PWK CB Series Service manual

CB SERIES
THREE PASS WETBACK COMPACTED FIRE BOILER
INSTALLATION,
OPERATING &
SERVICE INSTRUCTIONS

PWK CO., LTD.
CB I & O MANUAL
2
Important Information 3
General Information 5
Request PWK’s Certication 7
Installation Instructions 7
Minimum Piping For Single Low Pressure Firebox Steam Boiler 10
Minimum Piping For Single Low Pressure Firebox Water Boiler 10
Recommended Minimum Boiler Piping - CB Series Steam Boiler Gravity Return 11
Recommended Boiler Piping - Single Steam Boiler CB Series Pumped Return 11
Recommended Minimum Boiler Piping - CB Series Water Boiler 12
Recommended Water Boiler Recirculation Loop Piping 12
Operating Instructions 13
Service Instructions 17
Limited Warranty 21
Boiler Maintenance Check List 22
Example 23
TABLE OF CONTENTS

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IMPORTANT INFORMATION
Burner / boiler system, as used throughout this manual, shall mean all mechanical and/or
electrical equipment including the boiler, burner, pumps, compressors, feed water systems and
all associated piping, electrical and control systems used and maintained in the boiler room.
The following dened terms are used throughout this manual to bring attention to the
presence of hazards or various risk levels or to note important information concerning the
operating life of the product.
WARNING
Indicates presence of a hazard which will cause severe personal injury, death of
substantial property damage if ignored.
DANGER
Indicates presence of a hazard which can cause severe personal injury, death or
substantial property damage if ignored.
CAUTION
Indicates presence of a hazard which will or can cause minor personal injury or
property damage if ignored.
NOTICE
Indicates special instructions on installation, operation or maintenance
which are important but not necessarily related to personal injury hazards.
1. If you smell gas or fuel oil vapors, do not try to operate the burner/ boiler
system. Do not touch any electrical switch or use any phone in the building.
Immediately call the gas or oil supplier from a remotely located phone.
2. Burner/boiler systems produce steam or hot water in a pressurized vessel by
mixing extremely ammable gaseous, liquid or solid fuels with air to produce
combustion and very hot products of combustion.
Explosion, fires, severe personal injury, death and/or property damage
will result from improper, careless or inadequate installation, operation or
maintenance of fuel-burning and boiler equipment.
3. Insulate all steam and hot water piping, ttings and connections and
all other hot components and equipment from personnel contact.
4. Assure all pipes, ttings, electrical controls and all other associated burner/
boiler equipment is of proper design and construction for the intended use
and provides adequate protection from electrical shock and harmful physical
contact to personnel.
5. A leak-tight fuel delivery conduit and control system must be maintained at
all times.
6. Products of combustion must be transported from the boiler/burner system
to the outdoors in an approved, leak tight, insulated venting system. The
boiler room must be positively ventilated to prevent a concentration of
products of combustion and a reduction in the amount of oxygen in the air.
7. Burner/boiler materials of construction, products of combustion and fuels
contain alumina, silica, heavy metals, carbon monoxide, nitrogen

