Weil-McLain 88 User manual

Part No. 550-100-068/1009
for use with Gas, Light Oil, & Gas/Light Oil – Fired Burners
This manual must only be used by a qualified
heating installer/service technician. Read all
instructions before installing. Follow all in-
structions in proper order. Failure to comply
could result in severe personal injury, death
or substantial property damage.
When calling or writing about the boiler—
Please have the boiler model number from
the boiler rating label and the CP number
from the boiler jacket.
INSTALLER Consider piping and installation when determining
boiler location.
Any claims for damage or shortage in shipment must be
filed immediately against the transportation company
by the consignee.
USER . . . . This manual is for use only by your qualified heating
installer/service technician. Boiler and burner must be
installed by a qualified service technician. We recom-
mend regular service by a qualified service technician,
at least annually.
For additional
information, refer to . .
Burner
specification and
data sheets
for burners pre-tested
with model 88 boilers




Boiler Manual
Water & steam boilers – Series 2
88

Weil-McLain 88 Water and steam boilers — Series 2 — for Gas, Light Oil, & Gas/Light Oil-Fired Burners
2 Part No. 550-100-068/1009
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 concern-
ing the life of the product.
Indicates presence of hazards that  personal injury,
death or substantial property damage if ignored.
Indicates presence of hazards that  personal injury,
death or substantial property damage if ignored.
Indicates presence of hazards that  personal
injury, death or substantial property damage if ignored.
Indicates special instructions on installation, operation or maintenance
that are important but not related to personal injury.
Read before proceeding:
Read all instructions before installing. Failure to follow all instructions
in proper order can cause severe personal injury, death or substantial
property damage.
Do not use petroleum-based cleaning or sealing components in boiler
system. Severe damage to system components can result, causing sub-
stantial property damage.
 — Your propane supplier mixes an odorant
with the propane to make its presence detectable. In some instances,
the odorant can fade and the gas may no longer have an odor.
■ Propane gas can accumulate at floor level. Smell near the floor for
the gas odorant or any unusual odor. If you suspect a leak, do not
attempt to light the burner.
■ Use caution when attempting to light a propane burner (or pilot
burner). This should be done by a qualified service technician,
particularly if flame outages (or pilot outages) are common.
■ Periodically check the odorant level of your gas.
■ Inspect boiler and system at least yearly to make sure all gas piping
is leak-tight.
■ Consult your propane supplier regarding installation of a gas leak
detector. There are some products on the market intended for
this purpose. Your supplier may be able to suggest an appropriate
device.
Read before proceeding

Boiler manual: • Installation • Start-Up • Maintenance • Parts
3Part No. 550-100-068/1009
                      4
                        7
                       8
               11
                   12
14
                  16
                          20
                     25
                  26
27
           29
            31
32
                    33
34
                              35
36
38
Contents

Weil-McLain 88 Water and steam boilers — Series 2 — for Gas, Light Oil, & Gas/Light Oil-Fired Burners
4 Part No. 550-100-068/1009
Installation must comply with —
State, provincial and local plumbing, heating and electrical1.
codes.
Regulations of servicing utilities.2.
ASME Section IV, Low Pressure Boiler and Pressure Vessel Code.3.
National Fuel Gas Code, ANSI/NFPA 54, when applicable.4.
National codes where applicable.5.
Before selecting boiler location
Check for nearby connections to:1.
Fuel supply.a.
Electrical power.b.
System water or steam piping.c.
Venting systems - seed. page 29.
Combustion and ventilation air supply — seee. page 5.
Check area around boiler. Remove any combustible materials,2.
gasoline and other flammable vapors and liquids.
Failure to keep boiler area clear and free of combustible
materials, gasoline and other flammable liquids and
vapors can result in severe personal injury, death and
substantial property damage.
Provide clearance around boiler
Provide minimum clearances to combustible materials:1.
• — 24 inches.
• — 48 inches.
• — 9 inches.
• — 9 inches.
• — 6 inches.
• – 18 inches.
• – refer to vent pipe manufacturer's
recommendations for vent pipe clearances.
Boiler may be installed on combustible flooring.2.
See3. page 36 for boiler dimensions.
Flue pipe/breeching clearances take precedence over
jacket clearances.
Provide minimum clearances for servicing:4.
 • — for cleaning and tankless heater removal –
39 inches.
• — for breeching — 36 inches.
Allow sufficient space on remaining sides for cleaning, servicing•
and burner installation. See burner literature for length and
recommended service clearances.
Lay a foundation, if needed
Floor construction and condition must be suitable for weight of1.
boiler when filled with water. See page 35 for approximate boiler
operating weight.
A level concrete or brick foundation, constructed per2. Figure 1 and
Figure 2 is required when:
A floor could possibly become flooded.a.
Non-level conditions exist.b.
Before installing boiler
Boiler foundation, when required
Boiler foundation (see Figure 1)

 L
(inches)
488 33
588 41
688 49
788 57
888 65
988 73
1088 81
1188 89
1288 97
1388 105
1488 113
1588 121
1688 129
1788 137
1888 145

