CleaverBrooks CBLE User manual

Table Of Contents
Model CBLE
Packaged Boiler
250 - 350 HP
Operation and Maintenance Manual
750-91
12/09
Light OIl, Heavy Oil, Gas, or Combination
Compliments of Power Mechanical, Inc.
Used Boilers
Rental Boilers

ii
!DANGER WARNING
If the information in this manual is not fol-
lowed exactly, a fire or explosion may re-
sult causing property damage, personal
injury or loss of life.
— Do not store or use gasoline or other
flammable vapors and liquids in the vicin-
ity of this or any other appliance.
— WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do
not use any phone in your building.
• Immediately call your gas supplier
from a neighbor's phone. Follow the
gas supplier's instructions.
• If you cannot reach your gas supplier,
call the fire department.
— Installation and service must be per-
formed by a qualified Cleaver-Brooks,
service agency or the gas supplier.
Improper installation, adjustment, service, or
maintenance can cause equipment damage, per-
sonal injury, or death. Refer to the Operation and
Maintenance manual provided with the boiler. In-
stallation and service must be performed by a
qualified Cleaver-Brooks service provider.
!DANGER WARNING
!DANGER WARNING
Be sure the fuel supply which the boiler was de-
signed to operate on is the same type as specified
on the boiler name plate.
!DANGER
WARNING
Should overheating occur or the gas supply valve
fail to shut off, do not turn off or disconnect the
electrical supply to the boiler. Instead turn off the
gas supply at a location external to the boiler.
!DANGER
WARNING
Do not use this boiler if any part has been under
water. Immediately call your Cleaver-Brooks ser-
vice representative to inspect the boiler and to re-
place any part of the control system and any gas
control which has been under water.
!DANGER WARNING
To minimize the possibility of serious personal injury,
fire or damage to the equipment, never violate the fol-
lowing safety rules.
— Always keep the area around the boiler free of com-
bustible materials, gasoline, and other flammable liq-
uids and vapors
— Never cover the boiler, lean anything against it,
stand on it, or in any way block the flow of fresh air to
the boiler.
This manual must be maintained in legible condi-
tion and kept adjacent to the boiler or in a safe
place for future reference. Contact your local
Cleaver-Brooks representative if additional manu-
als are required.
Notice
Where required by the authority having jurisdic-
tion, the installation must conform to the Standard
for Controls and Safety Devices for Automatically
Fired Boilers, ANSI/ASME CSD-1.
Notice
The boiler and its individual shutoff valve must be
disconnected from the gas supply piping system
during any pressure testing of that system at test
pressures in excess of 1/2 psi (3.5 kPa).
!DANGER
WARNING
The installation must conform to the requirements
of the authority having jurisdiction or, in the ab-
sence of such requirements, to UL 795 Commer-
cial-Industrial Gas Heating Equipment and/or the
National Fuel Gas Code, ANSI Z223.1
!DANGER
WARNING

iii
Please direct purchase orders for replacement manuals to your local Cleaver-Brooks authorized representative
Manual Part No. 750-91
12/09 Printed in U.S.A.
Cleaver-Brooks 2009
CLEAVER-BROOKS
Model CBLE
250-350 HP
Light Oil, Heavy Oil, Gas, or Combination
Operation and Maintenance Manual

