Make sure on the new Digital Stat, that you switch it from HE to HG mode ( usually a lil switch on the back.. )
What the switch does:
HE -> Heat: Electric => Thermostat controls the fan in heat mode
HG -> Heat: Gas => Thermostat only controls the heat signal.. the Furnace controls the fan.
This is required since there is no fan control for Gas / Propane furnaces used in our coaches.
I've had mine on digial since the 1st week I had the RV ( Mid December ). LOVE IT!
Hope this helps,
LK