U.S. Boiler Company X-2 X-202 Service manual

106636-02 - 12/19
9700609
X-2 TM
Installation, Operating and Service Instructions for
• Water Boiler
• Cast Iron
• Chimney Vent
• Gas Fired
Models:
• X-202
• X-203
• X-204
• X-205
• X-206
• X-207
• X-208
• X-209
Manual Contents Page
Dimensional and Physical Data ............3
Pre-Installation..........................5
Removing Existing Boiler .................6
Unpack Boiler ..........................6
Venting ................................7
Water Piping...........................10
Gas Piping ............................13
Electrical..............................14
System Start-Up and Checkout ...........18
Operation .............................23
Before Leaving Jobsite ..................27
Service and Maintenance ................28
How It Works ..........................32
Troubleshooting........................34
Service Parts ..........................39
Appendix .............................46
TO THE INSTALLER:
Affix these instructions adjacent to boiler.
Provide model number and serial number when
seeking information and support.
TO THE CONSUMER:
Retain these instructions for future reference.
Contact heating contractor for all issues and support.
WARNING
Improper installation, adjustment, alteration, service, or maintenance can cause property damage, injury,
or loss of life. For assistance or additional information, consult a qualified installer, service agency or gas
supplier. Read these instructions carefully before installing.
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X-2 Installation, Operating & Service Manual
The following terms are used throughout this manual to bring attention to the presence of hazards of various
risk levels, or to important information concerning product life.
The City of New York requires a Licensed Master Plumber supervise the installation of this product.
The Massachusetts Board of Plumbers and Gas Fitters has listed the X-2TM Series Boiler. See the Massachusetts
Board of Plumbers and Gas Fitters website,
https://licensing.reg.state.ma.us/pubLic/pl_products/pb_product.asp for the latest Approval Code or ask your
local Sales Representative.
The Commonwealth of Massachusetts requires this product to be installed by a licensed Plumber or Gas fitter.
NOTICE: Indicates special instructions on
installation, operation, or service which are
important but not related to personal injury
hazards.
DANGER
Indicates a hazardous situation that, if not
avoided, will result in death or serious injury.
CAUTION
Indicates a hazardous situation that, if not
avoided, could result in minor or moderate
injury.
WARNING
Indicates a hazardous situation that, if not
avoided, could result in death or serious injury.
DANGER
Explosion Hazard. DO NOT store or use gasoline or other flammable vapors or liquids in the vicinity of
this or any other appliance.
If you smell gas vapors, DO NOT try to operate any appliance - DO NOT touch any electrical switch or
use any phone in the building. Immediately, call the gas supplier from a remotely located phone.
Follow the gas supplier’s instructions or if the supplier is unavailable, contact the fire department.
WARNING
This boiler must only be serviced and repaired by skilled and experienced service technicians.
• If any controls are replaced, they must be replaced with identical models.
• Read, understand and follow all the instructions and warnings contained in all the sections of this
manual.
• If any electrical wires are disconnected during service, clearly label the wires and assure that the wires
are reconnected properly.
• Never jump out or bypass any safety or operating control or component of this boiler.
• Assure that all safety and operating controls and components are operating properly before placing
the boiler back in service.
• Annually inspect all vent gaskets and replace any exhibiting damage or deterioration.
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X-2 Installation, Operating & Service Manual
Table 1-1: Dimensions and Connections
Boiler
Model Depth Width Height Supply NPT (inch)
Return NPT
(inch)
Vent
(inch)
Gas NPT
(inch)
Relief Valve
NPT (inch)
Drain
NPT (inch)
X-202 32 14 40 1¼ 1¼ 4 ½ ¾ ¾
X-203 32 14 40 1¼ 1¼ 4 ½ ¾ ¾
X-204 32 16 40 1¼ 1¼ 5 ½ ¾ ¾
X-205 32 19 40 1¼ 1¼ 6 ½ ¾ ¾
X-206 32 22 40 1¼ 1¼ 6 ½ ¾ ¾
X-207 32 25 40 1¼ 1¼ 7 ¾ ¾ ¾
X-208 32 28 40 1¼ 1¼ 7 ¾ ¾ ¾
X-209 32 31 40 1¼ 1¼ 8 ¾ ¾ ¾
Electrical Requirements: 120VAC, 60 Hz, 1-ph, Less than 12A
Maximum Allowable Working Pressure - 50 psi. Boiler shipped from factory with a 30 psi safety relief valve.
