Water pump is hot to the touch, was not in use

[dolfisherman]

This is my second trip where I'm using the fresh water supply and relying on the pump. No previous issues. Was out and about for a few hours and returned. I'd left the pump switch on, with battery power. Flushed the toilet, but noticed the low pressure and the pump didn't come on. Checked the fuse, it was good. Found the pump and discovered it was hot to the touch.

I left it off and turned the generator (external) on for the AC.

I turned the pump on a few minutes later and it worked like a champ.

Scratching my head as there are no leaks.

Any thoughts on why an unused pump would be hot?

Filters and screen are clean.
No air in the system.

I'll be turning the switch on, only when needed until I figure this out.

Thanks, dl

[persistent]

There are several possible failures that could cause the pump to become hot enough to trip an over-temp switch.

Air in the suction line will cause the pump to never bring pressure up to the 50 pound cut off. It should be self priming.

A kinked suction hoses can also cause failure to raise pressure high enough.

A defective or stuck pressure switch.

Many owners switch the pump off whenever they leave their unit. There are other failures that can happen when left "on" while unattended. Flooding inside is one of them.

I wish you good luck and happy trails ahead.

[dolfisherman]

Turning it off when I'm not there is good advice. I appreciate that!

[wis-redneck]

Apparently you were previously running on battery power. Did you run any water prior to leaving for a couple hours? It could be possible that your battery was getting low and if the pump tried to start without enough voltage, the pump could heat up trying to start. Also the pump most likely has a internal thermal overload, which will shut off the pump if it gets to hot. By Shutting it off any power source for a short period of time allows it to cool off and reset. Also by switching to a generator, you now should have supplied a full 12 volts, plus recharging the battery.

[kimbo@alum.mit.edu]

You would expect the positive to be switched in a negative ground system but if somehow the negative was switched and grounding of a winding in the motor occurred current could flow in the motor with no motion but still generate heat because you were switching the negative in a negatively grounded system. Note that I said negative and not the color of wire since the colors are normally red positive and black negative could also be reversed or different.