CleaverBrooks FLX Series Guide

Manual Part No. 750-177 R6
MODEL FLX
PACKAGED BOILER
1,500,000 to 12,000,000 Btu/hr
Hot Water and Steam
Fuel: Light Oil, Gas or Combination
5/2014

MODEL FLX
PACKAGED BOILER
Operation, Service, and Parts Manual
1,500,000 to 12,000,000 Btu/hr
Fuel: Light Oil, Gas or Combination
Please direct purchase orders for replacement manuals to your local Cleaver-Brooks authorized representative
Manual Part No. 750-177 R6
Revised 5/2014 Printed in U.S.A.
Cleaver-Brooks 2014

i
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 contents
carefully. The unit will provide good service and continued operation if proper operating and maintenance instructions are fol-
lowed. 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 ser-
vicing, 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 oper-
ating techniques and maintenance procedures must be followed at all times. Although these components afford 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 attempting to operate, main-
tain, 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 consid-
erably 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 uneco-
nomical 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 maintenance
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-con-
necting piping to low water devices must be internally inspected periodically to guard against any stoppages which could ob-
struct 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 frequently to
check for the presence of any mud, sludge, scale or corrosion.
The services of a qualified water treating company or a water consultant to recommend the proper boiler water treating practices
are essential.
The operation of this equipment by the owner and his or her operating personnel must comply with all requirements or regula-
tions of his insurance company and/or other authority having jurisdiction. In the event of any conflict or inconsistency between
such requirements and the warnings or instructions contained herein, please contact Cleaver-Brooks before 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

TABLE OF CONTENTS
Chapter 1
Basics of Flexible Watertube Operation
A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
B. The Boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
C. Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
D. Steam Controls (All Fuels) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
E. Hot Water Controls (All Fuels). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Chapter 2
ProFire™ V Burner
A. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
B. Firing Head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
C. Oil System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
D. Gas System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7
E. Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
F. Startup and Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19
G. Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-26
H. Gas System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-34
I. Oil System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-37
J. Combination Gas-Oil System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-39
K. Modulation Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-40
L. Air and Fuel Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-42
M. Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-43
N. Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-50
O. Burner Specs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-53
Chapter 3
Pressure Vessel Care
A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
B. Water Requirements (Hot Water Boilers) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
C. Water Requirements (Steam Boilers) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
D. Water Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
E. Blowdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
F. Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
G. Boilout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7
H. Washing Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
I. Periodic Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10
J. Preparation For Extended Layup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
ii

Chapter 4
Sequence Of Operation
A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
B. Circuit And Interlock Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
C. Sequence Of Operation - Oil Or Gas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
D. Flame Loss Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
Chapter 5
Adjustment Procedures
A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1
B. Linkage - Modulating Motor & Air Damper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
C. Modulating Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
D. Modulating Motor Switches - Low Fire and High Fire . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
E. Burner Operating Controls - General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2
F. Modulating Pressure Control (Steam) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
G. Operating Limit Pressure Control (Steam) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
H. High Limit Pressure Control (Steam) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
I. Modulating Temperature Control (Hot Water) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
J. Operating Limit Temperature Control (Hot Water) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
K. High Limit Temperature Control (Hot Water) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
L. Low Water Cutoff Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
M. Combustion Air Proving Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
N. Gas Pilot Flame Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
O. Gas Pressure and Flow Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7
P. Gas Fuel Combustion Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8
Q. Low Gas Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9
R. High Gas Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10
S. Fuel Oil Pressure and Temperature - General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-10
T. Fuel Oil Combustion Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12
U. Low Oil Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12
Chapter 6
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1
iii

Chapter 7
Inspection And Maintenance
A. General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
B. Periodic Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1
C. Fireside Cleaning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
D. Upper Pass Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
E. Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4
F. Oil Burner Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6
G. Gas Burner Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7
H. Refractory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7
I. Casing Seals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7
Chapter 8
Parts
Casing HW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2
Casing Low Pressure Steam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4
Casing High Pressure Steam. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
Steam Pressure Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8
Water Level Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-9
Water Column, Main and Aux. - 15# Steam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-11
Water Column, Main and Aux. - 150# Steam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-12
Safety Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-13
iv

