Weil-McLain SlimFit User manual

is manual must only be used by a qualied heating installer/service technician. Read all instructions, including this
manual and all other information shipped with the boiler, before installing. Perform steps in the order given. Failure to
comply could result in severe personal injury, death or substantial property damage.
DONOT operatetheboilerduring constructionunless combustion air is piped to the boiler air inlet from a dust-free
and contaminant-free area. e boiler can be severely damaged by drywall dust or other combustion air contaminants.
• Installation
• Startup
• Maintenance
• Parts
Boiler Manual
Gas-fired water boilers
Commercial Condensing
Part number 550-100-116/0713
TM

Part number 550-100-116/0713
2
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
The SlimFit
™
Commercial Condensing Water Boiler
SlimFit model numbers:
Left-hand boilers (cleanout access
on le side when facing burner end)
SF1000L  1000 MBH input
SF1500L  1500 MBH input
SF2000L  2000 MBH input
Right-handboilers (cleanout access
on right side when facing burner end)
SF1000R  1000 MBH input
SF1500R  1500 MBH input
SF2000R  2000 MBH input
1 Cast aluminum sectional heat exchanger
Heat exchanger can be supplied in le-hand or right-hand conguration. ey
CANNOT be eld converted. ey must be purchased as right or le.
Le-hand conguration  cleanout access and gas pipe on le side; supply and
return pipes on right side.
Right-hand conguration  cleanout access and gas pipe on right side; supply
and return pipes on le side.
2 Heat exchanger cleanout plate
3 Blower
Air enters through the air intake adapter, then enters the venturi. e blower
pulls air and gas through the venturi and pushes the mixture into the burner. e
advanced blower design and air inlet silencer yield very quiet operation.
4 Blower motor
5 Venturi
When air ows through the venturi, it creates a vacuum that is sensed by the gas
valve to regulate gas ow.
6 Acoustic adapter (Model SF1000 only)
is adapter includes an acoustic chamber that minimizes combustion noise.
7 Sola control module
e Sola control module responds to inputs from system heating or DHW controls
(or building management system), boiler sensors (boiler return, boiler supply, heat
exchanger, system return, system supply, ue temperature, and outdoor tempera-
ture, if used). e control module automatically adjusts blower speed (and gas
ow rate) to match boiler output to space heating and/or DHW heating demand.
e Sola control module includes versatile programmability, allowing for:
Operation of boiler pump, DHW pump, system pump and others.
Lead/lag regulation of multiple SlimFit boilers.
Priority regulation for DHW, space heating or other loads.
8 Sola touch-screen LCD display
e color display provides graphics and multi-line text display. Information and
programming functions are accessed via touch-screen navigation.
e display can be located on the front as shown on the next page or on the front-
le or front-right location by remounting the display bracket and swapping the
front door to the desired location.
9 Automatic gas valve
e automatic gas valve incorporates two solenoid-operated valve seats. e
valve senses the vacuum in the venturi (item 5) caused by owing air. Gas ows
in proportion to air ow, so fuel/air ratio remains constant as blower speed/air
ow changes.
10 Gas valve reference line
is line is used to measure the pressure of the incoming air to the venturi and
adjust the combustion accordingly.
11 Electrical entrance snap-in covers
Knockouts are provided in the jacket top panel, allowing conduit entry above the
low-voltage and line-voltage eld wiring terminal strips.
12 Gas valve test cock
13 Terminal strips
14 ON/OFF switch
15 Reset switch
16 Blower relay
17 Minimum air flow relay
18 Transformer
19 Spark generator
20 High gas pressure switch
21 Low gas pressure switch
22 Flue pressure switch
23 Minimum air flow switch
24 Low water cutoff circuit board
25 Low water cutoff test switch
26 Low water cutoff reset switch
27 Low water cutoff probe (not shown)
e low water cuto probe is mounted in a tapping in the right top corner of the
burner end section.
28 Premix gas burner (not shown)
Made with high-grade stainless steel and ber mesh construction, the burner uses
pre-mixed air and gas. e burner and control provide modulating ring.
29 Ignition electrode and flame sensor (not shown)
e burner ame is ignited by applying a high voltage to the ignition electrode,
located in the front section. is causes a spark (from electrode to ground). Aer
ignition, the ame sensor electrode (not shown, located in the rear section)
measures ame signal.
30 Flame inspection window
e quartz glass windows provides a view of the burner surface and ame (one
located on each boiler end section).
31 Water outlet pipe (system supply) — 3” flanged
32 Water return pipe (system return) — 3” flanged
33 Gauge tapping
e pressure/temperature gauge is shipped loose for eld installation in this
tapping.
34 Relief valve tapping
e relief valve is shipped loose for eld installation in this tapping.
35 Temperature sensor tapping — outlet temperature (not visible
in the view shown)
e outlet sensor tapping is located on top of the outlet pipe, just outside the heat
exchanger connection.
36 Temperature sensor tapping — return temperature (not visible
in the view shown)
e return sensor tapping is located on top of the return pipe, just outside the
heat exchanger connection.
37 Gas connection
38 Vent connection
Vent pipe connection, 10-inch nominal (9.85” I.D.). Installer must provide a vent/
air pipe manufacturer’s SlimFit Vent/Air Adapter to adapt to the vent pipe used.
Where the manual allows vent pipe smaller than the adapter outlet, a reducer must
also be provided by the installer.
39 Air intake connection
Air pipe connection, 10-inch nominal (9.85” I.D.). Installer must provide a vent/
air pipe manufacturer’s SlimFit Vent/Air Adapter to adapt to the air pipe used.
Where the manual allows vent pipe smaller than the adapter outlet, a reducer
must also be provided by the installer. Leave air connection open for inside air
applications (direct exhaust).
40 Condensate trap assembly
41 Burner end access doors
e three access panels on the burner end are interchangeable. is allows location
of the Sola display on either the front side or burner end of the boiler.
42 Piping end access doors
e three access panels on the piping end are removable for access and servicing.
43 Electrical access panel
44 Casters (used for locating boiler only)
45 Mounting legs (extended after boiler is in position)

Part number 550-100-116/0713 3
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
The SlimFit
™
Commercial Condensing Water Boiler (Model SF1000 shown)
Configuration options
(Order boiler as left-hand or right-hand)
Electrical panel components
Left-hand (suffix L)
• Cleanout panel access is on the le side
when viewed from the burner end.
• Control display is factory-mounted on
front (cleanout access side), but can be
eld relocated on burner end as instructed
in this manual.
Right-hand (suffix R)
• Cleanout panel access is on the right side
when viewed from the burner end.
• Control display is factory-mounted on
front (cleanout access side), but can be
eld relocated on burner end as instructed
in this manual.