(1) Input ratings can be used for elevations up to 2000 ft. Refer to System Start-up and Checkout
Sections for elevations 2000 ft. or higher.
Boiler
Model Input (MBH) (1) Shipping Weight (lbs)
Empty Weight
(lbs)
Water Content
(gal)
X-202 38 202 143 1
X-203 70 254 180 2
X-204 105 304 231 3
X-205 140 357 284 4
X-206 175 405 332 5
X-207 210 462 382 6
X-208 245 518 438 7
X-209 280 564 484 8
Table 1-2: Weights and Volume
1Dimensional and Physical Data

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X-2 Installation, Operating & Service Manual
Figure 1-4: Minimum Alcove Clearances
1Dimensional and Physical Data (continued)
Figure 1-3: Minimum Closet Clearances
* Minimum radial clearance around vent pipe and breeching for single-wall metal pipe vent connector.
Otherwise, follow vent connector manufacturer's recommended clearances.
** Additional height required to maintain 6" clearance from all breeching components. Vent damper may
be installed in vertical or horizontal section of vent connector within reach of vent damper harness.
*** Area of each opening to be 1 sq. inch for each 1000 BTU/hr input - with minimum of 100 sq. inches. Height
of opening should be half of width. 3" minimum dimension for air openings.
Model "W"
X-202 14"
X-203 14"
X-204 16"
X-205 19"
X-206 22"
X-207 25"
X-208 28"
Model "W"
X-209 31"

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X-2 Installation, Operating & Service Manual
2 Pre-Installation
WARNING
Carefully read all instructions before installing
boiler. Failure to follow all instructions in proper
order can cause personal injury or death.
A. Inspect shipment carefully for any signs of
damage. All equipment is carefully manufactured,
inspected and packed. Our responsibility
ceases upon delivery of boiler to carrier in good
condition. Any claim for damage or shortage
in shipment must be filed immediately against
carrier by consignee. No claims for variances or
shortages will be allowed by Boiler Manufacturer,
unless presented within sixty (60) days after
receipt of equipment.
B. Installation must conform to the requirements of
the authority having jurisdiction. In the absence
of such requirements, installation must conform to
National Fuel Gas Code, ANSI Z223.1/NFPA 54.
C. Appliance is listed for installation on combustible
flooring. The boiler must not be installed on
carpeting.
D. Provide clearance between boiler jacket and
combustible material in accordance with local
fire ordinance. Refer to Figures 1-3 and 1-4 for
minimum clearance from combustible material.
Provide 1/2" clearance from water piping to
combustible materials.
E. Provide practical service clearances. A minimum
of 24" from the left side and front jacket panels is
recommended for servicing but may be reduced
to minimums shown in Figures 1-3 and 1-4.
F. Install on level floor. For basement installation
provide concrete base if floor is not level or if
water may be encountered on floor around boiler.
WARNING
ASSURE THAT THE FRONT AIR DAM is in place and
undamaged. A damaged front air dam will negatively
affect the performance of this boiler, which can cause
serious property damage, personal injury or death.
G. Protect gas ignition system components from
water (dripping, spraying, rain, etc.) during boiler
operation and service (circulator replacement,
condensate trap, control replacement, etc.).
H. Provide combustion and ventilation air in
accordance with the section "Air for Combustion
and Ventilation," of the National Fuel Gas Code,
ANSI Z223.1/NFPA 54, or applicable provisions of
local building codes.
WARNING
Adequate combustion and ventilation air must
be provided to assure proper combustion.
I. Do not install boiler where gasoline or other
flammable vapors or liquids, or sources of
hydrocarbons (i.e. bleaches, cleaners, chemicals,
sprays, paint removers, fabric softeners, etc.) are
used or stored.
J. Consider using boiler bypass described in
Section 6 "Water Piping" for systems which have
a large volume or excessive radiation where low
boiler water temperatures may be encountered.
K. Where required by authority having jurisdiction,
installation must conform to standard for Controls
and Safety Devices for Automatically Fired
Boilers, ANSI/ASME CSD-1.
