Transcript Brought to You By

Featuring:
Mr. Robert Tribuot
Boiler Inspector
Travelers Insurance
Mr. James Hartory
Boiler Control Technology
Traditional Building Systems
Mr. Don Kobus
Water Treatment Consultant
GLA Water Consultants
Mr. Grant Roberts
Boiler Safety and Service
The PM Equipment Company
Written By: Grant Roberts, Jr. of:
Featuring:
Mr. Robert Tribuot
Boiler Inspector
Travelers Insurance
Mr. James Hartory
Boiler Control Technology
Traditional Building Systems
Mr. Don Kobus
Water Treatment Consultant
GLA Water Consultants
Mr. Grant Roberts
Boiler Safety and Service
The PM Equipment Company
Written By: Grant Roberts, Jr. of:
Featuring:
Mr. Robert Tribuot
Boiler Inspector
Travelers Insurance
Mr. James Hartory
Boiler Control Technology
Traditional Building Systems
Mr. Don Kobus
Water Treatment Consultant
GLA Water Consultants
Mr. Grant Roberts
Boiler Safety and Service
The PM Equipment Company
Written By: Grant Roberts, Jr. of:
Featuring:
Mr. Robert Tribuot
Boiler Inspector
Travelers Insurance
Mr. James Hartory
Boiler Control Technology
Traditional Building Systems
Mr. Don Kobus
Water Treatment Consultant
GLA Water Consultants
Mr. Grant Roberts
Boiler Safety and Service
The PM Equipment Company
Written By: Grant Roberts, Jr. of:
Getting Started…...
“Hey Jack, one of the boilers in elementary school is down
again. I want you to take a look at it and let me know what
you think!”
Sound familiar?
This is a common occurrence in many schools, plants, or factories. Your
job may or may not be to service boilers, but never the less, you must
take certain precautions before you even enter the boiler room.
A boiler can be a deadly piece of equipment, and since you don’t even
know why your boiler has failed, you can’t possibly know if you are in
danger when you enter the room.
The following list is the minimum of things you should possess before
you even open a boiler room door. These items can make the difference
between life and death, so take them seriously!
Before You take another step, Be sure to
Have...
AND
All the manuals for your boiler
All wiring diagrams
A record of all previous service problems
Proper tools
Proper safety equipment
Authority
Emergency Phone Numbers
A clear head
All the manuals for your boiler….A manual is the manufacture’s full explanation of the equipment.
Without it, you have nothing to reference “normal
operation.”
The
List
All wiring diagrams….Some where in your facility is wiring diagrams for your boiler, as well as any
related equipment. As you survey the situation, you must be able to define the electrical operation of your
equipment, without the temptation of guessing!
A record of all previous service….If You don’t have a file on hand with records from all your previous
service, (In house or contracted) you should start one right away! A service history will tell you who
worked on the last problem, when that problem was, if there is a reoccurring problem, and most
important, if there was any previous irregularities noted. At a minimum, you should hang a tag on the
boiler which includes a list of everyone who worked on the equipment and what they did.
Proper tools….You can’t check a boiler with a key ring screwdriver. Weather or not you intend to
actually fix the problem, don’t enter a boiler room to look at the boiler without the correct tools. You will
be tempted to open covers, check switches, reset switches, and a slue of other things, while looking at
your boiler. Doing this without proper tools can cause serious injury. Be prepared to check voltages with
a meter, and have the proper tools to open boxes, or covers. Also, be prepared to close off piping, or
valves in a hurry in case of gas, water, or steam leaks!
Proper safety equipment….Refer to O.S.H.A. and E.P.A. safety standards and abide….these are not
negotiable standards. Also, check with your safety director prior to working on any equipment.
Authority….Be sure you have been authorized by the proper personnel to look at this equipment. By
obtaining proper authorization, you will limit your liability, and more important, inform another of your
presence in the boiler room!
Emergency phone numbers….Know all your local emergency numbers while working on any piece of
equipment….minutes can save your life.
•A clear head….In this case, daydreaming can kill you!
Don’t work on equipment if you
are not in the correct frame of mind, or on any mind altering substances which may obstruct
your thought pattern.
