A. O. Smith LB-500 Installation Manual
MODELS:
LB/LW-500, 750 AND 1000
SERIES 400/401
GAS-FIRED POWER BURNER COPPER BOILERS
FOR HYDRONIC HEATING AND HOT WATER SUPPLY
• INSTALLATION • OPERATION • MAINTENANCE • LIMITED WARRANTY
H
WARNING: If the information in this
manual is not followed exactly, a fire or
explosion may result causing property
damage, personal injury or loss of life.
— Do not store or use gasoline or other
flammable vapors and liquids in the
vicinity of this or any other appliance.
— WHAT TO DO IF YOU SMELL GAS:
• Do not try to light any appliance.
• Do not touch any electrical switch;
do not use any phone in your
building.
• Immediately call your gas supplier
from a neighbor’s phone. Follow the
gas supplier’s instructions.
• If you cannot reach your gas
supplier, call the fire dep artment.
— Installation and service must be
performed by a qualified installer,
service agency or the gas supplier.
CAUTION
TEXT IN BLACK BOLD TYPE OR UNDERLINED CONT AINS
INFORMA TION RELATIVE T O YOUR SAFETY. PLEASE
READ THOROUGHL Y BEFORE INST ALLING AND USING
THIS APPLIANCE.
A DIVISION OF A.O. SMITH CORPORA TION
McBEE, SC RENTON, WA STRA TFORD, ONT ARIO
VELDHOVEN, THE NETHERLANDS
www.aosmithwaterheaters.com
PRINTED IN U.S.A. 1004
PLACE THESE INSTRUCTIONS ADJACENT TO BOILER AND
NOTIFY OWNER TO KEEP FOR FUTURE REFERENCE
1
PART NO. 212107-000 REV. 00
Minimum clearances to combustibles:
• 4” (102 mm) rear
• 0” (0 mm) top & sides
• 6” (152 mm) vent
ROUGH-IN DIMENSIONS
T ABLE 1, GAS AND ELECTRICAL CHARACTERISTICS
Manifold Pressure Maximum Supply Pressure Electrical Characteristics
Model Type of Gas Inches W.C. kP a Inches W.C. kPa Volts/Hz Amperes
LB/LW-500, 750, 1000 NATURAL 3.5 0.87 13.8 3.44 120/60 30
LB/LW-500, 750, 1000 PROP ANE 10 2.49 13.8 3.44 120/60 30
Minimum Supply Pressure, Natural Gas: 7.0 inches W.C. (1.74 kPa)
Minimum Supply Pressure, Propane Gas: 11.0 inches W.C. (2.74 kPa)
Minimum Pressures must be maintained under both load and no load (static and dynamic) conditions.
TABLE 2, ROUGH-IN DIMENSIONS
Models LB/LW-500 LB/LW-500 LB/LW-750 LB/LW-750 LB/LW-1000 LB/LW-1000
Gas Type Natural Gas Propane Gas Natural Gas Propane Gas Natural Gas Propane Gas
Dimensions inches m m inches m m inches m m inches mm inches m m inches m m
Exhaust Vent Diam. 6 152 6 152 6 152 6 152 7 178 7 178
Blower Inlet Diam. 4 102 4 102 4 102 4 102 6 152 6 152
A 53 1346 53 1346 53 1346 53 1346 60 1/2 1537 60 1/2 1537
B 23 584 23 584 23 584 2 3 584 27 1/8 689 27 1/8 689
C 32 813 32 813 32 8 13 32 813 38 3/16 9 70 38 3/16 970
D 13 1/2 343 13 1/2 343 13 1/2 343 13 1/2 343 13 3/4 349 13 3/4 349
E 4 3/8 111 4 3/8 111 4 3/8 111 - - 15 1/2 394 - F 3 1/4 83 3 1/4 8 3 3 1/4 83 - - 3 1/4 83 - -
G 6 3/8 162 6 3/8 162 6 3/8 16 2 6 3/8 162 8 1/8 206 8 1/8 206
H 7 1/2 191 7 1/2 191 7 1/2 1 91 7 1/2 191 8 1/4 210 8 1/4 210
J 3 1/2 89 3 1/2 89 3 1/2 89 3 1/2 89 3 1/2 89 3 1/2 89
K 19 483 19 483 19 483 19 483 36 914 36 914
L 14 1/2 359 14 1/2 359 11 1/4 286 11 1/4 286 12 318 12 318
M 5 127 5 127 5 127 5 127 6 3/4 171 6 3/4 171
N 5 1/4 133 5 1/4 133 5 1/4 1 33 5 1/4 133 4 1/8 105 4 1/8 105
P 11 1/2 292 11 1/2 292 11 1/2 292 11 1/2 292 13 3/8 340 13 3/8 340
Q 2 5 1 2 5 1 2 51 2 51 2 1/4 57 2 1/4 57
R 1 NPT 1 NPT 1 NPT - - 1 1/4 NPT - S ------11 3/4298--11 7/8302
T ------6 1/2165--7 5/8194
U ----- - 1NPT--1 1/4NPT
Approx. Shipping 425 lbs 193 Kg. 425 lbs 193 Kg. 528 lbs 240 Kg. 528 lbs 240 Kg. 934 lbs 424 Kg. 934 lbs 424 Kg.
