INSTALLATION, OPERATION AND MAINTENANCE MANUAL
Easco Boiler Corp 1175 Leggett Ave Bronx, NY 1047 T: 718.378.3000 F: 718.378.4560 [email protected] easco.com
Page 37 of 46
•
The amount of makeup water and blow-down required.
•
The use of the steam, i.e., for heating only or for other purposes.
•
The amount of supervision and control testing available.
7.3 Services of Water Treatment Specialist
Each Boiler installation should be considered on an individual basis. Review the final
decision with a reputable water treatment company. These companies furnish a
service and/or chemicals for boiler water treatment. They are in a position to make
recommendations based on local water conditions and the particular insulation in
evolved. They also furnish test kits accompanied by simple analytical procedures for
day-to-day analyzing by the local maintenance people. Samples are taken at suitable
intervals and sent to their laboratories for confirmatory analysis. When setting up
arrangements with such concerns, do not hesitate to ask for the chemical formula of
the treatments prescribed.
7.4 Conformity with Local Ordinances
Make sure the boiler compound used does not violate any local ordinance with respect
to disposal of blow-downs, draining of Boiler, etc.
7.5 Boiler Water Troubles
7.5.1 Corrosion – Raw water, as received from the city mains or wells, contains
impurities including dissolved gases such as oxygen and carbon dioxide. When the
water is soft, this makes the water acidic and corrosive. The boiler metal and condense
return lines will be attacked. This can be general overall corrosion or localized pitting
or cracking in stressed metal. High temperatures accelerate these reactions. If left
uncorrected, serious pitting can result with possible rupture of boiler tubes. Rusty water
in the gauge glass is a sure sign of corrosion in the heating system or in the Boiler itself.
7.5.2 Scale Deposits – All raw water contains dissolved salts. Where water is hard,
these are mainly calcium and magnesium compounds. Under boiler operating
conditions, these salts come out of solution and form scale deposits on the hot water
boiler metal. This is due to decomposition of the bicarbonates and to the decreased
solubility of calcium salts at higher temperatures. As the water is evaporated, the solids
are left behind and the scale deposits build up. Scale forms an insulating barrier on the
boiler tubes, resulting in heat losses and lower efficiency. Scale deposits can also cause
overheating and failure of boiler metal.
7.5.3 Metal (Caustic) Embattlement – Under certain conditions of high caustic
alkalinity where the metal is under stress, cracks can develop in the metal below the
waterline and in welds and longitudinal seams.
7.5.4 Foaming, Priming and Carryover – These difficulties, occurring in steam Boilers
only, are closely associated and refer to the formation of froth and suds on the surface
of the water.
Where this is severe, boiler water is carried over with the steam. Excessive dissolved
solids carried over can form deposits in the steam piping and valves.
