erensan°
“The Heating Engineer”
- 29 –
280111
obtained, improvement procedures should be performed
under control of expert water chemists. Our company
should be consulted on these topics.
• When water analyses cannot be done, bottom and
surface discharging should be performed at least 3 times
a day. Bottom discharging should be performed several
times with bottom discharge valve fully opened for at
most 3 seconds; surface discharge should be done
opening the surface discharge valve very little and
keeping it open for long times.
• The operation of the boiler gages and control devices
should be checked continuously every day and in case a
condition out of normal operational behavior is
observed, the boiler firing should be stopped under
control and the necessary inspections and evaluations
should be done. If needed, defective devices should be
replaced.
• Condenser tank temperature should be continuously
controlled and not let rise over 80
o
C. High water
temperature may cause cavitation in boiler feed pumps,
may result in pump failure in a short time and
intermittent water pumping into boiler may disrupt
normal operation. For this reason the condenser stops in
condenser lines should be checked and cleaned one by
one and should be replaced if steam leakage is still
observed.
• During the firing of boiler and pressure build up, the
boiler armatures and connections, manhole door gasket
edges should be controlled and any leakages should be
removed. The leakages detected after boiler operating-
pressure is reached, should not be handled immediately,
the required intervention should be performed after
combustion is stopped, boiler depressurized and
material temperature drops to enable handling.
• Steam valves should be opened and closed slowly.
Otherwise, steam impacts may form.
ADJUSTMENTS AND CONTROLS TO BE PERFORMED
Purchase of a boiler as a package with all armatures included,
is recommended. For steam boilers not purchased as a
package, armatures that suit the nominal values of boiler and
erensan
°
“The Heating Engineer”
- 30 –
280111
comply with standards should be used and support may be
requested from our company on armature selection.
Burner capacity adjustment should be made by the relevant
burner firm and not exceeded boiler nominal value.
Pressurestat adjustments should be made not to exceed boiler
operating pressure and in line with process requirements.
Boiler feedwater pump should turn in the direction indicated by
arrow, if it is in reverse, phase connections should be reversed.
The boiler water level should be checked from the level gage
and pressure from manometer and the boiler feed device
operation should be controlled continuously. Boiler safety valve
opening pressure (see safety valve adjustment table, page 28)
should be tested once a month and if weighted safety valve is
utilized, the weight positions should be constantly checked to
stay at marked positions.
Control of safety valves
The nominal values of safety values should be recorded at start
and these records should be kept. In boilers that have more
than one safety valve, the valve that opens at the greatest
pressure should be controlled first. For this purpose valves that
rate higher opening pressures should be locked with special
mechanisms and the safety valve spring to be controlled should
be released. When the boiler reaches operating pressure the
safety valve should be opened and closed manually several
times. This way the safety valve should be ensured to work
properly and valve body should be allowed to warm up.
After this, the boiler pressure should be raised to valve
discharge value and it should be checked whether the safety
valve opens automatically at required pressure. As soon as the
safety valve opens, combustion should be stopped and the
pressure should be dropped discharging steam to a level
enabling safe operation on valve.
Safety valves not rating desired nominal value are adjusted as
recommended by manufacturer. While adjusting safety valves
(especially high pressure and capacity boiler valves), the boiler
pressure should have been lowered to 20% under operating
pressure. The same inspection should be repeated after valve is
adjusted.
To Next Page