I have a older lennox (model # g1203-110 ) and change the thermocouple.The problem is that does not lite up when I turn on the heat. The fan works fine from the thermostat when I put the thermostat to fan on position and pilot stays on and I even hear it humming like it wants to go on but doesn't. fire.What could be wrong? I am okay with schmatics and wire diagrams so if you can please show me where the problem is on the wiring diagram I can better understand your explanation on how to fix it and maybe fix it myself next time. Thank you much Freezing in hickory hills
Your fan operates at two different speeds, high for cooling and low for heating. When you turn the fan switch to on the fan is being energized on the high speed winding. The fan is energized on the low speed winding after the temperature in the heat exchanger has risen enough so that you will get warm air from the vents. It is possible that the fan motor has a bad low speed winding. It is also possible that the control board is not energizing the relay. Your gas valve may have a bad solenoid. You may have a bad induced draft fan motor or the induced draft proving switch may be faulty. If the induced draft fan motor does not start, there will not be sufficient air in the burner compartment for combustion to take place properly. Without the induced draft the control board will not open the gas valve. You need to have a qualified service technician come in and check out the operation sequence. The technician should be able to locate the problem in about 30 to 45 minutes, perhaps less. They will know where the correct replacement parts are available. They may have the correct part in stock on their service vehicle. They should be able to tell you exactly how much the parts will cost and how much the labor will cost before any repairs are made.
Check the gas valve circuit wiring and connections. The humming could be coming from the solenoid on the valve. Tap it with a screwdriver handle to see if the plunger is stuck. Otherwise, make sure the tc is in the pilot flame
did you remember to turn the gas valve to ON ?
do not take any possibilities. It seems such as you ought to call your gas employer precise away. they are going to come out and connect your situation. i does not take the prospect of even turning on your furnace interior the period in-between. If there's a gas leak, your place might desire to blow up. Take the precautions and don't gamble consisting of your life JOHN i don't comprehend the place you reside, yet IN MY section THE community gas employer WILL come out here day AND the two restoration the situation at no value OR advise 2 OR 3 CONTRACTORS which you will USE OR not..