Weight
2
ROUGH-IN DIMENSIONS (Continued)
TABLE 3, RECOVER Y CAP ACITIES
U.S. Gallons/Hr and Litres/Hr at TEMPERATURE RISE INDICATED
GAS INPUT F° 18F° 20F° 30F° 36F° 40F° 50F° 54F° 60F° 70F° 72F°
MODEL TYPE BTUH KW C° 10C° 11C° 17C° 20C° 22C° 28C° 30C° 33C° 39C° 40C°
LB/LW-500 Natural 500,000 GPH 3030 2727 1818 1515 1364 1091 1010 909 779 758
146 LPH 11471 10324 6882 5735 5162 4129 3824 3441 2950 2868
LB/LW-500 Propane 450,000 GPH 2727 2455 1636 1364 1227 982 909 818 701 682
132 LPH 10324 9291 6194 5162 4646 3716 3441 3097 2655 2581
LB/LW-750 Natural 750,000 GPH 4545 4091 2727 2273 2045 1636 1515 1364 1169 1136
220 LPH 17206 15485 10324 8603 7743 6194 5735 5162 4424 4301
LB/LW-750 Propane 675,000 GPH 4091 3682 2455 2045 1841 1473 1364 1227 1052 1023
198 LPH 15485 13937 9291 7743 6968 5575 5162 4646 3982 3871
LB/LW-1000 Natural 1,000,000 GPH 6061 5455 3636 3030 2727 2182 2020 1818 1558 1515
293 LPH 22941 20647 13765 11471 10324 8259 7647 6882 5899 5735
LB/LW-1000 Propane 860,000 GPH 5212 4691 3127 2606 2345 1876 1737 1564 1340 1303
252 LPH 19729 17757 11838 9865 8878 7103 6576 5919 5073 4932
U.S. Gallons/Hr and Litres/Hr at TEMPERATURE RISE INDICATED
GAS INPUT F° 80F° 90F° 100F° 108F° 110F° 120F° 126F° 130F° 140F°
MODEL TYPE BTUH KW C° 44C° 50C° 56C° 60C° 61C° 67C° 70C° 72C° 78C°
LB/LW-500 Natural 500,000 GPH 682 606 545 505 496 455 433 420 390
146 LPH 2581 2294 2065 1912 1877 1721 1639 1588 1475
LB/LW-500 Propane 450,000 GPH 614 545 491 455 446 409 390 378 351
132 LPH 2323 2065 1858 1721 1689 1549 1475 1429 1327
LB/LW-750 Natural 750,000 GPH 1023 909 818 758 744 682 649 629 584
220 LPH 3871 3441 3097 2868 2816 2581 2458 2382 2212
LB/LW-750 Propane 675,000 GPH 920 818 736 682 669 614 584 566 526
198 LPH 3484 3097 2787 2581 2534 2323 2212 2144 1991
LB/LW-1000 Natural 1,000,000 GPH 1364 1212 1091 1010 992 909 866 839 779
293 LPH 5162 4588 4129 3824 3754 3441 3277 3176 2950
LB/LW-1000 Propane 860,000 GPH 1173 1042 938 869 853 782 745 722 670
252 LPH 4439 3946 3551 3288 3228 2959 2818 2732 2537
TABLE 4, HEAD LOSS at FLOW RA TES/MINUTE and TEMPERA TURE RISE SHOWN
INPUT F° 18F° 20F° HEAD LOSS Boiler
MODEL BTUH KW C° 10C° 11.1C° Feet Metres Inlet & Outlet
LB/L W-500 500,000 G P M 50 45 10 2” N PT
Natural 146 LPM 189 172 3.0
LB/L W-500 450,000 G P M 45 41 8.4 2” N PT
Propane 132 LPM 170 155 2.6
LB/L W-750 750,000 G P M 75 68 10.1 2” N PT
Natural 220 LPM 284 258 3.1
LB/L W-750 675,000 G P M 67 61 8.7 2” N PT
Propane 198 LPM 255 232 2.7
LB/LW -1000 1,000,000 G P M 100 91 8.9 2” NPT
Natural 293 LPM 378 344 2.7
LB/LW -1000 860,000 G P M 86 78 6.7 2” NPT
Propane 252 LPM 325 296 2.0
The ideal flow rate through the Legend models is considered to be the flow rate that results in
a 20 F° temperature rise across the unit. Table 4, shows head loss through units at
flow rate resulting in 20 F° rise. For head loss at other flow rates see sheet E202.2 in
A.O. Smith Architect’s & Engineer’s Manual.
3
CONTENTS
Page
ROUGH-IN DIMENSIONS .............................................................. 2-3
FOREWORD .................................................................................. 4
Grounding Instructions ............................................................. 5
Inlet Water Considerations ........................................................5
Correct Gas ............................................................................. 5
Precautions .............................................................................. 5
Liquid Petroleum Models............................................................ 5
HIGH ALTITUDE INSTALLATIONS.................................................... 5
Field Installed Components ........................................................ 6
Panels and Covers ................................................................... 6
FEATURES / CONTROLS
Electronic Ignition Control .......................................................... 6
Hot Surface Ignitor.................................................................... 6
Blocked Flue Switch ................................................................. 6
Blower Prover Switch .............................................................. 7
Low Gas Switch ...................................................................... 7
Water Flow Switch................................................................... 7
Air Shutter................................................................................ 7
Blower Speed Control............................................................... 7
Combination Gas Control........................................................... 7
Manual Reset Limit (E.C.O.) ....................................................... 7
Automatic Reset Limit ............................................................... 7
On / Off Switch ........................................................................ 7
Circulating Pump ....................................................................... 8
T ank T emperature Control ......................................................... 8
Low Water Cutoff (not supplied) .............................................. 8
Drain V alve............................................................................... 8
Relief Valves ............................................................................ 8
INST ALLATION INSTRUCTIONS
Required Ability ........................................................................ 9
Location ................................................................................... 9
Chemical Vapor Corrosion ........................................................ 9
Installation Clearances .............................................................. 9
Leveling.................................................................................... 9
Air Requirements ...................................................................... 9
VENTING ..................................................................................... 10
Special Installation Considerations . ........................................ 11
Venting System Using AL 29-4C®........................................... 11
General Installation Requirements ........................................... 11
General Exhaust Vent Installation Procedure........................... 11
Connecting Vent to Boiler................................................... 11-13
Venting Supports.................................................................... 13
Vertical Installation Requirements............................................ 13
Horizontal Installation Requirements ...................................13-16
Direct Vent Installation Requirements ...................................... 16
SYSTEM INST ALLATION
General .................................................................................. 16
Page
Hot Water Heating (Hydronic) Equipment................................. 16
Internal Contaminants ............................................................. 17
Hot Water Supply System General Water Line Connections .... 17
Hard Water Conditions ............................................................ 19
Thermal Expansion (Closed System). ...................................... 19
T ank Probe Installation Procedure............................................ 19
T ank Probe Set-Point Adjustment ............................................ 19
GAS CONNECTIONS .................................................................... 19
Gas Supply Line Sizing ........................................................... 20
WIRING ........................................................................................ 20
SUGGESTED PIPE SIZING TABLES ............................................... 21
WIRING CONNECTION DIAGRAM .................................................. 22
SCHEMATIC DIAGRAM................................................................. 23
OPERATION ................................................................................. 24
General .................................................................................. 24
Filling and Purging for Heating Boiler Installation ...................... 24
Filling for Hot Water Supply Boiler Installation .......................... 24
Purging Gas Line .................................................................... 24
LIGHTING & OPERA TING INSTRUCTIONS ................................. 25-26
Inlet Gas Pressure .................................................................. 27
Manifold Pressure Connections .............................................. 27
Gas Pressure Regulators ....................................................... 27
Safety Checks........................................................................ 27
Water T emperature Regulation ................................................ 28
Sequence of Operation........................................................... 28
MAINTENANCE
Venting Maintenance .............................................................. 29
Burner and Flame Pattern ....................................................... 29
Burner Maintenance ............................................................... 30
Condensate Removal System ................................................. 30
DIA-SCAN II SELF-DIAGNOSTIC SYSTEM..................................... 30
Line Polarity Indicator.............................................................. 31
Fuse Protection ...................................................................... 31
Dia-Scan II Display Board
Operating Procedures ............................................................ 31
T emperature Set-Point Adjustment Procedure ......................... 32
Switching Differential Adjustment Procedure .......................... 32
Circulating Pump Adjustment Procedure .................................. 32
Display Current Mode ............................................................. 33
Display T otal Cycle Count........................................................ 33
T ank Probe T emp. Set-Point Adjustment Procedure.................. 33
Display Board LED Indicators .................................................. 34
TROUBLESHOOTING
Short Cycling .......................................................................... 34
Hard Starts............................................................................. 34
Troubleshooting Error Codes .................................................. 34
LIMITED WARRANTY ................................................................... 36
FOREWORD
This design complies with the latest edition of the ANSI Z21.13 CSA 4.9 low-pressure boiler standard.
