I have a High efficiency Furnace 5000. The pilot turns on, the burners turn on, but the blower motor doesn't. After a few minutes, the burners turn off and the blower turns on. How can I correct this?

The control board has a time delay on and off for the blower in heat mode. Your board has gone bad and will need to be replaced. You can turn your fan switch to ON at the thermostat and set your thermostat to heat and desired temperature and it should get you by until you replace the control board. The blower will run all the time but you will have heat. My blower has not been shut of for years it runs 24/7.