How to choose gas , LPG,LNG Fired steam boiler?

Gas,LPG,LNG all can be fired at the same type of burner ,but need to control well about the pressure. the burner we choose original came from Europe brand,work stable and excellent.The boiler is horizontal, wet-back, triple back structure, it's easy operate and all automaticlly work 

Plz leave Mer boiler a message to get more cheap boiler price!