Compliance under this standard implies that when the boiler
underwent test, the gas manifold and control assembly provided
on the boiler met safe lighting and other performance criteria.
Detailed installation diagrams are found in this manual. These
diagrams will serve to provide the installer a reference for the
materials and methods of piping necessary. It is essential that
all water, gas piping and wiring be installed as shown on the
diagrams. You should thoroughly read and understand this
manual before installation and/or operation of this boiler.
The factory warranty will be
improperly installed or operated.
®AL 29-4C is a registered trademark of Allegheny Ludlum Corporation.
void if the boiler(s) have been
In addition to these instructions, the boiler(s) shall be installed in
accordance with those installation regulations in force in the local
area where the installation is to be made. These shall be carefully
followed in all cases. Authorities having jurisdiction should be
consulted before installations are made.
In the absence of local codes, the installation must comply with
the latest editions, as follows:
In the United States:
The National Fuel Gas Code, ANSI Z223.1/NFPA 54and the
National Electric Code, NFPA 70.
In Canada:
The installation Code CAN/CSA B149.1-00 and the Canadian
Electric Code, CSA C22.2.
4
These are available from the Canadian Standards Association,
8501 East Pleasant Valley Road, Cleveland, OH 44131, USA, or,
Canadian Gas Association Laboratories, 55 Scarsdale Road,
Don Mills, Ontario M3B 2R3, Canada.
GROUNDING INSTRUCTIONS
This boiler must be grounded in accordance with the National
Electrical Code and/or local codes. Boiler is polarity sensitive,
correct wiring is imperative for proper operation.
with age. For these reasons, the use of a propane gas detector
is recommended.
IF YOU EXPERIENCE AN OUT OF GAS SITUA TION, DO NOT TRY
TO RELIGHT APPLIANCES YOURSELF. Call your local service
agent. Only trained LP professionals should conduct the required
safety checks in accordance with industry standards.
HIGH AL TITUDE INST ALLATIONS
This boiler must be connected to a grounded metal, permanent
wiring system, or an equipment grounding conductor must be
run with the circuit conductors and connected to the equipment
grounding terminal or lead on the boiler.
INLET WATER CONSIDERATIONS
T o minimize the amount of condensate, a minimum inlet water
temperature to the heat exchanger of 140°F (60°C) shall be
maintained. This temperature can be acquired by returning 140°F
(60°C) water from the remote storage tank to the boiler or by
incorporating a by-pass loop between the boiler’s inlet and outlet
connections.
Circulating water through the boiler and to the remote storage
tank (if applicable) is accomplished by a built-in pump on LW
models only. For hot water heating systems using the LB model,
the circulating pump is NOT provided and must be field installed.
CORRECT GAS
MAKE SURE THE GAS ON WHICH THE BOILER WILL OPERA TE
IS THE SAME AS THAT SPECIFIED ON THE BOILER RATING
PLATE. DO NOT INSTALL THE BOILER IF EQUIPPED FOR A
DIFFERENT TYPE OF GAS — CONSUL T YOUR SUPPLIER.
PRECAUTIONS
IF THE UNIT IS EXPOSED TO THE FOLLOWING , DO NOT OPERA TE
UNTIL ALL CORRECTIVE STEPS HAVE BEEN MADE BY A
QUALIFIED SERVICEMAN:
1. EXPOSURE TO FIRE.
2. IF DAMAGED.
3. FIRING WITHOUT WA TER.
4. SOOTING.
IF THE BOILER HAS BEEN EXPOSED TO FLOODING , IT MUST BE
REPLACED.
LIQUID PETROLEUM MODELS
Boilers for propane or liquefied petroleum gas (LPG) are different
from natural gas models. A natural gas boiler will not function
safely on LP gas and no attempt should be made to convert a
boiler from natural gas to LP gas.
LP gas must be used with great caution. It is highly explosive
and heavier than air. It collects first in the low areas making its
odor difficult to detect at nose level. If LP gas is present or even
suspected, do not attempt to find the cause yourself. Leave the
building, leaving doors open to ventilate, then call your gas
supplier or service agent. Keep area clear until a service call has
been made.
At times you may not be able to smell an LP gas leak. One cause
is odor fade, which is a loss of the chemical odorant that gives LP
gas its distinctive smell. Another cause can be your physical
condition, such as having a cold or diminishing sense of smell
WARNING
INSTALLATIONS ABOVE 2000 FEET (600 M) REQUIRE
REPLACEMENT OF THE BURNER ORIFICE IN ACCORDANCE
WITH SECTION 8.2.1 OF THE NATIONAL FUEL GAS CODE (ANSI
Z223.1). FAILURE TO REPLACE THE ORIFICE WILL RESUL T IN
IMPROPER AND INEFFICIENT OPERA TION OF THE APPLIANCE
RESUL TING IN THE PRODUCTION OF INCREASED LEVELS OF
CARBON MONOXIDE GAS IN EXCESS OF SAFE LIMITS WHICH
COULD RESULT IN SERIOUS PERSONAL INJURY OR DEA TH.
Ratings specified by manufacturers for most appliances apply
for elevations up to 2000 feet (600 m). For elevations above 2000
feet (600 m), ratings must be reduced at the rate of 4% for each
1000 feet (300 m) above sea level. For example, if a boiler is
rated at 500,000 Btu/hr. at sea level, to rate the boiler at 4000 feet
(1200 m), the original rating is reduced by 16 percent (4 x 4%) to
a rating of 420,000 Btu/hr.