L. A hot water boiler installed above radiation level
or as required by the authority having jurisdiction
must be provided with a low water cutoff device.
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X-2 Installation, Operating & Service Manual
A. If an Existing Boiler is Removed:
When an existing boiler is removed from a
common venting system, the common venting
system is likely to be too large for proper venting
of the appliances remaining connected to it.
At the time of removal of an existing boiler, the
following steps shall be followed with each
appliance remaining connected to the common
venting system placed in operation, while the
other appliances remaining connected to the
common venting system are not in operation:
1. Seal any unused openings in the common
venting system.
2. Visually inspect the venting system for proper
size and horizontal pitch and determine
there is no blockage or restriction, leakage,
corrosion, and other deficiencies which could
cause an unsafe condition.
3. Insofar as is practical, close all building doors
and windows and all doors between the space
in which the appliances remaining connected
to the common venting system are located and
other spaces of the building. Turn on clothes
dryers and any appliance not connected to the
common venting system. Turn on any exhaust
fans, such as range hoods and bathroom
exhausts, so they will operate at maximum
speed. Do not operate a summer exhaust fan.
Close fireplace dampers.
4. Place in operation the appliance being
inspected. Follow the Lighting (or Operating)
Instructions. Adjust thermostat so appliance
will operate continuously.
5. Test for spillage at the draft hood relief opening
after 5 minutes of main burner operation. Use
the flame of a match or candle, or smoke from
a cigarette, cigar or pipe.
6. After it has been determined that each
appliance remaining connected to the common
venting system properly vents when tested as
outlined above, return doors, windows, exhaust
fans, fireplace dampers and any other gas-
burning appliance to their previous condition of
use.
7. Any improper operation of the common venting
system should be corrected so the installation
conforms with the National Fuel Gas Code,
ANSI Z223.1/NFPA 54. When resizing any
portion of the common venting system, the
common venting system should be resized
to approach the minimum size as determined
using the appropriate tables in Chapter 13
of the National Fuel Gas Code, ANSI Z223.1/
NFPA 54.
3 Removing Existing Boiler
4 Unpack Boiler
CAUTION
Do not drop boiler. Do not bump boiler jacket
against floor.
A. Move boiler to approximate installed position.
B. Remove all crate fasteners.
C. Lift outside container and remove with all other
inside protective spacers and bracing. Save two
of the wooden slats from the container sleeve for
use in Steps E and F.
D. Remove all boiler hold-down fasteners.
E. Tilt the boiler to one side and slide a wooden slat
under the two raised feet.
F. Tilt the boiler to the other side and slide another
wooden slat under the two raised feet.
G. Slide the boiler forward or backward off the skid
using the two wooden slats as runners.
H. Move boiler to its permanent location.
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X-2 Installation, Operating & Service Manual
A. Inspect chimney and remove any obstructions
or restrictions. Clean chimney if previously used
for solid or liquid fuel-burning appliances or
fireplaces.
B. Locate blocked vent switch on boiler draft hood.
Verify connections are made.
C. Install Vent Damper
OPEN THE VENT DAMPER CARTON and remove
Installation Instructions. READ THE INSTALLATION
INSTRUCTIONS THOROUGHLY before proceeding.
Automatic gas control valve supplied on each X-2
boiler provides redundancy referenced in vent
damper Installation Instructions.
CAUTION
Do not use one vent damper to control two
heating appliances.
1. Vent damper must be same size as outlet of
draft hood supplied with boiler (see
Table 1-1). Unpack damper carefully - DO
NOT FORCE IT CLOSED! Forcing damper
may damage motor and void warranty.
Insert pilot vent plug into gate and fold over
tabs.
2. Mount vent damper assembly onto draft hood.
(Refer to Figure 5-1 and to
instructions packed with vent damper for
specific instructions). Do not modify either
draft hood or vent damper.
NOTICE:
Provide adequate clearance for
servicing.
3. Locate vent damper position indicating means
to be visible following installation.
4. Plug factory harness vent damper connector
into damper motor polarized receptacle.
WARNING
Do not alter draft hood or place any obstruction
or non listed damper in breeching or vent
system. Flue gas spillage and carbon monoxide
production can occur.
