Evaporator Heater Selection

Units are being built with different length and wattage heaters. Use the following information to determine what heater to use for replacement.

  • Heater Long 1360 Watts (Normal) 45-2441

  • Heater Long 2000 Watts (Extended) 45-2451

Three Longer Heaters (1360 or 2000 Watts Each)
Parent topic: Electrical Maintenance

Extended Capacity Heaters

If a unit is equipped with the Extended Capacity heaters (2000 Watts) the main CB (42-0352) is adjustable and set to 27 amps. When changing out a controller, the HEATER ELEMENT TYPE needs to be changed in the configuration menu from NORMAL CAPACITY to EXTENDED CAPACITY. If the heater type is not change the unit will alarm during a PTI on heater capacity low. The only difference between the 1360 Watt (18 GA) and 2000 Watt (16 GA) heater is the wire gauge size. So care should be taken to confirm correct heater element is used when replacement is required.

Unit Configuration Menu
 Heater Type

Electric Heaters Malfunction

Three or six electric heater elements are located underneath the evaporator coil. If a heater element is suspected of malfunctioning, check the resistance of each individual heater element by performing the following procedure:

  1. Turn unit power supply off.

  2. Remove unit power plug from power supply receptacle.

  3. Open the control box door.

  4. Test the insulation of each individual heater element.

    1. Test all three legs of the heater circuit to a good ground connection. Connect a calibrated 500 Vdc insulation tester between each outgoing heater contactor terminal and ground.

    2. If the resistance between any contactor terminal and ground is below 1.0 meg ohms, isolate and check the resistance of each individual heater element.

  5. Check the resistance of each individual heater element.

    1. Disconnect and isolate each heater from the circuit in the control box.

    2. Check resistance of each heater with an insulation tester between each heater and ground. If the resistance between each heater and ground is below 1.0 meg ohms, the heater element is defective. On a loaded container, remove the defective heater from service by disconnecting at the control box. If the container is empty, remove the evaporator cover from the rear of the unit and replace the heater or correct any defective wiring. Repeat step 5a.

      Note When repairing heater connections, protect the new connections from the ingress of moisture with heat shrink tubing. All heaters should be secured to prevent contact with sharp metal edges.