Chapter 6 — Adjustment Procedures
6-8
Part No. 750-184
To properly set the
Modulating Control
, carefully adjust it under
load conditions, until the load is maintained with the burner firing
at a steady rate. The firing rate at that point may be full high fire or
slightly less, depending upon the relationship of the boiler size to
the load.
When the
Modulating Control
is set and the burner is in full high
fire, the scale setting of the
Modulating Pressure Control
on a steam
boiler will indicate the low point of the modulating range. The scale
setting of the
Modulating Temperature Control
on a hot water boiler
will have a reading that indicates the midpoint of the modulating
range.
The
Operating Limit
control should now be adjusted and the
differential established. In an installation that does not require a
very close control of steam pressure or water temperature the
adjustable differential (Figure 6-6 A to B) should be set as wide as
conditions permit, since a wide setting will provide less frequent
burner cycling.
The
High Limit Control
provides a safety factor to shut the burner
off in the event the
Operating Limit Control
should fail. The setting
of the control should be sufficiently above the
Operating Limit
Control
to avoid nuisance shutdowns. The setting must be within
the limits of the safety valve settings and should not exceed 90% of
the valve setting. The control requires manual resetting after it shuts
off the burner.
In the setting of the controls, consideration must be given to the
time required for a burner restart. Each start, requires a prepurge
period, plus the fixed time required for proving the pilot and main
flame. In addition, approximately one-half minute is required for the
damper motor to travel from low to high fire. The time lag may allow
pressure or temperature to drop below desirable limits.
F. MODULATING PRESSURE CONTROL (STEAM)
Turn the adjusting screw until the indicator is opposite the low point
of the desired modulating range. Modulated firing will range
between the low point and a higher point equal to the modulating
range of the particular control. In 0-15 psi controls the range is 1/
2 lb; in 5-150 psi controls the range is 5 lbs; in 10-300 psi controls
the range is 12 lbs.
!
Caution
To prevent burner shutdown at other than low-fire setting, adjust the
modulating pressure control to modulate to low fire BEFORE the
operating limit pressure control shuts off the burner. Failure to
follow these instructions could result in damage to the equipment.
G. OPERATING LIMIT PRESSURE CONTROL (STEAM)
Set the “cut-out” (burner-off) pressure on the main scale using the
large adjusting screw. Set the differential on the short scale by
turning the small adjusting screw until the indicator points to the
desired difference between cut-out and cut-in pressures. The “cut-
Summary of Contents for CB Ohio Special 100 HP
Page 2: ...ii ...
Page 8: ...viii ...
Page 42: ...Chapter 2 Burner Operation and Control 2 22 Part No 750 184 ...
Page 116: ...Chapter 6 Adjustment Procedures 6 28 Part No 750 184 ...
Page 126: ...Chapter 8 Inspection and Maintenance 8 6 Part No 750 184 ...
Page 153: ...Chapter 9 Parts Part No 750 184 9 3 Insulated Front Head Model CB LE ...
Page 154: ...Chapter 9 Parts 9 4 Part No 750 184 Insulated Front Head Interior Model CB LE ...
Page 155: ...Chapter 9 Parts Part No 750 184 9 5 Insulated Inner Door Model CB OS ...
Page 156: ...Chapter 9 Parts 9 6 Part No 750 184 Insulated Rear Head CB LE ...
Page 157: ...Chapter 9 Parts Part No 750 184 9 7 Insulated Rear Head CB LE ...
Page 158: ...Chapter 9 Parts 9 8 Part No 750 184 Insulated Rear Head CB OS ...
Page 159: ...Chapter 9 Parts Part No 750 184 9 9 Dry Oven Model CB LE ...
Page 161: ...Chapter 9 Parts Part No 750 184 9 11 Motor Impeller Model CB LE ...
Page 162: ...Chapter 9 Parts 9 12 Part No 750 184 Front Head Linkage ...
Page 170: ...Chapter 9 Parts 9 20 Part No 750 184 Control Cabinet Hawk ICS ...
Page 171: ...Chapter 9 Parts Part No 750 184 9 21 Control Panel Standard ...
Page 172: ...Chapter 9 Parts 9 22 Part No 750 184 Entrance Box ...
Page 173: ...Chapter 9 Parts Part No 750 184 9 23 Front Head Electrical CB LE ...
Page 174: ...Chapter 9 Parts 9 24 Part No 750 184 Front Head Electrical CB LE ...
Page 175: ...Chapter 9 Parts Part No 750 184 9 25 Front Head Electrical CB OS ...
Page 176: ...Chapter 9 Parts 9 26 Part No 750 184 Front Head Electrical CB OS ...
Page 179: ...Chapter 9 Parts Part No 750 184 9 29 Heavy Oil Piping 60 Steam CB LE ...
Page 180: ...Chapter 9 Parts 9 30 Part No 750 184 Heavy Oil Piping 60 Steam CB LE SEE TABLE NEXT PAGE ...
Page 181: ...Chapter 9 Parts Part No 750 184 9 31 Common Oil Parts Heavy Oil ...
Page 182: ...Chapter 9 Parts 9 32 Part No 750 184 Side Mounted Air Compressor Piping ...
Page 183: ...Chapter 9 Parts Part No 750 184 9 33 Air Compressor Piping CB OS ...
Page 185: ...Chapter 9 Parts Part No 750 184 9 35 Light Oil Piping ...
Page 186: ...Chapter 9 Parts 9 36 Part No 750 184 Light Oil Air Piping Front Head ...
Page 187: ...Chapter 9 Parts Part No 750 184 9 37 Light Oil Air Piping Front Head PAGE 9 31 ...
Page 191: ...Chapter 9 Parts Part No 750 184 9 41 Gas Train 125 150 HP ...
Page 193: ...Chapter 9 Parts Part No 750 184 9 43 Gas Train 200 HP ...
Page 195: ...Chapter 9 Parts Part No 750 184 9 45 Steam Pressure Controls ...
Page 196: ...Chapter 9 Parts 9 46 Part No 750 184 Hot Water Temperature Controls ...
Page 197: ...Chapter 9 Parts Part No 750 184 9 47 Water Column ...
Page 198: ...Chapter 9 Parts 9 48 Part No 750 184 Water Column ...
Page 199: ...Chapter 9 Parts Part No 750 184 9 49 Fireside Gaskets CB LE ...
Page 200: ...Chapter 9 Parts 9 50 Part No 750 184 Fireside Gaskets CB OS ...