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NOTICE
oxides, aldehydes, carbon dioxide, particulates and/or other toxic
or harmful substances which can cause death or serious illness and
which are known to the USA to cause cancer, birth defects and other
reproductive harm. Always use proper safety clothing, respirators and
equipment when servicing or working near the equipment.
WARNING
1. The equipment shall be installed in accordance with regulations in force
in the area where the installation is to be made. These regulations shall
be carefully followed in all cases. Authorities having jurisdiction shall
be consulted before installations are made. All boiler installation in the
Mechanical Room on Camp should comply with the current edition of the
following standards:
1) American national standard NFPA 31. “Installation of Oil Burning
Equipment”.
2) American national standard NFPA211. “ Chimneys, Fireplaces, Vents,
and Solid Fuel Burning Appliances”.
3) American society of mechanical engineers ASME CSD-1, “Controls and
Safety Devices for Automatically Fire Boilers”.
2. All wiring on boilers shall be made in accordance with the National Electrical
Code and/of local regulations.
3. Installation, start-up, operation and/or maintenance(service) of this burner/
boiler system must be undertaken only by trained and skilled personnel.
4. Failure to follow all instructions in the proper order can cause personal injury
or death. Read all instructions, including all those in other boiler/ burner
system manuals, which were provided with the equipment before installing,
operating or servicing.
5. Keep boiler area clear and free from combustible materials, gasoline and
other ammable vapors and liquids.
6. Provide positive assurance that adequate combustion and ventilation air is
provided from the outdoors to the burner/boiler system and boiler room.
7. Do not place any obstructions in the boiler room that will hinder the ow of
combustion and ventilating air.
8. Carefully read this and all other manuals and instructions provided before
proceeding with the installation or service of the burner/boiler system.
Post all instructions and manuals near the boiler for reference by service
personnel.
9. Refer to burner manufacturer’s installation manual provided for proper
venting of the gas train components that require atmospheric pressure to
balance a diaphragm.
10. High water temperatures increase the risk of burns or scalding injury. Install
an automatic mixing valve at any tankless heater outlet to avoidexcessively
hot water at the xtures.

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GENERAL INFORMATION
Oxygen corrosion The boiler is designed specically for forced draft ring, is available with
oil, gas or combination gas/oil burners, and operates with a combustion eciency of over 80%.
This manual gives the necessary information for the proper installation, operation,
maintenance and service of units. For special installation problems, contact PWK CO., LTD.,
B-dong 906-ho, 168, Gasan digital 1-ro, Geumcheon-gu, Seoul, 08507, South Korea,
Tel. [phone], Fax. [phone]..
Inspect shipment Carefully for any signs of damage.
1) All Equipment is carefully manufactured, inspected and packed. Our responsibility
ceases upon delivery of boiler to the carrier in good condition.
2) Any Claims for damage or shortage in shipment must be lled immediately against the
carrier by the consignee. No claims for variances from, or shortage in, orders will be
allowed by the manufacturer unless presented within 60 days after receipt of goods.
Setting the unit Most boilers are equipped with lifting lugs to be used in maneuvering the
boiler into position. On large boilers, where two lifting lugs are supplied, all two lugs should
be used when lifting the boiler. The unit should be located in the boiler room so as to provide
ease of venting and adequate clearance for maintenance, serviceability and installation of piping.
WARNING
11. All cover plates, enclosures and guards must be in place at all times,
except during maintenance and service.
NOTICE
1. This boiler has a limited warranty, a copy of which is printed on the back
page of this manual.
2. It is the responsibility of the contractor to see that all the controls are
correctly installed and are operating properly when the installation is
completed.
3. For optimum performance and serviceability form this unit adhere to the
following recommendations:
1) Clean retubes at least once a year, preferably at the end of theheating
to remove soot and scale. Inside surface of the furnace, front and rear
smokeboxs, and reversing chamber should also be cleaned at the same
time.
2) Have the burner and controls checked at least once a year or as
necessary.
3) Retain your contractor or a competent serviceman to assure that the
units is properly adjusted and maintained.

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The service clearnace listed in the PWK's product catalog must be provided at the
front of the boiler. The service clearnace must be maintained at the front of the boiler.
Floor construction should have adequate load bearing characteristics to bear the
weight of the boiler lled with water. A boiler foundation is recommended if the boiler
room oor is weak, uneven or if a water condition exists .
These boilers are not for installation on combustible ooring. If desiccant package was ordered, be
sure to remove from the boiler furnace using the rear access, and from the waterside using the
manhole cover.
Chimney or vent On installations where a natural draft stack is used, causing high
breeching drafts, the boiler locking blade damper (on boilers equipped with one) may
require adjusting, or one may need to be installed at the boiler breeching. In multiple boiler
installations, or in installations where the breeching draft may vary considerably, automatic
draft controls in combination with a motorized damper may be required.
When considering the stack and breeching, the design should take into account that the
boiler/burner combination will work best when the pressure at the boiler ue outlet is in the
range of + or - 1/10 inch WC.
Air supply A sucient air supply must be maintained at all times to the boiler room for
proper performance of the unit. A permanent opening of duct should be provided so that the
boiler input will not exceed 4,000 btuh/in2free area.
Example Firing Rate (Gas) = 528 MBH
528,000 BTUH
= 132 In2Free Area
4,000 BTUH/In2
Follow local building codes if they exceed these minimum requirements.
Figure 1 Typical arrangement for stub vent
Front of Boiler
Smokepipe : Do not reduce below
size of collar on rear smokebox
Thimble