iv
TO: Owners, Operators and/or Maintenance Personnel
This operating manual presents information that will help to properly operate and care for the equipment. Study its con-
tents carefully. The unit will provide good service and continued operation if proper operating and maintenance instruc-
tions are followed. No attempt should be made to operate the unit until the principles of operation and all of the
components are thoroughly understood. Failure to follow all applicable instructions and warnings may result in severe
personal injury or death.
It is the responsibility of the owner to train and advise not only his or her personnel, but the contractors' personnel who
are servicing, repairing or operating the equipment, in all safety aspects.
Cleaver-Brooks equipment is designed and engineered to give long life and excellent service on the job. The electrical
and mechanical devices supplied as part of the unit were chosen because of their known ability to perform; however,
proper operating techniques and maintenance procedures must be followed at all times. Although these components af-
ford a high degree of protection and safety, operation of equipment is not to be considered free from all dangers and
hazards inherent in handling and firing of fuel.
Any "automatic" features included in the design do not relieve the attendant of any responsibility. Such features merely
free him of certain repetitive chores and give him more time to devote to the proper upkeep of equipment.
It is solely the operator’s responsibility to properly operate and maintain the equipment. No amount of written instructions
can replace intelligent thinking and reasoning and this manual is not intended to relieve the operating personnel of the
responsibility for proper operation. On the other hand, a thorough understanding of this manual is required before at-
tempting to operate, maintain, service, or repair this equipment.
Because of state, local, or other applicable codes, there are a variety of electric controls and safety devices which vary
considerably from one boiler to another. This manual contains information designed to show how a basic burner operates.
Operating controls will normally function for long periods of time and we have found that some operators become lax in
their daily or monthly testing, assuming that normal operation will continue indefinitely. Malfunctions of controls lead to
uneconomical operation and damage and, in most cases, these conditions can be traced directly to carelessness and
deficiencies in testing and maintenance.
It is recommended that a boiler room log or record be maintained. Recording of daily, weekly, monthly and yearly main-
tenance activities and recording of any unusual operation will serve as a valuable guide to any necessary investigation.
Most instances of major boiler damage are the result of operation with low water. We cannot emphasize too strongly the
need for the operator to periodically check his low water controls and to follow good maintenance and testing practices.
Cross-connecting piping to low water devices must be internally inspected periodically to guard against any stoppages
which could obstruct the free flow of water to the low water devices. Float bowls of these controls must be inspected
frequently to check for the presence of foreign substances that would impede float ball movement.
The waterside condition of the pressure vessel is of extreme importance. Waterside surfaces should be inspected fre-
quently to check for the presence of any mud, sludge, scale or corrosion.
It is essential to obtain the services of a qualified water treating company or a water consultant to recommend the proper
boiler water treating practices.
The operation of this equipment by the owner and his or her operating personnel must comply with all requirements or
regulations of his insurance company and/or other authority having jurisdiction. In the event of any conflict or inconsis-
tency between such requirements and the warnings or instructions contained herein, please contact Cleaver-Brooks be-
fore proceeding.
DO NOT OPERATE, SERVICE, OR REPAIR THIS EQUIPMENT UNLESS YOU FULLY UNDERSTAND ALL
APPLICABLE SECTIONS OF THIS MANUAL.
DO NOT ALLOW OTHERS TO OPERATE, SERVICE, OR REPAIR THIS EQUIPMENT UNLESS THEY FULLY
UNDERSTAND ALL APPLICABLE SECTIONS OF THIS MANUAL.
FAILURE TO FOLLOW ALL APPLICABLE WARNINGS AND INSTRUCTIONS MAY RESULT IN SEVERE
PERSONAL INJURY OR DEATH.
!DANGER WARNING

750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual v
Model CB-LE Packaged Boiler 250-350 HP
750-91
Table of Contents
CHAPTER 1 Basics of Firetube Operation 1-1
1.1 — Introduction 1-1
1.2 — The Boiler 1-3
1.3 — Construction 1-4
1.4 — Steam Controls (All Fuels) 1-5
1.4.1 — Operating Limit Pressure Control 1-5
1.4.2 — High Limit Pressure Control 1-5
1.4.3 — Modulating Pressure Control 1-6
1.4.4 — Low Water Cutoff and Pump Control 1-6
1.4.5 — Water Column Assembly 1-7
1.4.6 — Water Column Drain Valve 1-7
1.4.7 — Water Gauge Glass Drain Valve 1-7
1.4.8 — Vent Valve 1-7
1.4.9 — Stack Temperature gauge 1-7
1.4.10 — Auxiliary Low-Water Cutoff 1-8
1.4.11 — Safety Valve(s) 1-8
1.5 — Hot Water Controls (All Fuels) 1-9
1.5.1 — Water Pressure and Temperature Gauge 1-9
1.5.2 — Operating Limit Temperature Control 1-9
1.5.3 — High Limit Temperature Control 1-9
1.5.4 — Modulating Temperature Control 1-9
1.5.5 — Low-Water Cutoff 1-9
1.5.6 — Auxiliary Low-Water Cutoff (optional) 1-10
1.5.7 — Safety Valve(s) 1-10
1.6 — IFGR Components 1-10
1.6.1 — Flue Gas Transfer Port, IFGR Damper, & Flange Collar 1-10
1.6.2 — IFGR Damper Linkage 1-10
1.6.3 — Over-Travel Mechanism 1-11
1.6.4 — Fuel Change-Over Linkage 1-11
1.6.5 — Fan/Motor Cassette 1-12
1.6.6 — Burner Drawer 1-12
1.6.7 — Combustion Air Inlet 1-12
1.6.8 — Front Door Insulation 1-12

