RBI LCD Series User manual

LCD SERIES FINNED COPPER
GAS BOILERS (MODEL LB) &
WATER HEATERS (MODEL LW)
INSTALLATION & OPERATION MANUAL
LCD-IOM-4
82-0278
7/1/02
260 North Elm Street 7555 Tranmere Drive
Westfield, MA 01085 Mississauga, Ontario L5S 1L4 Canada
Phone: [phone] Phone: [phone]
Fax: [phone] Fax: [phone]
INSTALLER, THESE INSTRUCTIONS TO BE AFFIXED ADJACENT TO THE BOILER/WATER HEATER.
CONSUMER: RETAIN THESE INSTRUCTIONS FOR FUTURE REFERENCE PURPOSES.
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 department.
Installation and service must be performed by a qualified installer, service agency or
the gas supplier.
MEA#117-96-E
DESIGNED AND TESTED ACCORDING TO A.S.M.E. BOILER AND PRESSURE
VESSEL CODE, SECTION IV FOR A MAXIMUM ALLOWABLE WORKING PRESSURE
OF 160 PSI, 1103 kPa WATER.
WARNING: Failure to properly vent this unit can cause excessive amounts of carbon
monoxide resulting in severe personal injury or death!
10/09

LCD INSTALLATION AND OPERATION INSTRUCTIONSPage 2
AVERTISSMENT. Assurez-vous de bien suivre les instructions données dans cette
notice pour réduire au minimum le risque d’incendie ou d’explosion ou pour éviter
tout dommoge matériel, toute blessure ou la mort
Ne pas entreposer ni utiliser d’essence ou ni d’autres vapeurs ou liquides inflammables
à proximité de cet appareil ou de tout autre appareil.
QUE FAIRE SI VOUS SENTEZ UNE ODEUR DE GAZ:
• Ne pas tenter d’allumer d’appareil.
• Ne touchez à aucun interrupteur; ne pas vous servir des téléphones se trouvant dans
le bâtiment.
• Appelez immédiatement votre fournisseur de gas depuis un voisin. Suivez les
intructions du fournisseur.
• Si vous ne purvez rejoindre le fournisseur, appelez le service des incendies.
L’installation et l’entretien doivent être assurés par un installateur ou un service
d’entretien qualifié ou par le fournisseur de gaz.
The LCD Series finned copper heating boiler/water
heaters have been design certified by CSA for use with
natural and propane gas under the latest revision of
ANSI-Z21.10.3/CSA 4.3, Gas Water Heaters, and ANSI-
Z21.13/CSA 4.9, Gas-Fired Low Pressure Steam and Hot
Water Boilers and CAN1-3.1 Industrial and Commercial
Gas Fired Boilers. Each unit has been constructed and
hydrostatically tested for a maximum working pressure of
160 psi, 1103 kPa in accordance with Section IV of the
A.S.M.E.Boiler and PressureVessel Code.
All aspects of the boiler/water heater installation must
conform to the requirements of the authority having
jurisdiction, or, in the absence of such requirements,
to the National Fuel Gas Code, ANSI Z223.1/NFPA 54-
latest revision.Where required by the authority having
jurisdiction, the installation must conform to the Standard
for Controls and Safety Devices for Automatically Fired
Boilers, ANSI/ASME CSD-1.
In Canada, the installation must be in accordance with
the requirements of CSA B149.1 or .2, Installation Code
for Gas Burning Appliances and Equipment.
If installed in the Commonwealth of Massachusetts, you
MUST FOLLOW the additional instructions located in the
back of this manual (MACODE-3).
The owner should maintain a record of all service work
performed with the date and a description of the work
done. Include the name of the service organization for
future reference.
Direct all questions to your RBI distributor or contact
the RBI Customer Service Department, 260 North Elm
Street, Westfield, MA 01085 for U.S. or 7555 Tranmere
Drive, Mississauga, ONT L5S 1L4 for Canada. Always
include the model and serial numbers from the rating
plate of the boiler/water heater in question.
CONTENTS
Before Your Start ................................................page 2
Ratings & Capacities ..........................................page 3
Boiler/Water Heater Location .............................page 3
Combustion Air & Ventilation ..............................page 3
General Venting Guidelines ................................page 9
Venting Options ..................................................page 9
Vertical/Chimney Venting ...................................page 9
Horizontal Venting ............................................page 10
Outdoor Venting ...............................................page 11
Common Vent Systems ....................................page 12
General Piping Requirements ..........................page 13
Heating System Piping .....................................page 14
Domestic Water Supply Piping .........................page 18
Gas Supply Piping............................................page 21
Electrical Wiring................................................page 22
General Operation............................................page 22
Operating Instructions ......................................page 25
Checking & Adjustments ..................................page 28
Control Description...........................................page 30
Maintenance.....................................................page 31
Troubleshooting ................................................page 34
Repair Parts......................................................page 36
Start Up Sheet..................................................page 44
Mass. Code.......................................................page 46
Warranty ...........................................................page 48
BEFORE YOU START
This manual covers the application, installation,
operation and maintenance of a LCD Series finned
copper heating boiler/water heater/pool heater.
To obtain the safe, dependable, efficient operation and
long life for which this heating boiler/water heater was
designed, these instructions must be read, understood
and followed.

