Hi, I have an oil boiler and the fan assemly that blows the oil into the boiler seems to be jammed. We had a period of low voltage and hat burned out the control box and the boiler fuse went. Fuse also replaced. Now when switched on the boiler hisses for a moment or two the makes a funny noise and locks out. The fan in the "squirrel cage" seems to be solid and won't turn at all. Should it be like this or has it jammed

Bill Hoskins, January 2009