Williamson GWC070 Gas-Fired Water Boilers User Guide
- June 3, 2024
- Williamson
Table of Contents
GWC070 Gas-Fired Water Boilers
GWC
Series 2 Gas-Fired Water Boilers
User’s Information Manual
If the information in this manual is not followed exactly, a fire or explosion
may result, causing property damage, personal injury or loss of life. Do not
store or use gasoline or other flammable vapors and liquids in the vicinity of
this or any other appliance. — WHAT TO DO IF YOU SMELL GAS — · Do not try to
light any appliance. · Do not touch any electrical switch; do not use any
telephone in your building. · Immediately call your gas supplier from a
neighbor’s telephone. Follow the gas supplier’s instructions. · If you cannot
reach your gas supplier, call the fire department. Installation & service must
be performed by a qualified installer, service technician or the gas supplier.
Part number 550-142-804/1021
GWC Series 2 Gas-fired water boiler — User’s Information Manual
Please read this page first
How to use this manual . . .
To . . .
Learn precautions
Prevent air contamination
Maintain boiler
Locate boiler components Start — or —
Shutdown boiler
Troubleshoot common problems
Read/use . . .
Page . . .
Warnings and definitions
3
Laundry room or pool — make sure boiler air is
piped to boiler per manual. Read list of air contaminants you must avoid. Have
4
boiler air piped in if you can’t avoid.
Set up a plan for maintaining the boiler using
the schedule included in this manual. Schedule an annual start-up by a qualified
5
service technician before every heating season.
How the boiler works and illustration.
10
Follow the Operating instruction sheet details to start or shutdown your boiler.
12
Use the common problems/solutions table to resolve typical heating system/boiler problems.
13
Hazard definitions
The following defined terms are used throughout this manual to bring attention to the presence of hazards of various risk levels or to important information concerning the life of the product.
Indicates presence of hazards that will cause severe personal injury, death or
substantial property damage.
Indicates presence of hazards that can cause severe personal injury, death or
substantial property damage.
Indicates presence of hazards that will or can cause minor personal injury or
property damage.
Indicates special instructions on installation, operation or maintenance that
are important but not related to personal injury or property damage.
Boiler service and maintenance
The Boiler manual is for use only by a qualified heating installer/ service
technician. Refer only to this User’s Information Manual for your reference.
Improper installation, adjustment, alteration, service or maintenance can
cause property damage, personal injury (exposure to hazardous materials) or
loss of life. Installation and service must be performed by a qualified
installer, service agency or the gas supplier (who must read and follow the
supplied instructions before installing, servicing, or removing this boiler.
This boiler contains materials that have been identified as carcinogenic, or
possibly carcinogenic, to humans).
2
When calling or writing about the boiler– Please have the boiler model number
from the boiler rating label and the CP number from the label located on the
top of the boiler next to the air inlet connection.
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GWC Series 2 Gas-fired water boiler — User’s Information Manual
STOP!! — Read before proceeding
User — Have this boiler serviced/inspected by a qualified service technician,
at least annually.
Failure to adhere to the guidelines on this page can result in severe personal
injury, death or substantial property damage.
Boiler service and maintenance —
· To avoid electric shock, disconnect all electrical supplies to the boiler
before performing maintenance if wiring will be exposed.
· To avoid severe burns, allow boiler to cool before performing maintenance.
· You must maintain the boiler as outlined in this manual and have the boiler
started up and serviced at least annually by a qualified service technician to
ensure boiler/ system reliability.
Boiler operation —
· Do not block flow of combustion or ventilation air to boiler. This boiler is
equipped with a control which will automatically shut down the boiler should
air or vent be blocked. If vent or air blockage is easily accessible and
removable, remove it. The boiler should attempt to restart within an hour. (If
blockage is not obvious or cannot be removed, have the boiler and system
checked by a qualified service technician.)
· Do not allow contaminated air to enter the boiler room (or air inlet pipe if
direct vented). See page 4 for details.
· Should overheating occur or gas supply fail to shut off, do not turn off or
disconnect electrical supply to boiler. Instead, shut off the gas supply at a
location external to the appliance.
