Low Pressure / Pump turns off after a few minutes

[ehurst]

I have scoured the internet looking for clues on my problem. A few I tried, but nothing has resolved it.

Here is my issue:
I discovered my pump/motor has not been running for a couple days and the house breaker was tripped. I reset the breaker and turned the pump on. It sounded "strained" once water was sucked into the pump. It actually slowed the motor. The motor is just over a year old and is a Marathon Electric C1306, single speed, 1HP, 115/230 Volts.

Here is what I have done so far:
1. Made sure all filter baskets were clean.
2. Made sure impeller was clean.
3. Replaced the capacitor on the motor (assuming is was the start capacitor since it is the only one and had a low farad rating)
4. Replaced the shaft seal ensuring it was installed correctly.
5. Replaced the house breaker to be safe (old house so it needed to done anyways).
6. Verified the voltage going into the motor (115 volts), it also checked it at the timer box.

As for right now it primes just fine and water flows and the motor seems to run good, but once all air is out the motor sounds like it kicks/slows down and after a few minutes it shuts off. Assuming the motor internal circuit breaker trips because the house breaker no longer trips. When it does run I am getting between 5-7 psi. There is only air after I open the the pump basket lid, there is no air in the system otherwise and the motor runs slow.

Here are my questions:
1. The motor has 3 leads; 1 ground and 2 power, what should the voltage be for each power lead? How do I truly test it?
2. The impeller and diffuser both look okay, they are older but don't look damaged. Could they still be the issue?
3. The motor does not make noise that bearings going out, but could it be bearing related?
4. Is the motor bad?
5. Could the timer be bad?


Since the motor seems to run good until under a load, I am confused. I am tying to narrow it down to see I need to call a pool company, and electrician, or if this is something I could handle. I thought about replacing the pump, but don't want to waste my money right now if it is the motor.

 

[Melt In The Sun]

Welcome to TFP!
I am not an expert on these things, but I do know that if you take of the back cover and expose the back end of the shaft, it should turn very easily. I'm gonna guess it won't.

 

[Bama Rambler]

Is the breaker single pole or double pole?
If it's a double pole breaker then you should have about 120 volts between each leg and ground.

 

[ehurst]

Thanks for the quick response Melt in the Sun! The shaft turns without any difficulty, but I also never noticed how good it turned when everything was functional. It doesn't take much effort to turn it though, even with the impeller connected. However, I only tried it when it was disconnected from the pump basket. I will try to turn it once I get home since everything is still hooked up.

 

[ehurst]

Is the breaker single pole or double pole?
If it's a double pole breaker then you should have about 120 volts between each leg and ground.

It is double pole. I will test each leg again, but I could swear it said 115 volts (with the pump running). I actually misspoke on my original post, at the timer box I was getting 120 volts.

I was thinking about replacing the wiring to the motor to be safe as well since it is older. So maybe if I did that I would get 120 volts at each leg.

 

[Bama Rambler]

Actually 115 volts is fine. If you get 115 or so on each leg, you're fine.

 

[ehurst]

Actually 115 volts is fine. If you get 115 or so on each leg, you're fine.

Thanks Bama Rambler! I will test it to verify. If I can rule out electrical, that is one more thing to mark off as the cause.

 

[jerryt]

Put an ampmeter on one of the two power wires. If the amp draw is over the specs on the motor data plate. I would suspect a shorted motor armature.

Motor most likely has a thermo breaker, you might measure the temperature of the motor housing when it kicks out. The thermo breaker could be bad, and kicking out early. But from your description it sounds like a blockage or bad armature.

Make sure there are not any blockages in the plumbing.

Is it 230 or 115?

 

[ehurst]

Is it 230 or 115?

115. I was thinking something with the motor breaker initially, but since I can actually hear it slow down, I strayed away from that idea. I will test the amperage and see where it is at. As for blockage, I could not find any. I also used a drain king from the skimmer basket and water flowed freely into the pump basked. Thanks for the info!

 

[ehurst]

So I ran home at lunch to run a few tests.

The shaft turns freely.
Test voltage on each leg when motor was running. Leg 1 - 115 volts, Leg 2 - 1 volt (yes, one volt)

I am wondering if I should have test the wires to the pump with them disconnected from it. If there was an issue with the motor, could that through the reading off? If not, I am thinking there is a bad wire.