Identifying Your boiler and Its Components
Boiler Identification Form: Boiler #____________________
Boiler Make:_______________ Model:______________Serial:_____________Location:_________
Burner Type:_______________Make:____________Model:______________Serial:_____________
Limits and Interlocks Identified on this unit:
•ow water cut off
L
Combustion air damper proving switch
•
•perator
O
Air flow switch
•
High limit
•
Gas Valve over travel switch
•
High gas pressure switch
•
High fire proving switch
•
Low gas pressure switch
•
Low fire proving switch
•
Time clock
•
Other_______________________
•
Energy Management System •
•
Other_______________________
Each boiler has characteristics of it’s own. It’s important for you to be able to identify these
characteristics, and have a basic idea of their responsibilities.
It is unlikely your boiler has all of these things, but in some rare cases it may have more.
The following pages will help you to identify your boilers components, and how they work.
By being able to identify the components, you’ll give a better description of the problem,
and improve your chance that the contractor arrives with the proper parts, and takes the
minimum amount of time to diagnose the problem.
So here we go….You’ve looked at your boiler and have decided to call in a contractor to
repair it.
Boiler Identification Form: Boiler #____________________________
Boiler Make:__________ Model:______________Serial:_____________Location:_________
Burner Type:____________Make:____________Model:______________Serial:__________
What type of
burner is on your
boiler?
ATMOSPHERIC
My boiler has an atmospheric burner! Atmospheric burners are
identified by the fact that the flame lights from underneath the unit,
and depends on a natural draft to carry the heat through the boiler.
Atmospheric burners usually have fewer components and safeties,
but rely heavily on the proper amount of combustion air in the
designated area.
FORCED DRAFT
My boiler has a forced draft burner! A forced draft burner, or power
burner forces the flame through the front of the boiler into a
combustion chamber. This chamber is usually sealed, and the
flame can only be seen through an eyepiece located somewhere on
the exterior of the boiler. Forced draft burners induce air with a
fan, mixing it with gas, and “forcing” it into your boiler. There are
many more components and safeties on a forced draft burner, but
they can be much more efficient, and offer more flexibility.
The idea here is not to teach you all the specifics of atmospheric as opposed to forced draft, but to allow
you to be able to distinguish the difference between the two types. This becomes important when you are
speaking to a contractor about a problem.
Both these types experiences very specific and different problems. Identifying which type you have, will
assist in narrowing the possibilities of your failures.
Before we start talking about
controls, limit circuits, interlocks,
and all that boring stuff, it’s
important to understand who the
brains of the whole operation is.
The flame safe guard is the one component
that coordinates all the others. It has the
ability to process information sent to it, and
send instructions out of it, based on what
the other components tell it.
The best part is, that in this day and age, they have become much more
sophisticated, smart, and attractive. So if your boiler still has one of those old
controls on it, look into updating. You won’t be sorry!!!
There are two main
manufacturers of these controls
and more than likely, one of them
is controlling your boiler!
• Honeywell
• Fireye
Operation and Advantages of newer flame safeguards
• The flame Safe Guard is located on every boiler. The one’s displayed here are of the newer
verity solid state controls.
•Just like a human brain, if anything within the flame safe guard should fail, than the boiler
will not operate. In trouble shooting your boiler, you may find, if no other problem can be
diagnosed, that it is possible that the flame safe guard is defective.
•Repairs should never be made to the flame safe guard, like in a Brain surgery, the risks are
very high and the liability is tremendous. Unlike the brain, you can buy another one at a
reasonable cost.
•These controls are not only able to run your boiler, but diagnose problems which have
occurred. This cuts down on service time, and the replacement of wrong parts.
•Behind the covers of these controls, is a simple micro processor. It waits for a signal from
various limits and safeties on your boiler, than commands various components operate. It
does this in a sequence of operation specified by the manufacturer meeting appropriate
codes.
There are certain components which talk to your flame safe guard, and certain components
that listen. The components that talk to the control, basically, check the boiler to be sure it’s
doing the things it’s suppose to. The control than processes that information to tell the
other components when to start doing their thing.
When it comes to trouble shooting the boiler, you will find many problems to be
somewhere in these circuits, about 90% of the time (that’s not scientific, just a
hypothesis). By understanding these circuits, it is my hope, that you will be able to
diagnose a simple problem with the boiler, and learn which components you should and
shouldn’t work on your self.
