Process for producing a polymer product in a slurry polymerization process, which slurry polymerization process includes a slurry heater for heating a stream of polymer product slurry withdrawn from a slurry reactor. The process includes reconfiguring the slurry heater from an initial slurry heater configuration to a subsequent slurry heater configuration and further where the slurry heater is reconfigured to form a subsequent slurry heater having a different total length and/or a different average internal diameter than the initial slurry heater.