Lately my well pump has been taking a long time to get to shut off pressure. When I am using 8 -10 gpm continuously (running my geothermal heat pump), the normal duty cycle of the pump was about 66% i.e. it ran for
4 minutes to get to shut off(60psi), then for 2 minutes to get to turn on pressure (40psi). This has been the case for the last 10 years.Now the off time is still 2 minutes but the pump runs (at 8-10gpm) for upwards of 45 - 60 minutes before it reaches shut off pressure. Also, in the past, I could run 18gpm steady and pump would hold 55 - 60 psi. Now the best it will do is 12gpm steady but pressure will not get above
27psi. Pump is a 1HP submersible Gould 10GS10412 3 wire with an 85gallon diaphragm pressure tank. Pump amp drain is normal at 10amps. Well is 200ft deep and a static water level at 45 ft. and was rated at 40gpm when drilled 10years ago. Pump is at 160ft. Terrain is granite and I have never had any problem with water supply; lake is 100ft away and 50 ft below well head. Pressure in system holds at 60psi when not used or pumping. Water is moderately hard with moderate level of iron bacteria. No sediment.People, could you give me your ideas on what might be going wrong here?
Pump motor was replaced after first 5 years due to motor winding failure. Now its another 5 years and trouble again. Same model of pump. Is it the type or brand of pump? (assuming I have a malfunctioning pump)
At this time of year, it is not unusual for the heat pump to be running
24/7 for days on end. In a normal winter, the heat pump may be on 50% of the time for 3 -4 months. So a lot of pumping but I understood this pump should be up to it. But maybe I'm misinformed???? Is this kind of problem a normal failure mode after heavy use? What would be an expected life under these conditions?Thanks for your input!