Page 73 - Boiler_Operators_Handbook,_Second_Edition

58 Boiler Operator’s Handbook

ing. Whenever possible have means of detecting the level Every time I’m told something was tested and I ask for
as the system fills so you will know what’s happening. the pressure, voltage, resistance, and I don’t get num-
bers I doubt it was done. Yesterday I checked on one of
Fill Systems those general statements and found it was a lie, the tests
Fill the system slowly. Whenever possible use by- hadn’t been done because there’s no way the results
pass valves even though the filling may be slower than would meet the requirements.
desired. The person attending to the valves controlling
fluid entering the systems should not leave that post Start Makeup Systems
and close the valves immediately upon instructions of, Once all pressure testing is completed, begin
or any sounds from, any observer. I must add that the operation of the systems in an orderly manner. Water
valve operator should announce at regular intervals af- softeners, dealkalizers, etc. should be placed in service
ter closing a fill valve. We once stood around waiting for to condition water to be fed to a boiler system. Provide
a boiler to fill for more than three hours when we finally means to drain water until water suitably conditioned
checked with the apprentice that was stationed on the for the boiler is produced. If the installing contractor
valve. He closed it when someone shouted “hold it” and was sloppy you’ll find yourself flushing mud, short
that’s how it had been for three hours. pieces of welding rod, and lunch bags containing left-
Observe vent valves and close them as fluid reach- overs out of the line and flushing will become a major
es them. After the system has filled operate the vent project. I can remember one job where we had to cut
valves again to bleed off any air that may have been the pipe caps off the bottom of drip legs to get the large
trapped and then migrated to the vents. When filling rocks out.
systems with compressible gas use testers and bleed
the system at the high or low points accordingly (high Establish Light-off Conditions
points for systems where the fluid is heavier than air, The combustible range (see fuels) is so narrow that
low points for fluids lighter than air). it really is difficult to establish conditions to create a fire
Allow the systems to reach supply pressure or in a furnace. Today’s modern boilers which surround
controlled pressure slowly while diligently looking for the fire with (relatively) cold surfaces don’t provide
leaks. Compressed gases (including air) will expand ex- heat or reflect it back to help maintain a fire making fir-
plosively if the container ruptures so your plan should ing difficult if conditions are not correct. On fixed fire
provide for small increases in pressure with hold points boilers (no modulation) check the instructions for any
at regular intervals to check for leaks and any signs of measurements that will help you establish the proper air
distortion of the vessel or piping that could be caused flow or conditions for the combustion air. On modulat-
by the pressure. A hold point, by the way, is when you ing boilers set the air flow at a low fire (minimum fire)
have reached a certain time or condition in an operation condition.
where you planned to hold everything while check- If there is no other means of determining where
ing that the procedure is happening as planned and all to set the air flow I start at maximum on fixed fire units
safety measures have been taken. In many cases they’re and 25% on modulating units. Yes, maximum is easy to
described in the SOP as a hold point. set and no, 25% isn’t that hard to determine. If you don’t
Hydrostatically test each system after it is filled fol- have a manometer make one by taping some clear tub-
lowing the procedures described for pressure testing. As ing to a yardstick (actually that’s a better manometer, I
with filling there should be a person assigned to control always have problems with the tubing coming off my
the pump or valve that is pressurizing the system. fancy purchased one); leave a loop of tubing hanging
Check electrical circuits that are connected to the off the low end to hold the water. You just need a way to
systems during hydrostatic tests to ensure the liquid did measure the air flow and pressure drop across anything
not introduce an undesirable ground. Check them again in the flow path is adequate.
after all test apparatus is removed and normal connec- Set up your manometer on a ten to one slope (Fig-
tions reinstated. ure 2-3) so every inch on the ruler is a tenth of an inch
Finally, make certain that all the tests performed in actual pressure. Position the end of the tubing at the
are documented. A note in the log saying “tested Boiler inlet of the forced draft fan or air inlet then fill the ma-
2” isn’t adequate. The documentation should contain nometer with water until the level is at zero. Run the fan
values that demonstrate you really did it. The log should to high fire (maximum) and record the reading on the
read “Tested Boiler 2 to 226 psig by the boiler gage.” manometer. Recall that pressure drop is proportional to