Dyna-Glo EG7500DG User's Manual And Operating Instructions page 7

CONNECTING THE POWER
If you will use an external temperature control (external thermostat) to
control the heater to be operated or not, please follow below attention
points:
1. Make sure that the heater's temperature control knob (thermostat knob) is
turned fully clockwise.
2. Connect the wire according to below wiring diagram.
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