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REQUEST PWK’S CERTIFICATION
If you have, More than three years of manufacturing or design working experience in
ASME or UL certied boiler or heater manufacture and have more than two certications from
commercial burner manufacture in USA.
INSTALLATION INSTRUCTIONS
Boiler piping Attach supply and return piping lines and insert plugs and bushings in
connections as required. Supply and return piping headers are detailed in Figure 2.
NOTE * All Horizontal Smokepipe should Slope Upward Not Less than 1" in 4 Feet.
CAUTION
It is important to comply with the minimum piping requirements in
order to ensure maximum performance and reliability. On steam boilers,
particular attention should be given to the construction of the supply header.
WARNING
The nominal temperature dierential between supply and return water
recommended for Powerwell retube water boiler is 20oF. As a precaution
against thermal shock, this dierential should never exceed 40oF.
When dierentials in excess of 30oF are anticipated on rebox boiler. the
return water should enter the boiler at the top tting (normally the supply)
and the supply water should leave the boiler through the bottom tting
(normally the return). This ow pattern directs the return water over the
relatively cool third pass rather than directly against the rear of the furnace.

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Recommended water boiler recirculation loop
The following guidelines relating to system
water temperature uctuation and ow though the boiler must be observed.
1) It is important to operate your boiler in such a manner as to prevent temperature
uctuation of more then 40oF at any time. Rapid temperature changes within the
boiler can create stresses in the boiler metal. These stresses can cause damage to the
boiler by loosening tubes, or in more severe instances can crack tube sheet ligaments,
furnaces, or waterlegs.
2) If temperature dierentials approach 40oF, to help prevent temperature uctuations
and insure proper circulation through the boiler, a recirculation loop as shown in
Figure 10 should be considered.
The recirculation ow should be at least 1⁄2GPM/ BHP at all times when the boiler is online
for operation
Tankless heater
1) If boiler is orderd with tankless heater, connect tankless heater piping as shown in
Figure 2.
YES
Smok epipeS mo kepipe
Smok epipe
Smo kepipe
Smok epipe
Smok epipe
Smok epipe
Smok epipe
Smok epipe
Chimn ey Chimn ey
Chimn eyChimn ey
Chimn ey
Chimn ey Chimn ey
Chimn eyChimn ey
Boiler Boiler Boiler
Boiler
Boiler
Boiler
Boiler
Boiler
Boiler
18" Min.
18" Min.
NO
NO
NO
NO
NO
NO
YES
OK
Unacceptable Location
Pro per Location
Pro per Location
Unacceptable Locations
WARNING
The boiler should not be operated for any length of time at a temperature
setting that allows the formation of condensation in the tube or smokebox.
This generally dictates a minimum setting of approximately 140oF on the low
limit in systems with a 20oF system dierential. On cold start up,
condensation can be expected until the boiler warms up. If formation of
condensate persists, the low limit should be adjusted upward until
condensate no longer forms.

