If it was leaking through the fridge gas valve into the burner then the fridge burner flame would never extinguish when they fridge control called for the gas valve to close. The other thing is that even if it is leaking through the amount is not enough to empty a tank in a few days. You can run a standard Dometic fridge 24 hours a day for almost two weeks on a single 20# tank before it's empty.

Did you check your hoses and regulator really good? It does seem to be too much of a coincidence that it all happened after switching the fridge to gas so maybe there's something going on there. The manometer will tell you what's going on.

Those Dometic thermostats are not very good and I never could get one to work right in my unit. And I know many others that have the same issues. Unfortunately they are not replaceable with a standard thermostat since they communicate digitally to the control board in the AC unit. There's a workaround where you use the Dometic as an A/D converter and use a standard thermostat. I tried that and it works but it's complicated.

I eventually went with the EasyTouch RV thermostat and it's much nicer and works great. A little pricey but they are the only ones out there that have a replacement product for the Dometic.

As the EasyTouch guy told me they are thankful every day for Dometics lousy engineering. It's what keeps them in business!