vi 750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual
CHAPTER 2 Burner Operation and Control 2-1
2.1 — The Burner 2-1
2.2 — Control and Component Function 2-3
2.3 — Components Common to All Boilers 2-3
2.4 — Controls for Gas Firing 2-5
2.5 — Controls Common to Oil-Fired Boilers 2-9
2.6 — Additional Controls for Heavy Oil 2-13
2.7 — Controls for Combination Burners Only 2-15
2.8 — Combustion Air 2-16
2.9 — Automatic Ignition 2-16
2.10 — Atomizing Air 2-17
2.11 — Oil Fuel Flow: Light Oil 2-17
2.12 — Oil Fuel Flow: Heavy Oil 2-19
2.13 — Gas Fuel Flow 2-21
2.14 — Modulating Firing 2-21
CHAPTER 3 Waterside Care and Requirements 3-1
3.1 — Overview 3-1
3.2 — Water Requirements: Hot Water Boiler 3-1
3.2.1 — Air Removal 3-1
3.2.1.1 — Minimum Water Temperature 3-2
3.2.1.2 — Rapid Replacement of Boiler Water 3-2
3.2.1.3 — Continuous Flow Through the Boiler 3-2

750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual vii
3.2.2 — Water Circulation 3-2
3.2.2.1 — Multiple Boiler Installations 3-3
3.2.2.2 — Pump Location 3-4
3.2.2.3 — Pump Operation 3-4
3.2.3 — Pressure 3-4
3.3 — Water Requirements: Steam Boiler 3-5
3.3.1 — Feed Pump Operation 3-5
3.3.2 — Water Feeder (optional) Operation 3-6
3.4 — Water Treatment 3-6
3.5 — Cleaning 3-7
3.5.1 — Hot Water and Steam Piping 3-7
3.5.2 — Pressure Vessel 3-7
3.6 — Boil-Out of a New Unit 3-8
3.7 — Washing Out 3-10
3.7.1 — Hot Water Boiler 3-10
3.7.2 — Steam Boiler 3-10
3.7.3 — Flushing of Pressure Vessel Interior 3-10
3.8 — Blowdown: Steam Boiler 3-10
3.8.1 — Intermittent Manual Blowdown 3-11
3.8.2 — Continuous Blowdown 3-11
3.8.3 — Frequency of Manual Blowdown 3-11
3.8.4 — Manual Blowdown Procedure 3-12
3.9 — Periodic Inspection 3-13
3.10 — Preparation for Extended Lay-Up 3-14
CHAPTER 4 Sequence of Operation 4-1
4.1 — Overview 4-1
4.2 — Circuit and Interlock Controls 4-2
4.3 — Sequence of Operation: Oil or Gas 4-3
4.3.1 — Pre-Purge Cycle 4-3
4.3.2 — Ignition Cycle 4-4
4.3.3 — Run Cycle 4-4
4.3.4 — Burner Shutdown: Post Purge 4-5

viii 750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual
4.4 — Flame Loss Sequence 4-5
4.4.1 — No Pilot Flame 4-6
4.4.2 — Pilot But No Main Flame 4-6
4.4.3 — Loss of Flame 4-6
CHAPTER 5 Starting and Operating Instructions 5-1
5.1 — Preparation for Startup: All Fuels 5-1
5.2 — Control Settings: Steam and Hot Water 5-2
5.2.1 — Operating Limit Control 5-2
5.2.2 — High Limit Control 5-2
5.2.3 — Modulating Control 5-3
5.2.4 — Low-Water Cutoff and Pump Control 5-3
5.2.5 — Additional Considerations 5-3
5.3 — Gas Pilot 5-3
5.4 — Atomizing Air 5-4
5.5 — Firing Preparations for No. 2 Oil (Series 100 - 200) 5-5
5.5.1 — Oil Flow 5-5
5.5.2 — Oil Pressure 5-6
5.5.3 — Starting 5-7
5.6 — Firing Preparation for No. 6 Oil (Series 400 - 600) 5-7
5.6.1 — Oil Flow 5-7
5.6.2 — Oil Pressure 5-8
5.6.3 — Oil Temperature 5-8
5.6.4 — Starting 5-9
5.7 — Firing Preparations for Gas (Series 200-400-700) 5-9
5.8 — IFGR Setup 5-11
5.9 — Startup, Operating and Shutdown: All Fuels 5-13
5.9.1 — Operating 5-14
5.9.2 — Shutdown 5-15
5.10 — Control Operational Test and Checks 5-15

