Originally Posted by Clarkboulder
Interesting. But wouldn't all this also prevent the propane stove from working?
Earlier this spring I am convinced they overfilled my tank. All summer long it was beyond 85-90% full. Its never worked since but I can't yet tie them to each other as cause and effect. But I have wondered. Its now at 3/4 full and I bled the lines to the stove (via burning the gas until it went out) in case the regulator was tripped somehow. then retried everything. No flame ignition. The fan works fine and so does the electrode spark.
I found that if you turn the gas off at the tank, then disconnect the gas line at the furnace, you should get a small amount of gas out of the supply line at the furnace. Very little gas escapes, but nonetheless do this in a ventilated area! That should tell you if the furnace line is seeing gas or not.
One simple test you have already done.. smelling for raw gas at the exhaust outlet. If you don't smell any gas after it tries to light several times, most likely the valve is not opening. There are 2 switches inside - the sail switch, which ensures the ventilation system is working, and a limiter switch, which is an over-temperature safety switch. Both have to be working correctly before the gas valve will open.
Finally, with the cover off the furnace, you can check for 12V at the gas valve solenoids (2 of them). If you have 12V, but no gas, the valve is stuck closed. Fortunately, it's easy to replace.