Fan and Heater
TROUBLESHOOTING
Fan Control Circuit
CAUTION! BE VERY
CAREFUL WHEN
CHECKING OUT 220V OR 460V CONTROL CIRCUIT.
SERIOUS INJURY OR DEATH MAY OCCUR IF PROPER PRECAUTIONS ARE NOT TAKEN.
Figure 3: Fan circuit board.
IMPORTANT: ALL OF THE BELOW SYMPTOMS MAY BE CAUSED BY LOOSE WIRING OR CONNECTIONS.
ALWAYS CHECK IT FIRST!
Push Start Button, Nothing Happens:
1.Check for 220V between points C and F. If no voltage present, check power at primary disconnect.
2.Check for 220V between points C and D. If no voltage present, check "J" (thermostat) wires. (on units with " J " wires)
3.Check for 220V between points C and E. If no voltage present, replace or reset thermal motor overload.
4.Check for 220V between points F and G. If no voltage present, replace 1/4 amp fuse.
5.Check for 220V between points F and H. If no voltage present, checkout stop switch and replace if necessary.
6.Check for 220V between points F and I (while pressing start button). If no voltage present checkout and replace start switch if necessary.
7.Check for 220V between points A and B (while pressing start button). If voltage present and no start, replace coil on contactor.
Push Start Button, Fan Starts but will not Continue after Start Switch is Re- leased
1.Auxiliary switch on contactor is probably bad, checkout and replace if necessary.
Note: Always check for 220 volts at check points. 110 volts to ground does not necessarily mean check point is okay. Voltage may bleed through contactor coil and other similar parts.
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