Catalytic stoves require special firing techniques. Instruction for these techniques will be found in the stove manufacturer's manual. If the manual for the appliance has detailed firing instructions, they should be followed. This is very important for smooth operation of the stove.
In short, the combustor needs light-off temperature before the by-pass should ever be closed.
A temperature of 500 degrees F. must be focused on the catalytic combustor for as least 25-30 minutes before the by-pass is closed. This will assure you that the combustor has had ample time to light-off. This is just a rule of thumb for any catalytic stove. Remember to read the manufacturer's manual before building the first fire in you stove or contact Applied Ceramics.