I tested the connections at the timer as well and the picture is labeled.

I know I need to look at replacing all the wires since I am sure they are old and doesn't help my cause.

 

[jerryt]

If it is truly a 115 volt wired pump, you will measure 115 volts between 1 and 3 (always), and 2 and 4 (with motor running)
In this case 1 and 2 will measure very low voltage to ground (green wire).


Is the circuit breaker in the house narrow or wide (Single or dual pole)?
Single narrow is 115 volt, wide dual pole is 230 volt.

Dual pole breaker;
You will have a 230 volt wired pump, you will measure 230 volts between 1 and 3 (always), and 2 and 4 (with motor running)
In this case 1 and 2 will measure 115 volts to ground (green wire).

 

[Bama Rambler]

Since you've already established that the breaker is a double pole breaker you should be getting 230 volts between the two legs at the pump. Since you're not, there's a bad connection somewhere. If you check the voltage at the breaker do you get about 230 volts?

 

[ehurst]

Here is what I found so far. I do have a double pole breaker. Each pole gets 115 volts and together I get 230 volts, so the breaker does not seem to be the issue. However, the wire labeled "a" from my picture seems to have a problem between breaker and the timer. I do not get 115 volts on that wire at all. I get just under a volt. I know it has a little juice because I can hear the timer ticking when the wire is connected and it stops ticking when I disconnect it. When I had the wire disconnected, I tested voltage from the wire to ground and barely got anything.

I guess that means I need to replace the wire and I will replace all the wires when I do it. Its a good 75-100 feet from the breaker box to the timer, so I am not sure how easy it will be to pull new wire. Sounds like a chore.

With that said, to at least get the water flowing, is there a way I can rewire the timer to use 115 volts instead of 230 volts? Or possibly wire the motor so I can plug it into an outlet.

I was hoping I could do that to limp a long until I get new wires pulled.

 

[Bama Rambler]

First let's make sure we're dealing with 230 volts. Is the timer running and keeping correct time?
Are there any markings on the timer that states the voltage of the clock motor?

You can rewire the pump motor for 115 volts but you'll need a pretty large cord to run it.

Can you post a picture of the way the motor is wired and the wiring diagram on the data plate?

 

[ehurst]

There is no label on the timer. I doesn't appear to be keeping the correct time but I do her it ticking when wire "a" is connected. The motor also does not work unless wire "a" is connected, I assume it is needed to complete the circut. I am not sure why wire "a" does not have any voltage since I do have a double pole breaker to the motor. Wires "a" and "c" are coming from the breaker.
The pictures below are from my motor. I do not have a picture of the wires on the back of the motor, so I will have to look and see which wires (b and d) are connected to the motor (L1 and L2) and post a picture.

Just to reiterate the voltage readings from the timer using my previous picture
1 - 3 = 120 volts
2 - 4 = 120 volts
1 - ground = 0-1 volt (I even tested the wire when disconnected from the timer)
2 - ground = 120 volts (timer on)
3 - ground = 120 volts (constant)
4 - ground = 120 volts (timer on)

Reading from the motor are:
L1 - ground = 115 volts
L2 - ground = 0-1 volt
L1 - L2 = 115 volts

 

[Bama Rambler]

When you open up the motor, see if the voltage selector is set for hi or low voltage.

 

[ehurst]

When you open up the motor, see if the voltage selector is set for hi or low voltage.

I know for a fact it is set for HI. I looked at that last night.

 

[jerryt]

I would say, "Time to call an electrician".

Wire to L2 would not normally be found completing the circuit, but missing voltage. (Neutral wire)

 

[Bama Rambler]

Sorry for all the questions, I just wanted to make absolutely sure about the voltage. It does sound like you have a wiring problem.

That motor draws over 18 amps on 115 volts so it would take a huge cord to run it. You'd probably be better off using a sump pump to circulate the water until you can get the wiring fixed.

 

[ehurst]

I would say, "Time to call an electrician".

Wire to L2 would not normally be found completing the circuit, but missing voltage. (Neutral wire)

Thanks for the info. I will be calling one soon. However, since the motor was running 230 volts, there should not be a neutral wire. My understanding is the wire to L2 should actually be 115 volts like L1.