When filling a pressure tank does the pump need to be plugged in to the outlet?

Can you give us more info?

Pressure tank for what?

Type of pump?

Type of outlet?

Answer these and anything else you can give us.

Chuck

Filling a well pressure tank? If you mean adding air to the top of a bladder tank, then that is done with the tank pressure drained to zero (open a low level faucet) and the pump off. Set pressure to 2# below the cut-on pressure for the pump.