My laundry sink has a trap primer for the floor drain that runs as a line from under the faucets. Lately, I've noticed a constant trickle of hot water running through the line, even when the faucet is off. There is a distinct noise coming from the copper pipe that leads to the faucet that was not audible before. Is the constant trickle normal and/or is the noise a problem waiting to happen? Thanks for any help.