Overheating 1hp Goulds Pumps

[Edrrt]

In the summer the ambient temp gets over 100F. When it is hot our 20gpm Goulds Booster overheats when it is asked to run for several hours continously. The pump is new. Pump is asked to make 60 psi from.a 10k gallon tank... moving the volume if the tank in a day sometimes for itrigation and wildfire suppression.

I will check for voltage drop today. Pump installer reccomended installing 2 pumps with a load alternating switch so when one shuts off the other will turn on and Pump allowing the other to cool. Basicly splitting the work between 2 1hp pumps.

Is this the best solution?

Would a much higher horsepower rating on the pump be a better choice? Or do they make pumps with more efficient cooling systems that are designed to run in hot weather?

I'm not sure why the installer insists on booster pumps for this application as they only need to make 60 PSI. I'm wondering if 1hp myers jet pumps would be just as effective since they are 1/4 the price.

20gpm goulds booster is around $1300
27.5 gpm myers jet pump is $375.

I'm not opposed to installing a large commercial pump if that solves the problem.

Would a large certerfugal type pump be better as the move much more water? The pump is lower than the supply tanks so no suction head is needed.

Thoughts?

 

[Reach4]

A submersible pump will be much more efficient and less problem than a jet pump. If the pump fails, you replace it. No cooling problems, since the water flows by the motor.

10000 gallons per day is 6.94 per minute. A 10 gpm 1/2 HP pump might provide all you need. That is a very common size. It would provide a lot more pressure than 60 if you want.

A 16 gpm 3/4 hp pump or 25 gpm 1 hp pump could give you higher volumes if you needed.

 

[Sponsor]

 

[Sylvan]

I like lead and lag pumping systems

If one fails you have redundancy


Same reason why I have two cars

 

[Valveman]

Booster pumps and jet pumps use the same motors. These motors have a fan and are air cooled. Make sure to have plenty of ventilation so the motor can get air. Cover the pump/motor to protect it from sunlight. Reducing the flow rate may reduce the amp draw as well. If that is not enough an additional cooling fan (box fan?) can be used to increase air flow. Other than that a submersible is only affected by the temp of the water, not the air.

Having two pumps is handy. But you shouldn't need to use a second pump to let the first rest. Pumps are made for "continuous duty". If it can't run 24/7/365 you need to fix the problem instead of adding another pump.

 

[Edrrt]

I feel like there has to be something wrong. I checked the wiring and it is wired appropriately for 230 volts.

I checked the voltage at the pump and the pump switch and it goes from 244 volts down to 236 volts during operation. That seems within specification. The wires do not get hot.

However the pump motor itself is so hot you can't even put your hand on it without being burned. I had just watered the lawn and so it had been cycling on for 1 minute, off for 3 minutes for an hour... and the Ambient Air Temperature was 66 degrees.

There's no way that it should be that hot from that. Something has to be wrong.

I have a 1hp Myers jet pump that just ran continuously for 1 hour and it is barely warm.

I can turn the motor windings by hand with the end cap off freely so I don't think it's a bearing. It sounds fine.

What else should I check?

 

[LLigetfa]

it had been cycling on for 1 minute, off for 3 minutes for an hour...

The cycling is what generates the heat as it invokes the start windings. Either match the sprinklers to the pump output so it doesn't cycle, or use a CSV.

 

[Edrrt]

The cycling is what generates the heat as it invokes the start windings. Either match the sprinklers to the pump output so it doesn't cycle, or use a CSV.

Is that right...

Well then that could be an issue. It clicks on and off a lot. The myers just runs an hour straight. Could that be it? The starting and stopping? I still feel like it shouldn't get that hot for the simple load its under.

I will try exceeding the pump rate on it so it can't charge the pressure tank and check if it heats up.

And benefit to measuring the amp draw?

 

[Valveman]

Yes measure the amps! Amps are what makes the heat. Running more water to keep the pump from cycling will make it draw max amps and produce max heat. But it is still better than letting the pump cycle on/off like that, and may help keep from tripping the overload. When the motor stops the fan also stops, and the motor still has all that heat from the 1 minute of running that it cannot dissipate away.

Jet pump amps do not drop much, but restricting the flow from the pump as when using a CSV will reduce the amps draw and make the pump/motor run cooler. The CSV will keep the pump from cycling even while using less water, which will reduce the amps and the heat.

 

[Fitter30]

Without a amp reading you have no idea what the load is. What overload is tripping a internal, breaker or motor starter.

 

[Reach4]

I agree. Measure the current!

There's no way that it should be that hot from that. Something has to be wrong.

What is the current in the motor? With a clamp-around ammeter, measure the current through ONE of the hot wires maybe 5 or 10 seconds after the pump starts.

Those meters are pretty cheap these days compared to the old days.
https://www.homedepot.com/b/Electri...Zchjc/Ntk-EnrichedProductInfo/Ntt-clamp+meter

Klein CL600 looks like a good choice currently -- no pun intended.

 

[Edrrt]

Without a amp reading you have no idea what the load is. What overload is tripping a internal, breaker or motor starter.

It trips the thermal sensor inside the pump until it cools.

Household use represents 1% of the water used by this pump. The rest is irrigation of 6 lawns and maybe 20 drip timers. Each uses prob 10gpm. And comes on at different times throughout the day.

Pressure switch is 20-70 psi. Pump installer though it might help reduce short cycling killing it.

The end result is the 1hp 20gpm pump cycles on and off every 1-2 min for hours and hours all day.

Our Pump man has to install a new pump every 4 years to the tune of $4,000 and doesn't understand why we eat pumps. He suggested 'maybe' there was an electrical problem over the phone but didn't check... on his $200 service call where he drew up an estimate for a new pump.

