The maximum temperature applied to a DME manifold is a function of what is being used with the manifold, and the type/grade of plastic processed. Please refer to the FAQ sheets associated to the DME Hot Runner nozzle that you intend to use, to find recommended temperature limitations for that nozzle type.
Please note: All DME manifold systems are designed with the intended molding application in mind. Since manifolds get very hot, they are designed to accommodate thermal expansion, such that at the desired operating temperature, melt channels in the manifold line up properly with hot runner nozzles. The desired operating temperature (melt processing temperature) is provided by the customer.