Boiler manual: • Installation • Start-Up • Maintenance • Parts
5Part No. 550-100-068/1009
Before installing boiler (continued)
Combustion and ventilation air openings
Adequate combustion and ventilation air must be
provided to assure proper combustion and prevent
possibility of flue gas leakage and carbon monox-
ide emissions, causing severe personal injury or
death.
Do not install an exhaust fan in boiler room. Incor-
rect burner operation can result.
When combustion and ventilation air enters
through side wall openings, ensure that the open-
ings comply with the requirements of Figure 3 and
Figure 4.
Opening sizes must comply with state, provincial
or local codes. In the absence of local requirements,
use the National Fuel Gas Code, ANSI/NFPA 54).
The following information is taken from ANSI/
NFPA 54. For details and information not addressed
below, refer to the standard.
Combustion air openings to inside
Required volume of interior spaces
ANSI/NFPA 54 allows combustion air to be supplied through openings
to interior spaces 
.
The minimum volume of interior spaces can be taken as 50 cubic feet
per 1,000 Btuh of all appliances in the spaces, or the minimum volume
can be calculated using the formulas given in ANSI/NFPA 54. Excep-
tion: If the air infiltration rate for the spaces is known to be less than
0.40 air changes per hour, the minimum volume must be calculated
as specified in the standard.
Inside air opening sizes and locations
For spaces that provide the minimum volume required by ANSI/
NFPA 54, the air openings must be sized per the following:
Each opening shall have
a minimum free area of 1 in2/1000 Btuh (2200 mm2/kW) of the total
input rating of all appliances in the space but not less than 100 in2
(0.06 m2). One opening shall commence within 12 inches (300 mm)
of the top, and one opening shall commence within 12 inches (300
mm) of the bottom, of the enclosure. The minimum dimension of air
openings shall be not less than 3 inches (80 mm).
The volumes of spaces
in different stories shall be considered as communicating spaces where
such spaces are connected by one or more openings in doors or floors
having a total minimum free area of 2 in2/1000 Btuh (4400 mm2/kW)
of total input rating of all appliances.
Combustion and ventilation air openings
— Boiler room below grade
Combustion and ventilation air openings
— Boiler room partially or completely
above grade
Combustion air openings to
outside
Outdoor combustion air can be taken through per-
manent openings (TWO or ONE), as described in the
following. The minimum dimension of air openings
shall not be less than 3 inches (80 mm).
Outside openingsTWO

Two permanent openings, one commencing within
12 inches (300 mm) of the top and one commencing
within 12 inches (300 mm) of the bottom of the enclo-
sure shall be provided. The openings shall communicate
directly, or by ducts, with the outdoors or spaces that

Weil-McLain 88 Water and steam boilers — Series 2 — for Gas, Light Oil, & Gas/Light Oil-Fired Burners
6 Part No. 550-100-068/1009
freely communicate with the outdoors, as follows:
Where directly communicating with the outdoors or where•
communicating to the outdoors through vertical ducts, each
opening shall have a minimum free area of 1 in2/4000 Btuh
(550 mm2/kW) of total input rating of all appliances in the
enclosure.
Where communicating with the outdoors through horizon-•
tal ducts, each opening shall have a minimum free area of
1 in2/2000 Btuh (1100 mm2/kW) of total input rating of all
appliances in the enclosure.
Outside openingsONE
One permanent opening, commencing within 12 inches (300 mm)
of the top of the enclosure, shall be provided. The appliance shall
have clearances of at least 1 in. (25 mm) from the sides and back
and 6 inches (150 mm) from the front of the appliance. The opening
shall directly communicate with the outdoors or shall communicate
through a vertical or horizontal duct to the outdoors or spaces that
freely communicate with the outdoors and shall have a minimum free
area of the following:
(1) 1 in2/3000 Btu/hr (700 mm2per kW) of the total input rating of
all appliances located in the enclosure, and . . .
(2) Not less than the sum of the areas of all vent connectors in the
space.
Combustion air — combination indoor and
outdoor openings
ANSI/NFPA 54 allows combustion air to be taken from a combination
of openings to outside and to interior spaces. Follow all requirements
of the standard to determine the minimum volume of interior spaces
and to calculate minimum sizes of openings.
Engineered Installations
Engineered combustion air installations shall provide an adequate sup-
ply of combustion, ventilation, and dilution air and shall he approved
by the authority having jurisdiction.
Mechanical Combustion Air Supply
Where all combustion air is provided by a mechanical air supply
Before installing boiler (continued)
system, the combustion air shall be supplied from
outdoors at the minimum rate of 0.35 ft3/minute per
1000 Btuh (0.034 m3/min per kW) for all appliances
located within the space.
Where exhaust fans are installed in the building,•
additional air shall be provided to replace the
exhausted air.
Each of the appliances served shall be inter-•
locked to the mechanical air supply system to
prevent main burner operation where the me-
chanical air supply system is not in operation.
Where combustion air is provided by the build-•
ing’s mechanical ventilation system, the system
shall provide the specified combustion air rate
in addition to the required ventilation air.
Louvers, Grilles, and Screens.
The required size of openings for combustion, venti-
lation, and dilution air shall be based on the 
 of each opening.
Where the free area through a design of louver or grille
or screen is known, it shall be used in calculating the size
opening required to provide the free area specified.
Where the louver and grille design and free area are not
known, it shall be assumed that wood louvers will have
25 percent free area, and metal louvers and grilles will
have 75 percent free area.
Non-motorized louvers and grilles shall be fixed in the
open position.
Minimum screen mesh size
Screens shall not be smaller than ¼ inch mesh.
Motorized louvers
Motorized louvers shall be interlocked with the appli-
ance so they are proven in the full open position prior
to main burner ignition and during main burner opera-
tion. Means shall be proved to prevent the main burner
from igniting should the louver fail to open during
burner startup, and to shut down the main burner if
the louvers close during burner operation.