The input reduction is primarily achieved by reducing the size of
the main burner orifice. T o do this, the main burner orifices require
replacement with an orifice sized for the particular installation
elevation. Part number for gas orifices for altitudes up to 4000
feet (1220 m) are given in Table 5. Orifices for higher altitudes
are special order and may be obtained from A. O. Smith Water
Products Company. When ordering, be sure to state the model
number and the altitude of the location where the boiler is installed.
TABLE 5. LEGEND 2000 ORIFICE T ABLE
Natural Gas Propane Size Elevation
Model Part No. Part No. (In.) (Ft.)
LB/LW-500 *191884-0 — 0.391 0-2000
LB/LW-500 191884-1 — 0.384 2001-3000
LB/LW-500 191884-2 — 0.374 3001-4000
LB/LW-500 — 192741-0 0.229 0-2000
LB/LW-500 -- 192741-1 0.226 2001-3000
LB/LW-500 -- 192741-2 0.223 3001-4000
LB/LW-750(USA) *191884-3 -- 0.484 0-2000
LB/LW-750(USA) 191884-5 -- 0.469 2001-3000
LB/LW-750 USA 191884-7 -- 0.461 3001-4000
LB/LW-750 CAN *191884-11 -- 0.464 0-2000
LB/LW-750 CAN 191884-12 -- 0.450 2001-3000
LB/LW-750 CAN 191884-13 -- 0.443 3001-4000
LB/LW-750 -- 192741-3 0.286 0-2000
LB/LW-750 -- 192741-4 0.282 2001-3000
LB/LW-750 -- 192741-6 0.278 3001-4000
LB/LW-1000 *192222-0 -- 0.555 0-2000
LB/LW-1000 192222-1 -- 0.537 2001-3000
LB/LW-1000 192222-2 -- 0.533 3001-4000
LB/LW-1000 -- *192739-0 0.333 0-2000
LB/LW-1000 -- 192739-1 0.329 2001-3000
LB/LW-1000 -- 192739-2 0.325 3001-4000
*Factory installed orifice.
Upon completion of derating of the boiler, adjustment to the gas
pressure regulator may be required. See GAS PRESSURE
REGULATORS in this manual for inlet and manifold pressure
requirements.
Also, due to the input rating reduction required at high altitudes,
the output rating of the appliance is also reduced and should be
compensated for in the sizing of the equipment for applications.
5
NOTE: Some gas utility companies derate their gas for altitude,
making it unnecessary to install high altitude orifices. Call the
local gas utility company to verify BTU content.
FIELD INSTALLED COMPONENTS
When installing the boiler, the following components MUST be
used, if applicable:
1) Circulating Pump (Hydronic)
2) Tank Temperature Control (Hot Water Supply)
3) Loop Temperature Control (Hydronic)
4) Low Water Cutoff Device
5) Relief Valve
6) Pressure Gauge
7) Manual Gas Shutoff Valve (Supply)
Check the FEATURES AND CONTROLS section for further
information.
system monitors the burner flame through the principle of flame
rectification. If a flame is not verified, the gas valve is immediately
closed.
FIGURE 2. FIGURE 3.
FIGURE 1.
P ANELS AND COVERS
All panels and covers (e.g. control and junction box covers; front,
side and rear panels of boiler) MUST be in place after service
and/or before operation of the boiler. This will ensure that all gas
ignition components will be protected from water.
NOTE: Remove the two (2) sheet metal screws from the rear of
the top cover and discard them, see fig 1. This will allow removal
of the top cover without the use of tools. Also, remove the sheet
metal screw from the bottom of the front panel.
FEATURES/CONTROLS
The Legend 2000® is a low-pressure boiler (Category IV) to be
used as either hot water supply (domestic/commercial water
heating) or hot water heating (hydronic) application. Category IV
boilers operate with a positive vent pressure and with a vent gas
temperature less than 140°F (60°C) above its dew point. Category
IV appliances are often termed “High Efficiency” appliances.
The control board provides a pre-purge period of twenty (20)
seconds and a post-purge period of twenty-five (25) seconds.
The flame establishing period is four (4) seconds.
This control is non-adjustable. Any attempts to modify the
performance, other than those listed in this manual, voids the
control warranty.
The 24 VAC circuitry of the ignition control system is protected
with a 3-amp fuse. If the fuse opens, a red LED located near the
fuse will light.
HOT SURFACE IGNITOR
The Hot Surface Igniter, fig. 3, is a device that ignites the main
burner by high temperature (>1800°F) [982°C]. The igniter is
made of recrystallized silicon carbide, and when 120 VAC is
applied to the igniter, sufficient heat is generated to ignite the
main burner. Although improvements have been made to
strengthen the igniter, it is still fragile and care must be taken in
handling the igniter to prevent breakage.
This high efficiency is obtained from a unique heat exchanger
design consisting of multiple integral high-finned copper tubes
brazed in parallel into two brass manifolds. The condensate
from the heat exchanger flows downward into the vent collector
housing then into the plastic condensate drain and through the
attached flexible hose which must terminate at a suitable floor
drain.
ELECTRONIC IGNITION CONTROL
The Legend 2000® is controlled by the WHC 1502 ignition system,
fig. 2. The WHC 1502 is a solid-state ignition control that ignites
the main burner by energizing the Hot Surface Ignitor, fig. 3. The
ignition control system continuously monitors the current of the
ignitor and will not allow gas to enter the main burner until current
flow reaches the preset ignition temperature threshold. Once
the ignition threshold has been reached, the control system will
open the gas valve(s). After the main burner ignites, the control
FIGURE 4.
BLOCKED FLUE SWITCH
The Blocked Flue Switch (BFS) fig. 4, is a single-pole, normally
closed pressure switch that will open its contacts when a rising
positive pressure of 1.0 in. w.c. (0.25 kPa) is encountered. The
contacts will close when the pressure falls below the fixed set
point of 1.0 in. w.c. (0.25 kPa) The BFS monitors the pressure
inside the venting system. If the venting system is blocked in
such a way that the build up in pressure exceeds the setting of
6
the BFS, the main burner is extinguished (if boiler is running) or
the boiler will not start up.