D. Install vent system in accordance with "Venting of
Appliances" of the National Fuel Gas Code, ANSI
Z223.1/NFPA 54, or applicable provisions of local
building codes.
The X-2 Series boiler is a Category I, draft hood
equipped appliance.
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1. Type B or Type L gas vent. Install in
accordance with listing and manufacturer's
instructions.
2. Masonry or metal chimney. Build and install
in accordance with local building codes;
or local authority having jurisdiction; or
Standard for Chimneys, Fireplaces, Vents,
and Solid Fuel Burning Appliances, ANSI/
NFPA 211.
Masonry chimney must be lined with listed
clay flue lining or listed chimney lining
system.
3. Single wall metal vent. Allowed by ANSI
Z223.1/NFPA 54 under very restrictive
conditions.
4. Do not use CPVC, PVC, Polypropylene or
any other non-metallic vent pipe. Do not
use cellular core PVC (ASTM F891), cellular
core CPVC, or Radel®(polyphenolsulfone).
5. Do not cover non-metallic vent pipe and
fittings with thermal insulation.
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5 Venting
Figure 5-1: Vent Damper Installation

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X-2 Installation, Operating & Service Manual
5 Venting (continued)
E. Install Vent Piping
1. Install vent piping from vent damper outlet
to chimney.
2. Vent pipes serving appliances vented by
natural draft shall not be connected into
any portion of mechanical draft systems
operating under positive pressure.
DANGER
Inspect existing chimney before installing
boiler. Look for corrosion holes. Failure to clean
chimney or replace corroded pipe or tile lining
will cause severe injury or death.
3. Do not connect into same flue of chimney
serving an open fireplace.
Figure 5-2: Vent Damper Position Indicator
4. Vent pipe to chimney must not be smaller
than outlet on draft hood or vent damper.
Arrange venting system so boiler is
served by vent damper device.
Exception: National Fuel Gas Code,
ANSI Z223.1/NFPA 54, and allow vent
downsizing when vent size
determined by their Vent Sizing
Tables is smaller than draft hood
outlet/vent damper. These codes
require all of following:
a. Total vent height (H) is at least
10 ft;
b. Vent not reduced more than one
table size;
and
c. Draft hood outlet/vent damper is
greater than 4 in. in diameter.
5. Vent pipe should have greatest possible
initial rise above draft hood consistent
with head room available and required
clearance from adjacent combustible
building structure. Vent pipe should be
installed above bottom of chimney to prevent
blockage.
6. Slope vent pipe upward from draft hood to
vent terminal not less than 1/4" per foot.
7. Support horizontal portions of venting
system to prevent sagging. Use pipe
straps, brackets or hangers spaced 4 ft. or
less.
8. Vent pipe must be inserted into but not
beyond inside wall of chimney liner. Seal tight
between vent pipe and chimney.
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X-2 Installation, Operating & Service Manual
5 Venting (continued)
F. Install vent termination (Masonry chimney and
single wall metal pipe)
1. Termination shall extend at least 5 ft.
in vertical height above highest connected
appliance vent outlet.
2. Termination shall extend at least 3 ft. (2 ft. for
single wall metal pipe) above roof penetration
and at least 2 ft. above any portion of building
within horizontal distance of 10 ft.
G. Install vent termination: (Gas Vent)
1. Termination shall extend at least 5 ft.
in vertical height above highest connected
appliance vent outlet.
2. For terminations located at least 8 ft. from
vertical wall or similar obstruction, termination
shall extend above roof in accordance with
Figure 5-3.
3. For terminations located less than 8 ft. from
vertical wall or similar obstruction, termination
shall extend at least 2 ft. above roof
penetration and at least 2 ft. above any
portion of building within horizontal distance
of 10 ft.
4. Termination shall be at least 3 ft. above forced
air inlet located within 10 ft.
Figure 5-3: Termination Location for Gas Vent
Roof Slope Heights
Roof Slope ft.