750-177 1-1
CHAPTER 1
General Description
A. General 1-1
B. The Boiler 1-2
C. Construction 1-2
D. Steam Controls (All Fuels) 1-2
E. Hot Water Controls (All Fuels) 1-4
A. General
!DANGER CAUTION
The care taken in placing the boiler into initial service
is vital to continuous, reliable operation. If the boiler is
to be used for temporary heat (for example in new con-
struction), properly treated water must be used. Fail-
ure to do so can be detrimental to the boiler.
This manual covers Cleaver-Brooks Model
FLX boilers in sizes ranging from 1,500,000
to 12,000,000 Btu/hr input.
Fuel Series
700 - Gas
100 - No.2 0il
200 - Combination Gas & No.2 Oil
Design Pressure
160 psig hot water
15 psig steam
150 psig steam
Figure 1-1: FLX cutaway view

Chapter 1 General Description
1-2 750-177
B. The Boiler
The Cleaver-Brooks Model FLX is a five-pass steel boiler with flexible watertubes formed and arranged so as
to direct the flow of combustion gases through the boiler. The pressure vessel conforms to Section I or IV of
the ASME code. The pressure vessel consists of the formed tubes, the external downcomer, and the top and
bottom drums to which they connect. The heated area of the pressure vessel is contained within a gas tight
insulated casing that is composed of removable formed steel panels.
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
comply, when equipped with optional equipment, to
Industrial Risk Insurers (IRI), Factory Mutual (FM), or
other insuring underwriters requirements.
Always order genuine Cleaver-Brooks parts
from your local Cleaver-Brooks authorized
representative.
The Model FLX boiler is a packaged watertube boiler of welded steel construction and consists of a pressure
vessel, burner, burner controls, forced draft fan, damper, refractory, and appropriate boiler trim.
Steam
Steam boilers are designed for low and high pressure applications. Low pressure boilers are limited to 15 psig
design pressure, and are typically used for heating applications. High pressure boilers are limited to 150 psig
design pressure, and are typically used for process steam applications.
Hot Water
Hot water is commonly used in heating applications with the boiler supplying water to the system at 180 F
to 220 F. The operating pressure for hot water heating systems usually is 30 psig to 125 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 thickness 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.
!DANGER CAUTION
Waterside care is of prime importance. For specific information or assistance with your water treat-
ment requirements, contact your Cleaver-Brooks service and parts representative. Failure to follow
these instructions could result in equipment damage.
Feedwater equipment should be ready for use upon installation of the boiler. Be sure that all valves, piping,
boiler feed pumps, and receivers are installed in accordance with prevailing codes and practices.
The careful observance of water requirements for both steam and hot water boilers is essential. Constant
attention to water requirements will pay dividends in the form of longer life, less down-time, 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 this
chapter before attempting to place the unit into operation.
ABC
D
EFG
8

General Description Chapter 1
750-177 1-3
C. Construction
Steam boilers designed for 15 psig and hot water boilers designed for 250F at 160 psi or less are constructed
in accordance with Section IV, Heating Boilers, of ASME Code. Steam boilers designed for 150 psig are
constructed in accordance with Section I, Power Boilers, of the ASME Code.
D. Steam Controls (All Fuels)
Figure 2-2: Steam Controls
1
23
4,5
6
7
1. 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
equipped with a manual reset.
2. 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.
3. Modulating Limit Pressure Control: Senses
changing boiler pressures and transmits the
information to the modulating motor to change the
burner firing rate when the manual-automatic
switch is set on “automatic.”
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; also causes 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.
!DANGER CAUTION
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.
5. Water Column Assembly: Houses the low-water cutoff and pump control and includes the water gauge glass and
gauge glass shutoff cocks.
6. Water Column Drain Valve: Provided so that the water column and its piping can be flushed regularly to assist in
maintaining cross-connecting piping and in keeping the float bowl clean and free of sediment. A similar drain valve
is furnished with auxiliary low-water cutoff for the same purpose.
7. Gauge Glass Drain Valve: Provided to flush the gauge glass.
AB

