Customer called stating heat wasn’t operating properly. Arrived and initiated heat sequence and gas valve opened but no flames, second attempt all burners lit ran for roughly three minutes and then out again. Upon third attempt only first two burners lit. Evaluated valve and found gas pressure was too low for propane. Adjusted the pressure and found that adjustment screw was stripped and possibly the cause of issue. Also found that fresh air intake has been leaking condensate onto valve since install due to no condensate trap being installed. Replaced gas valve under warranty for customer and added in a condensate trap to direct water to drain and not the interior of furnace. System operating normally upon departure.