· Do not use this boiler if any part has been under water. Immediately call a
qualified service technician to inspect the boiler and to replace any part of
the control system and any gas control that has been under water.
· Should overheating occur or gas supply fail to shut off, DO NOT turn off or
disconnect electrical supply to circulator. Instead, shut off the gas supply
at a location external to the appliance.
Combustion air —
· DO NOT install combustion air intake where there is a risk of combustion air
contamination.
Carbon monoxide detector —
· For Direct Exhaust units, a carbon monoxide detector is required in the
boiler room. The carbon monoxide detector must be wired on the same electrical
circuit as the boiler.
· For Direct Vent units, a carbon monoxide detector that is wired on the same
electrical circuit as the boiler is strongly recommended.
Boiler water —
· Have boiler water chemistry checked at least annually by a qualified service
technician.
· DO NOT use petroleum-based cleaning or sealing compounds in boiler system.
Gaskets and seals in the system may be damaged. This can result in substantial
property damage.
· DO NOT use “homemade cures” or “boiler patent medicines”. Serious damage to
boiler, personnel and/or property may result.
· Leaks in boiler or piping must be repaired at once to prevent make-up water.
Use this boiler ONLY in a closedloop system. Continual fresh make-up water
will reduce boiler life. Mineral buildup in heat exchangers reduces heat
transfer, overheats the materials, and causes failure. Addition of oxygen
carried in by make-up water can cause internal corrosion.
· Do not add cold water to hot boiler. Thermal shock can cause boiler heat
exchanger to crack.
Freeze protection fluids — · NEVER use automotive or standard glycol
antifreeze. Use
only freeze-protection fluids made for hydronic systems. Follow all guidelines
given by the antifreeze manufacturer. Thoroughly clean and flush any
replacement boiler system that has used glycol before installing the new
boiler.
Frozen Water Damage Hazard
Residences or buildings that are unattended in severely cold weather, boiler
system components failures, power outages, or other electrical system failures
could result in frozen plumbing and water damage in a matter of hours. For
your protection, take preventative actions such as having a security system
installed that operates during power outages, senses low temperature, and
initiates an effective action. Consult with your boiler contractor or a home
security agency.
If any part of a boiler, burner or its controls has been sprayed with or
submerged under water, either partially or fully, DO NOT attempt to operate
the boiler until the boiler has been either replaced or completely repaired,
inspected, and you are sure that the boiler and all components
are in good condition and fully reliable.
Otherwise, by operating this boiler, you will cause a fire or explosion
hazard, and an electrical shock hazard, leading to serious injury, death, or
substantial property damage. See the instructions at right.
Saltwater Damage — The exposure of boiler components to saltwater can have
both immediate and long-term effects. While the immediate effects of saltwater
damage are similar to those of freshwater (shorting out of electrical
components, washing out of critical lubricants, etc.), the salt and other
contaminants left behind can lead to longer term issues after the water is
gone due to the conductive and corrosive nature of the salt residue.
Therefore, Weil-McLain equipment contaminated with saltwater or polluted water
will no longer be covered under warranty and should be replaced.
Electrical Damage — If any electrical component or wiring came into contact
with water, or was suspected to have come into contact with water, replace the
boiler with a new Weil-McLain boiler.
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GWC Series 2 Gas-fired water boiler — User’s Information Manual
Prevent combustion air contamination —
Air contamination
Common household and hobby products often contain fluorine or chlorine
compounds. When these chemicals pass through the boiler, they can form strong
acids in the vent system or boiler. The acid can eat through the vent or
boiler wall, causing serious damage and presenting a possible threat of flue
gas spillage into the building.
Please read the information below. If the contaminating chemicals will be
present, have your installer pipe the boiler air from outside per the Boiler
manual.
If the boiler is installed in any area likely to cause contamination, or if
products which would contaminate the air cannot be removed, you must pipe
combustion air to the boiler air intake. Contaminated combustion air will
damage the boiler and vent system, resulting in possible severe personal
injury, death or substantial property damage.
