U.S. Boiler Company MPO - IQ Operating instructions

103859-05 - 10/14 Price - $5.00
9700609
INSTALLATION, OPERATING AND
SERVICE INSTRUCTIONS FOR
MPO -IQ™
3-PASS OIL Boiler
For service or repairs to boiler, call your heating contractor. When seeking information on boiler, provide
Boiler Model Number and Serial Number as shown on Rating Label.
Boiler Model Number
MPO - IQ
Boiler Serial Number Installation Date
Heating Contractor Phone Number
Address
As an ENERGY STAR®Partner, U.S. Boiler Company has determined that the MPO-IQ™ boiler meets the ENERGY STAR®
guidelines for energy efciency established by the United States Environmental Protection Agency (EPA).

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IMPORTANT INFORMATION - READ CAREFULLY
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.
DANGER
Indicates an imminently hazardous situation which,
if not avoided, will result in death, serious injury or
substantial property damage.
WARNING
Indicates a potentially hazardous situation which, if
not avoided, could result in death, serious injury or
substantial property damage.
CAUTION
Indicates a potentially hazardous situation which, if
not avoided, may result in moderate or minor injury
or property damage.
NOTICE
Indicates special instructions on installation,
operation, or maintenance which are important but
not related to personal injury hazards.
NOTICE
This boiler has a limited warranty, a copy of which is included with this boiler.
The warranty for this boiler is valid only if the boiler has been installed, maintained and operated in
accordance with these instructions.
Surface rust on cast iron sections may be attributed to the manufacturing process as well as condensation
during storage. Surface rust is normal and does not affect the performance or longevity of a boiler.
All boilers must be installed in accordance with National, State and Local Plumbing, Heating
and Electrical Codes and the regulations of the serving utilities. These Codes and Regulations
may differ from this instruction manual. Authorities having jurisdiction should be consulted
before installations are made.
In all cases, reference should be made to the following Standards:
USA BOILERS
A. Current Edition of American National Standard ANSI/NFPA 31, “Installation of Oil
Burning Equipment”, for recommended installation practices.
B. Current Edition of American National Standard ANSI/NFPA 211, “Chimneys, Fireplaces,
Vents, and Solid Fuel Burning Appliances”, For Venting requirements.
C. Current Edition of American Society of Mechanical Engineers ASME CSD-1, “Controls and
Safety Devices for Automatically Fired Boilers”, for assembly and operations of controls
and safety devices.
D. All wiring on boilers installed in the USA shall be made in accordance with the National
Electrical Code and/or Local Regulations.
CANADIAN BOILERS
A. Current Edition of Canadian Standards Association CSA B139, “Installation Code for Oil
Burning Equipment", for recommended Installation Practices.
B. All wiring on boilers installed in Canada shall be made in accordance with the Canadian
Electrical Code and/or Local Regulations.

3
DANGER
DO NOT store or use gasoline or other ammable vapors or liquids in the vicinity of this or any other
appliance.
WARNING
Improper installation, adjustment, alteration, service or maintenance can cause property damage, personal
injury or loss of life. Failure to follow all instructions in the proper order can cause personal injury or death.
Read and understand all instructions, including all those contained in component manufacturers manuals
which are provided with the boiler before installing, starting-up, operating, maintaining or servicing this
boiler. Keep this manual and literature in legible condition and posted near boiler for reference by owner
and service technician.
This boiler requires regular maintenance and service to operate safely. Follow the instructions contained
in this manual.
Installation, maintenance, and service must be performed only by an experienced, skilled and knowledgeable
installer or service agency.
All heating systems should be designed by competent contractors and only persons knowledgeable in
the layout and installation of hydronic heating systems should attempt installation of any boiler.
Installation is not complete unless a pressure relief valve is installed into the 3/4" tapping located on
return injector assembly that was installed into boss on top of rear section - See "Packaged Boiler Assy
- Trim & Controls", "Unit-Pak Boiler Assy - Trim & Controls" and "Water Boiler Piping" Sections of this
manual for details.
It is the responsibility of the installing contractor to see that all controls are correctly installed and are
operating properly when the installation is completed.
This boiler is suitable for installation on combustible ooring. Do not install boiler on carpeting.
Do not tamper with or alter the boiler or controls.
Inspect ueways at least once a year - preferably at the start of the heating season. The inside of
the combustion chamber, the vent system and boiler ueways should be cleaned if soot or scale has
accumulated.
When cleaning this boiler, take precaution to avoid damage to burner swing door insulation. If damaged,
or if there is evidence of previous damage, burner swing door insulation must be replaced immediately.
Oil Burner and Controls must be checked at least once a year or as may be necessitated.
Do not operate boiler with jumpered or absent controls or safety devices.
Do not operate boiler if any control, switch, component, or device has been subject to water.
Boiler construction materials, products of combustion and the fuel contain alumina, silica, heavy metals,
carbon monoxide, nitrogen oxides, aldehydes and/or other toxic or harmful substances which can cause
death or serious injury and which are known to the state of California to cause cancer, birth defects and
other reproductive harm. Always use proper safety clothing, respirators and equipment when servicing
or working nearby the appliance.
This boiler contains very hot water under high pressure. Do not unscrew any pipe ttings nor attempt
to disconnect any components of this boiler without positively assuring the water is cool and has no
pressure. Always wear protective clothing and equipment when installing, starting up or servicing this
boiler to prevent scald injuries. Do not rely on the pressure and temperature gauges to determine the
temperature and pressure of the boiler. This boiler contains components which become very hot when
the boiler is operating. Do not touch any components unless they are cool.

