750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual
3-13
3.9 — Periodic Inspection
5. Slightly crack the downstream valve and then close it tightly.
Under not circumstances should a blow-off valve be left open and the operator should never leave until the blow-
down operation is completed and the valves are closed.
3.9 — Periodic Inspection
Insurance regulations or local laws will require a periodic inspection of the pressure vessel by an authorized inspec-
tor. Sufficient notice is generally given to permit removal of the boiler from service and preparation for inspection.
When shutting down the boiler, 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 - 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, it is well to ask the inspector
observe the conditions prior to cleaning or flushing of waterside surfaces.
Be certain that a supply of manhole and handhole 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 a hydrostatic test.
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, fittings and
any previous repairs can be readily checked.
Be sure that steam valves, and valves to expansion tank (hot water), feedwater valves, blow-off valves, all fuel valves,
and electrical switches are shut off prior to opening handholes, manhole, and front or rear doors. Adequately vent
the pressure vessel prior to entry.
Clean out the low-water cutoff piping, the water level controls and cross-connecting pipes. Replace the water gauge
glass and clean out the water cocks. Also check and clean the drain and the blowdown valves and piping.
To avoid the hazard of electrical shock, we recommend the use of a low voltage flashlight during an internal inspection.
Preferably, inspectors should work in pairs. Failure to follow these instructions could result in serious injury or death.
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Warning
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