Page 72 - Boiler_Operators_Handbook,_Second_Edition

Boiler Plant Operations 57

you will be able to tell immediately if the valve is open even then you can’t be certain that the conditions in
because they’ll try to close it and it will make at least your plant are identical to the conditions in the factory.
a quarter turn toward closed. If you leave the valve So, the initial start-up of a boiler requires a careful ap-
jammed open someone can think it’s closed because proach to lighting the initial fire. You should ensure air
it doesn’t spin that quarter turn. I was so used to that flow, make certain it’s linear on modulating boilers and
practice, and still believe in it, that I’m regularly foiled establish safe light-off conditions before thinking about
by someone leaving a valve jammed open. Thank good- starting to fire.
ness the important ones have to be rising stem so I can The codes require a minimum amount of building
tell their position by looking at them. opening to admit fresh air for combustion but I’ve found
that it’s frequently overlooked. If you’re starting up the
only boiler in the plant it’s possible there’s no way for
NEW START-UP combustion air to enter that boiler room. If the boiler is
an addition to an existing plant the likelihood that some-
There is a significant difference between starting a one paid attention to the requirements for combustion
boiler plant that is new and one that has been in opera- air is even more remote.
tion. Hundreds of wiring connections, pipe joints, and A basic rule is two openings consisting of one square
other work went into preparing the boiler and there’s inch in each opening for every 1,000 Btuh of boiler input
bound to be a few unforeseen problems as the start-up and a minimum of 100 square inches for small boilers.
proceeds. These guidelines should help you achieve Larger installations allow 4,000 Btuh per square inch. One
a smooth start-up. They should also be used after any opening should be high up in the building and the other
maintenance that resulted in opening a system. near the floor. Prior to starting a new boiler the avail-
First, have a written procedure prepared, not an ability of fresh air should be confirmed and the openings
outline. Each step should be described along with who should be labeled “combustion air, do not cover.”
is responsible for the action. In many cases it will be I’ve ventured into many a building where the air
the installing contractor’s responsibility to produce this openings were blocked because the operators could
document but you should check it for completeness and feel a draft. Then they couldn’t understand why their
accuracy. Imagine the start-up proceeding and try to boiler was smoking. Once you’ve confirmed the fresh
imagine all the things that could go wrong as well when air source make sure you have linear air flow on any
preparing or checking a written procedure. The follow- modulating boiler; refer to the chapter on tune-ups for
ing should be addressed by the written procedure. establishing linearity.
Make sure each fluid system is closed and ready to
Preparing for Operation accept fluids before opening shut-off valves. When pre-
Be certain the safety shutdown push-buttons, paring to admit liquids identify vent valves and make
switches, valves, and other devices are in place and op- certain they are open, you can’t put much water in a
erational. Test each one if possible and refuse to contin- boiler plugged full of air. If the fluid is admitted through
ue the procedure if one is not present or not operational. a pressure reducing station position a person to monitor
Check all electrical circuits for shorts and grounds the pressure in the system.
before energizing them. Make sure all equipment and Position observers to detect leaks in the piping and
piping is electrically grounded before admitting fluids equipment. Be certain that observers are capable of see-
into the plant. Energize all electrical circuits before admit- ing all drains leaving the plant to ensure hazardous or
ting fluids into the plant to ensure they can be powered toxic materials don’t escape. Ensure the person control-
up. Test all electrical emergency trips and shutdown de- ling the valve(s) admitting the fluid is in contact with
vices. De-energize circuits before admitting fluids. all observers and can shut the valves immediately if a
Prior to closing a boiler or pressure vessel inspect problem arises. Ensure personnel are positioned to close
it to ensure there are no personnel, tools, or other things vent valves as the system is filled.
inside that shouldn’t be there. In Amsterdam in 1967 I Have I said it before? Look at the instruction manu-
almost closed a boiler with ten shipyard workers nap- als. Know how much fluid is required to fill the system
ping in its furnace. and estimate the filling time. It’s another way to ensure
Small boilers can come set up from the factory to you know the fluid is going where it’s supposed to. Won-
reduce the chances of a problem on initial start-up. It’s dering where all that fuel oil went several minutes after
rare that a boiler to be attended is factory tested and the tank should have been full is not a comfortable feel-