaker off and it still tripped the pool breaker. Suggests to me that you do have two independent circuits one for the pool pump and one for the water heater just as it should be.

P.S. I was just looking at the math behind your motor and I know I'm missing power factor information but the required horsepower doesn't sound correct.

A unit of horsepower = 746 Watts. So, to find the amperage needed that raw calc. I used was 746/120 and I came up with 6.2 amps (+/-). At 240 VAC it would yield 746/24 = 3.1 (+/-) amps.
I'm no where near your posted amperages of 16 to 18 amps running. What did I do incorrectly?

OK, you guys are great and I appreciate your patience with me. Here are the specs on the pump:
It is a Marathon pump Model 5KC38SN6084AX
HP 1
HZ 60
PH 1
Code M
SF 1.25
FR 56Z
V 115/230 (its amazing what is acyually on the label!)
RPM 3450
A
SFA 14.0 / 7.0
AMB 50 C
Suitable for field wiring
1080 Pool Pump Motor
CAT NO C1245

Looking at my breaker box I have 2- 20 amp breakers that go at the same time when it trips.
Looking back at my paper work from my warranty work, I bought the motor, installed it (awaiting reimbursement if warranty was approved on old pump. The pump work fine. But had a seal leak and I had to take it back so the seal was installed and I took it hom and connectid it the same way it was before. Now the breakers trip. That's all I got. The tester I have just tells me if the line is hot or not. Hope this is helpful and accurate

Don,


A unit of horsepower = 746 Watts. So, to find the amperage needed that raw calc. I used was 746/120 and I came up with 6.2 amps (+/-). At 240 VAC it would yield 746/24 = 3.1 (+/-) amps.
I'm no where near your posted amperages of 16 to 18 amps running. What did I do incorrectly?

Using the 746 watts for a motor is not how to arrive at the amp load, due to losses and many other factors that affect motor amps draw.

A watt is not AC power, Volt-amps. The 746 watts per HP does not work in electrical calculations.

As you can see from the nameplate data that wolfe98pr provided,the full running load amps at 115 volts is 14 amps.

AC single phase motors must use Table 430.148 to size branch circuit conductors, controllers, disconnects, short circuit protection devices (Fuses and circuit breakers). Table 430.148 lists a 1 HP motor at 16 amps for 115 volts and 8 amps at 230 volts, and these values are to be used when the supply voltage is 120/240 volts.

Wolfe98pr, you did state that the motor is supplied by 120 volts, but a 2 pole breaker. And you cannot confirm the voltage using a meter as you are using a proximity tester that only detects voltage and does not give a true reading.

This needs to get cleared up, is the motor getting 120 or 240 volts. Using a 2 pole breaker tells me the motor is being supplied by 240 volts.

So which is it.

I sure hope the connections and any jumpers in the motor connection compartment are clean, tight and properly connected for the supply voltage.

I get you changed motor for motor same size, so that is not an issue I speculated on.

If there was a 2 pole 20 amp breaker for the same size motor, this tells me the original motor was powered by and sized for with a 20 amp 240 volt circuit.

You need to confirm the motor is connected properly for the supply voltage. And be sure any jumpers are connected properly.

All I can offer as a reason for the breaker tripping is:

Bad breaker
Bad new motor
Motor not connected properly at motor.
Poor or loose connections in the motor and/or breaker.

Not much else I can help with. I don't get that your very knowledgeable working with wiring motors, etc. I don't mean any offense, just stating a fact. You may need to call in a professional to troubleshoot this problem.

TK, Thanks for the clarification on the math. Did you arrive at the amperage for the information given on the plate or the NEC table, just curious.

As to the circuit in general, since the old pump was replaced because of a mechanical failure, not electrical. It seems to me to be safe to say that the original circuit is correct.

This suggests to me, anyway, that the failure is at the new pump. Either the wiring or motor contacts are incorrect.