Bernard Logan - Watermaker Overheating, Shutting-Down

[bill good]

sounds a bit wrong if the unit has 2X HP pump motors of the same type one 3A & the other 20A driving a common shaft. What does the delivery pump do if it run on its own? (i.e. hook up a hose to outside, pump water check current & If the thermal protection operates then it is faulty for sure.
(I don't know the unit you have)

[drblogan]

I will take this up with VM.

[phorvati]

Originally Posted by TaoJones

According to this, Dr. Logan, the 4105-501 is spec'ed for intermittent duty: 4105 Series > General Purpose Pumps > Marine > Flojet - ITT.

TaoJones

I am trying to figure out the same thing. Feed pump overheated last night after 20 minutes. I have 4125-502. According to this catalog section, motor is continuous duty...
I have a pressure gauge instead of vacuum gauge between pre-filter and high pressure pump. It was continuously at 40psi for the duration of the runtime. Perhaps this pump is too much for my HP pump(Cat 290). Brine flow was 3.5 GPM

[bill good]

Bet the air temps are well above the 25 deg for the continious run specs. Try a computer cooling fan to reduce the heat. Water cool by passing inlet water thru a coil of copper around the body of the motor?
Regards Bill

[phorvati]

Originally Posted by bill good

Bet the air temps are well above the 25 deg for the continious run specs. Try a computer cooling fan to reduce the heat. Water cool by passing inlet water thru a coil of copper around the body of the motor?
Regards Bill

I'll try that tonight. i would love to add large heat sink, but need to machine it so that it optimizes the contact surface to the body of the motor, then add a fan.

[bill good]

Try to run first up in the mornings before the day heats up? If the pump is working too hard for the flow required, some form of PWM speed control could be added.
Might work.

Regards Bill

[phorvati]

Originally Posted by phorvati

I am trying to figure out the same thing. Feed pump overheated last night after 20 minutes. I have 4125-502. According to this catalog section, motor is continuous duty...
I have a pressure gauge instead of vacuum gauge between pre-filter and high pressure pump. It was continuously at 40psi for the duration of the runtime. Perhaps this pump is too much for my HP pump(Cat 290). Brine flow was 3.5 GPM

So if the pump syas 25psi max, and i am getting 40psi at the output of 5 micron pre-filter, this tells me that the feed pump is overloaded. It makes sense why it overheated.

[phorvati]

Originally Posted by bill good

Bet the air temps are well above the 25 deg for the continious run specs. Try a computer cooling fan to reduce the heat. Water cool by passing inlet water thru a coil of copper around the body of the motor?
Regards Bill

So i made a copper loop around the motor, but i teed it off at the feed pump output then fed it back at the brine output after the flow meter.
Helped with two things, kept the pump cooler, and lowered the feed pressure from 40psi to about 35psi, eventually dropping to 30psi at the end of my water making run. Pump did not overheat this time. I think I will add a larger ID copper loop. Tubing that relieves the pressure is only 3/16" ID so pressure is still over 25psi max. IR thermometer showed about 5F lower temp with each copper loop. Highest point of the motor got to as hot at 130F. I think a PC fan will add a lot more cooling. But I gotta get the pressure to below 25PSI.

[Tellie]

They do make heat sinks for a lot of these motors that just snap on. Also a cooling fan as mentioned above over the heat sink works wonders. But I do like the creativity of a water cooled heat sink.