BLOWER PROVER SWITCH
The Blower Prover Switch (BPS) fig. 4, is similar in construction
to the BFS. It is a single-pole, normally open pressure switch
that will close its contacts when a rising positive pressure of
1.0 in. w.c. (0.25 kPa) is encountered. The contacts will open
when the pressure falls below the fixed set point of 1.0 in. w.c.
(0.25 kPa) The BPS monitors the pressure inside the blower
elbow. If the blower is not operating at a sufficient blowing cap acity ,
the main burner is extinguished (if boiler is running) or the boiler
will not start up.
LOW GAS SWITCH
The Low Gas Switch (LGS) fig. 5, is a single-pole, normally open
pressure switch that will close its contacts when a rising pressure
of 5.0 in. w.c. (1.24 kPa) is encountered. The contacts will open
when the pressure falls below the fixed set point of 5.0 in. w.c.
(1.24 kPa) The LGS monitors the gas supply pressure to the
boiler. If the gas supply falls below 5.0 in. w.c. (1.24 kPa), the
main burner is extinguished (if boiler is running) or the boiler will
not start up.
AIR SHUTTER
The blower is equipped with an air shutter assembly for fine
adjustment of the air to gas ratio The assembly consists of a
shutter flange and the air shutter. The shutter may require
adjustment to achieve ideal start-up characteristics when fine tuning
the boiler for correct combustion specifications. Refer to the
Start-Up Procedures, part number 192077 Rev. 1, for the proper
combustion specifications and limits. If necessary, the shutter
may be adjusted by loosening the two nuts used to hold the shutter
and blower adapter assembly in place on the inlet of the blower.
Once the unit is set to the specifications called for in the Start-Up
Procedures, tighten the nuts to lock the shutter in place.
BLOWER SPEED CONTROL
The Blower Speed Control (BSC) permits variation of speed of
the blower during boiler (LB/LW-500 only) start-up. When the
1502 Control Board energizes the igniter, the BSC will lower the
speed (RPM) of the blower to a preset level. This lower speed
will be maintained until the igniter is de-energized by the Control
Board. Then, the blower will return to its normal operating speed.
COMBINATION GAS CONTROL
The Combination Gas Control (CGC) is a gas valve or valves that
controls the supply of gas to the main burner during operation of
the boiler. The CGC includes a manual main shutoff valve, two
(2) automatic valves and a pressure regulator, see figure 15.
FIGURE 5. LOW GAS SWITCH (LGS)
WATER FLOW SWITCH
The Water Flow Switch (WFS) fig. 6, is installed at the boiler water
outlet to prevent main burner operation in the event of inadequate
water flow through the boiler. The WFS is a single-pole, normally
open switch that will close its contacts when an increasing water
flow rate of approximately 25 GPM (1.61 lps) is encountered. The
contacts will open when the flow rate drops below this setting,
extinguishing the main burner flames (if boiler is running) or the
boiler will not start up .
The two-position gas control knob has “ON” and “OFF” positions
that allows or prevents the flow of gas to the main burner,
respectively. The first automatic valve is solenoid operated and
opens and closes when the main valve terminal on the Control
Board is energized or de-energized, respectively. The second
automatic valve is diaphragm operated and opens under control
of the pressure regulator and closes if gas or power supply is
interrupted. The pressure regulator is adjustable and maintains
an almost constant gas outlet pressure under wide fluctuations
in gas supply pressure.
MANUAL RESET LIMIT (E.C.O)
This device prevents the water temperature from exceeding 250°F
(121°C). It is located in the outlet waterway within the outlet
temperature sensing device and is monitored by the Control
Board. Commonly referred to as the “emergency cut out”, it is a
manually resettable control. The “ADJUST”, “SELECT” or
“ENTER/RESET” button on the display board must be depressed
to reset the unit if the water temperature reaches this limit. See
figure 20.
CAUTION
LIMIT CONTROLS ARE NOT TO BE USED AS A THERMOST A T OR
OPERA TING CONTROL.
AUTOMATIC RESET LIMIT
This limit is a safety device in series with the ignition system. Set
the limit control to a minimum of 30°F (16°C) above the maximum
designed system temperature. If the boiler outlet water
temperature should exceed the automatic reset limit setting, the
main gas valves will close. The automatic reset limit control is
factory set at 180°F (82°C) and has an adjustable range from
110 to 240°F (43° to 116°C). The operating differential is also
adjustable from 5 to 50°F (3° to 28°C).
FIGURE 6. WA TER FLOW SWITCH (WFS)
ON/OFF SWITCH
The ON/OFF Switch is a single-pole, single-throw rocker switch.
This switch provides 120V from the line source to the boiler.
7
CIRCULATING PUMP
DRAIN V AL VE
HOT WA TER SUPPLY SYSTEMS, the circulating pump is integral
to the LW models. This pump has been lubricated at the factory,
and future lubrication should be in accordance with the motor
manufacturer’s instructions provided as a supplement to this
manual.
FOR HOT WA TER HEA TING SYSTEMS-LB MODELS, the circulating
pump is NOT provided and must be obtained and installed in the
field.
NOTE: I f a system pump is to be installed on a Legend LB
model, the maximum rating of the pump motor must
not exceed 1 hp.
TANK TEMPERATURE CONTROL
A tank probe is provided with LW models to be used for tank
temperature regulations. The temperature setting for the tank is
set through the display.
Refer to figs. 7, 13, 14 and 16 for connecting the tank probe to the
boiler.
See TEMPERATURE SET POINT ADJUSTMENT PROCEDURE
for further instructions.
FOR HOT WA TER SUPPLY SYSTEMS, the boiler is supplied with
a Tank Probe to be field installed in the storage tank. Alternate
methods of temperature control, if desired, must be supplied by
the installer.
A change in water temperature in the storage tank lower than the
Tank Temperature Control setting will cause the sensor to close
its contacts and consequently, energize the boiler.
If the Tank Probe or Temperature Control is out of calibration,
replace it with a new one; do not attempt to fix this control.
A drain valve is factory installed in the heat exchanger manifold.
This will help to drain the heat exchanger.
Additional drain valves must be obtained and installed on each
boiler and tank for draining purposes, see figures 12, 13 and 14.
SAFETY RELIEF V AL VE
Your local code authority may have other specific safety relief
valve requirements not covered below.
WARNING
THE PURPOSE OF A SAFETY RELIEF VALVE IS TO AVOID
EXCESSIVE PRESSURE OR TEMPERA TURE INTO THE STEAM
RANGE WHICH MA Y CAUSE SCALDING AT FIXTURES, TANK
EXPLOSION, SYSTEM OR BOILER DAMAGE.
