Part # 18 on the Modine Parts Diagram
Transformer converts line 120v to low 24v for heater controls. Modine Part # 5H71956-1 (Works with most Modine PD, PDP, PAE, & PA heaters built after 1986)
Alternate part numbers: 5H71956B1, 5H71956A1, 5H0719560001