Part number 550-100-116/0713
4
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
Contents . . . . . . . . . . . . . . . . . . . 4
Hazard definitions . . . . . . . . . . . . . . . 4
Please read before proceeding . . . . . . . . . .5
Prepare boiler location . . . . . . . . . . . . . 6
Prepare boiler . . . . . . . . . . . . . . . . 10
Install water piping . . . . . . . . . . . . . . 14
Multiple boiler water piping . . . . . . . . . . 22
Venting/combustion air — general . . . . . . . 28
Venting/combustion air — options . . . . . . . 30
Appliances remaining on an existing vent system . 32
Venting/air piping — Massachusetts installations . 33
DIRECT EXHAUST — Boiler room air openings . . 34
DIRECT EXHAUST —Termination location . . . . 36
DIRECT EXHAUST — Sidewall . . . . . . . . . 37
DIRECT EXHAUST — Vertical. . . . . . . . . . 39
DIRECTVENT — Boiler room air openings . . . . 40
DIRECTVENT —Termination location . . . . . . 42
DIRECTVENT — Sidewall . . . . . . . . . . . 43
DIRECTVENT — Vertical. . . . . . . . . . . . 45
Install condensate components. . . . . . . . . 48
Gas piping . . . . . . . . . . . . . . . . . 49
Field wiring (see Figure 56 & Figure 57) . . . . . 51
Sola control overview & sequence of operation . . 58
Sola control interface and menus . . . . . . . . 60
Sola control express setup — single boiler . . . . 68
Sola control express setup — multiple boilers. . . 70
Sola control parameter table . . . . . . . . . . 72
Startup — fill the system . . . . . . . . . . . 87
Startup — final checks . . . . . . . . . . . . 89
Startup procedure . . . . . . . . . . . . . . 90
Sola Information and Operations screens . . . . 94
Annual startup and maintenance schedule . . . . 96
Annual startup. . . . . . . . . . . . . . . . 97
Troubleshooting . . . . . . . . . . . . . . . 103
Maintenance. . . . . . . . . . . . . . . . . 112
Replacement parts . . . . . . . . . . . . . .115
Dimensions . . . . . . . . . . . . . . . . .124
Ratings — SlimFit boilers . . . . . . . . . . . 126
Installation and Service Certificate . . . . . . . 128
Contents
e following dened terms are used throughout this manual to bring aention to the presence of hazards of various risk levels or to
important information concerning the life of the product.
Indicates presence of hazards that will cause severe
personal injury, death or substantial property
damage.
Indicates presence of hazards that can cause severe
personal injury, death or substantial property
damage.
Indicates presence of hazards that will or can cause
minor personal injury or property damage.
Indicates special instructions on installation,
operation or maintenance that are important but
not related to personal injury or property damage.
Hazard definitions
DO NOT STARTTHIS BOILER without
following all instructions and procedures
specified in the following sections:
“Startup — fill the system” on page 87
“Startup — final checks”on page 89
“Startup procedure”on page 90.
Failure to follow the instructions in this
manual could result in severe personal
injury, death or substantial property dam-
age.

Part number 550-100-116/0713 5
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
Failure to adhere to the guidelines below can result in severe personal injury, death or substantial property
damage.
When servicing boiler —
• To avoid electric shock, disconnect all
electrical supplies to the boiler before
performing maintenance.
• To avoid severe burns, allow boiler to
cool before performing maintenance.
• is boiler contains ceramic ber and
berglass materials. Refer to the WARN-
ING and instructions on page97.
Boiler operation —
• Do not block flow of combustion or
ventilation air to boiler.
• Should overheating occur or gas supply
fail to shut o, do not turn o or discon-
nect electrical supply to pump. Instead,
shut off the gas supply at a location
external to the appliance.
Boiler water —
• e SlimFit heat exchanger is made of
aluminum, and requires that system
pH always be between 7.0 and8.5 and
water chemistry be checked. Chemical
treatment is required. See page 87
for details.
• Thoroughly flush the system (with-
out boiler connected) to remove sedi-
ment. Install a strainer or other
sediment removal equipment if
necessary. e high-eciency heat ex-
changer can be damaged by build-up or
corrosion due to sediment.
• Do not use petroleum-based cleaning
or sealing compounds in boiler system.
Gaskets and seals in the system may be
damaged. is can result in substantial
property damage.
• Continual fresh make-up water will
reduce boiler life. Mineral buildup in
heat exchanger reduces heat transfer,
overheats the aluminum heat exchanger,
and causes failure. Addition of oxygen
carried in by make-up water can cause
internal corrosion. Leaks in boiler or pip-
ing must be repaired at once to prevent
make-up water. Use this boiler ONLY in
a closed-loop system.
• Do not add cold water to a hot boiler.
ermal shock can cause heat exchanger
to crack.
Freeze protection fluids —
NEVER use automotive or standard glycol
antifreeze, even glycol made for hydronic
systems. Use only freeze-protection uids
recommended in this manual (see page87).
Follow all guidelinesgiven. oroughly clean
and ush any replacement boiler system that
has used glycol before installing the new
SlimFit boiler.
If any part of a boiler, burner or its controls
has been sprayed with or submerged under
water,either partially or fully, DO NOT attempt
to operate the boiler until the boiler has been
either replaced or completely repaired, in-
spected, and you are sure that the boiler and
all components are in good condition and fully
reliable. Otherwise, by operating this boiler, you
will cause a re or explosion hazard, and an electri-
cal shock hazard, leading to serious injury, death, or
substantial property damage. See the instructions at
right.
Saltwater Damage  e exposure of boiler components to
saltwater can have both immediate and long-term eects. While the
immediate eects of saltwater damage are similar to those of fresh-
water (shorting out of electrical components, washing out of critical
lubricants, etc.), the salt and other contaminants le behind can lead
to longer term issues aer the water is gone due to the conductive and
corrosive nature of the salt residue. erefore, Weil-McLain equip-
ment contaminated with saltwater or polluted water will no longer
be covered under warranty and should be replaced.
Electrical Damage  If any electrical component or wiring
came into contact with water, or was suspected to have come into
contact with water, replace the boiler with a new Weil-McLain boiler.
Please read before proceeding
Installer Read all instructions, including this
manual and all other information shipped with the
boiler, before installing. Perform steps in the order
given.
User  is manual is for use only by a qualied
heating installer/service technician. Refer to User’s
Information Manual for your reference.
User  Have this boiler serviced/inspected by a
qualied service technician, at least annually.
Failure to comply with the above could result in severe
personal injury, death or substantial property damage.
Write in the CP number in the space provided on
the Installation certicate on page128 if not already
shown.
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.
Consider piping and installation when determining
boiler location.
Any claims for damage or shortage in shipment must
be led immediately against the transportation com-
pany by the consignee.
Commonwealth of
Massachusetts
When the boiler is installed within the Commonwealth of Massachuses:
• is product must be installed by a licensed plumber or gas er.
• If antifreeze is used, a reduced pressure back-ow preventer device shall be used.
• Sidewall vent air installations  see instruction on page33.

