Inspection and Maintenance
7-12
750-96 (revised 2010)
Model CB Packaged Boiler Manual
over-tightening as this can distort the seats. Use only flat-jawed wrenches on the flats provided. When installing a
flange-connected valve, use a new gasket and draw the mounting bolts down evenly. Do not install or remove side
outlet valves by using a pipe or wrench in the outlet.
A drip pan elbow or a flexible connection between the valve and the escape pipe is recommended. The discharge
piping must be properly arranged and supported so that its weight does not bear upon the valve.
Do not paint, oil, or otherwise cover any interior or working parts of the safety valve. A valve does not require any
lubrication or protective coating to work properly.
Follow the recommendations of your boiler inspector regarding valve inspection and testing. The frequency of test-
ing, either by the use of the lifting lever or by raising the steam pressure, should be based on the recommendation
of you boiler inspector and/or the valve manufacturer, and in accordance with sections VI and VII of the ASME
Boiler and Pressure Vessel Code.
Avoid excessive operation of the safety valve as even one opening can provide a means of leakage. Safety valves
should be operated only often enough to assure that they are in good working order. When a pop test is required,
raise the operating pressure to the set pressure of the safety valve, allowing it to open and reseat as it would in
normal service.
Do not hand operate the valve with less than 75% of the stamped set pressure exerted on the underside of the
disc. When hand operating, be sure to hold the valve in an open position long enough to purge accumulated for-
eign material from the seat area and then allow the valve to snap shut.
Frequent usage of the safety valve will cause the seat and disc to become wire drawn or steam cut. This will cause
the valve to leak and necessitate downtime of the boiler for valve repair or replacement. Repair of a valve must be
done only by the manufacturer or his authorized representative.
Avoid having the operating pressure too near the safety valve set pressure. A 10% differential is recommended.
An even greater differential is desirable and will assure better seat tightness and valve longevity.
Steam is expensive to generate and, for the sake of economy, wastage should be avoided whenever possible.
7.14 — Fuel Oil Metering Valve, Adjusting and Relief Valves
In the event that a leak occurs in the packing of the metering valve, the packing nut should be snugged gradually
to stop the leak.
If replacement of the metering valve packing is necessary, procure the P/N 880-370 kit and install per the follow-
ing instructions:
1. Shut off the oil flow. Be sure no pressure shows on the gauge.
2. Match mark the cam hub and drive shaft. This will enable replacement of the cam in its original position and
result in a minimum of cam adjustment when the burner is refired.
3. Clamp or hold the metering stem in the down position.
NOTE: Excessive tightening of the metering valve packing nut prevents free movement of the metering stem.
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