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WARNING
This boiler must be properly vented. The chimney must be inspected for any obstructions and cleaned
prior to each heating season. A clean and unobstructed chimney ue is necessary to produce the minimum
draft required to safely evacuate noxious fumes that could cause personal injury or loss of life. Evidence
of loose debris and or condensate induced stains at the base of the chimney ue, connector or smokepipe
joints may be signs of condensing ue gases. Flue gas condensate is corrosive, which requires special
consideration and must be addressed immediately. Refer to Section V, "Venting" or Section VI "Direct
Venting / Air Intake Piping".
This boiler needs fresh air for safe operation and must be installed so there are provisions for adequate
combustion and ventilation air.
This boiler is supplied with controls which may cause the boiler to shut down and not re-start without
service. If damage due to frozen pipes is a possibility, the heating system should not be left unattended in
cold weather; or appropriate safeguards and alarms should be installed on the heating system to prevent
damage if the boiler is inoperative.
This boiler is designed to burn No. 2 fuel oil only. Do not use gasoline, crankcase drainings, or any oil
containing gasoline. Never burn garbage or paper in this boiler. Do not convert to any solid fuel (i.e.
wood, coal). Do not convert to any gaseous fuel (i.e. natural gas, LP). All ammable debris, rags, paper,
wood scraps, etc., should be kept clear of the boiler at all times. Keep the boiler area clean and free of
re hazards.
All boilers equipped with burner swing door have a potential hazard which, if ignored, can cause severe
property damage, personal injury or loss of life. Before opening swing door, unplug burner power cord
from receptacle located in lower right corner of jacket front panel and turn off service switch to boiler
to prevent accidental ring of burner outside the combustion chamber. Be sure to tighten swing door
fasteners completely when service is completed.
TABLE OF CONTENTS
I. Pre-Installation ........................................................................................ 8
II. Packaged Boiler Assy. - Trim & Controls ................................................. 11
III. Unit-Pak Boiler Assy. - Trim & Controls..................................................... 20
IV. Water Boiler Piping .................................................................................. 26
V. Natural Draft Venting ............................................................................... 30
VI. Direct Venting / Air Intake Piping.............................................................. 34
VII. Electrical .................................................................................................. 41
VIII. Oil Piping ................................................................................................. 45
IX. System Start-Up ...................................................................................... 47
X. Operating.................................................................................................. 52
XI. Maintenance & Service Instructions ....................................................... 57
XII. Boiler Cleaning ........................................................................................ 59
XIII. Trouble Shooting ..................................................................................... 61
XIV. Repair Parts ............................................................................................ 69
XV. Burner Specications................................................................................ 83
Appendix A - IQ Oil Control System.......................................................... 85
Appendix B - Figures................................................................................ 89
Appendix C - Tables.................................................................................. 91

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Congratulations on your purchase of a new MPO-IQ™ boiler—designed and constructed to provide you with years
of reliable service.
• ENERGY STAR™ efciency – friendly on the environment and your wallet.
• Cast iron heat exchanger – for reliability and durability, nothing beats a cast iron heat exchanger.
• *IQ Control™ System– the most advanced and easiest to use controls available.
• System-friendly – built-in protection from condensation and thermal shock.
*IQ Control System Overview
MPO-IQ Boiler uses a microprocessor based control system called the "IQ Control System". This "IQ Control System"
consists of an IQ Oil Boiler Control (Boiler Control) in conjunction with an Oil Primary Control (Oil Primary)and an IQ Option
Panel (Option Panel) with optional "plug-in" IQ Option Cards (Option Card). The IQ Control System fully integrates both
factory and eld installed components, simplifying installation and troubleshooting. The IQ Control System is designed
to efciently operate the entire boiler system to save energy and installation and setup time, while ensuring adequate
supply of heat and domestic hot water.
What's in the crate?
Content Check List
1. MPO-IQ Boiler Assembly on Shipping Skid:
___ MPO-IQ84
___ MPO-IQ115
___ MPO-IQ147
___ MPO-IQ189
___ MPO-IQ231
2. Circulator & Gasket Kit:
___ Taco 007-2 - P/N 8056170
___ Grundfos UP-15 - P/N 102805-01
___ B & G NRF-22 - P/N 8056174
3. Parts Carton:
___ MPO-IQ84 - P/N 103088-01
___ MPO-IQ115 - P/N 103088-02
___ MPO-IQ147/231 - P/N 103088-03
4. Barometric Draft Regulator Carton
___ 5" Dia. - P/N 8116287
___ 6" Dia. - P/N 8116288
___ 7" Dia. - P/N 8116289
5. Instruction Envelope - P/N 103858-01
___ Installation & Operation Manual - P/N 103859-05
___ Boiler Warranty Sheet - P/N 103203-02
Warrantty Registration Tag - P/N 104409-01