Part number 550-100-116/0713
6
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
Prepare boiler location
Installations must comply with:
• Local, state, provincial, and national codes, laws, regulations and
ordinances.
• National Fuel Gas Code, ANSI Z223.1 – latest edition.
• Standard for Controls and Safety Devices for Automatically Fired
Boilers, ANSI/ASME CSD-1, when required.
• National Electrical Code.
• For Canada only: B149.1 or B149.2 Installation Code, CSA C22.1
Canadian Electrical Code Part 1 and any local codes.
e SlimFit boiler gas manifold and controls met safe
lighting and other performance criteria when boiler
underwent tests specied in ANSI Z21.13  latest
edition.
Before locating the boiler, check:
1. Check for nearby connection to:
• System water piping
• Venting connections
• Gas supply piping
• Electrical power
• Location of drain for condensate
2. Check area around boiler. Remove any combustible materials,
gasoline and other ammable liquids.
Failure to keep boiler area clear and free of combustible
materials, gasoline and other ammable liquids and
vapors can result in severe personal injury, death or
substantial property damage.
3. e SlimFit boiler must be installed so that gas control system
components are protected from dripping or spraying water or
rain during operation or service.
4. If new boiler will replace existing boiler, check for and correct
system problems, such as:
• System leaks causing oxygen corrosion or heat exchanger
cracks from hard water deposits.
• Incorrectly-sized expansion tank.
• Lack of freeze protection in boiler water causing system and
boiler to freeze and leak.
Flooring and foundation
Flooring
5. e SlimFit boiler is approved for installation on combustible
ooring, but must never be installed on carpeting.
Do not install boiler on carpeting even if foundation
is used. Fire can result, causing severe personal injury,
death or substantial property damage.
Foundation
1. e boiler mounting surface must be level and suitable for the load.
2. Provide a solid foundation pad, at least 2 inches above the oor,
if any of the following is true:
• oor can become ooded.
• the oor is dirt, sand, gravel or other loose material.
• the boiler mounting area is severely uneven or sloped.
3. e minimum foundation size is listed in Figure1.
4. Foundation may be of wood, brick or concrete (minimum 2 inches
thick) construction.
5. If ooding is possible, elevate boiler suciently to prevent water
from reaching boiler.
Figure 1 Minimum foundation size
Boiler model Minimum size (inches)
SF1000 33 x 75
SF1500 33 x 75
SF2000 33 x 87
Garage installation
Precautions
1. Take the following special precautions when installing the boiler
in a garage. If the boiler is located in a garage:
• Mount the boiler at a height above the oor as specied in
the National Fuel Gas Code, ANSI Z223.1 for U. S. installa-
tions, or CSA B149.1 and B149.2 for Canadian installations.
• Locate or protect the boiler so it cannot be damaged by a
moving vehicle.
• Ensure that the installation complies with all applicable codes.

Part number 550-100-116/0713 7
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
Figure 2 Clearances for LEFT-HAND boilers
Clearance
from:
Minimum
clearance to
combustible
surfaces (inches)
Minimum service
access clearances
(inches)
Front
(cleanout side) 0 36
Back 0 0
Burner end 0 24
Piping end 0 12
Top 4 18
Floor 0 —
Vent pipe ⁄ —
Hot water pipes ½ —
Figure 3 Clearances for RIGHT-HAND boilers
Clearance
from:
Minimum
clearance to
combustible
surfaces (inches)
Minimum service
access clearances
(inches)
Front
(cleanout side) 0 36
Back 0 0
Burner end 0 24
Piping end 0 12
Top 4 18
Floor 0 —
Vent pipe ⁄ —
Hot water pipes ½ —
Prepare boiler location (continued)
Clearance requirements
Clearances from combustible materials
1. Hot water pipes  at least ” from combustible materials.
2. Vent pipe  at least ” from combustible materials.
3. See Figure2 for other clearance minimums.
Clearances for service access
1. See Figure2 for recommended service clearances. If you do not
provide minimum clearances shown, it might not be possible to
service the boiler without removing it from the space.
Openings in oors, walls, ceilings or roofs must be
designed for re stopping as required by local codes.
Vent pipe openings through combustible materials
must be ” larger in diameter than the vent pipe. Air
pipe openings should be ” larger in diameter than the
pipe or as required by the pipe manufacturer.
Air openings
Provide air openings for combustion air and/or ven-
tilation of the room as specied in this manual and as
required by applicable codes.