750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual ix
CHAPTER 6 Adjustment Procedures 6-1
6.1 — Overview 6-1
6.1.1 — High Turndown Burner 6-1
6.2 — Linkage: Modulating Motor and Air Damper 6-2
6.3 — Modulating Motor 6-4
6.4 — Modulating Motor Switches: Low-Fire and High-Fire 6-4
6.5 — Burner Operating Controls: General 6-5
6.6 — Modulating Pressure Control: Steam 6-8
6.7 — Operating Limit Pressure Control: Steam 6-8
6.8 — High Limit Pressure Control: Steam 6-8
6.9 — Modulating Temperature Control: Hot Water 6-8
6.10 — Operating Limit Temperature Control: Hot Water 6-9
6.11 — High Limit Temperature Control: Hot Water 6-9
6.12 — Low Water Cutoff Devices: Steam & Hot Water 6-10
6.13 — Combustion Air Proving Switch 6-10
6.14 — Atomizing Air Proving Switch 6-10
6.15 — Gas Pilot Flame Adjustment 6-11
6.15.1 — Measure and Adjust Pilot 6-11
6.16 — Gas Pressure and Flow Information 6-12
6.16.1 — Pressure 6-12
6.16.2 — Gas Flow 6-15
6.16.3 — Pressure Correction 6-15
6.16.4 — Checking Gas Flow 6-16
6.17 — Gas Fuel Combustion Adjustment 6-17
6.17.1 — Standard Burner Low-Fire Adjustment 6-20
6.17.2 — High Turndown Burner Low-Fire Adjustment 6-21

x750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual
6.18 — Low-Gas Pressure Switch 6-21
6.19 — High-Gas Pressure Switch 6-21
6.20 — Fuel Oil Pressure and Temperature: General 6-22
6.21 — Fuel Oil Combustion Adjustment 6-23
6.21.1 — Standard Burner Low-Fire Adjustment: Heavy Oil 6-25
6.21.2 — High Turndown Burner Low-Fire Adjustment: Light Oil 6-25
6.22 — Burner Drawer Adjustment 6-25
6.23 — Oil Drawer Switch 6-26
6.24 — Low Oil Temperature Switch 6-27
6.25 — High Oil Temperature Switch (Optional) 6-27
6.26 — Low Oil Pressure Switch (Optional) 6-27
6.27 — Electric Oil Heater Thermostat (400 and 600 Series: Steam) 6-27
6.28 — Steam Oil Heater Thermostat: No. 6 Oil (400 and 600 Series: Steam) 6-28
6.29 — Hot Water Oil Heater Thermostat (400 and 600 Series) 6-28
6.30 — Steam Heater Pressure Regulator (400 and 600 Series: Steam) 6-28
CHAPTER 7 Troubleshooting 7-1
7.1 — Overview 7-1
CHAPTER 8 Inspection and Maintenance 8-1
8.1 — Overview 8-1
8.1.1 — Periodic Inspection 8-2
8.2 — Fireside Cleaning 8-2