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2) The following guidelines should be followed when piping the tankless heaters:
Flow regulation If ow through the heater is greater than its rating, the supply of adequate
hot water may not be able to keep up with the demind. For this reason a ow regulator
matching the heater rating should be installed in cold water liner to the heater. The ow
regulator should preferably be located below the inlet so it’s not subjected to excess
temperatures that may occur during“o” periods when it is possible for the heat to be
conducted back through the supply line. The ow regulator also limits the ow of supply water
regardless of inlet pressure variations in the range of 20 to 120 psi.
Tempering of hot water Installation of an automatic mixing valve will lengthen the
delivery of the available hot water by mixing some cold water with the hot. This prevents
excessive and possibly scalding hot water. Higher temperature hot water is possible
by piping the hot water from the heater prior to entering the mixing valve. The mixing valve
should be “trapped” by installing it below the cold water inlet to heater to prevent lime
formation in the valve.
Flushing the heater All water contains some sediment which settles on the inside of the
coil. Consequently, the heater should be periodically backwashed. This is accomplished by
installing hose bibs as illustrated and allowing water at city pressure to run into hosebib
A, through the heater, and out hosebib B until the discharge is clear. The tees in which the
hosebibs are located should be the same size as heater connections to minimize pressure drop.
Hard water May be applicable to some city and particularly well water. Have your water
analtzed by a qualied water treatment specialist to determine if a water softener, conditioner
or ltration is required. Treated water will ensure longer tankless heater life and performance
and is also benecial to all the piping and xtures in the building.
Figure 2 Schematic tankless heater piping
High Temp Water for
Automatic Washers, etc.
Tempered Hot Water to
Faucets and Showers
Globe Valve or SQ. HD. Cocx
Cold Water Supply
Safety Relief Valve
Tankless Heater
Hose Bib in not Water Line for
Periodic Flushing of Sediment
Automatic Making Valve
Flow Regulator in Cold Water Line at Least 3 feet
Ahead of Tankless Heater
WARNING
Install an automatic mixing valve at the tankless heater outlet to avoid risk
of burns or scalding due to excessively hot water at the xtures. Adjust
and maintain the mixing valve in accordance with the manufacturer’s
instruction.

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Figure 3 MINIMUM PIPING FOR SINGLE LOW PRESSURE FIREBOX STEAM BOILER
Figure 4 MINIMUM PIPING FOR SINGLE LOW PRESSURE FIREBOX WATER BOILER
Reducer
Stop Valve & Strainer
ASME Safety Valve(s)
Steam Pressure
/Temperature Gauge
Front of Boiler
Gauge Glass
To Drain
Aguastat
Stop Valve
Check Valve
Receiver Tank
Gate Valve
Drain Valve
Return from System
Stop Valve
Return
Check Valve
Boiler Make-up Water
Supply to System
Expansion Tank
Pressure / Temperature Gauge
Front of Boiler
To Drain
Thermometer (Not supplied with boiler)
Return from System
To Drain
ASME Safety Valve(s)
Supply to System
Aguastat

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Figure 5 RECOMMENDED MINIMUM BOILER PIPING  CB SERIES STEAM BOILER
GRAVITY RETURN
Figure 6 RECOMMENDED BOILER PIPING  SINGLE STEAM BOILER CB SERIES
PUMPED RETURN
Stop Valve
To Drain
To Drain
Boiler Make-up Water
Reducer
System Supply
Check Valve
Check Valve
Gravity Return
See Permissible Details
Lowest Permissible Waterline
Pump Control /
Front of Boiler
Steam Pressure
/ Temperature Gauge
Gauge Glass
Pressure Control
ASME Safety Valve
Aguastat
Stop Valve
To Drain
Supply to System
Reducer
Stop Valve &
Strainer
Above N.W.L.
Boiler Make-up Water
Check Vavle
Stop Valve
Return from System
Drain Valve
Gate Valve
Boiler Feedset
Check Valve
Stop Valve
Gauge Glass
Front of Boiler
Steam Pressure
/ Temperature Gauge
Pressure Controls
ASME Safety Valve
Top of Header
Aguastat

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Figure 7 RECOMMENDED MINIMUM BOILER PIPING  CB SERIES WATER BOILER
Figure 8 RECOMMENDED WATER BOILER RECIRCULATION LOOP PIPING
FORCED INTERNAL CIRCULATOR
LOOP PIPING DIAGRAM
DIRECTION OF FLOW
Front of Boiler
Pressure / Temperature Gauge
Recirculation Piping
Aguastat
ASME Safety Relief Valve
System Return
System Supply
Expansion Tank
To Drain