Boiler manual: • Installation • Start-Up • Maintenance • Parts
7Part No. 550-100-068/1009
Set boiler in place
Section assembly lifting weights






(pounds)


(from crane hook to
boiler lifting lugs)
488 2928 2' 6"
588 3490 3' 0"
688 4152 4' 0"
788 4714 4' 6"
888 5276 5' 0"
988 5838 6' 0"
1088 6400 6' 6"
1188 7062 7' 0"
1288 7624 8' 0"
1388 8186 8' 6"
1488 8748 9' 0"
1588 9310 10' 0"
1688 9872 10' 6"
1788 10,584 11' 0"
1888 11,146 12' 0"
Ensure the equipment and cables used for lifting are de-
signed to handle the load. See Figure 5 for approximate
weights of model 88 section assemblies. Failure to comply
can result in severe personal injury, death or substantial
property damage.
Cables used for lifting are NOT provided by Weil-McLain.
For packaged boiler:
Remove top jacket panels. Set aside until after boiler is piped.1.
The boiler contains ceramic fiber and fiberglass materials.
Use care when handling these materials per instructions on
"Handling ceramic fiber and fiberglass materials," page 34
of this manual. Failure to comply could result in severe
personal injury.
Remove lag screws (2 in front, 2 in rear) from shipping rails.2.
Remove boiler from skid. See3. Figure 5 for lifting weight.
Using crane — hook middle of each cable to eye of crane.•
Using hoist — hook middle of each cable to hoist. Raise boiler off•
skid. Use pipe rollers under skid angles to roll boiler.
Place boiler in final position. Center boiler on foundation, if used.4.
Level boiler. Shim under skid angles, if necessary.5.
Cut off cables.6.
Cables are not intended for long-term usage. Cables may
corrode inside boiler, weakening their lifting strength. Fail-
ure to remove cables can result in severe personal injury,
death or substantial property damage.
Proceed to7. "Perform hydrostatic pressure test," page 11.
For block assembly:
Remove lag screws (2 in front, 2 in rear) from shipping rails.1.
Remove boiler from skid. See2. Figure 5 for lifting weight.
• Usingcrane–attachfreeendofcablestoeyeofcrane.
• Usinghoist–attachfreeendofcablestohoist.Raiseboileroffskid.
Use pipe rollers under steel skid angles to roll boiler.
Place boiler in final position. Center boiler on foundation, if used.3.
Level boiler. Shim under skid angles, if necessary.4.
Cut off cables.5.
Cables are not intended for long-term usage. Cables may
corrode inside boiler, weakening their lifting strength. Fail-
ure to remove cables can result in severe personal injury,
death or substantial property damage.
Inspect block assembly for disjointed sections. Check gas-tight seal6.
of flue collector hood and cleanout plates.
Gas tight seal must be maintained to pre-
vent possible flue gas leakage and carbon
monoxide emissions, resulting in severe
personal injury or death.
Check inside section assembly for any lighta.
passing through unsealed areas.
Mark all unsealed areas.b.
At unsealed areas, check for:c.
Damaged gaskets.•
Sealing rope not in place.•
Loose bolts or nuts.•
Correct all conditions and repeat step b. If un-d.
sealed areas still exist, contact your Weil-McLain
distributor or sales office before continuing
installation.
Proceed to7. "Perform hydrostatic pressure test,"
page 11.

Weil-McLain 88 Water and steam boilers — Series 2 — for Gas, Light Oil, & Gas/Light Oil-Fired Burners
8 Part No. 550-100-068/1009
Assembling the block
Sections are top heavy. Unbolted sections may fall
if not supported, resulting in severe personal injury
or death.
Prepare and position back section
Apply1. 1 /8" continuous bead of sealing rope adhesive in sealing rope
grooves. See Figure 6. 
.
Place ½" sealing rope in groove. Around curves, grasp at 1" intervals2.
and push together. Do not stretch.
Do not pre-cut rope. Gas tight seal must be maintained
to prevent possibility of flue gas leakage and carbon
monoxide emissions, causing severe personal injury or
death. Cut rope as each section is completed.
Remove any grit from port machined surfaces with clean rag.3.
Do not use petroleum-based cleaning or sealing com-
pounds in boiler system. Severe damage to system
components can result, causing substantial property
damage.
Place 9" and 6" sealing rings in appropriate port openings. See4.
Figure 6. If sealing ring slips out of groove, stretch ring gently for
several seconds, then reposition in groove.
Apply continuous bead of silicone sealant no larger than5. 1
/16"
around entire outside edge of  machined surface of port.
Refer to Figure 7. 
.
Silicone sealant applied as specified above prevents un-
burned oil vapors from coming in contact with sealing
ring. Vapor contact can damage rings, resulting in severe
damage to boiler and substantial property damage.
Hoist back section upright. Then temporarily screw a 6-inch6.
threaded pipe at least 36 inches long into the lower (return) tap-
ping.
Hoist the section and put into position.7.
Place a block under the 6-inch pipe to hold the back section up-8.
right and plumb.
The back section must be plumb before installing other
sections to ensure the block will assemble correctly.
The 6-inch support pipe and block can be removed after several9.
sections have been installed, and the assembly is stable.
Install intermediate sections as described on the following page.10.
Sealing rope installation
Silicone sealant