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Figure 1: MPO-IQ84 Thru MPO-IQ231 Water Boiler

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TABLE 1A: DIMENSIONAL DATA (SEE FIGURE 1) TABLE 1B: RATING DATA
Boiler Model
No.
Dimensions See Figure 1 Water Content
- Gallons
Heat Transfer
Surface Area
- Sq. Ft.
Actual
Shipping
Weight (LB.)
“A” “B” “C”
MPO-IQ84 16-5/8” 24” 5” 7.70 13.29 430
MPO-IQ115 16-5/8” 24” 5” 7.70 13.29 430
MPO-IQ147 22-5/8” 24” 6” 11.08 20.29 545 MPO-IQ189 28-5/8” 30” 6” 14.46 27.29 658 MPO-IQ231 34-5/8” 36” 7” 17.84 34.29 771
NOTE: 1. Maximum Working Pressure: Water: 30 PSI Shipped From Factory (Standard), 40 PSI Optional, 50 PSI Optional
Boiler
Model No.
Burner Capacity NET AHRI
Ratings AFUE % Minimum Chimney
Requirements Direct Vent System
GPH MBH DOE Heating
Capacity MBH Water MBH Water
Boiler
Round
In. Dia.
Rectangle
In. x In.
Height
Ft. Model
Vent
Connector
Dia. Inch
MPO-IQ84 0.60 84 74 64 87 6 8 x 8 15 N/A N/A
MPO-IQ115 0.82 115 101 87 87 6 8 x 8 15 N/A N/A
MPO-IQ147 1.05 147 129 112 87 6 8 x 8 15 FDVS-56 5
MPO-IQI89 1.35 189 167 145 87 7 8 x 8 15 FDVS-56 5
MPO-IQ231 1.65 231 203 177 87 7 8 x 8 15 FDVS-67 6

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Figure 2A: Chimney Vented Boiler - Minimum Installation Clearances To Combustible Materials (Inches)
A. INSPECT SHIPMENT carefully for any signs of
damage.
1. All equipment is carefully manufactured, inspected and
packed. Our responsibility ceases upon delivery of crated
boiler to the carrier in good condition.
2. Any claims for damage or shortage in shipment must be
led 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
sixty (60) days after receipt of goods.
B. LOCATE BOILER in front of nal position before removing
crate. See Figure 1.
1. LOCATE so that vent pipe connection to chimney will
be short and direct.
2. BOILER IS SUITABLE FOR INSTALLATION ON
COMBUSTIBLE FLOOR. Boiler cannot be installed
on carpeting.
3. FOR BASEMENT INSTALLATION, provide a solid
elevated base, such as concrete, if oor is not level, or if
water may be encountered on oor around boiler.
4. PROVIDE RECOMMENDED SERVICE CLEARANCE,
if applicable, as follows:
a. Clearance from Jacket Front Panel -
•24" for servicing burner
• 24" for ueway cleaning (MPO-IQ84 thru 147)
• 30" for ueway cleaning (MPO-IQ189)
• 36" for ueway cleaning (MPO-IQ231)
b. Clearance from Jacket Side Panels -
•19" for burner swing door, if opened fully with
burner mounted, otherwise 1" with b u r n e r
removed.
• 12" access clearance to service rear of
boiler if other side clearance is less
than 12".
• 3" minimum if other side clearance is 12" or
larger to access and service rear of boiler.
c. Clearance from Jacket Rear Panel -
• 12" minimum for rear smokebox cleaning
(Note: This dimension will also be controlled
by horizontal to vertical to horizontal smokepipe
arrangement - Chimney Vent (see Figures 2A
and 15).
• 24" for rear smokebox cleaning and disconnecting
vent pipe from appliance adapter for servicing (if
required) - Direct Vent (see Figure 2B).
5. For minimum clearances to combustible materials. See
Figures 2A and 2B.
NOTICE
Clearance to venting is for single wall vent pipe. If
Type L vent is used, clearance may be reduced to the
minimum required by the vent pipe manufacturer.
I. PRE-INSTALLATION
NOTES:
1. Listed clearances comply with American National Standard ANSI/
NFPA 31, Installation of Oil Burning Equipment.
2. MPO-IQ boilers can be installed in rooms with clearances from
combustible material as listed above. Listed clearances cannot be
reduced for alcove or closet installations.
3. For reduced clearances to combustible material, protection must be
provided as described in the above ANSI/NFPA 31 standard.