TO A VOID SCALDING OR W ATER DAMAGE, A DRAIN LINE MUST
BE CONNECTED TO A SAFETY RELIEF VALVE TO DIRECT
DISCHARGE TO A SAFE LOCATION. A DRAIN LINE MUST NOT BE
REDUCED FROM THE SIZE OF THE VAL VE OUTLET AND IT MUST
NOT CONTAIN ANY V AL VES BETWEEN THE BOILER AND THE
RELIEF VA LVE OR THE RELIEF V AL VE AND THE DRAIN EXIT . IN
ADDITION, THERE SHOULD NOT BE ANY RESTRICTIONS IN A
DRAIN LINE NOR SHOULD IT BE ROUTED THROUGH AREAS
WHERE FREEZING CONDITIONS MIGHT OCCUR. DO NOT THREAD
OR CAP THE DRAIN LINE EXIT . RESTRICTING OR BLOCKING A
DRAIN LINE WILL DEFEAT THE PURPOSE OF THE SAFETY RELIEF
V ALVE AND MA Y CREA TE AN UNSAFE CONDITION. INST ALL A
DRAIN LINE WITH A DOWNWARD SLOPE SUCH THA T IT WILL
NATURALL Y DRAIN ITSELF .
If any pressure relief valve is replaced, the replacement valve
must comply with the latest version of the ASME Boiler and
Pressure Vessel Code, Section IV (“HEATING BOILERS”).
NOTE: If you are using an L W model in a hydronic (space heating)
application, do not use the tank probe as a loop temperature
regulation device. The tank probe’s maximum setting is
190°F (88°C). Therefore, 24 VAC connections (red/green wires)
are provided in the rear junction box for an alternate device. The
J33 board jumper must be removed to use a 24 VAC temperature
regulation device (See figures 21 and 22).
LOW WATER CUTOFF (Not Supplied)
If low water protection is required by the authorities having
jurisdiction, a low water cutoff switch should be installed next to
the boiler in the outlet water line as shown in figure 12. The
switch should receive periodic (every six months) inspection to
assure proper operation. A Low Water Cutoff device of the float
type should be flushed every six months.
Encase field-supplied wires
between tank probe and junction
box with 1/2" field supplied
conduit. "Pigtails" of fieldsupplied wires should be spliced
to "pigtails" of tank probe and
connected to 24V AC junction box.
This conduit and wiring should be
separate from any other conduit/
wiring to guard against EMI
(electromagnetic interference).
FIGURE 7. TANK PROBE INST ALLA TION
Select a relief valve with a discharge rating NOT LESS than the
boiler input, and a set pressure NOT EXCEEDING the working
pressure of any component in the system.
FOR HOT WATER SUPPLY SYSTEMS, the boilers are shipped
with a 125 psi (860 kPa) pressure relief valve that must be installed
in the water outlet as near to the boiler as possible.
This ASME-rated valve has a discharge capacity that exceeds the
maximum boiler input rating and a pressure rating that does not
exceed the maximum working pressure shown on the boiler rating
plate.
In addition, a CSA design-certified and ASME-rated temperature
and pressure (T & P) relief valve must be installed on each and
every water storage tank in the hot water supply system.
8
The T & P relief valve must comply with the applicable construction
provisions of the
Shutoff Devices for Hot Water Supply Systems, ANSI Z21.22-1999
or CAN/CSA-B149.1-00, or most recent edition. The T & P relief
valve must be of the automatic reset type and not embody a singleuse type fusible plug, cartridge or linkage.
The T & P relief valve should have a temperature rating of 210°F
(99°C), a pressure rating NOT exceeding the lowest rated working
pressure of any system component, and a discharge capacity
exceeding the total input of the water boilers supplying water to
the storage tank.
Locate the T & P relief valve (a) in the top of the tank, or (b) in the
side of the tank on a centerline within the upper 6 inches (152
mm) of the top of the tank. See figures 13 and 14. The tapping
shall be threaded in accordance with the latest edition of the
Standard for Pipe Threads, General Purpose (inch), ANSI/ASME
B1.20.1. The location of, or intended location for, the T & P relief
valve shall be readily accessible for servicing or replacement.
Standard for Relief Valves and Automatic Gas
If the boiler is installed above radiation level, a Low Water Cutoff
Device must be installed in the boiler outlet at the time of
installation.
CHEMICAL VAPOR CORROSION
Water boiler corrosion and component failure can be caused by
the heating and breakdown of airborne chemical vapors. Spray
can propellants, cleaning solvents, refrigerator and air
conditioning refrigerants, swimming pool chemicals, calcium and
sodium chloride (water softener salt), waxes, and process
chemicals are typical compounds which are potentially corrosive.
These materials are corrosive at very low concentration levels
with little or no odor to reveal their presence.
Products of this sort should not be stored near the boiler. Also,
air which is brought in contact with the water boiler should not
contain any of these chemicals. If necessary, uncontaminated
air should be obtained from remote or outside sources. Failure
to observe this requirement will void the warranty.
FOR HOT WATER HEATING SYSTEMS, the boilers are shipped
with a 50 psi (345 kPa) pressure relief valve. This relief valve
must be installed in the water outlet as near to the boiler as
possible.
INST ALLA TION INSTRUCTIONS
REQUIRED ABILITY
INSTALLATION OR SERVICE OF THIS BOILER REQUIRES
ABILITY EQUIV ALENT T O THAT OF A LICENSED TRADESMAN
IN THE FIELD INVOL VED. PLUMBING, AIR SUPPLY, VENTING,
GAS SUPPLY AND ELECTRICAL WORK ARE REQUIRED.
LOCATION
When installing the boiler, consideration must be given to proper
location. The location selected should provide adequate air
supply and be as centralized with the piping system as possible.
THE BOILER MUST NOT BE INSTALLED ON CARPETING.
THE BOILER SHOULD NOT BE LOCATED IN AN AREA WHERE IT
WILL BE SUBJECT TO FREEZING .
LOCATE IT NEAR A FLOOR DRAIN. THE BOILER SHOULD BE
LOCATED IN AN AREA WHERE LEAKAGE FROM THE BOILER OR
CONNECTIONS WILL NOT RESULT IN DAMAGE TO THE
ADJACENT AREA OR TO LOWER FLOORS OF THE STRUCTURE.
WARNING
THERE IS A RISK IN USING FUEL BURNING APPLIANCES SUCH
AS BOILERS IN ROOMS OR AREAS WHERE GASOLINE, OTHER
FLAMMABLE LIQUIDS OR ENGINE DRIVEN EQUIPMENT OR
VEHICLES ARE STORED, OPERATED OR REPAIRED.
