750-96 (revised 2010)
Model CB Packaged Boiler Manual
2-13
2.9 — Periodic Inspection
Under no circumstance should a blow-off valve be left open and the operator should never leave until the blowdown
operation is completed and valves closed.
2.9 — Periodic Inspection
Insurance regulations or local laws will require a periodic inspection of the pressure vessel by an authorized
inspector. Sufficient notice is generally given to permit removal of the boiler from service and preparation for
inspection.
When shutting down, the load should be reduced gradually and the pressure vessel cooled at a rate that avoids
damaging temperature differential that can cause harmful stresses. Vessels should not normally be drained until all
pressure is relieved, again to prevent uneven contraction and temperature differentials that can cause expanded
tubes to leak. Draining the unit too quickly may cause the baking of deposits that may be present on the heating
surfaces. Some heat, however, may be desirable to dry out the interior of the boiler.
If the internal inspection is being made at the request of an authorized inspector, ask him if he desires to observe
the conditions prior to cleaning or flushing of waterside surfaces.
Be certain that a supply of manhole and hand hole gaskets is available, along with any other gaskets or items
needed to place the unit back into operation after inspection.
Have available information on the boiler design, dimensions, generating capacity, operating pressure or tempera-
ture, time in service, defects found previously, and any repairs or modifications. Also have available for reference
records of previous inspections.
Be prepared to perform any testing required by the inspector including hydrostatic.
After proper cooling and draining of the vessel, flush out the waterside with a high pressure water hose. Remove
any scale or deposits from the waterside surfaces and check for internal or external corrosion and leakage.
The fireside surface should also be thoroughly cleaned so that metal surfaces, welds, joints, tube ends, fitting, and
any previous repairs can be readily checked.
Be sure that steam valves, system valves (hot water), feedwater valves, blow-off valves, all fuel valves, valves to
expansion tank, and electrical switches are shut off prior to opening hand holes, manhole, and front or rear doors.
Adequately vent the pressure vessel prior to entry. Flashlights rather than extension cords are recommended as a
safety factor. Cleansers should preferably work in pairs.
Clean out the low water cutoff piping, the water level controls, and cross-connecting pipes. Replace water gauge
glass and clean out water cocks and tri-cocks. Also check and clean drain and blowdown valves and piping.
Check all water and steam piping and valves for leaks, wear, corrosion, and other damage. Replace or repair as
required.
Courtesy of: C3 Surplus LLC
Surplus Industrial Superstore
305-428-2777
https://www.c3surplus.com
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