Part number 550-100-116/0713
8
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
Prepare boiler location (continued)
Placing multiple boilers
1. Locate multiple boilers in boiler room to
provide the clearances shown in:
a. Figure4 (side-to-side), or
b. Figure6 (mirror-image mounting).
c. Other layouts can be used if all re-
quired clearances are maintained.
2. Provide indicated clearances around
boilers for access and servicing. If rec-
ommended dimensions are not possible,
provide at least the minimum clearances
given on page7. Also follow local codes.
3. Construct boiler foundation if boiler
room oor is uneven or if there is a danger
of ooding. Size foundation to allow for
clearance and spacing dimensions shown
in either Figure4 or Figure6.
4. Chalk-line boiler locations on foundation
or boiler room oor.
5. Uncrate, assemble and mount boilers
according to instructions in this manual.
6. Provide clearance for installation of vent-
ing, air piping, gas piping, condensate
piping and components, expansion tank,
boiler pump and other accessories.
Figure 4 Side-to-side mounting of multiple SlimFit boilers — LEFT-HAND boilers only
Figure 5 Side-to-side mounting of multiple SlimFit boilers — RIGHT-HAND boilers only
Verify that boiler placement and clearances
comply with all applicable codes.

Part number 550-100-116/0713 9
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
Prepare boiler location (continued)
Figure 6 Side-by-side installation of multiple SlimFit boilers (using left-hand and right-hand boilers together)
Verify that boiler placement and clearances
comply with all applicable codes.

Part number 550-100-116/0713
10
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
Provide air openings to room
Air openings — General
Follow the National Fuel Gas Code (U. S.) or CSA B149.1 and B149.2
(Canada) and all applicable codes to size/verify size of the combus-
tion/ventilation air openings into the space. See the venting instruc-
tions section of this manual for required air openings and sizing for
either direct vent or direct exhaust installation.
Air openings — SlimFit boiler alone in boiler room
1. DIRECT VENT — For direct vent installations (air piped to
boiler), no air ventilation openings into boiler room are needed if
clearances around the SlimFit boiler are at least equal to the SER-
VICE clearances shown in Figure2,page7. For spaces that DO
NOT supply the minimum service access clearances, see the direct
vent venting instructions in this manual for required openings.
2. DIRECT EXHAUST — For direct exhaust installations (combus-
tion air from inside), provide air openings as specied in the direct
exhaust venting section of this manual.
Air openings — SlimFit boiler in same room with
other gas or oil-fired appliances
1. DIRECT VENT — For direct vent installations (combustion air
piped to boiler), size openings only on the basis of the other appli-
ances in the space. No additional air opening free area is needed for
the SlimFit boiler because it takes its combustion air from outside.
For direct vent installations, when the SlimFit boiler is
located in the same room as other appliances, provide
combustion air openings correctly sized for all appli-
ances in the room except the SlimFit boiler.
Failure to comply with the above warnings could result
in severe personal injury, death or substantial property
damage.
2. DIRECT EXHAUST — For direct exhaust installations, combus-
tion air openings into the room must be sized to handle the SlimFit
boiler and all other appliances. See the direct exhaust venting
instructions in this manual for required openings.
Direct exhaust installations  On direct
exhaust installations, the boiler draws combustion
air from the boiler room. If other appliances are
installed in the same room, provide combustion
air openings correctly sized for ALL appliances,
including the SlimFit boiler.
Failure to comply with the above warnings could
result in severe personal injury, death or substan-
tial property damage.
Vent and air piping requirements (page 28)
1. e SlimFit boiler requires a special vent system, designed for
pressurized venting.
a. SlimFit boilers are rated ANSI Z21.13 Category IV (pressur-
ized vent, likely to condense in the vent).
b. SlimFit commercial boilers can be either:
Direct-exhaust  vent to the outside, combustion air
from inside or . . .
Direct-vent  both vent and air piped outside.
c. See instructions beginning on page28 for vent/air congura-
tion options and installation requirements.
2. Note “Prevention of combustion air contamination” on page29
when considering vent/air terminations and boiler room condi-
tions when using inside air (direct exhaust installation).
3. Be sure to locate the boiler such that the vent and air piping can be
routed through the building and properly terminated. e vent/air
piping lengths, routing and termination method must all comply
with the methods and limits in instructions beginning on page29.
Prepare boiler

Part number 550-100-116/0713 11
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
Prepare boiler (continued)
Cold weather handling If boiler has been stored
in a very cold location (below 32°F) before installation,
handle with care until the plastic components come to
room temperature.
The boiler is heavy. Use caution not to drop
the boiler or cause bodily injury while liing and
handling.
Boiler supply, return and gas pipes  Do
not li or handle the boiler by the water or gas pipes.
Do not push on or apply weight to the pipes. Severe
damage can be done to the boiler.
Leave the plastic coverson the supply and return
anges and on the boiler vent and air adapters until
ready to aach piping. is will protect the anges
surfaces from damage and prevent debris from falling
into the vent or air adapter.
Uncrating the boiler
Do not drop the boiler. Damage to boiler components
can result. Leave the boiler on the crate pallet until
ready to place in nal location. Follow all uncrating
instructions.
Failure to comply could result in severe personal injury,
death or substantial property damage.
1. See Figure8 for the following.
2. Move the crate to a solid, level surface.
3. ere must be room at the piping end to place the ramp and roll
the boiler down o the the crate pallet.
4. Make sure the crate is siing securely.
5. Remove outer cardboard covering.
6. Remove the ramp from the crate and place the end of the ramp
into the notch in the pallet as shown in Figure8.
7. Follow the uncrating instruction label to secure the ramp to the
pallet.
8. Remove the sheet metal screws and lag bolts from the six shipping
brackets. Remove and discard the shipping brackets. Re-insert the
upper screws into the holes in the boiler frame for best appearance.
Moving/handling the boiler
When moving the boiler, apply pressure ONLY
at the jacket corner posts.
DO NOT use the piping or other extensions to manipu-
late the boiler.
Failure to comply could damage the boiler heat ex-
changer or other components.
Figure 8 SlimtFit boiler on pallet, with ramp in position
Ramp
Pallet
Brackets
Sheet metal
screws
Apply pressure only to jacket
corners when moving
Lag bolts

