Low water and high water casualty
A very important rule in the safe operation of boilers is to keep water in the boiler at the proper level an as steady as the circumstances permit. Never keep you full upon automatic alarms or feed water regulators. At frequent intervals compare the readings of the several methods of determining water level. The water gauge cocks must be kept in good working condition, without leaking, and these will be kept in good order by frequently blowing through. Blow through the drain cock at the bottom of the gauge and shut and open the steam and water cocks every few hours. These cocks must be blown through more frequently when the water is dirty, and foaming, priming or other feed water troubles occur. Should either of the passage become choked, or whenever the water in the gauge glass moves sluggishly, the passage must be cleaned. Always test the glass water gauge thoroughly when charge of the boiler is taken. This should be
done by first opening the drain cock and then shutting the upper cock, which should give water; the upper cock should then be opened and the bottom closed which should give steam. If water and steam do not appear in proper order, the choked cocks and the passage water cock should be reopened after the steam cock. Have the water column well illuminated and keep the glass clear.
In the case of high water in a boiler, reduce the feed water flow slightly below the steam rate and blow down to lower the water to a safe operating level.
If the super heater temperature shows a sudden drop, it indicates that water is carried over into the super heater, and in this case the fuel must be shut off, blow down water to lower level, feed the boiler with fresh water, blow down again if required and then put the boiler back in service.
Unusual fluctuations in the water level must be checked and the cause determined. If any unusual or serious foaming occurs as indicated by a fluctuation of water level or sudden drop in super heater temperature, reduce steaming rates until the water level in the gage glass stabilizes adequately, so that the true level of water can be ascertained. If the level of the water is sufficiently high, blow down some water and feed fresh water in the boiler. Resort to alternate blowing down and feeding several times and if the foaming does not stop, bank it fire and continue blowing down and feeding. After correcting the
water condition, test safety valves and the connections to pressure gauge and the water column for any sticking or choking. Blow out pressure gauge and water column gage glass drains.
Look for any signs of oil in water glasses, surface blow down and feed water heaters. If oil is found, shut down the boiler as soon as possible and clean the boiler thoroughly. If the amount of oil or grease is large, boil out the boiler. Find out the source of oil pollution and set it right before putting the boiler back into service. Oil or grease prevents free transmission of heat and leads to overheating with consequent bulging, distortion, rupturing etc.