Boiler manual: • Installation • Start-Up • Maintenance • Parts
9Part No. 550-100-068/1009
Sections are top heavy. Unbolted sections may fall
if not supported, resulting in severe personal injury
or death.
Install intermediate sections
Remove and discard1. 3/8" diameter shipping tie rods.
Remove grit from port machined surfaces with clean rag.2.
Do not use petroleum-based cleaning or sealing com-
pounds in boiler system. Severe damage to system
components can result, causing substantial property
damage.
Position intermediate section so aligning lugs fit into sockets of3.
next section. See Figure 8.
Install TI (tankless intermediate) and SI (supply intermediate)4.
sections (when used) in order shown in Figure 9, page 10.
Draw sections together until metal-to-metal contact is made5.
around machined port openings (see Figure 8):
Oil threads on 4 draw rods. (Use 13-inch rods on end sectionsa.
and 11-inch rods between intermediate sections.) Install washer
and nut on end to be tightened. Use nut only on other end.
Uniformly draw sections together, starting at washer/nutb.
end.
Important — Leave an equal amount of thread on each
end of the draw rod. This is needed to allow securing the
jacket support brackets in place.
Draw rods should be torqued to a range of 90 to 100 ft-lbs. Doc.
not back off draw rods.
Metal-to-metal contact will be achieved around port openings.d.
See Figure 8. If gap occurs, it should be no greater than .032".
Check with feeler gauge.
If, for any reason, gap around machined port opening exceedse.
.032", check for rope extending from rope grooves, dirt on port
openings or sockets, or misaligned lugs. If corrections are made
and gap still exists, contact your Weil-McLain distributor or
sales office before continuing installation.
Sealing ring installation and port
alignment
Assembling the block
After erecting first intermediate section,
check both sections for plumb. Failure
to plumb sections can cause misaligned
piping and breeching, possibly resulting
in property damage.
Repeat steps 1-5.6.
Check each section for proper sealing rope position7.
before proceeding to next section.
Failure to position sealing rope properly
can cause boiler to not seal gas-tight.
Gas tight seal prevents possible flue gas
leakage and carbon monoxide emissions,
resulting in severe personal injury or
death.
Install remaining intermediate sections and front8.
section using the same procedure.
If using tankless heater (TI)
sections
Install tankless heaters and gaskets or heater cover•
plates and gaskets. Use 3 /8" x 3/4" studs, washers
and nuts.

Weil-McLain 88 Water and steam boilers — Series 2 — for Gas, Light Oil, & Gas/Light Oil-Fired Burners
10 Part No. 550-100-068/1009
Assembling the block (continued)
Section arrangement


W= water
S= steam






(all heaters must be on left side of boiler)
F= front / B= back / I= Intermediate
TI = tankless intermediate SI = supply intermediate (steam only)
"I" can be substituted for "TI" sections
488 W&S 1F • TI • I • B
588 W&S 2F • TI • I • TI • B
688 W&S 2F • TI • I • TI • I • B
788 W&S 3F • TI • I • TI • I • TI • B
888 W&S 3F • TI • I • TI • I • TI • I • B
988 W&S 4F • TI • I • TI • I • TI • I • TI • B
1088 W&S 4F • TI • I • TI • I • TI • I • TI • I • B
1188 W&S 5F • TI • I • TI • I • TI • I • TI • I • TI • B
1288 W 5F • TI • I • TI • I • TI • I • TI • I • TI • I • B
1288 S 4F • TI • I • TI • I • SI • I • TI • I • TI • I • B
1388 W 6F • TI • I • TI • I • TI • I • TI • I • TI • I • TI • B
1388 S 6F • TI • I • TI • I • TI • SI • TI • I • TI • I • TI • B
1488 W 6F • TI • I • TI • I • TI • I • TI • I • TI • I • TI • I • B
1488 S 5F • TI • I • TI • I • TI • I • SI • I • TI • I • TI • I • B
1588 W 7F • TI • I • TI • I • TI • I • TI • I • TI • I • TI • I • TI • B
1588 S 7F • TI • I • TI • I • TI • I • TI • SI • TI • I • TI • I • TI • B
1688 W 7F • TI • I • TI • I • TI • I • TI • I • TI • I • TI • I • TI • I • B
1688 S 7F • TI • I • TI • I • TI • SI • TI • I • TI • I • TI • I • TI • I • B
1788 W 8F • TI • I • TI • I • TI • I • TI • I • TI • I • TI • I • TI • I • TI • B
1788 S 8F • TI • I • TI • SI • TI • I • TI • I • TI • SI • TI • I • TI • I • TI • B
1888 W 8F • TI • I • TI • I • TI • I • TI • I • TI • I • TI • I • TI • I • TI • I • B
1888 S 6F • TI • I • TI • I • SI • I • TI • I • TI • I • SI • I • TI • I • TI • I • B

