I installed a Goodman Gas furnace last year, and also installed the factory LP Gas conversion kit (gas valve regulator spring, and orifices). This furnace is installed on the second floor of my house, and the house has three other devices that are also fed from the same LP Gas tank. The tank is about 75 feet away from the house, and it has a Souther States regulator installed at the tank. The feed line is split at the house and feed two more low pressure regulators. One feed this new Goodman furnace, and a new Renzor hanging garage heater. The other regulator feeds the old part of the house that an OLD Lenox gas furnace and also one wall hanging space heater.

My question is this. Out of all four of these gas heaters, the Goodman is the only one that has ever given me a problem (I also installed the Renzor unit and did the same LP conversion to it and it is fine). When the furnace turns on, the exhaust blower starts, the hot surface igniter turns on, and then the gas valve tuns on. You can hear what should be gas coming out of the orifices, but never a flame. This furnace tries three times to start, and then locks out on the third try for an hour, then starts over again. Most of the time, the furnace will start on the third try, but if the Lenox furnace is on, or if the Goodman hasn't called for heat in several hours, then it mostly will not make the cycle.

Am I missing something here? I have checked for leaks on all the line (which is 1 inch black pipe inside by the way), I have cleaned the orifices, and I have cleaned the furnace. I still have the same problem.

Any Ideas?

Thanks

Test your pressure switch by jumping it out. Any way you can test your gas pressure at the Goodman? You should have 11 inches of water column when all other gas appliances are on. You sound like a talented sort of person so maybe you can make yourself a water manometer. Look on the net to see how to make one out of a 5 foot piece of clear tubing. You will need a barbed fitting that screws into the inlet side of the gas valve. Typically these are 7/16" but measure yours first. There is an adjustment on your gas regulator if you have more or less than 11". Make sure your ignitor is lined up correctly and in the flame. Lastly, make sure your venting is proper and there is enough combustion air getting into your furnace.