Chapter 1 General Description
1-4 750-177
8. Safety Valve(s): Prevent buildup over the design
pressure of the pressure vessel. The size, rating and
number of valves on a boiler is determined by the
ASME Boiler Code. The safety valves and the discharge
piping are to be installed to conform to the ASME code
requirements. The installation of a valve is of primary
importance to its service life. A valve must be mounted
in a vertical position so that discharge piping and
code-required drains can be properly piped to prevent
buildup of back pressure and accumulation of foreign
material around the valve seat area. Apply only a
moderate amount of pipe compound to male threads
and avoid overtightening, which 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.
DISCHARGE OPENING MUST BE
EQUAL TO OR LARGER THAN
INLET
CAUTION -
VENT PIPE
MUST NOT
TOUCH DRIP
PAN EXTEN-
SION
SUPPORT FROM BUILDING
CONSTRUCTION
VENT
DRIP PAN
EXTENSION
DRIP PAN
AND ELBOW
DRIP PAN
DRAIN
VENT PIPE
OPEN DRAIN
TO WASTE
BOILER SHELL
SAFETY VALVE
DRIP ELL DRAIN
WATER LEVEL
NOTICE: BACK-PRESSURE OF STEAM
EXHAUST SYSTEM MUST BE LESS THAN 6%
OF SAFETY VALVE SETTING.
TO STEAM
1 1/2”
MIN.
Figure 2-3: Recommended piping for steam relief
valve (not furnished by Cleaver-Brooks)
!DANGER
WARNING
Only properly certified personnel such as the safety
valve manufacturer’s certified representative can
adjust or repair the boiler safety valves. Failure to
follow these instructions could result in serious
personal injury or death
E. Hot Water Controls (All Fuels)
Figure 2-4: Hot Water Controls
1
2
3
4
5
6
1. Water Temperature Gauge: Indicates the boiler
internal water pressure.
2. Water Pressure Gauge: Indicates the internal
pressure of the boiler.
3. High Limit Temperature Control: Breaks a circuit to
stop burner operation on a rise of temperature at a
selected setting. It is adjusted to stop burner at a
preselected temperature above the operating control
setting. The high limit temperature control is
equipped with a manual reset.
4. Operating Limit Temperature Control: Breaks a
circuit to stop burner operation on a rise of boiler
temperature at a selected setting. It is adjusted to
stop or start the burner at a preselected operating
temperature.
5. Modulating Temperature Control: Senses changing
boiler water temperature and transmits the
information to the modulating motor to change the
burner firing rate when the manual-automatic switch
is set on “automatic.”
6. Low Water Cutoff: Breaks the circuit to stop burner operation if the water level in the boiler drops below safe operating
point, activating low-water light and optional alarm bell if burner is so equipped.

General Description Chapter 1
750-177 1-5
7. Auxiliary Low Water Cutoff (Not Shown) (Optional): Breaks the circuit to stop burner operation if the water level in
the boiler drops below the master low-water cutoff point.
8. Safety Valve(s): Prevent buildup over the design pressure of the pressure vessel. The size, rating and number of valves
on a boiler is determined by the ASME Boiler Code. The safety valves and the discharge piping are to be installed to
conform to the ASME code requirements. The installation of a valve is of primary importance to its service life. A
valve must be mounted in a vertical position so that discharge piping and code-required drains can be properly piped
to prevent buildup of back pressure and accumulation of foreign material around the valve seat area. Apply only a
moderate amount of pipe compound to male threads and avoid overtightening, which 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.
!DANGER
WARNING
Only properly certified personnel such as the relief valve manufacturer’s certified representative can adjust or
repair the boiler relief valves. Failure to follow these instructions could result in serious personal injury or
death.