Boiler manual: • Installation • Start-Up • Maintenance • Parts
11Part No. 550-100-068/1009
Perform hydrostatic pressure test
Prepare boiler and test:
See1. Figure 10 and Figure 11 for tapping locations. Install:
Boiler drain (not furnished).a.
Water pressure gauge — for test only. Be sure gauge can handleb.
test pressure — see step 3.
Air vent in upper tapping (K).c.
Plug remaining tappings.2.
Do not pressure test with any control installed. Damage
to control can occur due to overpressure.
Fill boiler. Vent3. all air. Pressure test at least 10 minutes at a pressure
not less than the following:
a. boiler: .
b. boiler:     
 (MAWP) stamped on the boiler nameplate, located
on boiler jacket front panel.
Do not exceed above test pressures by more than 10
psig.
Do not leave boiler unattended. Cold water fill could
expand and cause excessive pressure, resulting in severe
personal injury, death or substantial property damage.
Check for maintained gauge pressure and leaks. Repair if found.4.
Leaks must be repaired at once. Failure to do so can dam-
age boiler, resulting in substantial property damage.
Do not use petroleum-based cleaning or sealing com-
pounds in boiler system. Severe damage to system
components can result, causing substantial property
damage.
Drain boiler and remove air vent, boiler drain and gauge. Remove5.
plugs from tappings that will be used for controls and accesso-
ries.
Boiler tapping locations and sizes (see Figure 11)
   
A 2" Steam relief valve and/or
Skim tapping
High limit
Manual reset limit
B 2" Steam relief valve Water relief valve
L 1" Secondary probe LWCO Not used — Plug
C1 & C2 1" Low water cut-offs Alternate low water cut-offs
C1 — Combination high and low
limit control
D1 & D2 1" Alternate low water cut-offs Firing rate temperature
control (when used)
Low water cut-offs
E1 & E2 ½" Gauge glass —
F1 & F2 C\,"Try cock tappings —
G ¾" Pressure limit control,
Pressure operating control and
pressure gauge,
Firing rate pressure control
(when used)
Combination pressure–
temperature gauge
H ¾" Boiler drain (see Figure 17,
page page 15, for system blow-
off (drain) valve locations and
sizes
Boiler drain
K 1" — Piping to compression tank or
automatic air vent
Boiler tappings

Weil-McLain 88 Water and steam boilers — Series 2 — for Gas, Light Oil, & Gas/Light Oil-Fired Burners
12 Part No. 550-100-068/1009
Insert HXT-bars through cleanout openings as shown below (omit the bottom, blue-tipped, HXT-bar in the opening
between the front section and the first intermediate section)
Complete block assembly
Install burner mounting plate on front
section
Install four ½" x 3½" studs to secure burner mounting plate to1.
section:
Thread and lock together two nuts on rounded end of stud.a.
Thread flat end of stud into one of four holes located around
opening.
Remove nuts.b.
Repeat steps a and b for remaining studs.c.
Install burner mounting plate:2.
Applya. 1
/8" continuous bead of sealing rope adhesive in groove
around opening in section.
Position ½" sealing rope in groove. Overlap ends at least oneb.
inch.
Install burner mounting plate with part number and the word,c.
"" positioned at top. Use ½" washers and nuts.
Install observation port assemblies on front
and back sections
Install front observation port assembly:1.
Applya. 1
/8" continuous bead of sealing rope adhesive in groove
on observation port.
Positionb. 3/8" sealing rope in groove.
Secure assembly to section. Use 10-32 x ¾"c.
truss-head screws.
Repeat above steps for back observation port as-2.
sembly.
Insert HXT-bars
See1. Figure 12, page 12.
Flue HXT-bars are identified by painted ends. They2.
must be inserted as shown, with the HXT-bars in
the sequence:
• position
• -tipped, HXT-bar 24 inches long —
place on the top row of pins.
• position
• -tipped HXT-bar, 26 inches long —
place on the first row of pins below the top
clean-out plate boss.
• position
• -tipped HXT-bar, 34 inches long —
place on the first row of pins below the
bottom cleanout plate boss.

Boiler manual: • Installation • Start-Up • Maintenance • Parts
13Part No. 550-100-068/1009
Cleanout plate assembly
Complete block assembly (continued)
The boiler contains ceramic fiber and
fiberglass materials. Use care when han-
dling these materials per instructions on
page 34 of this manual. Failure to comply
could result in severe personal injury.
DO NOT insert a bottom HXT-bar into the opening
between the FRONT section and the first intermediate
section.
To remove flue HXT-bars when required to clean the boiler3.
flueways, grab the end of each HXT-bar with pliers and pull
straight out. Clean HXT-bars and replace as shown in Fig-
ure 12, page 12.
Install cleanout plates
Cleanout plates must be installed gas-tight to prevent
possibility of flue gas leakage and carbon monox-
ide emissions, resulting in severe personal injury or
death.
See1. Figure 13.
Position two ¼" x 1¾" carriage bolts in cleanout opening, be-2.
tween the cleanout plate bosses, as shown. Secure with washers
and nuts.
Place woven fiberglass gasket over carriage bolts.3.
Mount cleanout plate over opening. Secure with nuts and wash-4.
ers.
Repeat steps 1 through 3 for remaining cleanout plates.5.
Install draft hood collar
Install1. 1 /8" continuous bead of sealing rope adhesive in groove on
draft hood collar.
Position ½" sealing rope in groove. Overlap ends of rope at least2.
1 inch.
Mount collar over flueway outlet on back section. Secure with ½3.
x 1½" hex head cap screws and washers.

