IF the W/H has NOT been used on LP for sometime, I would attempt to light at least 10 times (30 ignition sequences as 3 per time as the board will attempt 3 times per attempt and then lock out). Now, IF the water was already heated to temp, the Ignition sequence would NOT happen. So, the LP tstat is calling for heat. YES, if LP is flowing you should smell unburnt LP.
1. LP gas valve Bad due to inactivity and has locked off
2. Gas Valve orifice clogged due to insects and lack of operation
3. Burner tube clogged(insects/webs) but you should still smell unburnt LP
4. Let the system attempt to light the 3 times(wait 5 minutes for the sequence). The RED indicator light at the On/Off switch SHOULD light to tell you failure of LP lighting. If NOT, then something else is wrong, possible bad circuit board
5. When the Spark sequence starts, put your hand on the Gas Valve. You should feel it open and also Click. That lets you know power is getting to the gas Valve. The CORRECT way to test this is, check for 12 volts on the BROWN wire connected to the Gas Valve when the spark starts. If NO 12 volts, then either the circuit board is bad or the connection of the harness to the circuit board is not tight. Doug