Chapter 1 General Description
1-6 750-177

750-177 2-1
CHAPTER 2
Profire V Burner
A. Introduction 2-1
B. Firing Head 2-4
C. Oil System 2-4
D. Gas System 2-7
E. Installation 2-9
F. Startup and Operation 2-19
G. Adjustments 2-26
H. Gas System 2-34
I. Oil System 2-37
J. Combination Gas-Oil System 2-39
K. Modulation Control 2-40
L. Air and Fuel Controls 2-42
M. Maintenance 2-43
N. Troubleshooting 2-50
O. Burner Specs 2-53
A. Introduction
V series burners are assembled, wired, and tested at the factory. They are listed by the Underwriters
Laboratory (UL), CSD-1, NFPA-85, Factory Mutual (FM), including the National Electrical Code (NEC), and
associated insurance underwriters. Where applicable, the Canadian Gas Association (CGA) B149 and the
Canadian Standards Association (CSA) B140 codes shall prevail. Other regulatory agency control options are
available.
!DANGER CAUTION
ONLY FACTORY AUTHORIZED BURNER SER-
VICE PERSONNEL SHOULD START UP, ADJUST,
OR SERVICE THIS EQUIPMENT.
DESCRIPTION
The V series burners are designed to operate with natural gas and light oil. The burners are designed for
automatic, unattended operation except for periodic inspection and maintenance. The burner and control
panel components require little attention except for occasional cleaning.
Model FLX boilers 150-1200 MBTU use the following size burners:
SIZE 1 - FLX 150-300 (Low-High-Low or Full Modulation)
SIZE 2 - FLX 350-550 (Low-High-Low or Full Modulation)
SIZE 3 - FLX 600 (Low-High-Low or Full Modulation)
SIZE 3 & 4 - FLX 700-1200 (Full Modulation)
2-1

Chapter 2 Profire V Burner
2-2 750-177
OPERATING CONTROLS - PANEL
The burner control panel may be integral to the burner or remote, and contains: a flame safeguard
programming control, motor relays (starters), and terminal strips mounted internally on a panel
subbase.Lights, switches, and a control circuit breaker are mounted externally on the panel.
The following table lists typical panel items. Some or all of the items may be provided depending on the burner
configuration selected.
1. ON-OFF BURNER SWITCH
2. FUEL SELECTOR SWITCH - Gas-Off-Oil
Gas position: Selects gas as the firing fuel
Off position: Burner off
Oil position: Selects oil as the firing fuel
3. CONTROL CIRCUIT BREAKER
Supplementary low overcurrent protection only. No larger than 15 amps.
4. AUTO-MANUAL MODULATION SELECTOR SWITCH
Auto position: Selects boiler modulation control. In this position, the burner will operate automatically in response
to load demand.
Manual position: Selects 135 ohm potentiometer for manual modulating control.
5. MANUAL MODULATING CONTROL - 135 ohm (full modulation burners only) increases or decreases the burner
firing rate.
6. SIGNAL LAMPS
a) LOAD DEMAND (white): Illuminates when the control circuit is energized (powered).
b) LOW WATER (red): Illuminates when the water level in the boiler gets too low.
c) FUEL VALVE (green): Illuminates when the main fuel valve or valves (gas or oil) are energized (open).
d) FLAME FAILURE (red): Illuminates when the flame safeguard system fails to detect pilot or main flame.
FLAME SAFEGUARD CONTROLS
The flame safeguard controls the burner's operating sequence: pre-purge, trial for ignition, main flame and
shutdown. This safety control also includes flame detection system to confirm proper operation or cause a
manual reset lockout in the event of a pilot or main flame failure. External controls connected to the flame
control's limit circuit, such as the boiler operating control, will trigger normal burner startup, and upon
reaching operating set point, normal burner shutdown. Safety devices in the flame control's running interlock
circuit, such as the combustion air switch, will cause an immediate safety shut down if conditions are not
correct for safe operation.
When a parallel positioning system is furnished, the flame safeguard may be incorporated as an integral
component to the parallel positioning control. Consult boiler controls documentation. If using a C-B Hawk
control system refer to manual 750-366 (Hawk 1000) or 750-342 (Hawk 4000) and to the flame safeguard
manual 750-234 (CB780E) or 750-264 (CB120).
FIRING RATE CONTROLS
LHL burners use a two position actuator and linkage to control the air and gaseous fuels (oil burners control
oil flow with electric valves). At startup fire, the air damper and fuel valves are positioned for stable low fire
operation. When the actuator is commanded to its second position, the linkage drives the air damper and fuel
valves open until high fire is reached. LHL burners typically use a boiler-mounted control that keeps the burner
at its low fire rate to prevent thermal shock, until conditions are suitable for high fire.
Full modulation burners are capable of firing at any rate between the burner's low and high fire limits. For
“single point” modulating systems, a single rotary actuator controls both air and fuel volume via control arms
and linkage attached to its shaft. As the actuator rotates from low to high fire, the linkage opens the air damper
ABC
D
EFG
8

