Pulmonary Ventilator Ventilator Circuit. Temperature Transducer (Heated-Wire) In the Ventilator Ventilator Circuit. Coded Products: (1) 780-19, 780-20,780-31 to 780-36,780-51, 780-52, 790-52; (2) 780-23 to 780-25, 780-30; (1 and 2) Lots # 42012 and below; products manufactured before October 15, 2001; units distributed within the US and internationally