01-23-2011, 05:51 PM
I recently purchased a used, early 1990's, Modine overhead 75K btu gas heater (PAE75). When I first got it home before I hung it up I hooked it up and it took right off and blew good heat. This weekend I finally got it hung up and I so I wanted to test it out again to make sure everything was working and it took right off again, but after running about 15 minutes I noticed it was blowing cold air and after investigating the burners weren't lit any longer, but the fan was still running. Now no matter what I do the main burners won't light. The pilot light is lit and is a good strong flame, so that's not the issue. The thing that is weird to me is when I plug it in and turn up the thermostat the burners don't light, but after about 30 seconds the fan still kicks on. I thought most heaters had a sensor that made sure the burners were lit before the fan kicked on, which makes this case confuse me that much more. I don't really have any experience working on heaters, but I'm usually pretty good with anything mechanical, I just have no idea what could be wrong with this thing. I have checked all the wires and connections and everything seems solid. I have not yet vented it through my roof, as I want to make sure this thing is going to work before I do that, but that wouldn't be causing this problem would it? Does anyone have any idea what could possibly be going on with this heater? Any help or suggestions would be great.