What are the precautions to be observed when starting any boiler that has been closed
dow overnight? Are there any special precautions required starting a gas burning
boiler? ...ANSWER...Make a physical observation of the boiler and its systems, walk
around the boilerto check for any abnormal conditions such as flammable material at
the dampers, fuel leaks,damaged electrical conduits, etc. Check all boiler systems
(feedwater, fuel, etc). Very important issue in starting a gas firing boiler is a furnace
prepurge. It is never has to be altered or bypassed.
How do you determine whether feedwater check valve for the boiler is not
closing? ...ANSWER...Check the temperature differential at the check valve when
feedwater pump is not in operation.
What causes foaming in the boiler? How would you know when a boiler is foaming?
How do you stop foaming in a boiler? ...ANSWER...High TDS, organic matter and oil in
the boiler cases foaming. If the water level in the gage glass fluctuates, the most
probable cause of thisis foaming. We reduce amount of TDS by continuous and bottom
blowdowns;we use anti-foaming chemicals to prevent foaming.
What is boiler priming? What causes priming? How can priming in a boiler damage an
engine or pump? ...ANSWER...When the liquid water from the boiler drum gets to the
steam lines it called priming. Priming can be caused by boiler drum level excessively
high, by foaming, sudden pressure drop,and firing ratebeing to high. Priming causes
water hammer that could destroy or shorten the life expectancy of a load (mechanical
damage)
What would you do if the pressure gauge on the boiler registers 150 psi and you knew
that the safety valve was set to open at 100 psi? ...ANSWER...Most likely pressure
gage failed. In order to get such excessive pressure both operating and high pressure
limit controls have to fail also, plus the safety valve. Also, if the boiler was over
pressurized to such extent, it would give some indications such as excessive vibration
and abnormal sounds.Pressure gage can be quickly isolated and changed.
How do you test a safety valve to see if it operates at the proper set pressure? What is
the difference between a safety valve and a relief valve? How often do you test these
valves? How is leaking safety valve repaired? ...ANSWER...Pressure valves can be
tested hydrostatically (boiler filled up with water pressure).Safety valves open
instantaneously and relief valves do not open fully with a set pressure.Safety valves are
tested manually once a month and pressure tested once a year.Safety valves can be
only repaired by a manufacturer or an authorized company.
, What causes heavy black smoke from the firebox of an oil-burning
boiler? ...ANSWER...Most likely it is incomplete combustion caused by either improper
air/fuel ratio or dirty burners.
What does heavy yellow smoke from the firebox of an oil-burning boiler
indicates? ...ANSWER...It is most likely a good combustion of #6 oil.It typically gives
yellow or brownish haze from the stack.
Name some of the causes of an excessive amount of accumulated soot in the firebox
and tubes of an oil burning boiler. ...ANSWER...Improper air/fuel ratio.Dirty burner
nozzles.Poor fuel atomization.
How often should a boiler be blown down? If the boiler water is treated, is it necessary
to blow down the boiler everyday? Why? What is the purpose of treating the boiler
water? What is TDS? ...ANSWER...Boiler should be blown down at least once every 24
hours, even if the boiler water is treated. By doing bottom blowdown we get rid of mud-
like sludge and solid sediments that settle at the mud drum bottom. We chemically treat
boiler water to prevent formation of scale on boiler heating surfaces,pitting of boiler
metal, foaming and priming. TDS stands for "total dissolved solids". For a boiler up to
250 psi amount of TDS shall not exceed 3000 -3500 ppm.
What would you do if you could not see the water level in the boiler gauge glass while
the boiler is in operation? What would you do if the water level in the gauge glass
shifted up and down? ...ANSWER...First of all the gauge glass needs to be blown down
to find out whether the gauge glass is full or completely empty. If the boiler water level is
above NOWL, the level has to be lowered by bottom blow down. If the level is such that
it can not be seen in the gauge glass, the boiler burners have to be secured
immediately. If the water level in the boiler shifts up and down, it is indication of foaming
caused by excessive amount of TDS. Continuous blowdown has to be increased and in
addition, the boiler has to be bottom blowdown.
If the boiler feedwater pump is operating and the boiler feedwater is not rising, what is
the best thing to do? Can you increase the speed of the feedwater pump for more water
volume? ...ANSWER...One of the options available is to decrease firing rate of the boiler
and see if the water level stabilizes. Another option is to bring the second pump on
line.If these two options do not remedy the situation and the boiler water level cannot be
maintained, the boiler must be secured.We cannot increase speed of the feedwater
pump.
What is the boiler water pH? What pH reading is considered acidic or alkaline? Give an
example. ...ANSWER...pH of the boiler water should be in the range between 9.0 and
11.0.Power of hydrogen (pH) has the range from 1 to 14, the middle point 7 is neutral,
below 7 is water has acidic properties, and above 7 water is alkaline.
What is a superheater? What is the purpose of superheating steam? Does a
superheater requirea safety valve? Are there any precautions to be taken when bringing