Cheese Pump

I’ve been using a server cheese pump to warm my cheese for our cheese fries, loaded fries and pretzels. The problem I am having is the cheese is burning on top. (This is set @ 100 degrees) Also it seems like the cheese is taking on a sour taste and smell to it. We have the insert for it. Any ideas on how to keep this fresher longer.

We get a loaf cheese, melt that, thein with heavy cream, and use ladles in correct portion sizes,

Could you lose the pump system and use proper size ladles, or get the crew to stir the cheese a few times through the shift?