Profire V Burner Chapter 2
750-177 2-3
and fuel metering valves increase the firing rate. Optional “CAM” trim provides additional precision to the air/
fuel mix with the use of several discrete set point adjustments across the modulation range. Further
combustion efficiency may be achieved with the use of parallel positioning controls which use multiple
directly-coupled actuators (linkeageless) to position the air damper, fuel metering valves and, if applicable,
flue gas recirculation (FGR) across the modulation range.
COMBUSTION AIR HANDLING SYSTEM
1. MOTOR AND BLOWER
The impeller is directly driven by the motor at 3450 rpm.
2. AIR VOLUME REGULATOR
Air dampers are located in the air inlet housing and mechanically linked to the modulating motor.
3. COMBUSTION AIR PROVING SWITCH
A pressure sensitive, differential switch actuated by air pressure created by the blower fan. Contacts close to
prove combustion air flow.
4. DIFFUSER
Contained by the burner’s firing head, an air flow diffuser shapes combustion air flow and improves flame
stability.
When determining boiler room air requirements, the size of the room, air flow, and velocity of air must be
reviewed as follows (fpm = feet per minute; cfm = cubic feet per minute):
Size (area) and location of air supply
openings in boiler room:
Two (2) permanent air supply openings in the outer walls of the boiler room are rec-
ommended. Locate one (1) at each end of the boiler room, preferably 7 foot or
lower. This allows air to sweep the length of the boiler.
A boiler room vent fan is not recommended. Under certain conditions, these fans
can cause a light vacuum and “steal” combustion air from the burner resulting in
unsatisfactory combustion performance.
A vent fan in the boiler room is not recommended, as it could create a light vacuum
under certain conditions and cause variations in the volume of combustion air. This
can result in unsatisfactory burner performance.
Under no condition should the total area of the air supply openings be less than
(1)square foot.
Size the openings by using the formula: Area (sq-ft) = cfm/fpm
Amount of air required (cfm): Combustion Air = Rated bhp x 8 cfm/bhp.
Ventilation Air = Maximum bhp x 2 cfm/bhp.
Total recommended air = 10 cfm/bhp – up to 1000 feet elevation. Add 3% more
per 1000 feet of added elevation.
Acceptable air velocity in Boiler Room
(fpm):
From floor to (7) foot height – 250 fpm
Above (7) foot height – 500 fpm
Example: Determine the area of the boiler room air supply openings for one (1) 300 hp boiler at 800 feet
altitude. The air openings are to be 5 feet above floor level.
1.Air required: 300 x 10 = 3000 cfm
2.Air velocity: Up to 7 feet - 250 fpm
3.Area required: Area = cfm = 3000/250 = 12 sq-ft total
4.Area/Opening: 12/2 = 6 sq-ft/opening (2 required)
AB

