Posted by: Pat on February 02, 2004 at 09:21:01

I've got an oil furnace that kicks out before the thermostat kicks in the blower...kicks out after about 10-15 secs. I've hit the reset button and it continues to kick out. The tank is still 1/4 full. I'm wondering how to tell if the nozzle is plugged and/or if the filter needs to be replaced. It's a Thermoflo Oil furnace model #LBO-12AF-BD and is 7 years old, but hasn't been used for the past 1.5 because of a wood burner we put in...in a different flue and part of the house.

Answer:
After you take a suction pressure reading with your vacuum gauge on the pump inlet port to determine if there is permissible suction less than 10 inches of HG, you are sure there is insufficient resistance to cause a problem.

If there are no air leaks in the suction chain, then the pump should force oil through the nozzle.

After all the repairs are made you still do not have the instruments to do a combustion efficiency test to make sure there is no smoke and proper CO2 over 11%, so you are just making a potential problem in a short while.

Call a pro who actually has and can show you the use of combustion test instruments to assure a safe burn.