Sure hope you can help me.
I've had this problem for 2 years now and am at my whits end. I installed a new 1.5 hp jet pump in my cottage, approximately 75ft from the lake with a vertical lift of 20ft or so. The pump will stay primed no issue at all... I will use the pump for a day or so then all of a sudden it begin to make a strange noise (like it does when it's being primed) and it takes a considerable amount of time for it to reach cut out pressure. Some times when this happens I turn the power on and off and the pump will make a sucking noise then will begin to charge properly. This usually fixes the problem for another day. Also, when it appears to be working correctly and I use too much water, like a toilet and the shower the pump will loose pressure and make the sound as if it lost prime again...and back to switching on an off the power.
The sound is almost like it's losing it prime ... I have replaced the switch and the foot valve... still no go.
Any words of wisdom?
you have either a suction leak, or the pipe length, lift and size are at the pumps limits and the pump is cavitating