Question: I am replacing my Ammark c20 draft control with a Samson draft control due to Ammark stopped making these, anyone have experience with the samson control? Thanks Answer: The Samson is a better control than the Ammark and you will be happier with it. Once you set it, it will maintain a setting within about 15 degree F of the setting. It is marked in Celcius degrees, and as I remember 80 degrees C is the best setting for most boiler systems. As far as your last question, if your boiler tend to overheat, you should make certain that your overheat zone is working. This is a zone of heat that should be activated by an aquastat whenever your boiler hits a certain temp...usually about 195 degrees F. This dumps the heat until the boiler cools a bit.