metal surfaces in which the temperature is 130F
boiler that has stainless-steel coils. You will need to
(54.4C) or above. In dealing with these characteristics,
check the DFT to make sure it is working properly. You
let's first briefly describe the test for chloride.
will use the feedwater dissolved oxygen test to detect a
malfunctioning DFT. In the case of a malfunctioning
CHLORIDE TEST.-- To perform the chloride test,
DFT, you must find the cause of the malfunction and
you should add two dippers of cupric sulfate to a 10 mL
have it corrected immediately. Dissolved oxygen
sample of Nalcool 2000 treated coolant. Allow it to stand
contamination can often be traced to the following
until the sample is filtered. Then, immerse the end of a
mechanical failures:
quantab chloride test strip in the sample. After an
exposure period, remove the quantab and read the scale.
1. Improper operation of the DFT spray valves or
Use the conversion chart included in the quantab test
steam atomizing valve
strip bottle to convert the scale reading to ppm chloride.
2. Inadequate venting of the DFT
NITRITE TEST.-- For the nitrite test, take 1 mL of
3. Excessive water level in the DFT, flooding the
Nalcool treated coolant and dilute it with 100 mL of
steam atomizing valve
distilled water. Dip a nitrite test strip into the diluted
4. A fluctuating steam supply pressure as a result
sample. After a brief development time, compare the
of a malfunction of the steam control valve
color on the stick with the color chart on the side of the
test stick container to determine the nitrite content.
CONTROL METHODS.-- For a brief review of the
methods you should use for feedwater contamination
When chloride and nitrite tests are performed, there
control, look again at the chart in table 2-1. Again, notice
are some important steps that are frequently overlooked.
that some of the test frequencies say "as required." All
You can avoid these mistakes by taking the following
of these areas are monitored by an individual
precautions:
salinity/conductivity indicator. The test frequency will
1. Always check the expiration date on the quantab
be based on the chemical test comparison results.
and nitrite test stick bottles. Do not use the test
To perform salinity indicator comparison tests
sticks if the date has expired.
correctly, there are two things you must keep in mind:
2. Do not try to use another quantab conversion
1. Do not perform a comparison test on a feedwater
chart if the one for the bottle you are using is
tank sample within 1 hour of adding distillate to
missing. Because the quantabs are produced in
the feed tank.
batches, the conversion chart with each quantab
bottle is specifically for use with the quantabs in
2. Do not perform comparison tests within 1 hour
that bottle.
after starting or securing a waste heat boils.
During start-up and securing, the water level in
3. Always keep the quantab and nitrite test stick
the steam drum/separator will increase and
bottles tightly closed when they are stored.
b o i l e r water will overflow into the
4. Never immerse the entire quantab test strip
steam/condensate system. This contamination
beneath the level of the solution you are testing;
will cause the indicators to read higher than the
otherwise, the test will give you a false low
chemical chloride test.
result.
By taking these precautions and preforming the tests
Jacket Water
correctly, you can obtain reliable test results that will
help you monitor and maintain the jacket water system.
You must test the jacket water system for nitrite and
chloride concentration levels. For proper protection of
Waste Heat Water
the jacket water cooling system, you should maintain the
nitrite (NO2) concentration level at a minimum of 1,000
The nitrite test is the only test you will need for the
ppm and the chloride level below 100 ppm. If the nitrite
level is below 1,000 ppm, the Nalcool 2000 will not
waste heat water system. To perform this test, dip a
provide adequate corrosion protection. Chloride levels
nitrite test stick directly into a sample of waste heat
water. After a brief development time, compare the color
above 100 ppm indicate that seawater has leaked into
on the stick to the color chart on the container to
the coding system. Another characteristic you should
know about seawater is that it contains "hardness." The
determine the nitrite concentration level. Ideally, the
nitrite concentration should he zero. From time to time,
hardness in seawater will cause scale formation on hot