Do not operate a GWC boiler in a laundry room or pool facility, for example,
without using ducted outside air. These areas will always contain
contaminants.
Combustion air contamination:
Ensure that the combustion air will not contain any of the contaminants in
Figure 1. Combustion air supply openings or intake terminations must NOT be
near a swimming pool, for example. Avoid areas subject to exhaust fumes from
laundry facilities. These areas will always contain contaminants.
Figure 1 Corrosive contaminants and sources
Products to avoid Spray cans containing chloro/fluorocarbons Permanent wave
solutions Chlorinated waxes/cleaners Chlorine-based swimming pool chemicals
Calcium chloride used for thawing Sodium chloride used for water softening
Refrigerant leaks Paint or varnish removers Hydrochloric acid/muriatic acid
Cements and glues Antistatic fabric softeners used in clothes dryers Chlorine-
type bleaches, detergents, and cleaning solvents found in household laundry
rooms
Adhesives used to fasten building products and other similar products
Excessive dust and dirt
Areas likely to have contaminants Dry cleaning/laundry areas and establishments Swimming pools Metal fabrication plants Beauty shops Refrigeration repair shops Photo processing plants Auto body shops Plastic manufacturing plants Furniture refinishing areas and establishments New building construction
4
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Perform maintenance per schedule below
Figure 2 Service and maintenance schedules
Service technician
(see Boiler Manual for instructions)
Owner maintenance
(see following pages for instructions)
Daily
· Check boiler area · Check air openings · Check pressure gauge
Monthly
Follow the procedures listed in the Boiler Manual.
Periodically
· Check boiler interior piping · Check venting system · Check air vents ·
Check condensate drain system · Check relief valve
· Test low water cutoff (if used) · Clean vent termination/air intake
screens
Annual start-up
Every 6 months
· Oil blower motor · Operate relief valve
End of season
· Shut down procedure
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GWC Series 2 Gas-fired water boiler — User’s Information Manual
User maintenance procedures
Boiler must be serviced and
maintained
The boiler should be inspected and started annually, at the beginning of the
heating season, only by a qualified service technician. In addition, the
maintenance and care of the boiler designated on page 5 and explained on the
following pages must be performed to assure maximum boiler efficiency and
reliability. Failure to service and maintain the boiler and system could
result in equipment failure, causing possible severe personal injury, death or
substantial property damage.
The following information provides detailed instructions for completing the
maintenance items listed in the maintenance schedule, page 5. In addition to
this maintenance, the boiler must be serviced and started up at the beginning
of each heating season by a qualified service technician.
DAILY
Maintenance
Check boiler area
To prevent potential of severe personal injury, death or substantial property
damage, eliminate all materials discussed below from the boiler vicinity. If
contaminants are found:
Remove products immediately from the area. If they have been there for an
extended period, call a qualified service technician to inspect the boiler and
vent system for possible damage from acid corrosion.
If products cannot be removed, immediately call a qualified service technician
to install an outside combustion air source for the boiler (if not already
installed).
1. Combustible/flammable materials — Do not store combustible materials,
gasoline or any other flammable vapors or liquids near the boiler. Remove
immediately if found.
2. Air contaminants — Products containing chlorine or fluorine, if allowed to
contaminate the boiler intake air, will cause acidic condensate in the vent
and boiler. This will cause significant damage to the vent and/or boiler if
allowed to continue. Read the list of potential materials listed on page 4 of
this manual. If any of these products are in the room from which the boiler
takes its combustion air, they must be removed immediately or the boiler
combustion air must be supplied from outside. See WARNING above.
Check air openings
1. Verify that combustion and ventilation air openings to the boiler room
and/or building are open and unobstructed.
2. Verify that boiler vent discharge and air intake are clean and free of
obstructions. Remove any debris on the air intake or flue exhaust openings.
Check boiler pressure/temperature gauge
1. Make sure the pressure reading on the boiler pressure/temperature gauge
does not exceed 24 psig. Higher pressure may indicate a problem with the
expansion tank.
