I asked R Shmuel Meir Katz who said it does not need tevilah because
true, the Anova does not come in contact with food, however a Chabad rov instructed us to toivel ours,
and especially because the Anova is made for long-term immersion in water (vs. the "sandwich maker") and also has removable metal housing,
we removed the housing and toiveled both, with the heating element up to the "max" line.