Weil-McLain 88 Water and steam boilers — Series 2 — for Gas, Light Oil, & Gas/Light Oil-Fired Burners
14 Part No. 550-100-068/1009
Connect water boiler piping
General water piping information
System water supply and return piping should be installed and1.
piping connections attached to boiler before erecting jacket or
installing controls.
Do not pipe in through supply and out through return. This creates2.
reverse water flow through boiler that must not be used.
When installing in a system in which return water temperature can3.
drop below 140°F, apply the by-pass piping with by-pass pump as
shown in .
Install piping
Install piping as shown in Figure 14, page 14 and Figure 18, page 15
(if applicable) for single boilers. For multiple boilers, see Fig-
ure 19, page 15.
Improperly piped systems or undersized piping can
contribute to erratic boiler operation and possible boiler
or system damage.
Connect supply and return piping:1.
Size according to tables below.a.
For•  (less than 20°F
temperature rise) through boiler, see Figure 15.
For•   , size piping per Figure 17,
page page 15, using 20°F temperature rise through
boiler.
Flow at higher rates than shown in the tables in this
manual for given pipe sizes can damage the boiler, caus-
ing substantial property damage.
Locate circulator in supply piping.b.
For return piping, use full diameter pipe for 10 times thatc.
diameter before making any reduction. For example, a 4-inch
return should not be reduced any closer to boiler return tap-
ping than 40 inches.
Install system blow-off (drain) valve in lowest part of returnd.
piping close to boiler. ASME minimum size requirements are
given in Figure 17, page 15.
Install expansion tank:2.
a. – connect to 1" tapping "K" (see page 11). Use
1" NPT piping. Any horizontal piping must pitch up toward
tank at least 1 inch per each 5 feet of piping.
b. – Refer to tank manufacturer's literature for
location. Install automatic air vent in "K" tapping.
Connect cold water fill to expansion tank piping.c. Figure 14
shows typical piping when using a closed type tank. Connect
to the same location as the expansion tank connects to the
system when using a diaphragm type tank.
Also shown are recommended valves and water meter, whend.
used. Water meter will detect added make-up water, indicating
leaks in system.
Water boiler piping, typical
Recommended minimum pipe sizes for
known flow rates (note 1)



A

B
 2" 2"
36–50 2½" 2½"
51–77 3" 3"
78–142 4" 4"
143–237 5" 5"
238–404 6" (note 2) 6"
Note 1 High temperature rise through boiler is permissible when boiler
piping connections are sized per this table. Intermittent
flow at high velocities may damage any boiler.
Note 2 6-inch piping requires nipples and 5" x 6" reducing couplings
(provided with 1288 through 1888 boilers only). The total
pressure drop through the 1888 boiler using the nipple and
reducing coupling will not exceed ¼ PSI. For smaller boilers, the
pressure drop will be less.

Boiler manual: • Installation • Start-Up • Maintenance • Parts
15Part No. 550-100-068/1009
Connect water boiler piping (continued)
Recommended minimum pipe sizes when flow rate is
not known (see Figure 14, page page 14) (note 1)



A

B
488 3" 3"
 4" 4"
 5" 5"
 6" (note 2) 6" (note 2)
Note 1 Pipe sizes are based on a 20°F temperature rise through the boiler. For applications
with higher flow rates (lower temperature rise), determine the flow rate and use
Figure 15, page page 14 to size the piping.
Note 2 6-inch piping requires nipples and 5" x 6" reducing couplings (provided with 1288
through 1888 boilers only). The total pressure drop through the 1888 boiler using the
nipple and reducing coupling will not exceed ¼ PSI. For smaller boilers, the pressure
drop will be less.
ASME drain valve size




 1"
 1¼"
 1½"
Piping multiple boilers
See1. Figure 18. (Expansion tanks, relief valves and other accessories
are required, but omitted from the illustration for simplicity.)
The boiler piping circuits are referred to as the secondary circuits2.
in the following.
The legend for3. Figure 18 and boiler pump sizing recommenda-
tions follow:
Size boiler pump GPM based on the following:A

 

Calculate only secondary (boiler) piping circuit resistance. Al-c.
low for head loss through the boiler equal to three 90 degree
elbows of secondary pipe size.
Operate each boiler and its pump with a Weil-McLain boilerd.
control panel.
Size secondary (boiler) circuit piping using the flow rate rangese.
given in Figure 17, page 15.
Primary pump GPM and head calculation should not includeB
secondary boiler circuits. Primary pump can operate continuously
during heating season.
Connection to primary circuit — Space 12" maximum or as closeC
as practical.
Check valve.D
Hand valve.E
By-pass piping for return water less than
140°F
By-pass circulator sizing:
Size system circulator as required. Determine GPM1.
and head requirements.
Provide a by-pass circulator for EACH boiler. The flow2.
rate for each by-pass circulator will be:
Flow = ¼ x (System circulator GPM) ÷ (# of boilers)
All circulators must run at the same time.3.
Example: For a 1,000,000 Btuh single boiler, with4.
system temperature drop of 20°F:
System GPM = 1,000,000 ÷ 20 ÷ 500 = 100 GPM•
By-pass GPM = ¼ x 100 GPM = 25 GPM•
Determine by-pass circuit head loss for pipe size•
and fittings used.
In most applications, a standard booster pump should5.
be adequate.
Multiple water boiler piping