Part number 550-100-116/0713
12
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
Prepare boiler (continued)
Placing the boiler
1. Roll the boiler down the ramp and move the boiler into position. Use
only the jacket corner posts to manipulate the boiler.
2. e piping end casters are swivel type. e burner end casters are xed.
3. Adjust the leveling legs down until they are rmly in contact with the
oor.
4. Continue adjusting the legs down until all the boom of the boiler base
is 5¼ inches above the oor.
5. Check level. Extend mounting legs further as needed until the boiler
is level.
e boiler should not be allowed to rest on the casters. ese
are intended for moving the boiler into position only. e
support legs must be extended to take the load of the boiler.
Bolting the boiler to mounting blocks
1. For applications requiring that the boiler be bolted down (such as
earthquake zone requirements), remove the casters and bolt the boiler
base to mounting blocks using the existing holes in the base.
2. See Figure9 for details.
e mounting blocks must position the boiler with at least
5¼ inches between the boom of the boiler base and the
oor.
Follow all applicable codes and recognized engineering
design practices to verify that the nal mounting will meet
all seismic, structural and other requirements.
Boiler relief valve and P/T gauge
DO NOT install arelief valve with a pressure higher
than 100 PSIG. is is the maximum allowable relief valve
seing for the SlimFit boiler. e boiler is shipped with a
30PSIG relief valve. See Replacement parts in the back of
this manual for alternate pressure seing relief valves.
e boiler is shipped with a ¼” NPT pressure and tempera-
ture gauge which has a pressure range up to 75 psig. is
gauge meets ASME requirements up to a relief valve seing
of 50 psig. For higher pressure rated relief valves, a dierent
pressure and temperature gauge with a higher pressure range
is required. When installing a gauge that requires a larger
tapping than the ¼” NPT tapping in the boiler supply mani-
fold, provide an additional tapping in the near boiler piping
BEFORE any isolation valve.
Figure 9 Removing the casters to allow bolting the
boiler to mounting blocks
Perform hydrostatic pressure test
Pressure test boiler before permanently aaching water or gas
piping or electrical supply.
Weil-McLain hydrostatically pressure tests
each SlimFit boiler in the factory to 1½ times
maximum allowable working pressure per ASME
SectionIV requirements.
A pressure test should be performed on site to
1½ times the pressure seing of the relief valve
to be installed on the unit (45psig for a 30-psig
relief valve; 75psig for a 50-psig relief valve; or
150 psig for a 100-psig relief valve).
Prepare boiler for pressure test
1. See Figure10, page13 for reference in following steps. Use
pipe dope sparingly.
2. At the boiler supply and return anges, temporarily aach
a 3-inch ANSI blind ange with tapping for a nipple and
valve as shown (anges, valves, gaskets nipples supplied
by installer).

Part number 550-100-116/0713 13
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
Prepare boiler (continued)
3. Aach a water supply and hand pump to the lower valves.
4. Aach a drain line to the upper valve.
5. Remove the pressure & temperature gauge from the trim box shipped
with the boiler.
6. Remove the factory-installed plug from the ½-inch tapping on top of
the boiler supply pipe.
7. Apply pipe dope to the P/T gauge and install in the ¼” tapping as shown.
Fill boiler and pressure test
1. Open the shuto valves installed on the supply and return connections.
2. Allow water to ow into the boom connection and air to ow out the
top connection.
3. When water reaches the shuto valve on top, allow water to ow long
enough to ensure all air is out of the heat exchanger. en close the
upper shuto valve.
4. Close o the water supply and use the hand pump to raise the water
pressure for testing.
5. e test pressure should be 1½ times the pressure seing of the relief
valve to be installed on the boiler (45psig for a 30-psig relief valve;
75psig for a 50-psig relief valve; or 150 psig for a 100-psig relief valve).
e test pressure MUST NOT exceed the maximum pres-
sure on the P/T gauge. If test pressure will be higher than the
maximum range of the P/T gauge, use a dierent gauge for
the test.
6. Gradually apply pressure until test pressure is reached. en close o
the shuto valve.
7. Hold at test pressure for 10 minutes.
Do not leave boiler unaended. A cold water ll could expand
and cause excessive pressure, resulting in severe personal
injury, death or substantial property damage.
8. Make sure that constant gauge pressure has been maintained through-
out test.
9. Check for leaks. Repair if found.
Leaks must be repaired at once. Failure to do
so can damage boiler, resulting in substantial property
damage.
Do not use petroleum-based cleaning or sealing
compounds in boiler system. Gaskets and seals in the
system may be damaged. is can result in substantial
property damage.
Drain and remove fittings
1. Disconnect ll water hose from water source.
2. Open upper shuto valve.
3. Drain boiler through lower shut-o valve.
4. Remove hose or drain piping aer draining.
5. Remove the blanking ange/valve assemblies from the boiler supply
and return anges.
6. See page14 to install relief valve in the 1¼” tapping on top of the boiler
outlet pipe.
Boiler drain valve (provided by installer)
1. If not installing a drain valve o of the return piping, install
a ¾-inch boiler drain valve in the ¾-inch tapping at the
lower right burner end of the heat exchanger (see Figure7).
Figure 7 Boiler drain valve tapping — optional
location for drain valve
¾-inch
drain valve
tapping
Figure 10 Hydrostatic test piping connections —
flanges, valves and gaskets provided by
installer

