2 - INSTALLATION
© Fulton 2018
2-20
VSRT_IOM_2018-1213
Be sure that the supplied feedwater pump will operate
at elevated feedwater tank temperatures. The standard
turbine pump has a maximum operating feedwater
temperature of 180
˚
F.
Reverse Osmosis / Deionized (RO/DI) water is water from
which all dissolved solids have been removed. (Consult
factory for recommended controls and equipment for
operating on RO/DI water.)
If RO/DI water is used as a water source in a carbon steel
boiler, it must be neutralized to pH >7.5 prior to entering
the boiler. Failure to neutralize the RO/DI will void the PV
warranty and cause high general corrosion rates.
The Fulton Warranty does not cover damage or failure that
can be attributed to excessive corrosion, scale or fouling.
GLOSSARY OF WATER SUPPLY TERMS
Dissolved Oxygen
: Oxygen that is dissolved in the
feedwater will cause the steel in the boiler and the
feedwater system to be attacked by the water in a
manner described as “pitting”. The pits that are produced
can vary from tiny depressions to holes large enough
to penetrate the boiler metal and are usually covered
with tubercles of iron oxide. Once pitting starts, it may
be extremely hard to arrest. Pitting can proceed at a
surprisingly rapid rate and can occur not only in the
boiler proper, but also in pre-boiler equipment such as
economizers, feedwater tanks, and feedwater lines.
Suspended Solids:
Suspended solids are the
undissolved matter in water, including dirt, silt,
vegetation, iron oxides, and any other insoluble matter.
Normally suspended solids are expressed in terms
of turbidity. Suspended solids may also deposit in
low velocity areas and create fouling. In line filters, or
various types of pretreatment can be used to lower
the suspended solids level. Periodic blowdowns will
eliminate suspended solids.
Alkalinity:
Alkalinity is the capacity of a water to
neutralize acids. Common water alkalinities consist of
bicarbonate, carbonates, hydroxide, phosphate, and
silicate. These alkalinities, especially bicarbonates and
carbonates, break down to form carbon dioxide in steam,
which is a major factor in the corrosion on condensate
lines. High alkalinity also causes foaming and carry over in
boilers. Both foaming and carry over cause erratic boiler
operation. The reason for the high alkalinity should be
determined. It may result from lack of sufficient blow off.
The source of alkalinity may be due to an overdose of
alkaline internal water treatment chemical.
pH:
pH is a measure of the degree of acid or base of
solution. A pH range of 8.5-10.5 will have little influence
on the corrosion rate of carbon steel. A low pH can
result in corrosion of metals, while a high pH can result
in scale formation or caustic embrittlement. In order
to control boilers and equipment used for the external
treatment of make-up water, it is essential that reliable
pH measurements be made. RO/DI water will have a low
pH and will require neutralization if used in a carbon
steel vessel. It is critical that the boiler pH be alkaline
(8.5-10.5) whenever water is in the boiler.
Chlorides:
If chloride levels are high enough to cause
severe corrosion, they can be controlled by limiting
the cycles of concentration and increasing boiler
blowdowns. Corrosion from chlorides can also be
controlled by increasing the amount of corrosion
inhibitor, or changing to a more effective inhibitor.
Oil:
Oil is not a natural constituent of boiler water;
still it can frequently enter a system through leaks
in a condenser or other heat exchanger. Oil can also
enter a system through the lubrication of steam driven
reciprocating equipment. Whatever the source, the
presence of oil in boiler water is undesirable. Oil can act
as a binder to form scale. In high heat-transfer areas oil
can carbonize and further contribute to the formation
of scale and low pH. Foaming is one indication of oil in
boiler water. Its presence can also be confirmed by first
shaking a bottle containing boiler water. If oil is present
foam will result. Often oil in boiler water will originate in
the condensate. This contaminated condensate should
be directed to the sewer until the source of the oil is
determined and corrective steps taken.
Iron (oxides):
Iron in any of its oxide or complex forms
is undesirable in boiler water. Iron in its various forms
can originate in the raw water makeup, condensate
return water, or form directly in the boiler as a result of
corrosion. It can concentrate in the boiler and it tends to
collect in stagnant areas.
Water Hardness:
Water hardness is the measure of
calcium and magnesium content as calcium carbonate
equivalents. Water hardness is a primary source of scale
in boiler equipment. Hardness is removed by softening.
Periodically, the ion exchange resin bed requires
regeneration by flushing through with a brine solution