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Since the Prusa i3 MK2.5S uses a PTFE/Teflon lined hot-end (link) (link), the nozzle temperature should not be set above 240 °C if possible. Prusa suggests a nozzle temperature of 240 °C. Though a Prusa forum post with hot-end supplier’s information suggests that temperature of up to 300 °C is ok.

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