Part number 550-100-116/0713
14
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
Install water piping
Use two wrenches when tightening water piping at boiler,
using one of the wrenches to prevent the boiler interior pip-
ing from turning. Failure to support the boiler piping con-
nections to prevent them from turning could cause damage
to boiler components.
General piping information
Additional controls, when required
e Sola module uses temperature sensors to provide both
high limit protection and modulating temperature control,
and is UL353 Limit Controls certied to meet ASME CSD-1
and Section IV requirements. e boiler is equipped with a
manual reset low water cut-o. e Sola module also provides
low water protection by sensing the temperature of the heat
exchanger. Some codes/jurisdictions may require additional
external controls.
Additional limit controls
1. Consult local requirements for other codes/standards to determine if
additional limit devices are needed.
Multi-temperature systems  If the heating system
includes circuits that require lower temperature water (radi-
ant slab circuits, for example) as well as higher temperature
circuits, it is recommended to protect low-temperature
circuits with limit controls that are wired to a Sola external
limit circuit (ILK terminals for manual reset or LCI terminals
for automatic reset).
2. See instructions beginning on page51 for wiring information.
a. e Sola control provides two sets of limit control contacts  one
set will cause automatic reset (LCI) and the other will cause manual
reset (ILK) of the Sola control.
b. e Sola control can be reset using the RESET switch on top of
the boiler.
Low water cutoff
1. A push-to-test low water cuto is factory-installed in the boiler. e low
water cuto probe is mounted on the front of the boiler heat exchanger.
2. e low water cuto is manual reset (pushbuon on top of boiler) and
is equipped with a push-to-test switch (top of boiler).
Pressure/temperature gauge
1. Mount the pressure/temperature gauge (shipped loose with the boiler)
in the ¼-inch tapping on top of the boiler supply outlet pipe.
e boiler is shipped with a ¼” NPT pressure and tempera-
ture gauge which has a pressure range up to 75 psig. is
gauge meets ASME requirements up to a relief valve seing
of 50 psig. For higher pressure rated relief valves, a dierent
pressure and temperature gauge with a higher pressure range
is required. When installing a gauge that requires a larger
tapping than the ¼” NPT tapping in the boiler supply mani-
fold, provide an additional tapping in the near boiler piping
BEFORE any isolation valve.
Installing relief valve
DO NOT install a relief valve with
a pressure higher than 100 PSIG.
is is the maximum allowable relief valve
seing for the SlimFit boiler. e boiler is
shipped with a 30PSIG relief valve. See Re-
placement parts in the back of this manual
for alternate pressure seing relief valves.
To avoid water damage or scalding
due to relief valve operation,as per
local or state codes:
Discharge line must be connected to re-
lief valve outlet and run to a safe place of
disposal. Terminate the discharge line in
a manner that will prevent possibility of
severe burns or property damage should
the valve discharge.
Discharge line must be as short as possible
and be the same size as the valve discharge
connection throughout its entire length.
Discharge line must pitch downward from
the valve and terminate at least 6” above
the oor drain where any discharge will be
clearly visible.
e discharge line shall terminate plain,
not threaded, with a material serviceable
for temperatures of 375 °F or greater.
Donotpipe the dischargetoany placewhere
freezing could occur.
No shutoff valve shall be installed be-
tween the relief valve and boiler, or in the
discharge line. Do not plug or place any
obstruction in the discharge line.
Test the operation of the valve aer lling
and pressurizing system by liing the lever.
Make sure the valve discharges freely. If the
valve fails to operate correctly, replace it
with a new relief valve.
Failure to comply with the above guidelines
could result in failure of the relief valve
to operate, resulting in the possibility of
severe personal injury, death or substantial
property damage.
Backflow preventer
1. Use backow check valve in cold water supply as required
by local codes.
Install relief valve
1. Install relief valve (shipped loose with the boiler) in the
1¼-inch tapping on top of the boiler supply outlet pipe.
2. Connect discharge piping to safe disposal location, follow-
ing guidelines in the WARNING below.

Part number 550-100-116/0713 15
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
Install water piping (continued)
Recommended pipe sizing
Size the piping and the pumps to provide the required temperature rise.
See Figure11 for boiler head loss curves. See Figure13 for maximum and
minimum ow rate through the boiler as well as head loss vs ow rate.
Size system piping following Figure12 or apply recognized engineering
practices to size the piping.
DO NOT design the piping and components for
a boiler flow rate above or belowthe range given in
Figure13. Insucient ow will cause nuisance outages due
to limit operation. Excessive ow can damage the boiler heat
exchanger from erosion.
For applications requiring system ow rates higher or lower
than those allowed in Figure13, use ONLY primary/second-
ary piping. Size the boiler pump for the proper ow rate.
Figure 11 Boiler head loss vs flow rate for SlimFit boilers
Figure 12 Recommended pipe sizing vs flow rate
Sch 40
Pipe
Diameter
Maximum
Flow rate
GPM
Sch 40
Pipe
Diameter
Maximum
Flow rate
GPM
2 45 6 800
3 140 8 1650
4 290 10 3000
5 500 12 4750
For pipe sizes other than 3 inch, provide reducers to adapt
from external piping to the boiler 3-inch supply and return
flanged connections.
DO NOTdesign for ow rates above or be-
low the range listed in Figure13. e boiler
and system components can be damaged by
excessive or insucient ow. Temperature
rises shown below apply to water only. For
glycol/water applications, the temperature
rise will be dierent, but the ow rate must
be maintained within the range listed below.
Figure 13 Flow rate and pressure drop data for
Slim-Fit boilers AT FULL INPUT
SF1000
GPM Temperature Rise (°F) Boiler head loss (Feet w.c.)
43 44.5 4.1
50 38.3 5.1
** 63 30.4 7.4
70 27.4 8.7
80 24.0 10.9
90 21.3 13.3
96 20.0 14.8
** Suggested design flow rate (30°F temp. rise, water only)
SF1500
GPM Temp.
Rise °F
Boiler head loss
Feet w.c.
64 44.9 4.8
75 38.3 6.3
** 96 29.9 9.7
105 27.4 11.3
120 24.0 14.3
135 21.3 17.7
144 20.0 19.9
** Suggested design flow rate (30°F temp. rise, water only)
SF2000
GPM Temp.
Rise °F
Boiler head loss
Feet w.c.
85 44.8 6.6
100 38.1 7.8
** 127 30.0 11.5
140 27.2 13.5
160 23.8 16.9
180 21.2 20.6
191 20.0 22.8
** Suggested design flow rate (30°F temp. rise, water only)