750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual xi
8.3 — Water Level Controls 8-3
8.3.1 — Steam Boiler 8-3
8.3.2 — Hot Water Boiler 8-4
8.4 — Water Gauge Glass 8-4
8.5 — Electrical Controls 8-4
8.6 — Flame Safety Control 8-6
8.6.1 — Checking Pilot Flame Failure 8-6
8.6.2 — Checking Failure to Light Main Flame 8-7
8.6.3 — Checking Loss of Flame 8-7
8.7 — Oil Burner Maintenance 8-7
8.7.1 — Oil Strainers 8-7
8.7.2 — Light Oil Strainers 8-7
8.7.3 — Heavy Oil Strainers 8-8
8.7.4 — Cleaning the Oil Nozzle 8-8
8.7.5 — Cleaning Air Purge Nozzle (No. 6 Oil) and Back Pressure Orifice Nozzle (No. 2 Oil) 8-9
8.7.6 — Ignition System 8-9
8.8 — Gas Burner Maintenance 8-9
8.9 — Motorized Gas Valve 8-10
8.10 — Solenoid Valves 8-10
8.11 — Air Control Damper, Linkage, and Cam Spring 8-11
8.12 — Forced Draft Fan 8-12
8.13 — Fan/Motor Cassette Removal 8-14
8.14 — Inspection and Adjustment 8-15
8.15 — Airbox Gasket Installation 8-16
8.16 — Fan/Motor Cassette Installation 8-17
8.17 — Safety Valves 8-18
8.18 — Fuel Oil Metering Valve, Adjusting, and Relief Valves 8-18
8.19 — Air Pump and Lubricating System 8-20

xii 750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual
8.19.1 — Air Compressor 8-20
8.19.2 — Lubricating Oil 8-20
8.19.3 — Lubricating Oil Strainer and Cooling Coil 8-21
8.19.4 — Air Cleaner 8-21
8.19.5 — Air-Oil Tank 8-21
8.19.6 — Lube Oil Cooling Coil 8-22
8.19.7 — Flexible Coupling Alignment 8-22
8.19.8 — Air Compressor Replacement 8-24
8.19.8.1 — Dismantling 8-24
8.19.8.2 — Reassembly 8-24
8.20 — Refractory 8-25
8.20.1 — Furnace Liner 8-26
8.20.2 — Throat Tile and Liner Installation 8-27
8.20.3 — Installation 8-28
8.21 — Head Inspection and Maintenance 8-29
8.21.1 — Front Head 8-30
8.21.2 — Rear Door 8-31
8.21.3 — Closing and Sealing 8-33
8.22 — Lubrication 8-34
8.22.1 — Electric Motors 8-34
8.22.2 — Control Linkage 8-34
8.22.3 — Solenoid and Motorized Valves 8-34
8.22.4 — IFGR Lubrication 8-35
8.23 — Oil Heater: Electric, Steam, Hot Water 8-35
8.24 — Combustion 8-36
8.26 — Recommended Boiler Inspection Schedule 8-37
CHAPTER 9 Parts 9-1
9.1 — Ordering Parts 9-1
9.2 — Parts Lists and Drawings 9-2
9.2.1 — Air Compressor and Piping 9-2
9.2.2 — Side Mounted Air Compressor Piping 9-3
9.2.3 — Air Line Piping 9-4
9.2.4 — Burner Housing Support & Front Head Plt 9-5
Burner Housing Support & Front Head Plt 9-6
9.2.5 — Control Panel 9-7
9.2.6 — Entrance Box 9-9
9.2.7 — Front Head (Electrical) 9-10
9.2.8 — Front Davit 9-11

750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual xiii
9.2.9 — Front Head Insulation 9-12
9.2.10 — Front Head Linkage 9-13
9.2.11 — Gas Train 9-14
9.2.12 — Light Oil/Air Piping 9-16
9.2.13 — Heavy Oil/Air Piping 9-18
9.2.14 — Heavy OIl Alstrom Heater 9-20
9.2.15 — CB-LE IFGR 9-22
9.2.16 — IFGR Impeller 9-24
9.2.17 — Pressure Controls 9-25
9.2.18 — Temperature Controls 9-26
9.2.19 — W.C. - Main & Aux. 9-27
9.2.20 — Vessel Handholes & Manways 9-29
9.2.21 — Rear Head Sealing - Davit 9-30
9.2.22 — Throat Tile and Furnace Liner 9-31