For that money he should get it right. So im trying to do his job because this is ridiculous. His current suggestion was to go up to a 1.5hp and 'see if it helps.'

I want to diagnose the problem and not pay him thousands for trial and error on overpriced installations.

I ordered a amp clamp. Is there anything I can do in the short term?

Adjust all timers to draw pump over its rated gpm, pressure switch changes etc?

Sounds like a csv might be the ticket.

 

[Valveman]

Pressure switch is 20-70 psi. Pump installer though it might help reduce short cycling killing it.
The end result is the 1hp 20gpm pump cycles on and off every 1-2 min for hours and hours all day.
Our Pump man has to install a new pump every 4 years to the tune of $4,000 and doesn't understand why we eat pumps. He suggested 'maybe' there was an electrical problem over the phone but didn't check... on his $200 service call where he drew up an estimate for a new pump.

Sounds like a csv might be the ticket.

And you wonder why so many pump installers and especially pump manufacturers try to keep people from using a CSV. They hope you don't find out about it. When you find out on your own they try to tell you it will cause backpressure that will tear up your pump. There are times when the ambient temperature will cause a jet pump to trip a thermal overload. But the vast majority of all pump system problems are caused by cycling the pump on/off too much.

 

[LLigetfa]

Pressure switch is 20-70 psi.

That is way too wide a delta and is torture on the diaphragm in the pressure tank. If the tank has an internal dome limiter, then you are not getting that range anyway.

 

[TVL]

That is way too wide a delta and is torture on the diaphragm in the pressure tank. If the tank has an internal dome limiter, then you are not getting that range anyway.

Not trying to steal this thread, but I have a question for LLigetfa:

In reference to the pressure range of a pressure switch - do you feel it's critical to maintain no more than a 20 PSI range on the pressure switch to eliminate the possibility of "torturing" the diaphragm in the pressure tank? The reason I ask is I've been maintaining a 25 PSI range on my submersible pump setup (40 PSI to 65 PSI), but I hadn't really thought of what the additional 5 PSI range might be doing to the pressure tank!

Thanks

 

[LLigetfa]

It may vary from tank to tank but I would not be too concerned about going 5 PSI over the standard delta. I would however be concerned about a 50 PSI delta.

 

[Valveman]

Actually we do wide deltas between on and off all the time. Especially when there are multiple pumps, the tank may operate between 70 and 120 PSI. These tanks last as long as any because it is not the wide delta but rather repetitive cycling that causes tank diaphragms to fail. A Cycle Stop Valve takes the repetitive cycling out of the equation. The tank diaphragms can stretch a lot. But the wider the delta, the can survive fewer cycles.

 

[Edrrt]

Yes measure the amps!

Ok.

AMPS when running start at 9 and drop to around 8.8.

INRUSH PEAK AMPS at start 35.8.

The data plate says

It is just pumping the pressure up from 40-60 psi at 8.8 amps. So thats a little over its rating. Unsure why. Maybe I should check the suction side.

If the suction side is clear my options are:

1) get a csv
2) get larger or multiple pressure tanks
3) get a 2hp pump

Thoughts?

I compared it against my myers 1hp jet pump. 42A inrush peak at start but only 7A running. I'm guessing a high inrush is normal... odd it doesn't blow fuses or trip Breakers since it's exceeds the rating. Maybe cuz its so brief.

 

[Fitter30]

Motor amps are influenced by the service factor (SF) which is 1.4 which is a very good motor. Max amp draw is calculated SF x name plate. Your max amps on 230v is 8.1 so your over amped. Need to look at a pump curve to find out what the shut off pressure is supposed to be. Thats measuring the pressure, amp drawn with discharge valve closed. If pressure is higher than it should be pump needs to be inspected as to why. Is the pump happen to be in a enclosure and have the sun beating down on it.

 

[Edrrt]

Motor amps are influenced by the service factor (SF) which is 1.4 which is a very good motor. Max amp draw is calculated SF x name plate. Your max amps on 230v is 8.1 so your over amped. Need to look at a pump curve to find out what the shut off pressure is supposed to be. Thats measuring the pressure, amp drawn with discharge valve closed. If pressure is higher than it should be pump needs to be inspected as to why. Is the pump happen to be in a enclosure and have the sun beating down on it.

No sun. It's dangerously hot even when cold outside.

I am not exactly sure what model pump it is. SEE PHOTO. The numbering on it does not pull up any information online. It's a goulds water gun style booster my dealer says makes 20gpm. These are rated up to 300psi out. I only ask it to go 40-70 and it draws 8.7 amps the whole way. I dont think it's maxing the pump curve.

An upstream obstruction is a possibility? Maybe an intake screen in the pump?

Should a booster be able to pull its GPM off of a tank ground level with it? Or will that make it work hard and a jet pump would be better?

 

[Valveman]

Any obstruction in the screen would actually decrease the amp draw. Can't see the model number of the pump? But being a Goulds it should reduce in amp draw when restricting the discharge. This can be done with a valve or by just running fewer sprinklers. Check the amps draw when using less water and see if you can't get it below service factor.

Those motors are made to run hot anyway. They don't put any more meat in them than necessary to keep them just below critical temperature. Any increase in ambient temp or amp draw makes them run at a critical temp, and the bearings don't last long. Once the bearings are bad the pump needs to be replaced. Pump manufacturers can build in just how long they want pumps to last this way. If restricting the flow causes the amps to increase, the bearings are already bad. That is how you test a trust bearing.

Over-sizing the motor is possible, running at lower amperage, increasing air flow and/or decreasing ambient temp will help air cooled motors last longer. But eliminating the cycling and all that heat from inrush currents is the number one way to make pump/motors last longer.