FLAMMABLE VAPORS ARE HEAVY AND TRA VEL ALONG THE
FLOOR AND MA Y BE IGNITED BY SP ARKS CAUSING FIRE OR
EXPLOSION. SOME LOCAL CODES PERMIT OPERA TION OF GAS
APPLIANCES IF INSTALLED 18 INCHES (457 MM) OR MORE
ABOVE THE FLOOR. THIS MA Y REDUCE THE RISK IF LOCATION
IN SUCH AN AREA CANNOT BE A VOIDED.
WARNING
FLAMMABLE ITEMS, PRESSURIZED CONTAINERS OR ANY
OTHER POTENTIAL FIRE HAZARDOUS ARTICLES MUST NEVER
BE PLACED ON OR ADJACENT TO THE BOILER. OPEN
CONTAINERS OR FLAMMABLE MATERIAL SHOULD NOT BE
STORED OR USED IN THE SAME ROOM WITH THE BOILER.
INST ALLATION CLEARANCES
This boiler is approved for installation on combustible flooring in
an alcove with minimum clearances to combustibles of:
4" (102 mm) Rear; 0" (0 mm) Top and Sides; 6" (152 mm) Vent.
Two inch (51 mm) clearance is allowable from combustible
construction for hot water pipes.
Sufficient area should be provided at the front and rear of the unit
for proper servicing. Service clearances of 24" (610 mm) in front,
rear, top and left side are recommended. In a utility room
installation, the door opening shall be wide enough to allow the
boiler to enter or to permit the replacement of another appliance
such as a water heater.
LEVELING
Each unit should be checked after installation to be certain that it
is level.
If the unit is not level, obtain and insert shims under the nylon
protective feet at the frame base to correct this condition.
AIR REQUIREMENTS
WARNING
FOR SAFE OPERA TION, AN AMPLE SUPPL Y OF AIR MUST BE
PROVIDED FOR PROPER COMBUSTION AND VENTILA TION IN
ACCORDANCE WITH SECTION 8.3, AIR FOR COMBUSTION AND
VENTILA TION, OF THE
OR SECTION 7.4 OF CSA-B149.1-00 OR APPLICABLE
PROVISIONS OF THE LOCAL BUILDING CODES. AN INSUFFICIENT
SUPPL Y OF AIR WILL RESULT IN A YELLOW , LUMINOUS BURNER
FLAME, CAUSING CARBONING OR SOOTING OF THE FINNED HEAT
EXCHANGER AND CREA TING A RISK OF ASPHYXIATION. DO NOT
OBSTRUCT THE FLOW OF COMBUSTION AND VENTILA TION AIR.
UNCONFINED SPACE
In buildings of conventional frame, brick or stone construction,
unconfined spaces may provide adequate air for combustion.
If the unconfined space is within a building of tight construction
(buildings using the following construction: weather stripping,
heavy insulation, caulking, vapor barrier, etc.), air for combustion,
ventilation and draft hood dilution must be obtained from outdoors
9
NATIONAL FUEL GAS CODE, ANSI Z223.1
or spaces freely communicating with the outdoors. The
installation instructions for confined spaces in tightly constructed
buildings must be followed to ensure adequate air supply.
CONFINED SPACE
Where power vented equipment is used in the same room as the
boiler, sufficient air openings must be supplied.
UNDERSIZED OPENINGS MAY RESULT IN INSUFFICIENT AIR
FOR COMBUSTION.
A. U.S. INSTALLA TIONS
When drawing combustion and dilution air from inside a
conventionally constructed building to a confined space, such a
space shall be provided with two permanent openings, ONE IN
OR WITHIN 12 INCHES (305 MM) OF THE ENCLOSURE TOP
AND ONE IN OR WITHIN 12 INCHES (305 MM) OF THE
ENCLOSURE BOTTOM. Each opening shall have a free area of
at least one square inch per 1000 Btu/hr (2,225 mm
the total input of all appliances in the enclosure, but not less than
100 square inches (645 cm
2
).
2
per kw) of
If the confined space is within a building of tight construction, air
for combustion, ventilation and draft hood dilution must be
obtained from outdoors. When directly communicating with the
outdoors or communicating with the outdoors through vertical
ducts, two permanent openings, located in the aforementioned
manner, shall be provided. Each opening shall have a free area
of not less than one square inch per 4000 Btu/hr (551 mm
2
per
kw) of the total input of all appliances in the enclosure. If horizontal
ducts are used, each opening shall have a free area of not less
than one square inch per 2000 Btu/hr (1,101 mm
2
per kw) of the
total input of all appliances in the enclosure.
B. CANADIAN INST ALLATIONS
Ventilation of the sp ace occupied by the boiler(s) shall be provided
by an opening for ventilation air at the highest practical point
communicating with outdoors. The total cross-sectional area
shall be at least 10% of the area of the combustion air opening
but in no case shall the cross-sectional area be less than
10 square inches (6500 mm
2
).
In addition to the above, there shall be permanent air supply
opening(s) having a cross-sectional area of not less than 1 square
inch per 7,000 BTUH (315 mm
BTUH
plus 1 square inch per 14,000 BTU (158 mm2/kW) in
2
/KW) up to and including 1,000,000
excess of 1,000,000 BTUH. This opening(s) shall be located at,
or ducted to, a point neither more than 18” (457 mm) nor less
than 6 inches (152 mm) above the floor level.
Where an exhaust fan is installed in the same room with the
boiler, sufficient openings for air must be provided in the walls.
UNDERSIZED OPENINGS WILL CAUSE AIR TO BE DRA WN INTO
THE ROOM THROUGH THE CHIMNEY OR OTHER OPENINGS,
CAUSING POOR COMBUSTION. SOOTING MA Y RESUL T WITH
AN INCREASED RISK OF ASPHYXIA TION.
VENTING
WARNING
THE INSTRUCTIONS IN THIS SECTION ON VENTING THE BOILER
MUST BE FOLLOWED TO AVOID CHOKED COMBUSTION OR
RECIRCULATION OF FLUE GASES. SUCH CONDITIONS CAUSE
SOOTING OR RISKS OF FIRE AND ASPHYXIATION.
VENT SIZING , INST ALLA TION AND TERMINA TION SHALL BE IN
ACCORDANCE WITH THIS INST ALLA TION MANUAL.
ALL ELECTRICAL POWER AND GAS MUST BE TURNED OFF
PRIOR TO ANY INSTALLA TION OF THE VENTING SYSTEM.