xiv 750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual

750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual 1-1
CHAPTER 1 Basics of Firetube Operation
1.1 — Introduction
Firetube boilers are available for low or high pressure steam, or for hot water applications. Firetube boilers are typ-
ically used for applications ranging from 15 to 800 horsepower. A firetube boiler is a cylindrical vessel, with hori-
zontal tubes passing through and connected to the front and rear tube sheets. The vessel contains the water and
absorbs the energy generated from the flame. The front door and rear door provide the seal to contain the hot
combustion gasses. Baffles designed into the doors serve to redirect the combustion gasses through the various
firetube passages. The flame originates in the furnace. As the combustion gasses travel down the furnace and
through the various firetube channels, heat from the flame and combustion gasses is transferred to the water.
Transferred energy develops into the required steam or hot water. The primary purpose of the boiler is to supply
energy to the facility’s operations — for heat, manufacturing processes, laundry, kitchen, etc. The nature of the
facility’s operation will dictate whether a steam or hot water boiler should be used.
The general information in this manual applies directly to Cleaver-Brooks Model CBLE Boilers in sizes ranging
from 250 through 350 boiler horsepower for the following fuels:
•Series 100 Light Oil (No. 2) only
•Series 200 Light Oil (No. 2) or Gas
•Series 400 Heavy Oil (No. 6) or Gas
•Series 600 Heavy Oil (No. 6) only
•Series 700 Gas only

Basics of Firetube Operation
1-2 750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual
FIGURE 1-1. Firetube Boiler (cutaway view)
The LE (Low Emission) feature reduces nitrogen oxide (NOX) emissions, a major precursor to ozone pollution
(smog). Carbon monoxide (CO) emissions also tend to be lower, die to increased turbulence caused by the addition
of the flue gasses into the combustion air stream, thereby improving combustion.
The LE Option is used on Cleaver-Brooks Model CB firetube boilers firing either natural gas and/or light oil, and
is compatible with both hot water and steam systems.
Rated Capacity 250 through 350 hp
Operating Pressure Steam: 15 - 250 psig, or higher if specified
Hot Water: 30 - 250 psig, or higher if specified
Fuel Oil or Gas or Combination
Ignition Automatic
Firing Full Modulation Through Operating Ranges
Burner (Oil) (Low Pressure) Air Atomizing
Burner (Gas) Non-premix, Orificed Type
Air Damper Rotary Type (Electrically Modulated)
Steam Trim ASME Code
Water Trim ASME Code

750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual 1-3
1.2 — The Boiler
The IFGR system mixes a portion of the relatively cool flue gas from the exit of the fourth-pass tubes with the
incoming combustion air to reduce the furnace flame temperature, thereby reducing NOXemissions. In this
approach, the combustion air fan handles both the combustion air and the recirculated flue gasses. Accordingly,
this method is called Induced Flue Gas Recirculation (IFGR) because the flue gas is “induced” into the fan inlet.
The LE Option, with its various levels of IFGR systems, can affect the selection of the combustion air fan, motor,
burner, and other components. Several different system configurations are available, depending on the require-
ments for NOXemissions and the fuels used. All systems use similar primary components, but may have different
linkage controls, IFGR damper, fan, and motor sizes.
When firing heavy oil in a gas/oil CBLE boiler, the heavy oil isolation valve is required in order to protect the
IFGR system from soot buildup and corrosion. See CB manual 750-171 for operating details on the Heavy Oil Iso-
lation system.
Always order genuine Cleaver-Brooks parts from your local Cleaver-Brooks authorized representative.
The boiler and related equipment installation are to be in compliance with the standards of the National Board of
Fire Underwriters. Installation should also conform to state and local codes governing such equipment. Prior to
installation, the proper authorities having jurisdiction are to be consulted, permits obtained, etc. All boilers in the
above series comply, when equipped with optional equipment, to Industrial Risk Insurers (IRI), Factory Mutual
(FM), or other insuring underwriters requirements.
1.2 — The Boiler
The Model CBLE boiler is a packaged firetube boiler of welded steel construction and consists of a pressure vessel,
burner, burner controls, forced draft fan, damper, air pump, refractory, and appropriate boiler trim.
The horsepower rating of the boiler is indicated by the numbers following the fuel series. Thus, CB700-250 identi-
fies a gas-fired 250 hp boiler.
The firetube construction provides some characteristics that differentiate it from other boiler types. Because of its
vessel size, the firetube contains a large amount of water, allowing it to respond to load changes with minimum
variation in steam pressure.
Firetube boilers are rated in boiler horsepower (BHP), which should not be confused with other horsepower mea-
surements.
Hot water is commonly used in heating applications with the boiler supplying water to the system at 180º F to 220º
F. The operating pressure for hot water heating systems usually in 30 psig to 125 psig.
Steam boilers are designed for low pressure or high pressure applications. Low pressure boilers are limited to 15
psig design, and are typically used for heating applications. High pressure boilers are typically used for process loads
and can have a design pressure of 75 to 350 psig.
Steam and hot water boilers are defined according to design pressure and operating pressure. Design pressure is the
maximum pressure used in the design of the boiler for the purpose of calculating the minimum permissible thick-