Limit circuits vary from
boiler to boiler. They may
have different types of
switches. A hot water
boiler would have
aquastats which controls
the boiler by
temperature, and a steam
boiler would be
controlled by pressure.
Basically, this circuit is a series of switches telling the control that the boiler has a need to
fire when they are all closed. They are wired to each other, in series, so if any one of the
switches opens, than the boiler will not be able to fire. The power, when all switches are
closed, goes back to one single contact in the control and that voltage “tells” the control
that the circuit is completed and ready to fire.
Power: It’s important to understand that power is a part of the limit circuit. Without it, the boiler doesn’t go. Always
check all fuses and breakers.
On/Off Switch: This switch usually dollows the fuses, and is an easy way to temporarily turn off the boiler. Remember,
just because the switch is off, doesn’t mean that the panel is not powered.
Operator: Either an aquastat (hot water) or pressuretrol (steam). Both act just as a thermostat does. When you have
reached the setpoint, than the switch opens.
High Limit: Usually an exact copy of the operator. It is in place for one purpose, and that is to stop the boiler from firing
in the event the Operator fails to open. May be a manual reset, meaning the boiler will not start until the high limit is
physically reset.
Low water cut off: This is on all boilers in the form of a float, or probe type. Either one proves that there is water in the
boiler to avoid melting down the unit. The flow type works like a toilet ball. As the water level goes up, so does the float.
The float is attached to a switch that closes when the water level is correct. The probe simply toughes the water at the
level the rod is cut and sends a signal abck to a low water control which closes an internal switch.
Low gas pressure switch: Piped to the gas train to sense the incoming gas pressure. If the pressure drops below its
setting, the switch opens to avoid firing the unit with too little gas to ignite.
High gas pressure: This switch is piped to the gas train near the manifold to sense proper gas pressure. In this cuase the
switch will open if the pressure rises above the setting, to avoid over firing the boiler.
Energy Management: Many buildings have some tuype of management system, controlled by an outside source or time
clock. It is intended to save money by setting back temperatures when the space is not occupied. They often tie their
switch into this circuit to turn the uniton andoff.
You should note that the limit circuit is best diagnosed and identified using a wiring diagram. I don’t
recommend taking covers off a limit to see if there is power. The better choice is to locate where the
switches are in the panel (if provided and check power there.
NEVER JUMPER OUT SWITCHES IN ORDER TO MAKE A BOILER OPERATE!!!
Well, your limit circuit is complete. All the switches are closed, and the last switch in the
line “talks” to the control by sending it voltage acknowledging the limits are ready. The
control, in turn, “talks” to the blower to let it know the limits are ready and it can start!
(If you have an atmospheric boiler, your control is of the simpler verity, and would not tell the blwoer to
start (because there is no blower), but instead jump forward to the ignition process.)
Okay, now that your boiler has proven all it’s limits, and started the blower, the control will go to
the next line of communication which is the interlock circuit. The interlock circuit resembles the
limit circuit a great deal, but has one very important difference, Any of the switches in the
interlock circuit which open will actually throw your control into an alarm state. The switches in an
interlock circuit are mainly safeties, and when they open they “lock” your boiler out, or put it into
an alarm, in order to tell you that you have a safety concern, The control can not start until you
have physically reset it.
The Interlock Circuit
The interlock circuit is critical to safe operation of your boiler. As you can see above, the
switches included in an interlock circuit are very important to combustion safety. This is
not a slight. The importance of the limit circuit, but failure to prove the interlock circuit,
could result in an explosion.
The above pictured interlocks are not in every boiler room, and the same token, there can be
many more interlocks than what’s shown. Outside of the air flow switch, many of the other
interlocks are customized for your application, or situation.
Air Flow Switch: There are many different types of air flow switches, but in the case of a power burner,
they all have one purpose, and that is to prove that the fan is creating air flow at the point of combustion.
Combustion Air Damper (CAD): The combustion air damper provides the appropriate make up air for
the boiler room during combustion. As the damper opens, it makes an end switch of some type to prove
the dampers are open, prior to the boiler firing.
Stack Damper: If there is anykind of damper inside the stack of a boiler, it must be proven “open” by an
end switch. A stack damper may be used to increase chamber pressure, or trim your draft, but in a
completely closed positon, it may cuase a very serious explosion!