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OPERATING INSTRUCTIONS
1. Always inspect installation before starting burner.
2. Fill heating system with water.
Important Any time that raw water is introduced to the boiler it must be heated to at least
18oF immediately to dissipate the dissolved gases which can otherwise cause internal
corrosion to the boiler.
1) Steam boilers ll boiler to normal water line. Water should be visible in the gauge
glass. After boiler is inoperation, make up water should be added slowly to maintain
the water level.
2) Hot water boilers in a hot water heating system, the boiler and the entire system (other
than the tank) must be full of water for satisfactory operation. Water should be added
to the system until the boiler pressure gauge registers normal system design operating
pressure. To ensure that the system is full, water should come out of all air vents when
opened.
Burner Recommended water boiler recirculation loop piping.
1) Check wiring of all fuel valves. Verify that wiring is correct according to the factory
supplied wiring diagram.
2) Leave all manual fuel valves closed. This includes manual shuto valves supplied with
the boiler and facility installed valves at the boiler site.
3) Perform all burner pre-startup checks according to the burner manufacture’s
specications. Refer to the burner manufacture’s installation manual furnished with
the boiler.
4) Turn boiler on and verify that fuel valves are closed during the burner pre-purge cycle.
Turn boiler o and disconnect power.
5) Adjust burner according to the burner manufacturer’s speicatrions.
Test controls
WARNING
On a hot water system the pressure must not exceed 30 pounds unless the
boiler is especially designed for a higher maximum working pressure. If a
boiler pressure exceeds pressure setting of safety relief valve, valve will
relieve immediately, but cause of relief must be investigated and corrected.
Excess pressure is dangerous, in addition, could cause damage to heating
system, personal injury or serious property damage.
DO NOT draw water from the boiler while in use. When adding water while
boiler is in operation, do not open the supply valve fully, but add water
slowly.
WARNING
Before installation of the boiler is considered complete the operation of the
boiler controls should be checked, particularly the low water cuto and the
high limit control.
1) Check operating control Raise and lower operating control
setting as required to start and stop burner.

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Cleaning a new steam boiler Oil, grease & sediments which accumulate in a new boiler and
piping must be removed from the system in order to prevent an unsteady water line and carry
over of the water into the supply main above the boiler. Operate the boiler with steam in the
entire system for a few days allowing the condensate to return to the boiler. If the condensate
can temporarily be wasted, operate the boiler only for the length of time it takes for condensate
to run clear. If the latter cannot be achieved or if the condensate is returned to the boiler, boil
out the boiler using the SURFACE BLOWOFF connection on the boilers so equipped.
1) Drain boiler until water is just visible in gauge glass. Run temporary pipe line from
the surface blow-o to an open drain or some other location where hot water may be
discharged safely. Do not install valve in this line.
Certain state and local codes may restrict the use of some chemicals listed for cleaning and
maintaining the boiler. Check with local authorities before proceeding with the use of any of
chemicals.
2) Drain about 5 gallons of hot water from boiler into a container and dissolve into it
1 pound of caustic soda and one pound of trisodium phosphate for each 5 gallons of
boiler water. Additional containers may be required to dissolve sucient chemicals for
large models. Remove safety valve and add solution to boiler water through exposed
tapping.
Use extreme care in handling these chemicals. Caustic soda is harmful to skin, clothing and
eyes. Do not permit the dry material or the concentrated solution to come into contact with the
skin or clothing.
WARNING
2) Check high limit control Jumper operating control terminals.
Allow burner to operate until shut down by limit. Installation is
not considered complete until this check has been made. REMOVE
JUMPER.
3) Check low water cut-o control with water level at normal
waterline. Raise operating control setting to allow burner to operate.
Open boiler drain to allow water level to drop until burner operation
is shut down by low water cut-o.
DANGER
Do not allow the boiler to operate below the minimum permissible water
level as indicated on the boiler.
Close boiler drain and rell to normal water line. Unless boiler is equipped
with a manual reset low water cuto, burner should automatically restart
during ll. Reset operating control.
IMPORTANT
Probe and oat type low water cut-o devices require annual inspection and
maintenance. Refer to Service Instructions for proper cleaning instructions.
4) Check Operating Control on boiler equipped with a tankless
heater. With burner o, draw hot water until burner starts, then turn
o hot water and check burner shut down.