Chapter 2 Profire V Burner
2-4 750-177
B. FIRING HEAD
Two side access covers provide access to the firing head internal components. Figure 2-1 shows a a radial spud
firing head typically used on watertube applications
RADIAL
GAS SPUDS
CHOKE RING
MOUNTING FLANGE
AIR BAFFLE
GAS MANIFOLD
NOZZLE BODY
AND TIP
DIFFUSER
Figure 2-1: Profire V firing head
C. OIL SYSTEM
The V series burners pump high pressure fuel oil to the spray nozzle resulting in combustion-ready finely
atomized oil spray.
Fuel Unit Standard V13-55 have an oil pump flex-coupled to the blower motor; these units may be
optionally equipped with a remote pump.The larger V60-168 use a remote pump with separate
motor.
Oil Nozzle Pump pressurized oil discharges from the nozzle in a fine conical spray pattern. The burner's
nozzle is sized to provide the burner's high fire rate, rated gallons per hour (gph). Smaller gph
nozzles may be used to match burner output to a heat exchanger's required input. Models V13-
34 are supplied with simplex nozzles (return flow nozzles optional on V25-34). Models V35-
168 are supplied with return flow nozzles.
Nozzle Adapter A nozzle adapter provides the means for connecting fuel lines with the nozzle.
Oil Solenoid Valves Two normally closed (N.C.) and one normally open (N.O.) solenoid valves are part of the oil sys-
tem on LHO and LHL burners. The two (2) N.C. valves provide positive shutoff of fuel oil while
the one N.O. valve cycles the burner to high fire when closed.
Oil Metering Valve The firing rate is controlled by an adjustable metering valve in the return line. At low fire, the
metering valve is open, and is closed at high fire.
Oil Filter The oil filter prevents foreign matter from entering the burner oil system. This item is provided
as an option and shipped loose with the burner.
Oil System Components

Profire V Burner Chapter 2
750-177 2-5
OPERATION: Fuel oil is delivered to the fuel pump, either by gravity, fuel pump suction, or by a circulating
pump, through a fuel oil filter. Pressurized fuel returns to the storage tank until the two solenoid valves open.
Straight oil burners (VL13-55) employ direct spark ignition where the oil is ignited when the oil solenoid valves
open and the spray contacts the electrical discharge from the direct spark electrodes.
Gas-oil VLG burners use a proven gas pilot where the oil is ignited when the oil solenoid valves open and the
oil spray contacts the established gas pilot flame.
On full modulation units, the modulating actuator varies the oil metering valve setting. The metering valve
located in the return oil loop reduces the firing rate by opening and allowing more oil to return to the supply
tank. Conversely, at high fire, the valve is closed, forcing all oil to exit the spray nozzle.
On LHL units, bypass piping routes most of the oil back to the storage tank while at low fire. At high fire, a
valve blocks the return loop and forces all the oil through the nozzle.
MODULATING
MOTOR
FUEL UNIT
PRESSURE TAP
FUEL UNIT
OIL
METERING
VALVE
OIL
NOZZLE
OIL RETURN
TO TANK
OIL
PRESSURE
SWITCH
OIL SUPPLY
656-10211-000
Figure 2-2: Full Modulation Oil System with Integral Pump & Simplex Nozzle (V13-34)

