That can be accomplished with a modestly-priced mechanical timer.
Like *expletive deleted*it it can!
And trying to control a pellet stove like that can have some damned bad consequences!
Pellet stoves aren't on-off devices like a lamp. There's considerable computerized control and programming behind them and they require constant power to maintain programming presets.
My pellet stove has a power supply rocker switch that controls power to the entire stove, but that switch does NOT control the stove's cycle.
If the stove is on and running and the power goes out, when power is restored to the stove it doesn't start running again, it defaults to off. In order to restart it you have to physically interact with the control panel.
In essence, using a mechanical timer would replicate a power failure.
Even worse, it can be anywhere from bad to VERY bad to continually interrupt line power to a pellet stove. More than a few people have reported control board failures due to power outages and the surges that can result when power is restored.
It's also QUITE bad to have the stove shut down while it's still got a fire going in it. Pellet stoves have preprogrammed shutdown sequences that are designed to prevent smoke from backing up into the house, and that requires power to run the fans and cycle through the various stages of the shutdown process.