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3) Close all valves leading to and from the system to isolate the cleaning solution from the
system.
4) Start burner and operate suciently to boil the water without producing steam
pressure. Boil for about 5 hours. Open boiler feed pipe suciently to permit a steady
trickle of water from the surface blowo pipe. Continue this slow boiling and trickle of
overow for several hours until the water coming from the overow is clear.
Stop burner and drain boiler in a manner and location that hot water can be discharge
safety.
5) When the boiler has cooled to 12OF or less rell boiler to normal water line. If water
in gauge glass does not appear to be clear, repeat steps A thru E, boiling out the boiler
for a longer time.
6) Remove temporary piping, plug tapping and/or reinstall safety valve. Boil to bring
water temperature to 18OF promptly in order to drive o any dissolved gases in the
fresh water.
Cleaning a water boiler The oil and grease which accumulate in a new hot water boiler
can be washed out in the following manner.
NOTICE
1) Remove safety relief valve using extreme care to avoid damaging it.
Certain state and local codes may restrict the use of some chemicals listed
for cleaning and maintaining the boiler. Check with local authorities before
proceeding with the use of any chemicals.
2) Drain about 5 gallons of hot water form boiler into a container and
dissolve into it 1 pound of caustic soda and one pound of trisodium
phosphate for each 50 gallons of boiler water.
3) Add solution through exposed tapping, and reinstall safety valve.
4) Fill the entire system with water.
5) Start ring the boiler
6) Circulate the water though the entire system
7) Vent the system, including the radiation.
8) Allow boiler water to reach operating temperature, if possible.
9) Continue to circulate the water for a few hours.
10) Stop ring the boiler
11) Drain the system in a manner and to a location that hot water can be
discharged safety.
12) When the boiler has cooled down to 120OF or less, remove plugs
from all available returns and wash the water side of the boiler as
thoroughly as possible, using a high-pressure water stream.
13) Rell the system with fresh water, and bring water temperature to
180OF promptly in order to drive o any dissolved gases.

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uctuation and ow through boiler must be observed.
1) It is important to operate your boiler in such a manner as to prevent temperature
uctuation of more than 4oF at any time. Rapid temperature changes within the
boiler can create stresses in the boiler metal. Theses stresses can cause damage to the
boiler by loosening tubes, or in more severe instances can crack tube sheet ligaments,
furnace, or waterlegs.
2) It is equally important to insure that there is circulation through the boiler of at least
1/2 GPM/BHP at all times when the boiler is ring.
Boiler water treatment Boiler water treatment will help maximize the eectiveness and
prolong the life of pressure vessels.
The general objectives of boiler water treatment are;
1) Remove corrosive gases from feedwater and boiler water.
2) Prevent sludge and scale deposits on the water side heating surfaces.
3) Prevent foaming and carryover.
Make PH or Alkalinity test After boiler and system have been cleaned and relled as
previously described, test the PH of the water in the system. This can easily be done by drawing
a small sample of boiler water and testing with hydrion paper which is used in the same
manner as litmus paper, except it gives exact readings. A small color chart on the side of the
hydrion dispenser given the reading in PH. Hydrion paper is inexpensive and obtainable from
any chemical supply house or through your local druggist. The PH should be higher than 7 but
lower than 11. Add some washout chemical (caustic soda), if necessary, to bring the PH within
the specied range.
IMFORTANT
If, during normal operation, it is necessary to add water to this boiler more
frequently than once a month, consult a qualied service technician to check
your system for leaks. A leaky system will increase the volume of make-up
water supplied to the boiler which can signicantly shorten the life of the
boiler. Entrained in make-up water are dissolved minerals and oxygen. When
the fresh, cool make-up water is heated to the boiler the minerals fall out as
sediment and the oxygen escapes as a gas. Both can result in reduced boiler
life.
Problems caused by oxygen and mineral contamination of boiler water are
not covered under PWK CO., LTD. standard warranty.
Therefore, it is in everyone’s best interest to prevent this type of system
failure. The maintenance of the system integrity is the best method to achieve
this.
NOTICE
Consult with a local water treatment company regularly engaged in the
treatment of boiler water for advice in maintaining the proper feed water,
boiler water, and condensate chemistry.
Certain state and local codes may restrict the use of some chemicals listed
for cleaning and maintaining the boiler. Check with local authorities before
proceeding with the use of any chemicals.