FUEL UNIT
OIL RETURN
TO TANK
OIL
NOZZLE
OIL
METERING
VALVE
FUEL UNIT
PRESSURE TAP
N.C.
VALVES
NODULATING
MOTOR
FUEL UNIT
PRESSURE TAP
OIL SUPPLY
656-10211-000
Chapter 2 Profire V Burner
2-6 750-177
Figure 2-3: Full Modulation Oil System with Integral Pump & Return Flow Nozzle (V13-55)
OIL
NOZZLE
OIL
PRESSURE
SWITCH
N.C.
VALVES
FUEL UNIT
PRESSURE TAP
MODULATING
MOTOR
OIL RETURN
TO TANK
OIL
SUPPLY
OIL
METERING
VALVE
REMOTE FUEL
UNIT
OIL SUPPLY
TO NOZZLE
656-10211-000
Figure 2-4: Full Modulation Oil System with a Remote Pump (V60-168)

Profire V Burner Chapter 2
750-177 2-7
D. GAS SYSTEM
Gas is introduced into the combustion zone from a circular manifold through multiple ports in the manifold.Firing rate
is determined by the size and number of ports, by manifold pressure, and by combustion zone pressure. The firing
rate is regulated by a rotary, butterfly-type throttling valve at the manifold inlet. The valve is actuated by adjustable
linkage from the modulating motor. Depending upon specific requirements, one or two gas safety shutoff valves are
provided for installation in the gas train upstream of the butterfly valve. Safety shutoff gas valves are wired into the
programming control to automatically open and close at the proper time in the operating sequence.
MAIN GAS TRAIN COMPONENTS
Depending upon the requirements of the regulating authority, the gas control system and gas train mayconsist of
some, or all, of the following items:
Gas Volume Valve The butterfly type valve is positioned by linkage from the modulating motor and controls the gas flow rate.
Main Gas Valves Electrically operated safety shutoff valve(s) that open to admit gas to the burner.lowfire Standard UL burn-
ers include:
• Models V13-25: diaphragm gas valve & solenoid valve
• Models V30-50: one (1) motorized gas valve w/proof of closure or two (2) safety shutoff valves
• Models V55-120: one (1) motorized gas valve w/proof of closure and one (1) safety shutoff valve
• Models V126-168: two (2) motorized gas valves (two motorized gas valves can be optionally provided
on all models)
Main Gas Regulator Regulates gas train pressure to specified pressure required at the burner manifold.Input is set by main gas
pressure regulator adjustment.
Main Gas Cocks Used for manual shutoff of the gas supply upstream of the pressure regulator. A second shutoff cock
downstream of the main gas valve(s) provides a means of testing for leakage through the gas valve(s).
High Gas Pressure Switch
(Models V30-168)
A pressure actuated switch that remains closed when gas pressure is below a selected setting. Should the
pressure rise above the setting, the switch contacts will open causing the main gas valve(s) to close. This
switch requires manual reset after being tripped.
Low Gas Pressure Switch
(Models V30-168)
A pressure actuated switch that remains closed when gas pressure is above a selected setting. Should the
pressure drop below this setting, the switch contacts will open, causing main gas valve(s) to close. This
switch requires manual reset after being tripped.
OPERATION: Metered gas flows through the main gas shutoff cock, through the pressure regulator to the automatic
gas valves and butterfly valve to the gas manifold.
The butterfly gas valve modulates flow to burner input demand. The butterfly valve is positioned through mechanical
linkage by the modulating motor. The air control damper is positioned simultaneously by the modulating motor.
The automatic gas valve(s) cannot be energized unless the combustion air proving switch is closed. The low and high
gas pressure switches must be closed to prove proper gas pressure.
A normally open vent valve, if required, is located between the two automatic gas valves. This valve is shut when the
automatic gas valves are open. When the automatic valves are closed, the vent valve is open for venting gas to the
outside, should any be present.

Chapter 2 Profire V Burner
2-8 750-177
Figure 2-5: Typical Gas Train for Full Modulation System (V13-34)
Figure 2-6: Typical Gas Train for LHO/LHL Systems (V35-63) & Full Modulation Systems (V35-168)