Part number 550-100-116/0713
16
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
Install water piping (continued)
Expansion tank and make-up water
1. Ensure expansion tank size will handle boiler and system water volume
and temperature. See page126 for boiler water content.
Undersized expansion tanks cause system water to be lost
from relief valve and make-up water to be added through
ll valve. Eventual boiler failure can result due to excessive
make-up water addition.
2. Tank must be located as shown in this manual, or following recognized
design methods. See tank manufacturer’s instructions for details.
3. Connect the expansion tank to the air separator only if the separator is
on the suction side of the pump. Always install the system ll connec-
tion at the same point as the expansion tank connection to the system.
4. Most piping drawings in this manual show diaphragm expansion tanks.
See Figure14 for piping from air separator to expansion tank and make-
up water line using a closed-type expansion tank.
5. Most chilled water systems are piped using a closed-type tank, as shown
in Figure20, page21.
Diaphragm (or bladder) expansion tank
1. (Figure14) Always install an automatic air vent on top of the air separa-
tor to remove residual air from the system.
When using diaphragm or bladder tanks only  when the
boiler is installed above the system main piping, install an
automatic air vent in the top of the outgoing boiler piping
to prevent air pocketing.
e expansion tank needs to be pre-charged to the required
system ll pressure before being connected to the system.
Closed-type expansion tank
1. See Figure15, Alternate, for piping connections when using a closed-
type expansion tank.
2. Pitch any horizontal piping up towards tank 1 inch per 5 feet of piping.
Connect to tank with at least ¾” piping to allow room for air to rise.
DO NOT install automatic air vents on closed-type expan-
sion tank systems. Air must remain in the system and return
to the tank to provide its air cushion. An automatic air vent
would cause air to leave system, resulting in water-logging
the expansion tank.
Figure 14 Expansion tank piping — diaphragm-type
expansion tank
To system F
rom boiler/system
7
1
3
4
5
8
Figure 15 Expansion tank piping — closed-type
expansion tank
To system F
rom boiler/system
2
3
6
7
8
1 Diaphragm-type expansion tank
2 Closed-type expansion tank
3 Make-up water line
4 Fill valve, typical
5 Air separator
6 Tank ing
7 System pump (when used)
8 Automatic air vent

Part number 550-100-116/0713 17
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
Legend — Figure 16
1 SlimFit boiler
2 Indirect water heater (DHW), if used
3 Boiler relief valve (see page14 for piping details)
4 Relief valve discharge piping (see page14 for details)
5 DHW pump
6 Isolation valves
7 System pump (see information above for wiring)
8 Diaphragm (or bladder) type expansion tank (see page16 for piping of
closed-type expansion tank, if used)
9 Air separator [with automatic air vent only on systems using diaphragm
(or bladder) type expansion tank]
10 Flow/check valves
11 Purge/drain valves
12 Boiler pump
13 Zone valves, typical
20 Make-up water supply
21 Primary/secondary connection (tees no more than 8 pipe diameters apart)
25 Systems using high-head pumps require a bypass pressure regulator to
prevent damage to control valves.
26 External drain/blowdown valve, when used
33 Strainer, recommended
Items supplied with boiler
Items supplied by others
NOTE 1: Use at least 3-inch schedule 40 pipe on all
boiler loop piping (connecting boiler to and
from the primary/secondary connection, item21). Pipe sizing is based on a
temperature rise of 30°F, corresponding to the recommended maximum ow
rate. Failure to follow these guidelines could result in system problems.
Install water piping (continued)
Figure 16 Zone valve zoning plus optional DHW
piping
Zoning with zone valves — primary/
secondary piping
1. When using a closed-type expansion tank, connect the expansion tank
and make-up water piping as shown in Figure15, page16.
2. Connect DHW (domestic hot water) piping to indirect storage water
heater as shown. Connect from the DHW tank aquastat to the DHW
terminals on the SlimFit boiler.
DHW tanks piped using this arrangement need to be sized
for the required load, with a DHW pump selected to provide
a ow rate through the boiler and tank that is within the
allowable ow rate range listed in Figure13, page15 of this
manual.
3. DHW priority  Set the Sola control for the desired DHW priority
mode. Set the boiler pump to be OFF during DHW  it is not needed.
e ow/check valve shown on the boiler outlet piping prevents gravity
circulation in the boiler loop.
4. Controlling the pumps
a. e Sola can control up to three pumps. In this application, set the
Sola control to operate the boiler pump, system pump and DHW
pump.
b. Refer to Field wiring, beginning on page51, for instructions on
wiring to pumps.
c. e factory default seings are:
Pump A  Boiler pump
Pump B  System pump
Pump C  DHW pump.

Part number 550-100-116/0713
18
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
Legend — Figure 17
1 SlimFit boiler
2 Indirect water heater (DHW), if used
3 Boiler relief valve (see page14 for piping details)
4 Relief valve discharge piping (see page14 for details)
5 DHW pump
6 Isolation valves
7 System pump (see information above for wiring)
8 Diaphragm (or bladder) type expansion tank (see page16 for piping of
closed-type expansion tank, if used)
9 Air separator [with automatic air vent only on systems using diaphragm
(or bladder) type expansion tank]
10 Flow/check valves
11 Purge/drain valves
12 Boiler pump
13 Zone valves, typical
20 Make-up water supply
21 Primary/secondary connection (tees no more than 8 pipe diameters apart)
23 DHW secondary connector piping  no more than 8 pipe diameters apart
25 Systems using high-head pumps require a bypass pressure regulator to
prevent damage to control valves.
26 External drain/blowdown valve, when used
33 Strainer, recommended
Items supplied with boiler
Items supplied by others
NOTE 1: Use at least 3-inch schedule 40 pipe on all
boiler loop piping (connecting boiler to and
from the primary/secondary connection, item21). Pipe sizing is based on a
temperature rise of 30°F, corresponding to the recommended maximum ow
rate. Failure to follow these guidelines could result in system problems.
Install water piping (continued)
Figure 17 Zone valve zoning plus optional DHW
piping
Zoning with zone valves — primary/
secondary piping — alternate method for
High-flow-rate/high-head-loss DHW circuits
1. For applications requiring DHW circuit ow rates higher than allow-
able for the boiler, or for high pressure-drop coil-type DHW tanks,
connect the piping as in Figure17. e DHW water only ows through
the secondary circuit connection piping. NOTE: Make sure to size the
connection piping (Figure17, item23) for the total ow it must handle.
2. When using a closed-type expansion tank, connect the expansion tank
and make-up water piping as shown in Figure15, page16.
3. Connect DHW (domestic hot water) piping to indirect storage water
heater as shown. Connect from the DHW tank aquastat to the DHW
terminals on the SlimFit boiler.
4. DHW priority  Set the Sola control for the desired DHW priority
mode. Set the boiler pump to be ON during DHW. e ow/check
valve shown on the boiler outlet piping prevents gravity circulation in
the boiler loop.
5. Controlling the pumps
a. e Sola can control up to three pumps. In this application, set the
Sola control to operate the boiler pump, system pump and DHW
pump.
b. Refer to Field wiring, beginning on page51, for instructions on
wiring to pumps.
c. e factory default seings are:
Pump A  Boiler pump
Pump B  System pump
Pump C  DHW pump.
For systems with low-temperature radiant heating, the sys-
tem pump (item7) MUST be OFF during DHW heating to
prevent possible overheating in the radiant system.

