Warming plate boils coffee.

Make sure you are using the type of commercial coffee pot like the one in the picture. They don't have to have to be plastic with the metal bottom, they can be all glass. The commercial pots are heavy duty and usually disperse the heat well.

If you are using commercial pots the only solution without replacing the warmers is to put three pennies on the warmer and to put the pot on top of them. The pennies will get hot so don't forget and grab them but the pennies help to move the pot just a little way away from the direct heat.

If you are handy the problem is a defective thermal switch on the warmer. Unfortunately this would only be accesable from the bottom of the machine and since the machine holds about 2.5 quarts of water it can not be laid on it's back without emptying the water tank. Other than that the switch is cheap and can be obtained from some appliance supply shops but I would take the defective one with me to be sure to get the right one. It would be easier to replace the warmer or try the pennies first.

Make sure voltage to the warming heaters is correct.

Whe a pot of coffee is done brewing, Lift up the pot towards a light and look through it. Sometimes more than often you will see coffee grounds near the bottom. When the pot of coffee is on the burner, heat from the burner will make the grounds rise to the top and surface the top of the coffee making you think the coffee is boiling. Burner plates hardly ever more than 100w. They really do not generate enough power to boil water and or brewed coffee.

Robb
Certified Beverage Equipment Mechanic