Discussions

Hey guys, seems like i have been on here a lot lately. I have some furnace troubles. I had a plumber here and he said that it needs a new "heat limit control". I was just wondering if anyone has any past experiences in replacing these or where I should be going next. he has been looking for a part and its been going on three days now.(I know there will be get a new plumber discussions). I am not sure where to go or what to do. I know its an old furnace but would like to keep this one going instead of purchasing a new one.  
 
Any help would be great. Thanks.