A. It will eventually cause them to leak.
Q. How should a fire be regulated in case of temporary stoppage by accident or otherwise under full head of steam?
A. Close the damper and keep the fire door closed; then open small door in smoke box or the damper in chimney.
Q. Why not leave the fire door open?
A. Because it would allow the cold air to come in contact with flue sheet and flues, and consequent damage to boiler.
BANKING FIRES.
To bank a fire in a furnace, push the fire in a heap at the back of the furnace against the flue sheet; leaving a large portion of the grate open, to allow the air caused by the natural draught to pass up over the fire to the flues; then cover it over with fine coal or a layer of dry ashes, and see that the draught door is closed to prevent draught as much as possible.
This being done, the fire will last over night, and when ready to start again in the morning, all that is necessary to do is to rake the fire over the grates, open the damper and apply more fuel.
Q. What benefit is derived from banking the fire?