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C. PROVIDE COMBUSTION AND VENTILATION
AIR. Local and National Codes may apply and should
be referenced.
WARNING
Adequate combustion and ventilation air must
be provided to assure proper combustion and to
maintain safe ambient air temperatures.
Do not install boiler where gasoline or other
flammable vapors or liquids, or sources of
hydrocarbons (i.e. bleaches, fabric softeners,
etc.) are used or stored.
1. Determine volume of space (boiler room). Rooms
communicating directly with the space in which the
appliances are installed, through openings not furnished
with doors, are considered a part of the space.
Volume(ft3) = Length(ft) x Width(ft) x Height(ft)
2. Determine total input of all appliances in the space.
Add inputs of all appliances in the space and round the
result to the nearest 1000 BTU per hour.
3. Determine type of space. Divide Volume by total input
of all appliances in space. If the result is greater than or
equal to 50 ft3/1000 BTU per hour, then it is considered
an unconned space. If the result is less than 50 ft3/1000
BTU per hour then the space is considered a conned
space.
4. For boiler located in an unconfined space of a
conventionally constructed building, the fresh air
inltration through cracks around windows and doors
normally provides adequate air for combustion and
ventilation.
5. For boiler located in a conned space or an unconned
space in a building of unusually tight construction,
provide outdoor air.
a. Outdoor air for combustion may be provided
with an optional Fresh Air Accessory Kit (ONLY
AVAILABLE WITH BECKETT BURNER).
Metal cover applications, P/N 611280031. Plastic
cover applications, P/N 102119-01. Refer to Fresh
Air Accessory Kit instructions for installation and air
intake piping details. See Section V for installation
details.
or
b. Outdoor air may be provided with the use of two
permanent openings which communicate directly or
by duct with the outdoors or spaces (crawl or attic)
freely communicating with the outdoors. Locate one
opening within 12 inches of top of space. Locate
remaining opening within 12 inches of bottom of
space. Minimum dimension of air opening is 3 inches.
Size each opening per following:
i. Direct communication with outdoors.
Minimum free area of 1 square inch per
4,000 BTU per hour input of all equipment
in space.
ii. Vertical ducts. Minimum free area of 1 square
inch per 4,000 BTU per hour input of all equipment
in space. Duct cross-sectional area shall be same
as opening free area.
iii. Horizontal ducts. Minimum free area of 1 square
inch per 2,000 BTU per hour input of all equipment
in space. Duct cross-sectional area shall be same
as opening free area.
Alternate method for boiler located within
conned space. Use indoor air if two permanent
openings communicate directly with additional
space(s) of sufcient volume such that combined
volume of all spaces meet criteria for unconned
space. Size each opening for minimum free area
of 1 square inch per 1,000 BTU per hour input
of all equipment in spaces, but not less than 100
square inches.
Figure 2B: Direct Vent Boiler - Minimum Installation Clearances To Combustible Materials (Inches)
I. PRE-INSTALLATION (continued)

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6. Louvers and Grilles of Ventilation Ducts
a. All outside openings should be screened and louvered.
Screens used should not be smaller than 1/4 inch mesh.
Louvers will prevent the entrance of rain and snow.
b. Free area requirements need to consider the blocking
effect of louvers, grilles, or screens protecting the
openings. If the free area of the louver or grille is not
known, assume wood louvers have 20-25 percent free
area and metal louvers and grilles have 60-75 percent
free area.
c. Louvers and grilles must be xed in the open position, or
interlocked with the equipment to open automatically
during equipment operation.
D. DIRECT VENT CONFIGURATIONS requires:
1. Beckett NX Burner
2. Direct Vent Conversion Kit
3. Double Wall Flex Oil Vent Pipe (FOVP)
Boiler
Model No.
Beckett NX
Oil Burner
Part No.
Direct Vent
Conversion Kit
Part No.
FOVP Carton Part
No.
MPO-IQ147 103896-03
102130-02
100211-02 - 5 ft.
100212-02 - 10 ft.
MPO-IQ189 103897-04
100213-02 - 15 ft.
100214-02 - 20 ft.
MPO-IQ231 103898-05 102130-03
100211-03 - 5 ft.
100212-03 - 10 ft.
100213-03 - 15 ft.
100214-03 - 20 ft.
TABLE 2: DIRECT VENT CONFIGURATION
COMPONENTS
I. PRE-INSTALLATION (continued)

