Service & Troubleshooting Guide #18-07-038

equipment: Jacketed Firebox Hot Oil Heaters


Troubleshooting the Fenwal high limit switch

used on older CEI hot oil heaters

Many older CEI jacketed firebox hot oil heaters are still in service around the country. Many of these older heaters use the Fenwal high limit switch as a high temperature limit controller.

If the thermal oil temperature reaches the pre-set set point on this switch, the heater will shut down to prevent over-heating. This Service & Troubleshooting Guide from the CEI Service Dept explains how to troubleshoot the Fenwal high limit switch.

If the old switch needs to be replaced, CEI offers a new retrofit upgrade. Just contact our parts department at 800.545.4034.

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Troubleshooting the Fenwal high limit switch