Pump overheating

[Jwestman]

Woke up this morning to dead batteries. I suspect the shur flow pump. It overheated yesterday but was operating again after 20 minutes rest. This is a 2012. Does it sound like I've killed it? It may have been run dry since the micro pulse does not work accurately......grrrr

Thanks for any help

[Protagonist]

Originally Posted by Jwestman

I suspect the shur flow pump. It overheated yesterday but was operating again after 20 minutes rest.

Does it sound like I've killed it? It may have been run dry since the micro pulse does not work accurately.

If you killed it, it wouldn't operate again. Diaphragm pumps are very forgiving of being run dry— BUT they are cooled by the water they pump, so if they run dry they will overheat.

But unlike an impeller pump— where running it dry will tear up the impeller because it's not only cooled by the water it pumps, the impeller is also lubricated by the water it pumps— a diaphragm pump doesn't need to be lubricated by the water it pumps. You don't tear up a diaphragm by running the pump dry.

[Jwestman]

Originally Posted by Protagonist

If you killed it, it wouldn't operate again. Diaphragm pumps are very forgiving of being run dry— BUT they are cooled by the water they pump, so if they run dry they will overheat.

But unlike an impeller pump— where running it dry will tear up the impeller because it's not only cooled by the water it pumps, the impeller is also lubricated by the water it pumps— a diaphragm pump doesn't need to be lubricated by the water it pumps. You don't tear up a diaphragm by running the pump dry.

I realized after asking the question that there was still about a 1/4 tank of fresh water. Would that suggest there is a problem with water draw from the tank? Over the last month I've noticed that the pump will "gurgle" for a second or two like it might be adding pressure in the line but I have not been able to find a leak.
If the pump seriously over heats - Hot to the touch - is there a chance that I burned it out and it needs to be replaced? Obviously, I know nothing about this and very much appreciate your guidance!! j

[nrgtrakr]

Level gauges can be off, the hose feeding the pump could be not at the bottom of the tank (possibly your gurgling sound), or the check valve at the pump which keeps the pump primed and prevents the water from draining back into the tank is bad (possible, but not likely, more likely would be it has junk in it so it cannot close - another potential gurgling sound).

If possible add more water to the tank, maybe even fill it, check that the filter before the pump is clean and the valves are open all of the way, then turn the pump on. Use a little water, check for hot/noisier than usual; use a lot of water and check again.

Motors and pumps do work, and so generate heat in the process. Melting hot, too hot to touch, or a smell of electrical components failing is a problem. Hotter than the surroundings is normal. A pump running with no fluid passing through it (not pumping) will be hotter than normal.

[Protagonist]

Originally Posted by Jwestman

Over the last month I've noticed that the pump will "gurgle" for a second or two like it might be adding pressure in the line but I have not been able to find a leak.

We're about to hit the edge of my knowledge about pumps. I'm no expert, and most of what I do know about pumps I learned here on the Forums from other people who are experts. Or from boaters and bilge pumps, which are also usually diaphragm pumps.

Anyway, I would speculate that if you can't find a leak and you hear a "gurgling" noise when the pump starts, it could be that the pump's internal check valve isn't working properly, allowing water to run back into the tank when the pump shuts off, so that it has to prime itself again every time it starts. The fact that it does prime means that it's not sucking air through a leak in the inlet line.

[A W Warn]

Originally Posted by Jwestman

I realized after asking the question that there was still about a 1/4 tank of fresh water. Would that suggest there is a problem with water draw from the tank? Over the last month I've noticed that the pump will "gurgle" for a second or two like it might be adding pressure in the line but I have not been able to find a leak.
If the pump seriously over heats - Hot to the touch - is there a chance that I burned it out and it needs to be replaced? Obviously, I know nothing about this and very much appreciate your guidance!! j

The only way the water pump motor will get hot is from running continuously without water passing through the pump. If the motor still runs I doubt that it has been damaged.

If you are hearing a gurgling sound every time the pump starts up, air is getting into the intake pipe prior to the pump or at the pump head.

If there is water in the fresh tank, first I suggest you look at the inlet pipe where it connects to the pump head make sure it is not loose. Then check the clear filter bulb to make sure it is assemble correctly. The filter bulb twists apart if there is a need to clean the filter. If there is nothing loose check very closely for cracks in the pump head. (few drops of water left last winter could have frozen)
If none of the above is the cause, the pump diaphragm could be cracked.

add edit: If your batteries were fully charged the evening before, even if the pump ran all night it should not have completely discharged the batteries. It may be time for new batteries.

[Jwestman]

Originally Posted by Protagonist

If you killed it, it wouldn't operate again. Diaphragm pumps are very forgiving of being run dry— BUT they are cooled by the water they pump, so if they run dry they will overheat.

But unlike an impeller pump— where running it dry will tear up the impeller because it's not only cooled by the water it pumps, the impeller is also lubricated by the water it pumps— a diaphragm pump doesn't need to be lubricated by the water it pumps. You don't tear up a diaphragm by running the pump dry.

I filled the water tank today, checked the in line fuse at the pump and in the converter panel (both okay) switched the pump on and nothing. Would you suspect that the pump is toast or the problem is electrical? I would have thought that a fuse would have blown.

[A W Warn]

I would check the voltage at the pump to see if the pump is actually getting power before considering a replacement.

There may be an inline fuse at the wire right where the pump wire connects to the trailer wiring harness, at the pump location. If it is there, this fuse is in addition to the fuse in the panel.

This weblink might be of help in trouble shooting.
Shurflo 5.7 Water Pump Troubleshooting

[nrgtrakr]

Also sniff it ... burned out motors have a particular odor.