Water Pump issues

Thanks to all for your input. I'm going with the "debris in the pump" scenario because it seems to be working perfectly now. Fingers crossed...

wnjj wrote:
You had some debris in the pump diaphragm which acts as a check valve. When it leaks the pressure drops and the pump runs. The “leak” sends water back into the tank. If it’s working now it likely cleared itself up.

Most likely scenario.....

The pump was cycling because the system was losing pressure. The loss of pressure was due to either a leak or the pump check valve had debris in it.

How is the supply line from the tank plumbed? I ask because it sound like it's losing its prime.
Manufacturers ignore pump installation guidelines and place them way too far from the tank. My last TT had a horizontal run of about 15' and would not hold a prime.
I liken it to holding your finger on the end of a straw full of water and then turning it horizontal. The water will run out.
I moved the pump directly over the tank and never had a problem again.

Other possibilities are that it has sucked debris up. If so, take the head of the pump apart and rinse all the parts off. Reassemble and it will be good.
Or it could be you have a leak someplace or the water heater is dripping from its TPO valve.

You had some debris in the pump diaphragm which acts as a check valve. When it leaks the pressure drops and the pump runs. The “leak” sends water back into the tank. If it’s working now it likely cleared itself up.

Sounds like a water leak somewhere, possibly a faucet not shut off all the way. maybe when you shut it down you finished the job.