I have the following cheapo pump and good pressure switch with a foot valve on a 300 gallon rain barrel. A hose is connected to the pump to water plants and such.

http://www.lowes.com/pd_67599-296-FS...la&cagpspn=pla

http://www.northerntool.com/shop/too...duct_7738_7738

The pressure switch works find when the hose is cycled for watering for about ten minutes and then the pressure switch fails to work anymore. If I let things 'cool' down or wait for period of time then it all starts working again. I did one test where I just turned on the hose for about 5 minutes and then when the hose was turned off the pump continued to run. So, it is tied to how long the pump operated. I do not see any leak in the system. I am guessing maybe the foot valve is leaking but that is hard to get at as it is at the bottom of the tank. Or some kind of air is getting into the system. Water discharge from the hose does not change when it starts failing. I took the top off the pressure switch and all looks well, no rusting or bugs, etc.

Any ideas on what is happening here? Thanks, Tom