7. Route the crankcase heater leads along the existing compressor lead wires, underneath the coil and up into the top of the control box. Use wire ties to secure the crankcase heater wires to the compres-sor lead wires. Care must be taken to ensure the leads do not come in contact with the compressor discharge line, with any moving parts, or any sharp edges.. When you replace a single pole with a two-pole contactor in this type, you need to make sure you connect BOTH sides of the crankcase circuit across the L1 and L2 line side of the contactor to ensure the heater can function when the compressor is off. Want to know something even more confusing than that? Look at the diagram at the top.
 Commercial Sales Aluminum CCH Heater NMH Isometric View.jpg "Compressor & Crankcase Heaters")
![[36+] Trane Water Source Heat Pump Wiring Diagram, Trane Heat](https://f01.justanswer.com/pGoWKXbI/Electrical+schematic-2.jpg "[36+] Trane Water Source Heat Pump Wiring Diagram, Trane Heat Pump")
Learn how to wire a crankcase heater with this detailed diagram. Ensure your HVAC system stays warm and functional all year round with the proper installation of a crankcase heater.. 9. Place the wiring diagram provided with the kit on the inside of the control box cover. 10. Reinstall the side panel and the unit top, and the control box cover. 11. Reapply power to the unit. 12. The crankcase heater should immediately begin to heat. 13. The crankcase heater will heat at all times. 14. Reset the thermostat.