11
II. PACKAGED BOILER ASSEMBLY - TRIM & CONTROLS
A. REMOVE CRATE.
1. Remove all fasteners at crate skid.
2. Lift outside container and remove all other inside
protective spacers and bracing. Remove miscellaneous
parts carton.
B. REMOVE BOILER FROM SKID.
1. To reduce the risk of damage to boiler jacket, use the
following procedure to remove from skid, see Figure 3:
Step 1. Boiler is secured to base with (4) 5/16" cap screws,
(2) in front and (2) in rear of shipping skid, see Figure
3. Remove all securing hardware.
Step 2. Place wooden block(s) 12" from rear of skid as
shown (one piece 4" x 4" x 16" lg. or two pieces of
2" x 4" x 16" lg.)
Step 3. Insert 1" Sch. 40 pipe handles through leg hole
in front and rear legs. Center end of pipe on wooden
blocks as shown in Figure 3.
NOTE: Pipe handles should extend a minimum of
48" beyond jacket front panel for best leverage.
Step 4. Using the pipe handles, lift boiler until adjustable
legs are elevated above the deck boards.
Step 5. Remove skid from underneath the boiler.
Step 6. Lower pipe handles until front adjustable legs touch
oor. If necessary, place wooden blocks under front
legs before lowering to provide hand clearance.
Step 7. To lower rear of boiler, tilt boiler slightly forward
by pushing on smokebox collar or lift pipes protruding
through rear legs until wooden blocks can be removed
(see Figure 3). Slowly allow the weight of the boiler
to tilt backward until rear legs rest on oor.
Step 8. If wood block was placed under front legs, lift
pipe handles, remove wooden block and lower front
legs to oor. Remove pipe handles.
CAUTION
Do not drop boiler. Do not bump boiler jacket
against oor.
C. MOVE BOILER TO PERMANENT POSITION by
sliding or walking.
D. PROCEDURE TO OPEN, CLOSE AND SECURE
BURNER SWING DOOR
Throughout this manual you will be instructed to open and
close the burner swing door for various reasons. There is
a proper and improper method to closing and securing the
burner swing door opened for inspection, cleaning or eld
service.
1. TO OPEN BURNER SWING DOOR
(see Figures 4A and 4B).
Step 1. Loosen but do not remove left side latching
hardware (3/8" x 1-3/4" lg. tap bolt).
Step 2. Loosen and remove right side latching
hardware (3/8" x 1-3/4" lg. tap bolt and washer).
Step 3. Remove left side latching hardware (3/8" x
1-3/4" lg. tap bolt and washer).
Figure 3: Packaged Boiler Removal from Skid

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Figure 4A: Partial Front View - Burner Swing Door Mounted to Boiler - Fully Closed and Secured
Step 4. Disconnect burner power cord from receptacle
located in lower right corner of jacket front panel.
Step 5. Door can be swung to the fully open position,
approximately 90° to 120°, with the burner mounted
providing that there is 19" of clearance to the adjacent
wall, see Figures 1 and 4B.
NOTE: If reduced clearance prevents the door from
opening fully, one of the following can provide full
access:
a. Burner can be removed to allow full rotation of
door.
b. Door with burner mounted can be lifted off
mounting bracket and set aside during servicing.
c. The door mounting hardware is reversible from
left side hinge (as shipped) to right side hinge.
To reverse hinge arrangement (see Figure 4A):
• Lift door off mounting bracket and set
aside.
• Remove mounting bracket and hardware
from left side.
• Remove upper jacket front panel retaining
screw (5/16" x 1/2" lg. Phillip Pan head
machine screw) from right side of door
and re-install in vacated upper mounting
bracket tapping. Do not tighten.
• Move lower jacket panel retaining screw
from right side to left tapping. Do not
tighten.
•Rotate door mounting bracket 180°.
Insert 5/16" cap screw through top hole in
bracket and install in upper vacated jacket
hole on right side of door.
•Install second 5/16" cap through bracket
hole into lower vacated tapping on right
side.
•Tighten both sets of hardware to secure
jacket and mounting bracket.
•Lift door and place integral cast hinge
pins on door into slotted mounting bracket
holes.
2. Perform routine inspection, service or cleaning as
necessary.
3. To close Burner Swing Door (see Figures 4A and 4B):
Step 1. From the fully open position, rotate Burner Swing
Door to the closed position.
II. PACKAGED BOILER ASSEMBLY - TRIM & CONTROLS (cont'd)