Flat to 6/12 1.0
Over 6/12 to 7/12 1.25
Over 7/12 to 8/12 1.5
Over 8/12 to 9/12 2.0
Over 9/12 to 10/12 2.5
Over 10/12 to 11/12 3.25
Over 11/12 to 12/12 4.0
Over 12/12 to 14/12 5.0
Over 14/12 to 16/12 6.0
Over 16/12 to 18/12 7.0
Over 18/12 t 20/12 7.5
Over 20/12 to 21/12 8.0

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X-2 Installation, Operating & Service Manual
6 Water Piping
WARNING
Failure to properly pipe boiler may result in
improper operation and damage to boiler or
building.
A. Design and install boiler and system piping to
prevent oxygen contamination of boiler water.
Oxygen contamination sources are system leaks
requiring addition of makeup water, fittings,
and oxygen permeable materials in distribution
system. Eliminate oxygen contamination by
repairing system leaks, repairing fittings, and
using non-permeable materials in distribution
system.
B. Install circulator with flanges, gaskets and bolts
provided.
C. Install Safety Relief Valve. See Figure 6-1. Safety
Relief Valve must be installed with spindle in
vertical position.
WARNING
Safety relief valve discharge piping must
be piped near floor to eliminate potential
of severe burns. Do not pipe in any
area where freezing could occur. Do
not install any shut-off valves between:
1. Safety relief valve and boiler
2. Safety relief valve and discharge
Union may be installed in safety relief valve
piping.
D. Connect system supply and return piping to
boiler. Refer to Figures 6-1, 6-2, and 6-3. Also
consult Residential Hydronic Heating Installation
and Design I=B=R Guide. Maintain minimum
½ inch clearance from hot water piping to
combustible materials.
E. If boiler is used in connection with refrigeration
systems, See Appendix: "Combination
Refrigeration/Heating System".
F. Use a boiler bypass if boiler is to be operated in
a system which has a large volume or excessive
radiation where low boiler water temperatures may
be encountered (i.e. converted gravity circulation
system, etc.). See Appendix: "Low Return Water
Temperatures".
G. Perform a long term pressure test of hydronic
system, isolate boiler to avoid a pressure loss due
to escape of air trapped in boiler.
To perform a long term pressure test including the
boiler, ALL trapped air must first be removed from
the boiler.
A loss of pressure during such a test, with no
visible water leakage, is an indication that the
boiler contained trapped air.
Figure 6-1: Near Boiler Piping
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106636-02 - 12/19 11
X-2 Installation, Operating & Service Manual
Figure 6-2: Recommended Water Piping for Direct Connection Systems
At least 18"
of straight pipe
for conventional
air separator
To
System
To
System
Optional Circulator Zone
Controlled System
Optional Zone Valve
Controlled System
System
Circulator
System
Zone
Valves
Zone Circulators
Full Port Isolation Valves
Flow Check
From System
Full Port Isolation Valves
Drain Valve
Safety Relief Valve
Pipe within 6" of floor or drain
Drain Valve
IWH
Return
IWH
Supply
Indirect Water Heater (IWH)
Air Separator
& Air Vent
Expansion Tank
Backflow Preventer
Fill Valve
Cold
Water
Return
Full Port Isolation Valves
Unions
Flow Check
IWH Circulator
Full Port Isolation Valve
Unions
Full Port Isolation Valve
6 Water Piping (continued)

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X-2 Installation, Operating & Service Manual
6 Water Piping (continued)
'C'
'B' 'A'
To
System
To
System
Optional Circulator Zone
Controlled System
Optional Zone Valve
Controlled System
System
Circulator
System
Zone
Valves
Zone Circulators
Full Port Isolation Valves
Flow Check
From System
Full Port Isolation Valves
Drain Valve
Safety Relief Valve
Pipe within 6" of floor or drain
Drain Valve
IWH
Return
IWH
Supply
Indirect Water Heater (IWH)
Air Separator
& Air Vent
Expansion Tank
Backflow Preventer
Fill Valve
Cold
Water
Return
Full Port Isolation Valves
Unions
Flow Check
IWH Circulator
Full Port Isolation Valve
Unions
Full Port Isolation Valve
A. At least eight pipe diameters upstream of boiler return tee. B. No further apart than 12" (~30cm) or four pipe diameters, whichever is smaller. C. At least 18" (~46cm) of straight pipe for
Conventional Air Scoop.