Stack Draft Proving Switch: In the event the boiler room is at such a negative pressure, it may be
necessary to have an induced draft fan in the stack to pull the gasses through the boiler. For obvious
reasons, it would be necessary to prove the draft exists prior to firing the unit.
Gas Valve Over Travel: This switch is located in an actuator type gas valve. Because these types of
valves rely on a plunger to open the valve, the switch proves that the valve has returned to a fully closed
positon.
Spill Switch: This type safety is lcoated at the opening of a barometric damper. Because a barometric
damper swings open and closed to baclance the stakcs draft, there is always the possibility that the hto
gasses could enter into the room, under the correct circumstances, This switch detects a dangerous
temperature, and shuts down the boiler.
•Stack Limit: Simply monitors the temperature of your stack, and if it reaches a critical point, shuts
down the boiler.
Your control has finally gotten through it’s first two stages, the limits and
interlocks, and now you finally “may” get to see a flame!
Your control does
this is by sending
out voltage to both
your pilot gas valve
(to open them) and
your ignition
transformer (to
create a spark and
ignite the gas).
It’s very important to understand that the ignition systems can vary dramatically from burner to burner.
There are many different shapes, sizes, and types. You should refer to your boiler manual for a complete
understanding of how your system works, but from a control standpoint, this is the stage that the flame
safe guard sends voltage to the various parts of your ignition system to get the ball rolling. Here are some
pilot terms to help you determine what you have on your boiler:
•Standing Pilot: Usually on an
atmospheric type boiler. Pilot flame is
constant and proven once you’ve reached
this stage. Standing pilots are becoming rare
due to new codes.
•Interrupted Pilot: These types of pilots
are energized, lit off, and proven during this
stage but only stay lit until the main flame is
proven to be running.
•Intermittent Pilot: These pilots are energized
at this stage, lit, proven and ramain on throughout
the main flame running period. Usually used in
applications using an alternative fuel.
•Direct Spark Ignition: This type of ignition
relies 100% on igniting the main flame using a
spark only, and does not use a fueled pilot to light
off the burner. Usually found in oil burning
applications.
We’re almost ready to go into the final stages. We’ve proven all of the limits, started the
blower, proven the interlocks, and lit our pilot. So what’s next………?
The Scanner! Any time we mechanically light off a flame, we must have a way to prove it. The scanner, is
the preferred method of proving a flame on most forced draft burners. Some describe it as the “eye” of
the burner because it “sees” the flame and sends a signal back to the Flame safe guard telling it that there
is a physical flame present. If the scanner does not “see” a flame, than the control will lock the burner
out and send it into an alarm.
The Scanner “sees” the pilot flame, then “tells” the control what it looks like!
•The scanner not only “sees” the flame, but it is capable of letting the control know just how
good a flame it is. The signal it sends back to the control, is converted into voltage or
microamps by a flame amplifier. The better the flame, the better the signal.
•There are two major types of scanners: Inferred and Ultravilot. The application determines
the best one for the job, and you should not take it into your own hands to convert one to
the other.
•A flame can also be detected using rectification. This is the
process by which a rod actually “feels” or touches the flame in order
to determine it’s strength. It sends a voltage back to the flame amp
in the same manner.
BOILER
WAS
LIMIT
TURNED
CIRCUIT
ON
WAS
AT
THE
ENERGIZED.
“POWER”
SWITCH!
THE
THE
INTERLOCKS
SCANNER
CONTROL
THE
LIMITS
CONTROL
THE
TOLD
“TOLD”
TOLD
“ASKED”
THE
INTERLOCKS
“TOLD”
THE
THE
“TOLD”
BLOWER
THE
THE
PILOT
CONTROL
THE
MAIN
CONTROL
THE
WERE
CONTROL
SCANNER
STARTED
LIT!
GAS
PILOT
THE
ENERGIZED
VALVES
TOTO
PILOT
TO
HOW
PROCEED
START.
PROCEED.
TO
THE
WAS
OPEN.
PILOT
OKAY!
LOOKED.
THE BURNER LIGHTS OFF!
Some Service Safety Tips…
•If you are unsure about anything in the boiler room, than don’t work on it!! Help is a phone
call away. You should contact a reliable contractor, or the manufacturer to have all your
questions answered prior to working on any piece of equipment.