13
Figure 4B: Top View - Burner Swing Door Mounted to Cast Iron Block Assembly (Jacket Removed for Clarity)
II. PACKAGED BOILER ASSEMBLY - TRIM & CONTROLS (cont'd)

14
Step 2. If necessary, place your right hand under the
burner air tube to lift upward. Lift the door up unto
the built-in cast ramp/door rest (protruding from the
bottom of the front section casting - see Figure 4A).
Step 3. Use one hand to help hold door in position by
lifting up on rear burner housing or applying pressure
directly to the door while re-installing the securing
hardware with your opposite hand. Always install
right side latching hardware (3/8"-16 x 1-3/4" lg.
tap bolt and at washer) rst, then install left side
hinge hardware (3/8"-16 x 1-3/4" lg. tap bolt and
at washer) second. Apply additional pressure while
hand tightening the hardware as far as possible, then
release the pressure.
NOTICE
When securing burner swing door make sure door
is drawn-in equally on both sides.
Step 4. Use a hand wrench to tighten door hardware and
always start with the right side cap screw rst.
Use an alternating tightening method from right side
tap bolt to left side tap bolt to tighten door equally
until sealed without applying excessive torque. Never
tighten left side ange bolt rst or tighten either piece
of hardware 100% without using the alternating
tightening method described above.
Failure to follow the prescribed procedure could cause
thread damage to casting or a leak in the door seal.
If left side tap bolt is tightened before right side tap
bolt, right side of door can not be drawn-in to provide
an air tight seal, as shown in Figure 4C. Applying
excessive torque will only cause thread damage.
E. INSPECT SWING DOOR INSULATION AND ROPE
GASKET.
1. Open burner swing door using procedure previously
outlined in Paragraph D of this section.
2. Inspect berglass rope located on the swing door. The
rope must be evenly distributed around the perimeter of
the door groove and cannot bunch or overhang. There
must not be a gap where the two ends of the rope meet.
Repair or replace if the rope is damaged or if there is a
gap between the ends.
3. Inspect burner swing door insulation for damage and
proper type, refer to Figure 4D.
a. By design, cast bars on front section between the
combustion chamber and between the left and right
side 2nd and 3rd pass ueway should make an impression
in door insulation to seal the chambers.
b. By design, door insulation on model MPO-IQ231 will
have two (2) by-pass pockets cast into the insulation
centered on the bar between the combustion chamber
and 3rd pass ueways.
On models MPO-IQ84 thru MPO-IQ189 these pockets
should not be present. If insulation is damaged or not of
proper type regarding pockets, it must be replaced.
4. Do not close and secure door at this time, proceed to Field
Assembly Details, Paragraph F.
F. FIELD ASSEMBLY OF BOILER
Open miscellaneous parts carton and remove contents.
Identify the components using the illustrations (Figures 5
thru 9) throughout the assembly sequence outlined below
as it applies to your installation.
Figure 4C: Top View - Burner Swing Door
Fully Closed but
Not Properly Secured or Sealed
II. PACKAGED BOILER ASSEMBLY - TRIM & CONTROLS (cont'd)

15
Figure 5: Return Injector Piping and Relief Valve
Assembly Details
II. PACKAGED BOILER ASSEMBLY - TRIM & CONTROLS (cont'd)
Figure 4D: Burner Swing Door Insulation
1. Install return injector piping and relief valve, refer to
Figure 5.
Step a. Locate the return pipe ttings and injector. Apply
sealant to the 2” NPT injector threads. Insert injector
into 2” NPT upper rear tapping on rear section. Thread
2” NPT x 1-1/2” Reducing Elbow onto 2” NPT injector.
Apply thread sealant to the 1-1/2” NPT nipple. Thread
1-1/2” NPT nipple into 1-1/2” NPT end of reducing
elbow. Thread 1-1/2” NPT x 1-1/2” NPT x 3/4” NPT
Tee onto 1-1/2” NPT nipple. Tighten pipe ttings until
relief valve orientation is correct for your installation
and joints are watertight.
Note: Based on system return piping and access to service
boiler, see Figures 1, 13A and 13B, predetermine if
injector piping orientation is to be positioned for
vertical, horizontal left or horizontal right side return
piping as shown in Figure 5.
Step b. Install relief valve using 3/4" NPT tapping on tee.
Relief valve must be installed in vertical position. If
orientation of return injector piping is for:
• 1-1/2" NPT vertical return piping - Install
3/4" NPT x 90° street ell (not furnished)
into 3/4” NPT tapping on tee. Install relief
valve vertically into street ell. See Figure 5.

