Annually, check the operation , have the burner and combustion chamber cleaned as well. Some of the older models with cast iron burners need to be cleaned every couple of years. One of the telltale signs that cleaning is necessary is soot streaks on the outside wall above the furnace vent. On electronic ignition models, make sure that the electrode is in good condition and properly gapped. If you find you are having ignition problems with direct ignition furnaces, don’t just change the ignition control board without testing the rest of the furnace. There are several other things that can cause a malfunction that appears to be a bad control board. If it is necessary to replace the control board, consider one of the new boards from Dinosaur Electronic, which have several improvements over the original equipment boards. And last, but not least, make sure that your gas system pressure is checked and the regulator adjusted if necessary. If you haven’t already done so, make a note of the furnace brand name, model number and the serial number. Put these somewhere for quick reference. It’s also a good idea to do this for the rest of your appliances.
Trouble shooting blower models:
- power to the furnace
- blown fuses
- thermostat contacts (do not short across teh thermostat wires)
- damaged wiring
Blower Runs but no Ignition:
- LP gas supply
- low voltage
- correct 12 volt polarity
- blocked exhaust or intake
There are other causes for these problems, all of which are best left to qualified technicians.