2. Contact a qualified service technician if problem persists.
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User maintenance procedures (continued)
MONTHLY
Maintenance
Check boiler interior piping
1. Remove boiler jacket top.
2. Visually inspect for leaks around internal piping, circulators, relief
valve and other fittings. Immediately call a qualified service technician to
repair any leaks.
Have leaks fixed at once by a qualified service technician. Continual fresh
makeup water will reduce boiler life. Minerals can build up in sections,
reducing heat transfer, overheating cast iron, and causing section failure.
Do not use petroleum-based cleaning or sealing compounds in boiler system.
Severe damage to boiler and system components can occur, resulting in possible
severe personal injury, death or substantial property damage.
Check venting system
1. Visually inspect the flue gas vent piping for any signs of blockage,
leakage or deterioration of the piping. Notify your qualified service
technician at once if you find any problem.
Failure to inspect the vent system as noted above and have them repaired by a
qualified service technician can result in vent system failure, causing severe
personal injury or death.
Check automatic air vents (if used — use automatic air vents with diaghragm-
type expansion tanks only)
1. See Figure 3.
2. Remove the cap from any automatic air vent in the system and check
operation by depressing valve “B” slightly with the tip of a screwdriver.
3. If the air vent valve appears to be working freely and not leaking,
replace cap “A”, twisting all the way on.
4. Loosen cap “A” one turn to allow vent to operate.
5. Have vent replaced if it does not operate correctly.
Figure 3 Automatic air vent
A
B
85036
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GWC Series 2 Gas-fired water boiler — User’s Information Manual
User maintenance procedures (continued)
MONTHLY
Maintenance
Check condensate system
1. NOTICE — To improve clarity, this illustration of the condensate trap is
shown with no air inlet pipe attached. If your boiler has an air pipe
connected here, DO NOT tamper with it. The trap is also shown as item l on
page 11.
2. Inspect the condensate P-trap (item 1 in the illustration at right). If
the trap does not contain water, turn off the boiler ON/OFF switch and call
your boiler service technician immediately.
3. Item 2 in the illustration is the drain tubing to the condensate pump.
Inspect this tubing or piping, making sure it is in good condition and not
obstructed.
If the condensate trap is dry or the condensate line is damaged or obstructed,
there is a risk of flue gas flow into the building. The boiler must not be
operated and must be inspected and serviced only by a qualified service
technician. Failure to comply with this directive could result in the
possibility of severe personal injury, death or substantial property damage.
Check boiler relief valve
1. Inspect the boiler relief valve and the relief valve discharge pipe for
signs of weeping or leakage.
2. If the relief valve often weeps, the expansion tank may not be working
properly. Immediately contact your qualified service technician to inspect the
boiler and system.
PERIODIC
Maintenance
Test low water cutoff (if installed)
1. If the system is equipped with a low water cutoff, test the low water
cutoff periodically during the heating season, following the low water cutoff
manufacturer’s instructions.
Clean vent termination & air intake screens
1. Remove all lint and debris from both the boiler air intake screen and the
flue discharge screen.
2. The boiler control module will sense blockage of the air intake or flue
and lockout if the blockage is excessive. It will signal the failure by
flashing the appropriate indicator lights on the control board.
3. If removing the debris does not allow the boiler to operate correctly
afterwards, contact your qualified service technician to inspect the boiler
and vent/air systems.
8
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User maintenance procedures (continued)
EVERY 6 MONTHS
Maintenance
Oil blower motor
1. Remove the jacket top panel to access the blower motor.
2. Use only Anderol 465. DO NOT use household universal oils.
Use only Anderol 465 to lubricate the blower motor. Do not use common
universal household oils.
3. See Figure 4
4. Place a few drops of oil in each of the two oiler cups on the side of the
blower motor.
Figure 4
Blower motor
Operate boiler relief valve
1. Before proceeding, verify that the relief valve outlet has been piped to a
safe place of discharge, avoiding any possibility of scalding from hot water.
To avoid water damage or scalding due to valve operation, a metal discharge
line must be connected to relief valve outlet and run to a safe place of
disposal. This discharge line must be installed by a qualified heating
installer or service technician in accordance with the instructions in the GWC
Boiler Manual. The discharge line must be terminated so as to eliminate
possibility of severe burns should the valve discharge.
