The Thermo-switch (left) should be left ON for the duration of any working period or for any length of time the enlarger is in use. This automatically pre-heats and maintains the optimum operating temperature in the unit. Because of this feature, there is no need for time consuming warm-ups or constant burning-in of the unit. The pilot light on the power pack indicates when the thermostat is on. Turn the thermostat switch OFF at the end of each day or working period to prolong the life of the components.

For Maximum diffusion, insert the lamp housing into the lower condenser compartment: for less diffusion, leave the lower condenser in place and use the upper condenser compartment.

Caution:  Use only with 120 Vac current unless unit was specifically built for 220V/50Hz