Weil-McLain 88 Water and steam boilers — Series 2 — for Gas, Light Oil, & Gas/Light Oil-Fired Burners
16 Part No. 550-100-068/1009
Connect steam boiler piping
General steam piping information:
Hartford loop piping arrangement and wet return are required for1.
steam boilers. Use the Hartford loop for both pumped-return and
gravity-return systems.
Maintain 24-inch minimum from waterline to bottom of header (63"2.
from bottom of section).
When using condensate receiver, feed pump must be energized by3.
boiler-mounted pump controller.
Install piping:4.
Install piping as shown ona. page 17 through page 18 for single boil-
ers. See page 19 for additional requirements when piping multiple
boilers.
Return pipe sizing.b.
Pumped return — Size return piping by pump.•
Gravity return — Size gravity return same as Hartford loop•
equalizer pipe size.
Drain valve — Install system drain valve in lowest part of returnc.
piping close to boiler. See Figure 17, page 15, for sizing.
Cold water fill piping — Connect cold water fill piping as shown ind.
Figure 20. Also shown are recommended valves and water meter,
if used. Water meter will detect added makeup water, indicating
leaks in system.
Condensate return piping:e.
Satisfactory operation of any steam heating system depends on•
adequate return of condensate to maintain steady water level.
Avoid adding excessive amounts of raw make-up water.•
Where condensate return is not adequate, a low water cutoff•
with pump control, condensate receiver, and condensate boiler
feed pump should be installed.
See• Figure 21 for piping and Figure 22 for sizing.
Cold water fill piping
Condensate piping to boiler
Condensate receiver capacity required
Boiler
model number
I=B=R gross output
(lbs steam per hour)
Gallons condensate
per hour
Minimum condensate receiver capacity (gallons) (Note 1) Recommended condensate
feed pump capacity
GPM at 15 PSI
15-minute boiler
operation
30-minute boiler
operation
45-minute boiler
operation
60-minute boiler
operation
488 810 97 29 58 87 116 3.2
488R 794 95 28 57 85 114 3.1
588 1084 130 39 78 117 156 4.3
688 1358 163 49 98 147 196 5.4
788 1632 195 59 117 176 234 6.5
888 1904 228 68 137 205 273 7.6
988 2170 261 78 157 235 313 8.7
988R 1991 239 72 145 217 289 8.0
1088 2452 294 88 176 265 353 9.8
1088R 2304 277 83 166 249 332 9.2
1188 2724 327 98 196 294 392 10.9
1288 3000 360 108 216 324 432 12.0
1388 3270 392 117 235 353 470 13.1
1488 3550 426 127 255 383 511 14.2
1588 3820 458 137 274 412 550 15.3
1688 4090 490 147 294 441 588 16.4
1688R 3980 478 143 287 430 574 15.9
1788 4370 524 157 314 471 629 14.5
1888 4640 557 167 334 501 668 18.6
Note 1 — Maximum time to when condensate returns to boiler — the longer the time for condensate to return, the larger the receiver must be.

Boiler manual: • Installation • Start-Up • Maintenance • Parts
17Part No. 550-100-068/1009
Connect steam boiler piping (continued)
Model 488 through 688 steam (1 riser)
Model 788 through 1188 steam (2 risers required)
Improperly piped systems or undersized piping can
contribute to erratic boiler operation and possible boiler
or system damage. Piping system must be installed as
shown, using pipe sizes shown. Pipe sizes shown are for
two-pipe, pumped-return systems. Adjust pipe sizing
as needed when connecting to gravity-return systems.
Consult local Weil-McLain distributor or sales office
before installing alternate piping.
Steam boiler piping guidelines
Minimum height of header above water line must
be 24 inches
The boiler header must always be at least  
above the water line, as shown in all steam boiler piping
diagrams. Installing the pipe lower will result in increased
water carryover to the system, resulting in potential seri-
ous damage to system components and oxygen corrosion
due to excess make-up water.
Hartford loop piping for all steam boilers
You must install the system supply pipe between the equalizer1.
elbow and the last boiler riser pipe connection to the header. This
assists in separating water from the steam as it turns upward into
the steam supply pipe.
Locate the top of the Hartford loop return nipple at least 4 inches2.
below the water line, as shown.
Drawing legend & notes
(Figure 23 through Figure 26)
Riser pipes (one for each supply intermediate
section)
Horizontal pipes needed to offset the header

to allow for expansion and contraction of the
header
Steam supply must be located between last riser

connection and equalizer elbow
Equalizer elbow — full size or reducing

Equalizer pipe
Close nipple at Hartford loop tee to reduce water
hammer potential
Condensate return line (gravity or pumped)

Minimum 4 inches between water line and top
of Hartford loop return nipple
Boiler water line — all automatic water level

controls must be set to maintain this level
Minimum 24 inches between water line and

bottom of header

Weil-McLain 88 Water and steam boilers — Series 2 — for Gas, Light Oil, & Gas/Light Oil-Fired Burners
18 Part No. 550-100-068/1009
Connect steam boiler piping (continued)
Model 1288 through 1888 steam (3 or 4 risers required)
Drawing legend & notes
(Figure 23 through Figure 26)
Riser pipes (one for each supply intermediate section)
Horizontal pipes needed to offset the header to allow for expansion and contraction of the header
Steam supply must be located between last riser connection and equalizer elbow
Equalizer elbow — full size or reducing
Equalizer pipe
Close nipple at Hartford loop tee to reduce water hammer potential
Condensate return line (gravity or pumped)
Minimum 4 inches between water line and top of Hartford loop return nipple
Boiler water line — all automatic water level controls must be set to maintain this level
Minimum 24 inches between water line and bottom of header