Circulator
Figure 6-3: Recommended Water Piping for Primary/Secondary Systems

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X-2 Installation, Operating & Service Manual
Figure 7-2: Pilot and Gas Piping
A. Size gas piping. Design system to provide
adequate gas supply to boiler. Consider these
factors:
1. Allowable pressure drop from point of delivery
to boiler. Maximum allowable system pressure
is ½ psig. Minimum gas valve inlet pressure is
listed on rating label. See Table 7-1.
Table 7-1: Gas Pressure
Natural
Gas
Inlet Min (in
w.c.)
Inlet Max
(in w.c.)
Manifold (in
w.c.)
All Sizes 4.5 14.0 3.5
LP Gas Inlet Min (in
w.c.)
Inlet Max
(in w.c.)
Manifold
(in w.c.)
All Sizes 11.0 14.0 10.0
2. Maximum gas demand. Consider existing and
expected future gas utilization equipment (i.e.
water heater, cooking equipment).
B. Connect boiler gas valve to gas supply system.
1. Use methods and materials in accordance with
local plumbing codes and requirements of gas
supplier. In absence of such requirements,
follow National Fuel Gas Code, ANSI Z223.1/
NFPA 54.
2. Use thread compounds (pipe dope) resistant
to action of liquefied petroleum gas.
3. Install sediment trap, ground-joint union and
manual shut-off valve upstream of boiler gas
control valve. See Figure 7-2 (within 6 ft of
boiler).
4. All above ground gas piping upstream from
manual shut-off valve must be electrically
continuous and bonded to a grounding
electrode. Do not use gas piping as grounding
electrode. Refer to National Electrical Code,
ANSI/NFPA 70.
C. Pressure test. Boiler and its gas connection must
be leak tested before placing boiler in operation.
See "System Start-Up and Checkout" section and
"Gas Leak Test" for guidance.
7 Gas Piping
Figure 7-3: Gas Manifold and Control Assembly

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X-2 Installation, Operating & Service Manual
A. Install wiring so boiler is electrically bonded
to ground in accordance with requirements of
authority having jurisdiction, or in absence of such
requirements, with the National Electrical Code,
ANSI/NFPA 70.
B. Install thermostat. Locate on inside wall
approximately 4 feet above floor. Do not install on
outside wall, near fireplace, or where influenced
by drafts or restricted air flow, hot or cold water
pipes, lighting fixtures, television, or sunlight.
Allow free air movement by avoiding placement of
furniture near thermostat.
C. Wire boiler. Boiler is rated for 120 VAC, 60 hertz,
less than 12 Amperes. A separate electrical
circuit must be run from main electrical service
with an over-current device/disconnect in circuit.
A service switch is recommended and may be
required by some local jurisdictions. Connect to
black and white wires and green ground screw.
See Figures 8-1 and 8-2.
D. For installations using zone valves, provide
separate transformer for zone valve wiring.
Consult zone valve manufacturer for assistance.
See Figure 8-3.
CAUTION
This boiler contains controls which may cause
the boiler to shut down and not restart without
service. If damage due to frozen pipes is a
possibility, heating system should not be left
unattended in cold weather; or appropriate
safeguards and alarms should be installed on
heating system to prevent damage if boiler is
inoperative.
8 Electrical
!
WARNING
Electrical Shock Hazard. Wiring errors can
cause improper or dangerous operation. Verify
proper operation after installation.
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X-2 Installation, Operating & Service Manual
Figure 8-1: Wiring Connection Diagram
8
Electrical (continued)

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16
X-2 Installation, Operating & Service Manual
Figure 8-2: Schematic Ladder Diagram
8 Electrical
(continued)

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X-2 Installation, Operating & Service Manual
8
Electrical (continued)
Figure 8-3: Wiring Schematic, Zone Valves
Figure 8-4: Wiring Schematic, Zone Circulators

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X-2 Installation, Operating & Service Manual
9
System Start-up and Checkout
A. Visual Main Burner Check
Inspect burners for dislodgement during
shipment. Rear of burners should be in vertical
slots in rear of burner tray and front of burners
should be seated completely on orifices.
B. Initial LWCO Test
Before filling boiler with water, turn on power
to boiler and set thermostat to call for heat.
