Maintenance; Maintenance And Cleaning Procedures - Xylem BCF Instruction Manual

3. In shutting down, flow of hot medium should be shut off
first. If it is necessary to stop circulation of cooling medium
the circulation of hot medium should also be stopped by
by-passing or otherwise.
4. Do not operate equipment under conditions in excess of
those specified on nameplate.
WARNING:
Failure to operate the heat exchanger
within the design pressure and temperature on the
nameplate may result in damage to the heat exchanger and
potential injury to adjacent personnel.
5. Drain all fluids when shutting down to eliminate possibility
of freezing and corrosion. To guard against water
hammer, condensate should be drained from steam
heaters and similar apparatus both when starting up and
when shutting down.
6. In all installations there should be no pulsation of fluids
since this causes vibration and strain with resulting leaks.
7. All gasketed joints should be checked after starting for
leaks and tightened if necessary.
WARNING:
The BCF, HCF & SSCF exchangers are
suit able for use as heaters using steam as the heating
medium. These exchangers are, however, fixed tubesheet
units and, therefore, not designed to absorb thermal shock
inherent in the intermittent service of on and off heating with
frequent short intervals of demand. Their recommended use
is where service is continuous or steady, with relatively long
periods between shutdown and start-up. Heat exchanger
failure due to thermal shock may result in potential personal
injury.

MAINTENANCE

1. Do not open heads until all pressure is off equipment and
the unit is drained.
2. Remove the bonnets. Inspect all tubes carefully for
possible erosion, corrosion, or foreign material.
3. Inspect all anodes to be sure they are neither excessively
corroded nor insulated with scale. Scrape to a bright
surface.
4. Inspect filters in the system to prevent foreign matter from
entering the exchanger.
BCF HCF & SSCF Heat Exchangers Installation, Operation, and Maintenance Manual
5. Do not blow out heat exchangers with air when operating
fluids are of a flammable or otherwise hazardous nature.
WARNING:
Proper precautions must be taken (special
clothing, equipment, etc.) to protect personnel from injury
due to escaping fluids.
f. Provide convenient means for frequently cleaning heat
exchangers as suggested below:
a. Circulating hot wash oil or light distillate through tubes
or shell at good velocity will effectually remove sludge or
other similar soft deposits.
b. Soft salt deposits may be washed out by circulating hot
fresh water.
c. Some cleaning compounds on the market, such as
"Oakite" may be used to advantage for removing sludge
or coke, provided hot wash oil or water, as described
above, does not give satisfactory results.
d. If none of the above described methods are effective for
the removal of hard scale or coke a mechanical means
may be used. The interior of the tubes may be rodded.
e. The exterior or shell side of the tubes of a fixed sheet
heat exchanger can only be cleaned chemically by
using a chemical dissolved in water solution. We
suggest that the user contact the manufacturer of the
cleaning chemical for instructions.
WARNING:
Proper precautions must be taken (special
clothing, equipment, etc.) to protect personnel from injury
due to escaping fluids.
7. When replacing heads, use a torque wrench.* Tighten 1/4"
diameter bolts (2" diameter units) to 6 ft-lbs., 5/16"
diameter bolts (3" & 4" diameter units) to 16 ft-lbs., and 3/8"
diameter bolts (5", 6", & 8" diameter units) to 24 ft-lbs. If the
gasket joint still leaks, tighten in 2 ft-lb. increments until
leak stops.
*The above torque values apply to well lubricated nut
bearing surfaces.
7