Cycling Shurflo Smart Sensor pump

I neglected to mention that I have found no evidence of any water leakage, at least nowhere I can get access to. But that does give me an idea to stop at a hardware store and buy a 1/2" MPT cap to put on the pump outlet and eliminate any chance of system leakage beyond the pump.

There is no system filter, the tank is right next to the pump, I can see the entire 15" supply line, and the screen in the intake bowl is clear. So the problem will be in the pump itself.

If you have a whole house filter and it is getting plugged it will do the same thing. Easy..change the filter. If not...all the advice above is good. :) :)

You have a small leak.......could be at a fitting, could be toilet water valve, could be dripping faucets/shower head, could be drip at low point drains, could be dripping at 'city water' inlet check valve, could be water heater PRV weeping etc.

Could be pump diaphragms have debris/scale built up.....that pump doesn't have an internal check valve just 4 pump diaphragms.
Spec sheet/parts......LINK

dbbls wrote:
It sounds like you have a leak. If you can not find one in the plumbing it may be a leaking check valve in the pump.

As just said, you described a classic sign of a water leak. Time to trace out all water lines.

It sounds like you have a leak. If you can not find one in the plumbing it may be a leaking check valve in the pump.