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SERVICE INSTRUCTIONS
General Inspection should be conducted annually. Service as frequently as specied in
paragraphs below. Before service or maintenance is performed complete boiler shutdown/
cooldown procedure.
Boiler shut down and cooldown procedure This procedure is generally required in
preparation for corrective or preventative maintenance in the unit. This procedure must be
supervised by an individual who is thoroughly qualied in operation and maintenance of the
equipment at hand. This is written with steam boilers in mind, but the principles are applicable
to Hot Water Boilers as well.
1) Decrease plant load as much as possible.
2) Turn boiler switch o. If control power from burner is used to support accessories,
leave on until boiler system has cooled down.
3) Shut and lock manual gas and oil valves as applicable.
4) In single boiler installations, some small steam loads can remain on to assist in a
controlled cooldown of the boiler. In multiple boiler installations, shut down the nonreturn
valve and the back up valve. Lock them shut.
5) Allow the boiler feed pump to remain active. As the boiler cools down, the water level
is reduced by demand or shrinkage. It is best to be aware of the boiler level at all times.
6) When boiler pressure has decreased to 5 to 1 psi on the pressure gauge, open the
boiler manual vent valve on the top of the boiler. This is to act as a sentinel against
the increase in pressure and to prevent the boiler from going into a vacuum. Lock the
valve open.
Depending on the size of the boiler, the large mass of heating surfaces that are still hot can
cause the boiler water temperature to increase, even if the gauge pressure is“”. It is better
to allow the entire system to cool gradually, never force cool the boiler as damage can also be
inicted due to “thermal shock.”
7) When boiler and water are below 12OF, shut o power to the unit and lock out the
circuit breakers.
8) If required, open front and rear doors for observation of reside surfaces.
9) Drain boiler down as far as required (usually completely). Make sure the vent valve
on the top of the boiler remains open. Open and lock the oat control low water cuto
drain valves. These will serve as additional vents.
1) Shut and lock the boiler feed valves, and any blowdown valve that can be aected by
other boilers in the same facility (i.e., bottom blow down valves can tie into a common
blowdown separator in a multiple boiler installation).
11) If necessary to remove handhole and/or manhole plates for water side inspection or
inspection or maintenance, use extreme caution.