16
• 1-1/2" NPT horizontal left or right side return
piping - Install relief valve vertically in 3/4" NPT
tapping on tee. See Figure 5.
Step c. Pipe discharge of relief valve as shown in Figures
13A and 13B. Installation of the relief valve must
be consistent with ANSI/ASME Boiler and Pressure
Vessel Code, Section IV.
WARNING
Safety valve discharge piping must be piped near
oor to eliminate potential of severe burns. Do not
pipe in any area where freezing could occur. Do not
install any shut-off valves, plugs or caps.
2. Install drain valve, see Figure 6.
Step a. Apply pipe sealant to both ends of 1-1/4" NPT
x 5" lg. nipple. Thread nipple into 1-1/4" NPT lower
rear tapping on rear section.
Step b. Thread 1-1/4" x 1-1/4" x 3/4" NPT tee on opposite
end of 5" lg. nipple installed in Step a.
NOTE: Based on access for servicing and location
of sewer or oor drain, when tightening these ttings,
determine if drain valve is to be located on the left or
right side.
Tighten nipple and tee into 1-1/4" NPT lower rear
tapping on rear section until joints are water tight for
desired position.
Step c. Apply sealant to 3/4" NPT thread on drain valve.
Thread into 3/4" NPT tapping on side outlet of tee. Use
hex nut portion to tighten valve until water tight.
3. Connecting eld wiring, refer to Figures 7, 28A thru
28C.
Step a. Locate the black, white and green harness wires
labeled "120V Power Supply" inside internal junction
box, see Figure 7. Using wire nuts, connect the 120
volt power supply eld wires to the harness wires.
Step b. Locate the yellow and white wires labeled "System
Circulator" inside internal junction box, see Figure 7.
Using wire nuts, connect the 120 volt eld wires to
the harness wires.
Step c. If applicable, locate the violet and white wires
labeled "DHW Circulator" inside internal junction
box, see Figure 7. Using wire nuts, connect the 120
volt eld wires to the harness wires.
Step d. If applicable, locate the brown wire labeled "DHW
Demand" inside internal junction box, see Figure 7.
Using wire nut, connect the 120 volt eld wire to the
harness wire.
Step e. 24V thermostat eld wiring will enter through
5/16" snap bushing located on either the right side or
left side jacket panel. Connect the 24V wiring from
the thermostat to the "T-T" terminals on the Option
Control Panel.
Step f. To connect other external devices, refer to the
instructions included with these devices.
II. PACKAGED BOILER ASSEMBLY - TRIM & CONTROLS (cont'd)
Figure 6: Piping Arrangement for Drain Valve and Indirect Water Heating Return

17
Figure 7: Internal Junction Box and Wiring Harness Details
TABLE 3: BAFFLE USAGE
Boiler Model
Bafe Usage
2nd Pass 3rd Pass
MPO-IQ84 None [2]
P/N 100081-01
MPO-IQ115 [2]
P/N 102066-01
MPO-IQ147
[2]
P/N 100042-01 NoneMPO-IQ189
MPO-IQ231
WARNING
Wire an additional safety limit such as a low water
cut-off or temperature limit device, other than an IQ
Control device, in series with the 120V circuit used
to power the boiler. Do Not alter the boiler's factory
wiring when adding additional limit.
4. Installing Boiler-ECOM harness (only used with
Honeywell Oil Primary).
Step a. Locate the black Cat5 harness in the miscella-
neous parts carton.
Step b. Plug RJ45 plug into receptacle on right side
panel, see Figure 1.
Step c. Connect other end of harness into ECOM jack
on Oil Primary.
Step d. Secure harness to right side jacket using the
two wire clamps located in miscellaneous parts
carton.
5. Installing stainless steel ueway bafes. Bafe
requirements differ from model to model, see Table 3.
NOTE: Read caution statement before proceeding.
II. PACKAGED BOILER ASSEMBLY - TRIM & CONTROLS (cont'd)
CAUTION
These bafes will generate higher efciencies and
lower stack temperatures. Under certain conditions,
alowergrossstacktemperatureenteringthechimney
has the potential to be cooled below the dew point
and create condensate on interior surfaces. Flue
gas condensate is corrosive, which requires special
consideration and must be addressed immediately.
DO NOT install bafes until you have read Section
V, "Venting" completely.

