Inspection and Maintenance
8-20
750-211 (revised 2009)
Promethean Boilers, Model 4WI Manual
2.
Position the cassette into the front door.
3.
Slide the cassette into position until it begins to contact the airbox gasket then measure the clearance between
the cassette flange and the front door mounting face. There must be clearance of at least 1/4” to provide ade-
quate gasket compression when the cassette is mounted tightly to the door.
4.
Secure the cassette with the fastening nuts.
5.
After the cassette has been secured to the front head, reconnect the davit to the front door by screwing in the
retaining bolt at the top centerline.
Check occasionally that the fan is securely tightened to the motor shaft. Check the clearance between the fan vanes
and housing as outlined in Section 8.13.
8.15 — Safety Valves
The safety valve is a very important safety device and deserves
attention accordingly.
Follow the recommendations of your boiler inspector regard-
ing valve inspection and testing. The frequency of testing,
either by the use of the lifting lever or by raising the steam
pressure, should be based on the recommendation of your
boiler inspector and/or the valve manufacturer, and in accor-
dance with Sections VI and VII of the ASME Boiler and Pres-
sure Vessel Code.
FIGURE 8-24.
Safety Valves
Avoid excessive operation of the safety valve; 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 oper-
ating pressure to the set pressure of the safety valve, allowing it to open and re-
seat 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 foreign 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 down time
of the boiler for valve repair or replacement. Repair of a valve must be done only
by the manufacturer or his authorized representative.
FIGURE 8-25.
Operating Safety Valves
Summary of Contents for 4WI
Page 46: ...Burner Operation and Control 2 22 750 211 revised 2009 Promethean Boilers Model 4WI Manual...
Page 62: ...Waterside Care and Requirements 3 16 750 211 revised 2009 Promethean Boilers Model 4WI Manual...
Page 70: ...Sequence of Operation 4 8 750 211 revised 2009 Promethean Boilers Model 4WI Manual...
Page 114: ...Adjustment Procedures 6 28 750 211 revised 2009 Promethean Boilers Model 4WI Manual...
