I have a Tran gas forced air heater at home. I noticed it wasn't coming on the other day. So, I reset the thermostat and then switched it on again. The heater attempted to come on, but once the blower came on, it shut off after a minute of operation. I power cycled it again and took a look at what was happening. When it initially turns on a small blower on the side of the unit turns on and the ignition coil lights up briefly and then shuts off, but no gas ignites at this point. A few seconds later the main blower turns on. A few seconds pass and the ignition coil lights up again. This time the gas turns on and immediately ignites, but then shuts off after less than a second of operation. A minute or so later the both blowers shut off.

Any idea what's going on here? The gas valve seems to open, but then shut after a second... bad valve? Bad controller or relay?

Thanks.