•Be sure the power if off!! Most boilers have a single disconnect in the way of a breaker, or
emergency shut off. Flipping the on/off switch will only break the limit circuit, and power to
the top of your blower motor contactor, and fusses will still be there. Always check power
with a reliable meter.
•Do not wear jewelry when working in electrical panels! In this case guys, its okay to tak
eyour wedding ring off. Jewelry is a great electrical conductor, and can cause you serous
injury when working in any electrical panel. Take a second, take it off!!
•Never jumper out a limit or safety! Now that you have a basic idea of how the circuits work,
you may have realized that you can get a boiler running by jumping across the contacts on
any of these switches. Do Not Do It!! Your boiler is designed one way….don’t change it.
Without a full understanding of what a particular switch is doing, you can not possibly
understand the risk you put yourself, and the plant at when you jumper it!!!
•Use reliable contractors! The service contractor must be familiar with your equipment, so
ask him! Are they authorized by the manufacturer to work on your equipment? What is the
full scope of their business? How long have they been in business? Don’t just trust a
contractor because he has a flashy van with cool lettering…check them out!!
Sounds like an odd question, doesn’t it? The truth of the matter, is that all boilers
have an explosion relief point. Through a manufacturer doesn’t want their boiler
to explode, it’s imperative that if it does, they can direct the force of the explosion.
•WHAT TYPE OF BOILER DO
YOU HAVE?
•WHERE ARE THE RELIEF
POINTS ON YOUR BOILER?
Compare what you know with the information provided
in your book.
The strange thing about explosion, is that most people enjoy a controlled explosion (like the
4th of July) yet are scared to death by it, in an uncontrolled environment!
The best way to look at a explosion of any type is to understand why it happens and what happens if there
is one. You must know what will happen if your boiler explodes, and if it does, where’s the safest place for
you to be? Obviously, you would want to be in another state if you knew a unit was going to explode, but
since we don’t know if it is going to happen, than we need to look at the best way to avoid an explosion,
and the safest place to be if one should occur.
There are two basic types of explosions:
Combustion Explosion
•A Combustion Explosion generally
occurs when a build up of unburned
fuel ignites suddenly. There are
degrees of severity ranging from a
“puff” (lighting a stove top with a
match after the gas has been on for a
couple of seconds), to a deadly
“bang” (leaving the gas on your stove
top on for 6 hours without lighting it,
when lighting a cigarette or match).
Thermal Explosion
A Thermal Explosion: is perhaps the
most overlooked, yet common, type of
explosion in the boiler industry. This is a
process by which cold water is added to
a very hot surface causing it to expand
or contract so quidckly that it explodes.
The key to maintaining and safely operating a boiler is to keep it clean! The State requires you to open
your boiler for an internal inspection every three years for Low Pressure hot water or steam, and every
year for high pressure units. It is a good practice to do this every year or have a qualified contractor
complete a yearly inspection and cleaning.
Steps to Cleaning Your Boiler:
•Drain the boiler and open all water side opening s available.
•Flush the water side to remove ALL scale and mud.
•Open the Low Water Cut Off and clean the float, rods, bowls, etc…to be sure there is no obstruction to its operation.
•Open all fireside access or doors to expose the fireside of the boiler.
•Brush the fireside to remove all combustion deposits, and vacuum.
•Inspect the chamber insulation, and brick work for cracks.
•Clean the blower on power burners, and flush the burners on atmosphere boilers.
These are just basic steps to cleaning your boiler, but take all safety measures when doing
this procedure:
•Be sure all electric is off and locked out.
•Be sure if entering the boiler, you follow proper confined space regulations set forth by your plant, and/or O.S.H.A.
•Be sure to use all new gasket material when closing back up your unit.
•Be sure to stop all running pumps.
•Be sure all manual gas valves are in the closed position and locked out.
•Check your unit for leaks prior to closing the fireside.
•Check your relief valve for proper opening pressure, and that it seals closed independently and without
your help or adjustment!
9.00%
8.00%
INCREASE IN
FUEL
CONSUMPTION
7.00%
6.00%
EFFECT OF SOOT
ON FUEL
CONSUMPTION
5.00%
4.00%
3.00%
2.00%
1.00%
0.00%
1/32"
1/16"
1/8"
SOOT LAYER ON HEATING
SURFACES