Modine Heater Help

[boaty3]

Guys I got a modine heater Model PDP200. Problem I am having is the unit will light across all the burners just fine and the fan comes on and works just fine, basically the heater works great. BUT, after it runs for a couple minutes occasionally it will make slight bang noise and a small flame blows out the vent on the bottom of the heater. Only seems to do it once but when it cycles on again later it may do it again. What could cause this? I've already checked the heat exchanger visibly for cracks or holes but dont see any. Thanks for the help.

 

[JC23]

Sounds serious. Have you called Modine?

 

[Captain Sparky]

A couple of things you can check is to drop the burner out of the heater and see if any of the ports on top of the burner have split where the have been spot welded together and you can also run something inside the burner orifices to make sure no spider webs have been built inside them.

 

[Vegaman_Dan]

Does thsi have the right orifice and pressure set? It almost sounds like it's building up too much pressure and blowing past a seal. Was it set for propane instaed of NG?