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Clean the boiler heating surfaces and ue At least once each year, preferably at the end of
the heating season.
Clean the Vent System Vent system should be checked annually for;
1)Obstructions.
2)Accumulations of soot.
3)Deterioration of vent pipe or vent accessories due to condensation or other reasons.
4)Proper support no sags, particularly in horizontal runs.
5)Tightness of joints.
Remove all accumulations of soot with a wire brush and vacuum. Remove all obstructions.
Replace deteriorated parts and support properly. Seal all joints.
Clean the Boiler Heating Surfaces At the end of the heating season, clean boiler heating
surfaces thoroughly. Access to boiler retubes may be gained by removing the front and
rear smokeboxes or smokebox doors. Where applicable, remove the turbulators, paying
close attention to which tubes have turbulators. Clean retubes with ue brush and reinstall
turbulators. If turbulators are corroded or deteriorated, replacing them will ensure a high level
Maintenance of low water cut-o devices
Probe Type Low Water Cut O Although these devices are solid state in design, the probe
is exposed to possible contamination in the boiler water.
It is important to physically remove the probe from the boiler tapping annually and inspect
it for accumulation of scale or sediment.
Following these steps inspect, clean and/or replace the probe
1. Turn o electric service to the boiler.
2. Drain boiler water to a level below the tapping for the probe
3. Disconnect the wiring connections between the low water cuto and the probe.
4. Dismount the low water cuto control from the probe.
5. Unscrew the probe from the boiler tapping.
6. Inspect that portion of the probe that is exposed to the boiler water for scale or sediment
buildup.
7. Light deposits may be removed by wiping the probe with a damp cloth. Wiping the
probe with a cloth soaked in vinegar will remove more tenacious lime deposits. The
most stubborn deposits may be removed from the probe by using a diluted amount (3
part of water to 1 part) of 3 part of water to 1 part phosphoric acid (H2PO4).

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8. Wire brushing of the probe is not recommended.
9. Clean the pipe threads of the probe to remove old, hardened pipe dope and other
foreign matter.
1. Apply a moderate amount of good quality pipe dope to the pipe threads on the probe,
leaving the rst two threads bare. Do not use PTFE (Teon) tape.
11. Screw the probe into the boiler tapping.
12. Mount the low water cuto control on the probe.
13. Reconnect the control on the probe wiring.
14. Fill the boiler to its normal waterline.
15. Add boiler water treatment compound as needed.
16. Restore electric service to boiler.
17. Fire burner to raise water temperature to above 18OF to drive o free oxygen.
Float Type Low Water Cut-O During the heating season, if external low water cuto is
on the boiler, the blow o valve should be opened once a month (use greater frequency where
conditions warrant), to ush out the sediment chamber so the device will be free to function
properly.
Low water cutos and water feeders should be dismantled annually by qualied personnel,
to the extent necessary to insure freedom from obstructions and proper functioning of the
working parts. Inspect connecting lines to boiler for accumulation of mud, scale, etc., and clean
as required. Examine all visible wiring for brittle or worn insulation and make sure electrical
contacts are clean and that they function properly. Give special attention to solder joints on
bellows and oat when this type of control is used. Check the oat for evidence of collapse
and check mercury bulb for mercury separation or discoloration. Do not attempt to per air
mechanism in the eld. Complete replacement mechanisms, including necessary gaskets and
installation instructions, are available from the manufacturer.
Check burner and controls At least once a year. See item 4 under Operating instructions
for control checks. See Burner Manual for burner tests and adjustments.
Lubricate boiler components According to manufacturer’s instructions. Generally, this
involves burner and circulator.
Check safety valve At the start of each heating season and once or twice during the season
to be sure it is in working condition. To do this, fasten wire or cord to the lever of the valve and
pull the lever standing a safe distance away from the valve.
WARNING Before returning boiler to service : Follow the low water cuto check out
procedure.
CAUTION Exercise caution when handling phosphoric acid and follow the instruction
label on its container.

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Attention to the boiler while not in operation
Repair parts Give boilers series and model number when ordering repair parts. All repair
parts can be ordered through PWK CO., LTD. call us at Tel.[phone],
Fax.[phone].
IMFORTANT
1)If a boiler is not used during the winter months, and it is in a place
subject to freezing, it must be fully drained to prevent freeze damage.
2)Steam boiler - Procedure for taking steam boilers o line at the
end of heating season Drain o boiler water until it runs clear
while holding the boiler temperature between 180OF and 200OF. Then
rell to top of gauge glass.
3)Water Boilers - Since a water boiler is a closed system, no draining /
relling should be necessary.
4)Note any time raw water is introduced into the boiler it must be
immediately heated to 180OF to drive o dissolved gases. If water
treatment is used, sucient water treatment compound should be
added to condition the make-up water.