2. Read the boiler pressure/temperature gauge to make sure the system is
pressurized.
3. Lift the relief valve top lever slightly, allowing water to relieve
through the valve and discharge piping.
4. If water flows freely, release the lever and allow the valve to seat.
Watch the end of the relief valve discharge pipe to ensure that the valve does
not weep after the line has had time to drain. If the valve weeps, lift the
seat again to attempt to clean the valve seat. If the valve continues to weep
afterwards, contact your qualified service technician to inspect the valve and
system.
5. If water does not flow from the valve when you lift the lever completely,
the valve or discharge line may be blocked. Immediately shutdown the boiler,
following the lighting instructions on the inside jacket top. Call your
qualified service technician to inspect the boiler and system.
END OF SEASON
Maintenance
Follow boiler shutdown procedure
1. Follow “TO TURN OFF GAS TO APPLIANCE” on the Operating instruction on the
inside of the jacket top panel. You will also find these instructions on page
12 of this manual.
2. Do not drain system unless exposure to freezing temperatures will occur.
3. Do not drain the system if it is filled with an antifreeze solution.
4. Do not shut down boilers used for domestic water heating. They must
operate year-round.
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GWC Series 2 Gas-fired water boiler — User’s Information Manual
How it works . . .
1 Integrated boiler control
The integrated boiler control (IBC) responds to signals from the room
thermostat, air pressure switch, inlet water sensor, boiler water temperature
sensor and boiler limit circuit to operate the circulators, gas valve, igniter
and blower. When a room thermostat calls for heat, the IBC starts the system
circulator and blower. The IBC runs the blower to purge the boiler flue
passages, then turns on the igniter and lets it warm up. After igniter warm-
up, the IBC opens the gas valve, turns the igniter off, and checks for flame.
The flame must come on within 4 seconds or the IBC will shut down and try the
full cycle again. When the room thermostat is satisfied, the IBC turns off the
boiler components and waits for the next heat call. The IBC indicator lights
show normal sequence when the lights are on steady. When a problem occurs, the
IBC flashes combinations of lights which indicate the most likely reason for
the problem. While attempting to satisfy the heat demand, the control module
monitors the boiler temperature changes via the temperature sensors and
determines whether or not the available hot water will satisfy the demand,
only running the circulator. If additional heat is needed, the sequence
continues. When DHW (if used) calls for heat, sequence above is bypassed.
2 Transformer
The control transformer reduces line voltage to 24 volts for the gas valve and
limit circuit.
3 Blower
The blower pulls in air and mixes it with gas from the gas valve. The blower
forces this mixture into the burner for combustion inside the boiler chamber.
4 Recuperator
The recuperator is a stainless steel heat exchanger that increases boiler
efficiency by extracting additional heat from the flue gases. Return water
passes through the recuperator before entering the boiler.
5 Water temperature sensor
The water temperature sensor provides a signal to the control module to turn
off the gas valve if the temperature in the boiler goes above its setting.
(The circulator will continue to run as long as there is a call for heat.)
6 System circulator
The system circulator circulates water through the external (system) piping.
The flow rate of the circulator is controlled by the IBC, depending on the
temperature of the water entering the boiler sections. Pump must remain on
boiler — do not remove.
7 Bypass circulator
The IBC operates the bypass circulator to mix hot water from the boiler outlet
with colder return water from the system as needed to prevent condensation of
flue gases in the cast iron heat exchanger. When the water returning to the
boiler is below 140°F, the IBC regulates the bypass circulator and system
circulator flow rates to raise the return water temperature up to 140°F before
it enters the cast iron sections. By balancing these flow rates, the IBC can
protect against condensation even if return water is as low as 60°F. Pump must
remain on boiler — do not remove.
8 Air pressure switch
The air pressure switch signals the IBC, telling the control whether air is
moving through the blower.
9 Return water temperature sensor
The water temperature sensor monitors the temperature of the water entering
the boiler sections. The sensor sends this information to the IBC. The IBC
determines how much to adjust the circulator flow rates to provide at least
140°F water to the cast iron heat exchanger.
