Electrical Projects The simplest and most popular electric heater is a heating coil connected to a line cord. A more'complicated type is shown in the exploded view in Fig. 5-5. This is a room heater with a two-speed fan and automatic temperature control. It uses two finned heating elements and a switch for a selection of one element or two. A control lever regulates the temperature. When set to the extreme left, the unit is off. A slight movement to the right turns on a light to indicate the unit will go on when the thermostat calls for heat. The unit automatically maintains the desired temperature in the area it is capable of heating. Many models similar to the one shown have a tip-over switch to automatically shut off the heat if the unit is tilted more than 30 degrees from the upright position.

The fan operates at 2100 and 2700 rpm. The unit is rated at 1650- 1200W, 120V, 60 Hz, and delivers 5600 BTU / hr.


Thermostat Calibration

Although many space heaters have nonadjustable thermostats, the thermostat used in this particular unit is adjustable. The thermostat uses a bimetal leaf with two adjusting screws. Access by removing the two expansion-clip plugs located underneath the shell. The thermostat also has a back contact to activate the light. This contact is nonadjustable. The adjusting screws have a slotted head to accept a screwdriver. When making an adjustment, turn the adjusting screw only a quarter turn at a time and then remove the screwdriver as the slight pressure of the tool will give a false reading.




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Home > Electrical Projects > Repairs > Electric Heaters

October 6, 2008