The delivered Peltier, heat sink and fan stack cannot cool the 16-well block at PCR ramp rates, and the Peltier listed limit of 80 C sits below the 95 C denature step. The team now wants every later firmware and hardware choice checked against a written thermal budget, not vendor copy, and the legacy sketch truncated the thermocouple reading to an int with a hard-coded plus 1 C offset.