
Chapter 4 — Sequence of Operation
4-4
Part No. 750-184
• Main gas valve (MGV)
• Main gas vent valve (MGVV) (if provided)
• Oil valve (OV)
• Main fuel valve light (FVL)
Firing Rate Circuit
• Damper motor transformer (DMT)
• Modulating damper motor (MDM)
• Manual-automatic switch (MAS)
• Manual flame control (MFC)
• Modulating control (MC)
To comply with requirements of insurance underwriters such as Factory
Mutual (FM), Industrial Risk Insurers (IRI) or others, additional interlock
devices may be used in addition to the circuits mentioned in section B.
High Fire Proving Circuit
• High fire switch (HFS)
Running Interlock and Limit Circuit
• Low oil pressure switch (LOPS)
• High oil pressure switch (HOPS)
• High oil temperature switch (HOTS)
• Auxiliary low-water cutoff (ALWCO)
C. SEQUENCE OF OPERATION - OIL OR GAS
On a combination fuel unit, the gas/oil switch must be set for the proper fuel.
The following sequence occurs with power present at the program relay (PR)
input terminals and with all other operating conditions satisfied.
Pre-Purge Cycle -
When the burner switch (BS) is turned “on,” and controls
wired in the “limit” and “fuel valve interlock” circuits are closed and no flame
signal is present, the “blower motor start circuit” is powered energizing the
blower motor starter (BMS). The load demand light (LDL) turns on. When
firing oil, the air compressor motor starter (ACMS) (if provided) is also
powered. Air purge valve (APV) (Nos. 5 and 6 oil only) remains deenergized.
At the same time, the program relay signals the modulating damper motor
(MDM) to open the air damper. The damper begins to open and drives to its
full open or high fire position. Opening the damper motor allows a flow of
purging air through the boiler prior to the ignition cycle.
On certain boilers the circuitry will include a high fire switch (HFS). The
purpose of the switch is to prove that the modulating damper motor (MDM)
has driven the damper to the open position during the pre-purge cycle. In
this instance, the “high fire proving circuit” is utilized.
The controls wired into the “running interlock circuit” must be closed within
10 seconds after the start sequence. In the event any of the controls are not
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 ...