Part number 550-100-116/0713 19
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
Install water piping (continued)
Figure 18 Pump zoning plus optional DHW piping
— primary/secondary piping
Zoning with pumps — primary/secondary
piping
1. Connect boiler to system as shown in Figure18 when pump zoning.
e boiler pump cannot be used for a zone. It must supply only the
boiler loop.
2. Install a separate pump for each zone.
3. When using a closed-type expansion tank, connect the expansion tank
and make-up water piping as shown in Figure15, page16.
4. Connect DHW (domestic hot water) piping to indirect storage water
heater as shown. Connect from the DHW tank aquastat to the DHW
terminals on the SlimFit boiler.
DHW tanks piped using this arrangement need to be sized
for the required load, with a DHW pump selected to provide
a ow rate through the boiler and tank that is within the al-
lowable ow rate range listed in Figure13, page15 of this
manual.
5. DHW priority  Set the Sola control for the desired DHW priority
mode. Set the boiler pump to be OFF during DHW  it is not needed.
e ow/check valve shown on the boiler outlet piping prevents gravity
circulation in the boiler loop.
6. Controlling the pumps
a. e Sola can control up to three pumps. In this application, set the
Sola control to operate the boiler pump and DHW pump.
b. Refer to Field wiring, beginning on page51, for instructions on
wiring to pumps.
c. e factory default seings are:
Pump A  Boiler pump
Pump C  DHW pump.
d. e zone pumps in Figure18 must be controlled by pump relays
activated by the zone thermostats or zone controller.
Legend — Figure 18
1 SlimFit boiler
2 Indirect water heater (DHW), if used
3 Boiler relief valve (see page14 for piping details)
4 Relief valve discharge piping (see page14 for details)
5 DHW pump
6 Isolation valves
8 Diaphragm (or bladder) type expansion tank (see page16 for piping of
closed-type expansion tank, if used)
9 Air separator [with automatic air vent only on systems using diaphragm
(or bladder) type expansion tank]
10 Flow/check valves
11 Purge/drain valves
12 Boiler pump
14 Zone pumps, typical
20 Make-up water supply
21 Primary/secondary connection (tees no more than 8 pipe diameters apart)
26 External drain/blowdown valve, when used
33 Strainer, recommended
Items supplied with boiler
Items supplied by others
NOTE 1: Use at least 3-inch schedule 40 pipe on all
boiler loop piping (connecting boiler to and
from the primary/secondary connection, item21). Pipe sizing is based on a
temperature rise of 30°F, corresponding to the recommended maximum ow
rate. Failure to follow these guidelines could result in system problems.

Part number 550-100-116/0713
20
SlimFit™ commercial condensing gas-fired water boiler — Boiler Manual
Figure 19 Typical radiant heating system piping
plus optional DHW
Radiant heating applications
1. e SlimFit boiler is ideal for use in radiant heating. e SlimFit boiler’s
unique heat exchanger design allows it to work well even in condensing
mode. So there is no need to regulate boiler return water temperature
in radiant heating applications.
2. Adding the recommended high limit control (Figure19, item22) can
help ensure supply water temperature will not exceed the maximum
allowable for the radiant system. Wire this limit control in either the
manual reset or automatic reset external limit circuit of the Sola.
3. When using a closed-type expansion tank, connect the expansion tank
and make-up water piping as shown in Figure15, page16.
4. Connect DHW (domestic hot water) piping to indirect storage water
heater as shown. Connect from the DHW tank aquastat to the DHW
terminals on the SlimFit boiler.
DHW tanks piped using this arrangement need to be sized
for the required load, with a DHW pump selected to provide
a ow rate through the boiler and tank that is within the al-
lowable ow rate range listed in Figure13, page15 of this
manual.
5. DHW priority  Set the Sola control for the desired DHW priority
mode. Set the boiler pump to be OFF during DHW  it is not needed.
e ow/check valve shown on the boiler outlet piping prevents gravity
circulation in the boiler loop.
6. Controlling the pumps
a. e Sola can control up to three pumps. In this application, set the
Sola control to operate the boiler pump, system pump and DHW
pump.
b. Refer to Field wiring, beginning on page51, for instructions on
wiring to pumps.
c. e factory default seings are:
Pump A  Boiler pump
Pump B  System pump
Pump C  DHW pump.
Install water piping (continued)
Legend — Figure 19
1 SlimFit boiler
2 Indirect water heater (DHW), if used
3 Boiler relief valve (see page14 for piping details)
4 Relief valve discharge piping (see page14 for details)
5 DHW pump
6 Isolation valves
7 System pump (see information above for wiring)
8 Diaphragm (or bladder) type expansion tank (see page16 for piping of
closed-type expansion tank, if used)
9 Air separator [with automatic air vent only on systems using diaphragm
(or bladder) type expansion tank]
10 Flow/check valves
11 Purge/drain valves
12 Boiler pump
13 Zone valves, when used (zoning may also be done using manifold-mounted
valve actuators)
20 Make-up water supply
21 Primary/secondary connection (tees no more than 8 pipe diameters apart)
22 Optional high limit temperature control, set to protect radiant tubing
25 Systems using high-head pumps require a bypass pressure regulator to
prevent damage to control valves.
26 External drain/blowdown valve, when used
33 Strainer, recommended
Items supplied with boiler
Items supplied by others
NOTE 1: Use at least 3-inch schedule 40 pipe on all
boiler loop piping (connecting boiler to and
from the primary/secondary connection, item21). Pipe sizing is based on a
temperature rise of 30°F, corresponding to the recommended maximum ow
rate. Failure to follow these guidelines could result in system problems.