Coil Type Steam Boilers The combustion chamber and the smoke passages are accurately designed, which ensures that combustion occurs perfectly. It does not require any qualified boiler attendant. It is ideal for small and medium sized plants, where average steam pressure (10 Bar) is required. Units can also be designed for higher pressures.Salient Features of the SU - OilGas Fired, 3 Pass, Water Tube Coil Type Steam Boilers are Reverse flue design