18
Figure 8: Bafe Orientation in Flueways
Step a. Install stainless steel bafes provided in
miscellaneous parts carton as follows, refer to Table
3 and Figure 8:
• Model MPO-IQ84 - To install ueway bafe in 3rd
pass on left side of boiler, hold bafe with word
"Left" readable at the top. Slide bafe in ueway
until position tab touches ns on left side of 3rd
pass ueway. To install ueway bafe in 3rd pass
ueway on right side of boiler, hold bafe with
word "Right" readable at the top. Slide bafe in
ueway until position tab touches ns on right
side of 3rd pass ueway.
• Model MPO-IQ115 - To install ueway bafe in
3rd pass on left side of boiler, hold bafe with word
“Left” readable at the top. Slide bafe in ueway
until position tab touches ns on left side of 3rd
pass ueway. To install ueway bafe in 3rd pass
ueway on right side of boiler, hold bafe with
word “Right” readable at the top. Slide bafe in
ueway until position tab touches ns on right
side of 3rd pass ueway. To install ueway bafe
in 2nd pass on left side of boiler, hold bafe with
word “Left” readable at the top. Slide bafe in
ueway until position tab touches ns on left side
of 3rd pass ueway. To install ueway bafe in 2nd
pass ueway on right side of boiler, hold bafe
with word “Right” readable at the top. Slide
bafe in ueway until position tab touches ns
on right side of 3rd pass ueway.
• Models MPO-IQ147, MPO-IQ189 and MPO-
IQ231 - To install ueway bafe in 2nd pass
ueway on left side of boiler, hold bafe with
word "Left" readable at the top. Slide bafe in
ueway until position tab touches ns on right
side of 2nd pass ueway. To install ueway bafe
in 2nd pass ueway on right side of boiler, hold
bafe with word "Right" readable at the top. Slide
bafe in ueway until position tab touches ns
on left side of 2nd pass ueway.
NOTE: 2nd and 3rd pass ueway bafe are not
interchangeable.
6. Close the burner swing door and securely seal the door
to the boiler front section by reinstalling the hardware and
securing the door using procedure previously outlined in
Paragraph D of this section.
NOTICE
When securing burner swing door make sure door
is drawn-in equally on both sides.
II. PACKAGED BOILER ASSEMBLY - TRIM & CONTROLS (cont'd)

19
Figure 9: Oil Burner Installation (Beckett shown)
7. Install oil burner. (See Figure 9)
Step a. Open burner carton and remove contents.
Step b. Place oil burner gasket on burner and align
holes.
CAUTION
Do not install burner without gasket.
Step c. Remove three (3) 5/16-18 x 3/4 lg. cap screw from
burner swing door used for mounting burner.
Step d. Thread (1) 5/16-18 x 3/4 lg. cap screw,
approximately three (3) full turns, into tapping
located at 12:00 o'clock on burner swing door.
II. PACKAGED BOILER ASSEMBLY - TRIM & CONTROLS (cont'd)
Step e. Insert oil burner into the opening of burner swing
door. Align and engage keyhole slot in burner ange
over head of protruding cap screw installed in previous
Step. Rotate burner to the right to lock ange behind
head of cap screw.
Step f. Align holes and install two (2) remaining cap
screws. Level burner and fully tighten all three (3)
screws.
Step g. Plug burner power cord into power outlet receptacle
located in lower right corner of front panel.
Step h. Check oil nozzle in burner for size, angle and
spray type; inspect electrode settings and head/air
plate setting. Refer to Tables 15Athru 15C and 16 and
Section IX. Refer to Burner Manufacturer's Manual
for detail instructions.

20
III. UNIT-PAK BOILER ASSEMBLY - TRIM & CONTROLS
MPO-IQ Unit-Pak Boiler Assembly Shipment (-LLU)
Content Check List (see Figure 10)
1. ___ Cast Iron Section/Burner Swing Door/Smoke Box Assembly Mounted on Shipping Skid:
____ MPO-IQ84/115 – Part # 103071-02 / 100045-01 / 100021-01
____ MPO-IQ147 – Part # 103071-03 / 100045-01 / 100021-01
____ MPO-IQ189 – Part # 103071-04 / 100045-01 / 100021-01
____ MPO-IQ231 – Part # 1030711-05 / 100045-02 / 100021-01
2. ___ Jacket Carton 4. ____ Control Carton
____ MPO-IQ84/115 – Part # 103069-02 ____ Control Assembly
____ MPO-IQ147 – Part # 103069-03 Part # 103857-01
____ MPO-IQ189 – Part # 103069-04 ____ Jacket Poly Front Cover
____ MPO-IQ231 – Part # 103069-05 Part # 102600-06
3. ___ Part Carton ____ MPO-IQ Logo Plate
____ MPO-IQ84 – Part # 103112-01 Part # 102502-04
____ MPO-IQ115 – Part # 103112-02
____ MPO-IQ147/189 – Part # 103112-03
____ MPO-IQ231 – Part # 103112-05
Figure 10: MPO-IQ Unit-Pak Boiler Shipment Contents (outside container removed)