LEGEND a Supply to system, 1″ NPT b Return from system, 1″ NPT c Combustion
air inlet fitting —
3″ PVC connection d Flue outlet — 3″ PVC connection e Gas valve — negative
pressure
regulated gas control f Pressure/temperature gauge g Flueway inspection port
cover h Sensor hose trap i Manual air vent j Relief valve k Thermal switch — a
device that
shuts boiler off if flue temperature exceeds its setpoint l Condensate trap
line — shipped loose with boiler, field installed
This boiler uses a negative-pressureregulated gas valve, set for an outlet
pressure approximately 0.20″ water column.
DO NOT set the outlet pressure higher than factory setting.
10
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GWC Series 2 Water Boiler
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11
GWC Series 2 Gas-fired water boiler — User’s Information Manual
Operating instructions
Before attempting to start the boiler, check the boiler pressure temperature
gauge. If boiler and system are full of water and properly pressurized, the
gauge should read at least 12 psig on most systems. Operating the boiler
without proper water content will damage boiler and controls and could result
in severe personal injury, death or substantial property damage.
Figure 5 Operating instructions
12
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Common problems and solutions
Symptom
Common Causes Possible Corrections
Rapid cycling — boiler turns Thermostat installed where drafts Locate thermostat on inner wall away from
on and off frequently
or heat affect reading
heat sources or cool drafts.
Heat anticipator in thermostat adjusted incorrectly
Adjust thermostat per manufacturer’s instructions.
Incorrect boiler temperature setting
Insufficient water flow through boiler
Set boiler temperature according to system needs. Maximum setting is 200°F.
Increase boiler temperature setting to decrease cycling.
Check all valves to and from boiler. Return to proper setting.
Confirm circulator size.
Frequent release of water through relief valve
Expansion tank sized too small
Call qualified service technician to check expansion tank operation and size.
Flooded expansion tank
Call qualified service technician to check expansion tank operation.
Inoperative limit control
Call qualified service technician to replace limit control.
Need to frequently add makeup water
Leaks in boiler or piping
Have qualified service technician repair leaks at once to avoid constant use of makeup water. Makeup water can cause mineral deposits which, in turn, can cause boiler section failure. Do not use petroleum-base stop-leak compounds.
Black water condition
Oxygen corrosion due to leaks in Have qualified service technician repair
boiler and piping
at once. Keep pH of water between 7.0 to
8.5.
Large temperature swings in Incorrect Economy setting living space
Adjust Economy setting on boiler control.
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GWC Series 2 Gas-fired water boiler — User’s Information Manual
Common problems and solutions (continued)
Symptom
Common Causes Possible Corrections
Popping or percolating noise Mineral deposits in sections due
heard in boiler
to constant use of makeup water
Call qualified service technician to delime boiler, if necessary. In some cases, deposits will be too heavy to remove with de-liming procedures.
Have qualified service technician repair leaks to eliminate need for constant
makeup water.
Incorrect pH of boiler water
Call qualified service technician to check pH level and correct. pH should be
maintained between 7.0 to 8.5.
Insufficient water flow through boiler
Metal flakes found in vent outlet or vent starter tee —
flueway corrosion
Contaminated combustion air supply — See page 4 in this manual.
Condensation of combustion gases in boiler sections
Check all valves to and from boiler. Return to proper setting.
Confirm circulator size.
Remove any contaminating products. See page 4 in this manual.
Provide outside air for combustion. Have qualified service technician pipe-up
kit.
Have qualified service technician check operation of mixing system. Repair/
replace if necessary.
Some radiators or baseboard Air in system units do not heat or are noisy
Low system pressure
Boiler temperature set too low
Bleed air from system through air vents in radiators or baseboard units.
Fill to correct pressure.
Check for leaks in boiler or piping. Have qualified service technician repair
at once.
Adjust boiler temperature to higher setting.
14
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NOTES
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15
GWC Series 2 Gas-fired water boiler — User’s Information Manual
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