CleaverBrooks 4WI, Operation, Service And Parts Manual

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750-211 (revised 2009)
Promethean Boilers, Model 4WI Manual 3-13
3.8 — Periodic Inspection
3.7.3 — Manual Blowdown Procedure
Blowdown is most effective at a point when the generation of steam is at the lowest rate and feedwater input is also
low.
Be sure the blowoff piping and separator tank are in proper operating condition. Discharge vents should be clear of
obstruction, and the waste should be piped to a point of safe discharge.
If a quick opening valve and globe type of slow opening valve are in combination, the former is normally opened
first and closed last with blow down accomplished with the globe or slow opening valve.
When opening the second slow opening valve, crack it slightly to allow the lines to warm, then continue opening
slowly.
The length of each blow should be determined by actual water analysis. Lowering the water in the gauge glass
approximately 1/2” is often acceptable as a guide to adequate blow. However, lowering the water 1/2” should not
be interpreted as a rule since water analysis procedures should prevail. If the glass cannot be viewed by the party
operating the valve, another operator should watch the glass and direct the valve operator.
Close the downstream (slow opening) valve first and as fast as possible. Then close the valve next to the boiler.
Slightly crack the downstream valve and then close it tightly.
Under no circumstances should a blowoff valve be left open and the operator should never leave until the blow-
down operation is completed and the valves are closed.
3.8 — 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.
Do not pump the lever action valve open and closed, as water hammer is apt to break the valve bodies or pipe fittings.
Failure to follow these instructions could cause damage to the equipment.
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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Caution
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Warning