SPECIAL INST ALLATION CONSIDERA TIONS
The Legend 2000® is listed as a Category IV appliance and utilizes
a mechanical forced draft system. The vent system shall be
designed to prevent leakage of flue gases and condensate. The
condensate must be allowed to flow to a suitable drain. Since
the condensate is known to be detrimental to conventional vent
materials (galvanized steel, some stainless steels), the vent
material for the boiler’s exhaust shall be approved and certified
for the venting of low temperature condensing flue gasses. AL
®
is one such material.
29-4C
The exhaust gases of this boiler are generally only 15°-20°F (8°C
to 11°C) higher than the boiler’s operating temperature, much
lower than a standard boiler. In cold climates any water vapor
remaining in the flue gases will condense into a cloud of vapor at
the point where the vent system exits the building. Special
FIGURE 8. SIDEWALL EXHAUST VENTING
10
consideration is recommended, before locating the vent
termination near walkways, windows and building entrances.
Direct venting into dead spaces such as; alleys, atriums and
inside corners can cause recirculation of flue gases. Recirculation
of flue gases will cause sooting, premature failure of the heat
exchanger and icing of the combustion air intake during severe
cold weather. To prevent the recirculation of flue gases, maintain
as much distance as possible between the combustion air intake
and the exhaust vent terminal. Due to large volumes of flue gases,
multiple boiler applications also require additional distance
between the intake and exhaust terminals.
VENTING SYSTEM USING AL 29-4C
®
The LEGEND 2000® may be installed in four separate orientations
depending on the requirements of the building and the appliance.
The installer must decide which method is most appropriate for
each installation. These orientations are:
1. Vertical Termination — vertical vent termination through un-
enclosed or enclosed areas with roof penetration, see fig. 9.
2. Through-the-Wall Termination (TWT) — horizontal vent
termination directly through an outside wall, see figure 9A.
3. Direct Vent — using TWT to exhaust flue products and PVC
piping to bring combustion air to the boiler from the outside,
see figures 11 and 11C.
4. Vertical Direct Vent — using a vertical vent termination to
exhaust flue products and PVC piping to bring combustion air
to the boiler from outside, see figures 11A and 11B.
GENERAL INST ALLA TION REQUIREMENTS
COMMOM VENTING LEGEND BOILERS.
Common venting of multiple Legend boilers are not allowed
except with either a U.L. or CSA approved power venter.
• All the vent pipe(s) and power venter must be sized by and
installed as per the recommendations of the power venter
manufacturer. Please see boiler’s wiring label for electrical
hook-up of power venter to the ignition control.
• When multiple Legend boilers are connected using a common power venter and common power venter and common
vent pipe; the power venter and vent piping should be sized to
maintain a -0.0 IWC to -0.04 IWC draft in the common vent
downstream of the boilers, when any one of or all boilers are
firing. A positive pressure of +.02 IWC to =.05 IWC should be
seen 12" above the boot tee of each unit when the unit is firing.
• All Venting material must be AL29-4C venting material.
• A factory start-up of the engineered power venting system must
be preformed by an authorized factory start-up agent of the
power venter system manufacturer.
• To assure proper boiler and power venter operation, both the
power venter start-up and A.O. Smith Authorized boiler start-up
must be performed simultaneously.
1. Failure to conform with any of these requirements may violate
local, state/provincial or federal codes as well as create
conditions which may cause catastrophic property damage or
personal injury . The vent system must terminate so that proper
clearances are maintained as cited in local codes or the latest
edition of the National Fuel Gas Code, ANSI Z223.1 or
CSA-B149.1-00 and latest addenda. The vent system must
not have external runs greater than that allowed by local codes
or the National Fuel Gas Code.
2. AL 29-4C® sections and fittings MUST be used for the entire
length of the exhaust system; alternatives such as galvanized
pipe, PVC, CPVC or Type B Vent sections must
3. Install a AL 29-4C
®
drain fitting as close as possible to the
not be used.
boiler vent connector outlet. See “CONNECTING VENT TO
BOILER” on the installation of this drain fitting.
4. Horizontal runs of vent pipe shall be securely supported by
adequately placed (approximately every 6 feet [2 m])
non-combustible hangers and/or slip joints suitable for the
weight and design of the material employed to prevent sagging
and to maintain a minimum upward slope of 1/4" per foot (21
mm) from the boiler to the vent terminal (see “VENTING
SUPPORTS” and figures 9A and 11).
The upward slope allows any build up of condensate to flow
back towards the boiler and drain fitting preventing the
accumulation of condensate. See “CONNECTING VENT TO
BOILER.”
EXCEPTION: The vent connector on the boiler is sloped
downward to direct condensate towards the “field-installed”
drain fitting.
5. All joints in the venting system MUST be sealed with RTV 106
or equivalent sealant.
6. NO other appliances may be interconnected to any part of this
venting system, including vent connectors which serve
appliances vented by NATURAL DRAFT.
7. The venting system must be planned so as to avoid possible
contact with concealed plumbing or electrical wiring inside
walls.
8. The venting system must be planned to maintain an airspace
clearance from combustibles of at least 6 inches (152 mm)
®
for any conduit and fittings of single wall AL 29-4C
vent and at
least 4 inches (102 mm) for any conduit and fittings of double
wall AL 29-4C® vent. Double wall AL 29-4C® vent must be
used when penetrating any floors, walls or ceilings and any
penetration must be properly fire stopped. All insulation
material must be removed from any wall, floor or ceiling cavity
for at least 4 inches (102 mm) from the conduit.
9. The venting system in a multi-family structure must be planned
to be enclosed when passing through occupied or unoccupied
spaces above the connected boiler. This enclosure is to be of
materials no less fire resistant than surrounding floors and
walls. It is recommended that the system be enclosed
whenever passing through occupied spaces.
GENERAL EXHAUST VENT INST ALLA TION PROCEDURE
Prior to beginning the installation of the vent system, determine
and obtain all parts required for the installation. Refer to the
DIRECT VENT KIT PAR TS LIST (p art no. 192109), for a list of the
vent sections and fittings.
Proper operation of the boiler and venting system is dependent
upon use of all specified parts and installation techniques; both
safety and proper performance of the system may suffer if
instructions are not followed.
CONNECTING VENT TO BOILER
At the outlet of the boiler vent, see figure 10, the AL 29-4C® Vent
Boot-T ee and Boot-Tee Drain Cover must be used as the transition
from the horizontal to vertical run. This is where the bottom most
support bracket should be located.
11
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