Boiler manual: • Installation • Start-Up • Maintenance • Parts
19Part No. 550-100-068/1009
Multiple Steam Boiler Piping Gravity Condensate Return
Connect steam boiler piping (continued)
Pipe as shown for gravity return systems, connect-A
ing point Ato the wet gravity return.
For pumped-return systems, install boiler water•
level control on each boiler with body mark at
level indicated in Figure 42, page 28. Provide at
point Aeither:
Separate feed pumps and check valves for each•
boiler, or . . .
Single feed pump, with separate solenoid valve•
for each boiler.
For pumped-return systems, install a combination
B
float and thermostatic trap on each boiler to prevent
flooding of one boiler while other boiler is firing.
Install trap in skim tapping (see Figure 39, page 27).
Connect traps to condensate receiver.
Gravity-return systems are self-levelling if the wet
returns are piped to the common system wet return.
Install boiler piping as shown in the preceding pagesC
of this manual.
Install stop valves per ASME code requirements.D
For pump-return systems, if using automatic•
steam valves, use only slow-opening automatic
valves. Use a Weil-McLain Boiler Control Sys-
tem (such as a BCP panel) to open each steam
valve automatically before firing burner.
Construct common supply drop header with pipe
E
size at least same size as largest boiler header size.
Use:
F
A Weil-McLain Boiler Control System (such as•
a BCP panel) with header-mounted pressure
control(s) to sequence boilers, or . . .
A steam pressure controller.•
Install drip line in common supply drop header.
G
Gravity-return: Pipe drip line to wet return.•
Pumped-return: Use combination float and•
thermostatic trap and drain to condensate
receiver.
See page 18 for numbered
circle references.

Weil-McLain 88 Water and steam boilers — Series 2 — for Gas, Light Oil, & Gas/Light Oil-Fired Burners
20 Part No. 550-100-068/1009
Install jacket
Before installing jacket
The boiler contains ceramic fiber and fiberglass materials.
Use care when handling these materials per instructions
on page 34 of this manual. Failure to comply could result
in severe personal injury.
These parts1. :
Plugs for unused tappingsa.
Supply and return piping and steam supply headerb.
Cleanout platesc.
Tankless heaters (when used), tankless heater cover platesd.
(when used), tankless heater piping (when used)
Flue damper assemblye.
Observation port assembliesf.
These parts2. :
Burner mounting platea.
These parts3. :
Water or steam gaugea.
Limit control and low water cutoffb.
Gauge glass and gauge glass cocks, tri-cocksc.
Drain cockd.
Remove jacket parts from cartons
Locate jacket cartons.1.
Remove jacket parts from cartons as needed. Leave in cartons as2.
long as possible to avoid damage.
Jacket parts are in the boxes listed below:3.
Part Box label descriptions
Jacket screws (in jacket corner boxes) included in CRNR boxes
Jacket support brackets & hex nuts BKT
Jacket side support channels, upper & lower included in  boxes
Jacket front/rear support channels, upper & lower 
Jacket front panel 
Jacket back panel 
Jacket side and top panels 
Jacket corners CRNR
Jacket trim 
Install support brackets/channels
Place upper and lower support brackets over draw rods as shown1.
in Figure 29, page 21. Place the brackets on the sections as given
in Figure 27. Sections are numbered from front to back.
Fasten each bracket loosely using two 5/8" nuts screwed onto the2.
ends of the tie rods as shown.
Models 488 through 988 do not require lower support
brackets. Only upper brackets are required.
Fasten all nuts and screws loosely during assembly to
allow adjustment after all jacket frame parts are in-
stalled.
Place support brackets as listed below
Boiler Upper brackets on
sections:
Lower brackets
on sections:
488 2, 3 None
588 2, 4 None
688 2, 5 None
788 2, 6 None
888 3, 6 None
988 2, 5, 8 None
1088 3, 6, 9 6
1188 3, 6, 9 6
1288 3, 7, 10 7
1388 3, 7, 11 7
1488 3, 7, 10, 13 7
1588 2, 5, 8, 11, 14 8
1688 2, 5, 9, 12, 15 9
1788 2, 5, 9, 13, 16 9
1888 2, 6, 10, 14, 17 10
Attach the upper channels to the upper supports as3.
shown in callouts , and , Figure 29, page 21.
Use two #10 x ½" screws at each bracket. Models
988 and larger have two-piece channels.
The side channels are labelled• Aand Bin Fig-
ure 29. Figure 28 gives the lengths of the side
channel parts for each model.
The channels at the boiler front and rear are•
part numbers 426400030 & 426400031, re-
spectively.
Upper and lower side channel lengths
Boiler Upper channel lengths
(inches)
Lower channel lengths
(inches)
ABAB
488 30 NA 26 NA
588 38 NA 34 NA
688 46 NA 42 NA
788 54 NA 50 NA
888 62 NA 58 NA
988 35 35 66 NA
1088 43 35 40 34
1188 43 43 40 42
1288 51 43 48 42
1388 51 51 48 50
1488 51 59 48 58
1588 59 59 56 58
1688 67 59 64 58
1788 67 67 64 66
1888 71 71 72 66
Attach the four jacket corners to the upper channels4.
as shown in callout , Figure 29, page 21. Corner
part numbers are: 426400054 (front left), 055 (front
right), 056 (back left), and 057 (back right).
Attach the lower side, front and rear channels5.
to the jacket corners as shown in callouts and
of Figure 29, page 21. Models 1088 and larger
have two-piece side channels. The channels are
labelled Aand Bin Figure 29. Figure 28 gives the
lengths of these parts for each model. Front and
rear lower channels are part numbers 426400032
and 426400033.