RV Repair: heat wont work after converter replacement, purge air, gulfstream

Question
We have a '07  conquest supreme by gulfstream. Recently my  husband replaced the converter
, now the heat will start up but blows  out cold and then will kick off.  We would love your  opinion,   do you think the converter wasn't installed properly?  Or is it a problem with the furnace?  Thanks!

Answer
since the furnace tries to start, I am going to say not the converter.  

Usually this type of problem is due to ventilation in the burner area, or lack of propane.  The cold air is the purge air that comes out first.  It is so any residual vapors are not present before the ignition process.  Once a time has passed, the furnace will try to ignite a controlled amount of gas.  If it does not ignite or the thermal couple does not sense the heat of the fire, the furnace will shut down to protect itself.  

Check the regulator and propane.  then make sure the burner area can breathe.  It uses a vent door on the outside wall of the RV.  Then watch the start up process to see what is not taking place.  

Good luck.