Evaporative Water Coolers - Evaporative cooler vibrates where the line connects to it

I have a 3 year old evaporative cooler and I noticed last year that it will start vibrating whenever the water level goes down and the pump lets water into the cooler to fill the pan. It will start vibrating where the line connects to the cooler. This vibration is loud and will not stop until the water level reaches a certain level. If you anyone has had this problem before or knows how to fix it, I would appreciate it if you would tell me how. Thank you in advance.

Sounds like the float valve is chattering for some reason. If the line going to the cooler has a manual shut off valve try closing it slowly while the noise is occurring to see if it will stop but keep a sufficient flow of water to cooler.
Mike

secure the copper to the side of the cooler. As the water travels at fast pace it tends to pulse.
so... secure it to the side and the sound should go away.