Basics of Firetube Operation
1-4 750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual
ness or physical characteristics of the pressure vessel parts of the boiler. Typically, the safety valves are set at or
below design pressure. Operating pressure is the pressure of the boiler at which it normally operates. The operating
pressure usually is maintained at a suitable level below the setting of the pressure relieving valve(s) to prevent their
frequent opening during normal operation.
The type of service that your boiler is required to provide has an important bearing on the amount of waterside
care it will require.
Feedwater equipment should be checked and ready for use. Be sure that all valves, piping, boiler feed pumps, and
receivers are installed in accordance with prevailing codes and practices.
Water requirements for both steam and hot water boilers are essential to boiler life and length of service. Constant
attention to water requirements will pay dividends in the form of longer life, less downtime, and prevention of
costly repairs. Care taken in placing the pressure vessel into initial service is vital. The waterside of new boilers and
new or remodeled steam or hot water systems may contain oil, grease, or other foreign matter. A method of boiling
out the vessel to remove accumulations is described in Chapter 3.
The operator should be familiar with Chapter 3 before attempting to place the unit into operation.
1.3 — Construction
Steam boilers designed for 15 psig and hot water boilers designed for 250º F at 125 psi or less are constructed in
accordance with Section IV, Power Boilers, of ASME Code.
Steam boilers designed for operating pressures exceeding 15 psig are constructed in accordance with Section 1,
Power Boilers, of the ASME Code. Hot water boilers designed for operating temperatures above 250º F or 125 psi
are likewise built to ASME Code Section 1.
Waterside care is of prime importance. For specific information or assistance with your water treatment requirements,
contact your Cleaver-Brooks service and parts representative. Failure to follow these instructions could result in equip-
ment damage.
!Caution

750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual 1-5
1.4 — Steam Controls (All Fuels)
FIGURE 1-2. Steam Boiler: Light Oil or Gas Fired
1.4 — Steam Controls (All Fuels)
1.4.1 — Operating Limit Pressure Control
Breaks a circuit to stop burner operation on a rise of boiler pressure at a selected setting. It is adjusted to stop or
start the burner at a preselected pressure setting.
1.4.2 — High Limit Pressure Control
Breaks a circuit to stop burner operation on a rise of pressure above a selected setting. It is adjusted to stop the
burner at a preselected pressure above the operating limit control setting. The high limit pressure control is nor-
mally equipped with a manual reset.

Basics of Firetube Operation
1-6 750-91 (revised 2009)
Model CB-LE Packaged Boiler Manual
1.4.3 — Modulating Pressure Control
Senses changing boiler pressures and transmits the information to the modulating motor to change the burner fir-
ing rate when the manual-automatic switch is set on “automatic.”
FIGURE 1-3. Boiler Controls
1.4.4 — Low Water Cutoff and Pump Control
Float-operated control responds to the water level in the boiler. It performs two distinct functions:
•Stops firing of the burner if water level lowers below the safe operating point. Energizes the low-water light in
the control panel, and it also causes the low-water alarm bell (optional equipment) to ring. Code requirements of
some models require a manual reset type of low-water cutoff.
•Starts and stops the feedwater pump (if used) to maintain water at the proper operating level.
The CB Level Master is the standard low water cutoff on high pressure steam boilers. See CB manual 750-281 for
complete operation, maintenance, and parts information.
1.4.5 — Water Column Assembly
Houses the low-water cutoff and pump control and includes the water gauge glass and gauge glass shutoff cock.
Determine that the main and auxiliary low water cutoffs and pump control are level after installation and throughout
the equipment’s operating life. Failure to follow these instructions could result in equipment damage.
!Caution