Both the green "POWER" LED and amber "LOW
WATER" LED should illuminate (see Figure 9-1).
Burner should not fire.
D. Purge Air from System
1. Fill entire heating system with water and
vent air from boiler, radiators and system,
one zone at a time.
2. Isolate boiler by closing isolation valves. For
primary - secondary systems, close additional
isolation valve to ensure water flows through
zones.
3. Isolate all circuits by closing zone valves
or turning off zone circulators.
4. Attach hose to drain valve located
on return piping (see Figure 6-2 and 6-3).
Note-Terminate hose in five gallon bucket,
at a suitable floor drain, or outdoor area).
5. Starting with one circuit, open zone valve or
start circulator.
6. Open drain valve.
7. Open fill valve.
8. Allow water to flow through system until
discharge from hose is bubble free for 30
seconds.
9. Open zone valve or start circulator to second
zone to be purged, then close first.
Repeat this step until all zones have
been purged, but always have one zone
open. At completion, open all zone valves.
10. Close hose bib, open boiler isolation
valve, continue filling system until
pressure gauge reads 12 psi.
Close fill valve. (Note - If make-up water
line is equipped with pressure reducing
valve, system will automatically fill to 12
psi).
11. Remove hose from drain valve.
Figure 9-1: IDL 1200 Low Water Cut-Off
C. Fill Boiler with Water
1. Proceed to fill boiler with water. When water
reaches IDL 1200 Sensor, "LOW WATER" LED
will turn off and burner will fire.
2. Turn off power to boiler and finish filling
system.
WARNING
If the burner fires with no water at probe,
immediately shut down power to boiler and
contact customer service for assistance.
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X-2 Installation, Operating & Service Manual
Figure 9-2: Operating Instructions
9
System Start-up and Checkout (continued)

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X-2 Installation, Operating & Service Manual
9
System Start-up and Checkout (continued)
2. PURGE AIR FROM GAS PIPING by loosening
(or removing) “Inlet Pressure Tap” plug on gas
valve (See Figure 9-3). Tighten (or replace)
plug when you start to smell gas. Adequate
ventilation must be provided and no smoking
or open flame permitted.
3. Locate and address leaks using listed
combustible gas detector,a non corrosive leak
detection fluid or other listed leak
detection method.
a. Check pipe fittings up to inlet of gas valve
b. Check piping between gas valve and
orifices (after boiler is operating).
c. Check piping between gas valve and pilot
(after boiler is operating).
4. Tighten appropriate pipe connections.
I. Check pilot burner flame.
Natural Gas Only. Pilot produces single flame.
Flame should be steady medium hard blue
enveloping 3/8 to 1/2 inch of igniter-sensor tip.
See Figure 9-4.
3. Tighten appropriate pipe connections.
F. Perform limit check
1. Ensure gas to boiler is off
2. Set ROOM THERMOSTAT to lowest setting.
3. If limits are functioning properly (LWCO,
Auxiliary limit, flame rollout switch, blocked
vent switch, damper), boiler should spark.
If boiler does not spark, see Section 14
"Troubleshooting" for guidance.
4. Turn "OFF" the electric switch to boiler.
G. Start boiler according to "Operating Instructions"
in Figure 9-2.
H. Perform gas leak test downstream of boiler
manual shutoff valve.
1. Open manual shutoff valve.
E. Perform gas leak test upstream of boiler shutoff
valve.
1. Protect boiler gas valve.
a. For all testing over ½ psig, boiler
and manual shutoff valve must be
disconnected from gas supply piping.
b. For testing at ½ psig or less, isolate
boiler from gas supply piping by closing
boiler manual shutoff valve.
2. Locate leaks using listed combustible
gas detector, a noncorrosive leak detection
fluid or other listed leak detection method.
Figure 9-4: Pilot Burner Flame (NG Only)
Figure 9-5: Pilot Burner Flame (LP Only)
DANGER
Do not use matches, candles, open flames, or
other ignition source.
!
Figure 9-3: Top View of Gas Valves
LP Gas Only. Pilot burner produces three (3)
flames. The center flame should be steady,
medium hard blue enveloping 3/8 to 1/2 inch of
sending probe. See Figure 9-5.