The desire to reduce NOx at low ambient temperatures drives the use of heating methods to make DEF available by thawing the solution in the tank. Methods to validate modelling used to design hardware options require testing to gauge the accuracy of the prediction. Using a climactic chassis dynamometer (CCD) to demonstrate the EPA guidance procedure is expensive and time consuming. A method of utilizing a flow controlled cooling supply combined with a standard cold chamber is described as a precursor to running the demonstration in the CCD. Testing multiple quantities of design iterations produced unexpected variation in the results. The sources of the variation and modifications taken to minimize them are discussed and presented. Several design iterations were compared with varying degrees of success. The method was modified as variation between tanks of the same design was noted. System description details as well as modifications to the process are discussed. Test apparatus details are described. The DEF heating loop system is exposed to varying temperatures and flows in the truck. Selection of a representative coolant flow and temperature is discussed. The EPA certification test method options are referenced. Control parameters are defined as to applicability with the intent of demonstrating a test practice that accurately predicts hardware performance on the cert test. A complete review of previous work detailed in SAE publications is provided.