LCD INSTALLATION AND OPERATION INSTRUCTIONS Page 3
RATINGS & CAPACITIES
Before undertaking the installation of the LCD Series
boiler/water heater check the rating plate to ensure
that the unit has been sized properly for the job. The
“Net I=B=R Ratings” specify the equivalent amount
of direct cast iron radiation that the unit can supply
under normal conditions. Also ensure that the unit has
been set up for the type of gas available at the
installation site. Other important considerations are
the availability of an adequate electrical supply, fresh air
for combustion and a suitable chimney or vent system.
BOILER/WATER HEATER LOCATION
1. This boiler/water heater is suitable for indoor and
outdoor installations. Locate the boiler/water heater
in an area that provides good access to the unit.
Servicing may require the removal of jacket panels.
Allow the minimum clearances between adjacent
construction and the boiler/water heater as listed in
Table 1.
NOTE: Service clearances are not mandatory, but
are recommended to ensure ease of service should
it be required.
Table 1
Clearance to Service
Combustibles Clearance
in mm in mm
Top 6153 20 508
Back 6153 24 610
Left Side 6153 24 610
Right Side 6153 24 610
Front 6153 30 762
Flue 6153
2. An optimum site will be level, central to the piping
system, close to a chimney or outside wall and have
adequate fresh air for combustion. Ensure that the
boiler/water heater is level from front to back and
from side to side. Use metal shims to level the
boiler/water heater. Electrical and electronic
components must also be protected from exposure
to water during operation and maintenance. DO
NOT install this boiler/water heater in a location that
would subject any of the gas ignition components
to direct contact with water or excessive moisture
during operation or servicing.
3. Ensure that the floor is structurally sound and will
support the weight of the boiler/water heater.
NOTE: The LCD may be installed directly on
combustible flooring, but never on carpeting.
4. Locate the boiler/water heater in an area that will
prevent water damage to adjacent construction should
a leak occur or during routine maintenance. If such a
location doesn’t exist, a suitable drain pan that’s
adequately drained must be installed under the unit.
5.
DO NOT place this boiler/water heater in a location
that would restrict the introduction of combustion air
into the unit or subject the air inlet to a negative
pressure, see “GENERAL VENTING GUIDELINES”.
WARNING: Never store combustible materials,
gasoline or any product containing flammable
vapors or liquids in the vicinity of the boiler/
water heater. Failure to comply with this warning
can result in an explosion or fire causing
extensive property damage, severe personal
injury or death!
6. NEVER place this boiler/water heater in a location
that would subject it to temperatures at or near
freezing. See the “Freeze Protection Section” on
page 14.
CAUTION: Units installed outdoors MUST be
protected from ice and snow accumulation or the
unit will be damaged voiding the warranty!
COMBUSTION AIR & VENTILATION
WARNING: This boiler/water heater must be
supplied with combustion air in accordance with
Section 5.3, Air for Combustion & Ventilation, of
the latest revision of the National Fuel Gas Code,
ANSI Z223.1/NFPA 54 and all applicable local
building codes. Canadian installations must
comply with CSA B149.1 or .2 Installation Code
for Gas Burning Appliances and Equipment, or
applicable provisions of the local building codes.
Failure to provide adequate combustion air for
this boiler/water heater can result in excessive
levels of carbon monoxide which can result in
severe personal injury or death!
To operate properly and safely this boiler/water
heater requires a continuous supply of air for
combustion. NEVER store objects on or around
the boiler/water heater!
CAUTION: Combustion air contaminated with
fluorocarbons or other halogenated compounds
such as cleaning solvents and refrigerants will
result in the formation of acids in the combustion
chamber. These acids will cause premature failure
of the boiler/water heater voiding the warranty!
CAUTION: If the boiler/water heater is operated while
the building is under construction it MUST be
protected from wood, concrete, sheet rock and other
types of dust. Failure to properly protect the unit
from construction dust will damage the unit voiding
the warranty!

LCD INSTALLATION AND OPERATION INSTRUCTIONSPage 4
Buildings will require the installation of a fresh air duct
or other means of providing make-up air if the intake
air option isn’t used. Any building utilizing other gas
burning appliances, a fireplace, wood stove or any type
of exhaust fan must be checked for adequate
combustion air when all of these devices are in
operation at one time. Sizing of an outside air duct must
be done to meet the requirements of all such devices.
WARNING: Never operate the LCD in an
environment subjected to a negative pressure
unless the air intake is connected to the
outdoors. Failure to comply with this warning
can result in excessive levels of carbon
monoxide causing severe personal injury or
death!
All Air From Inside The Building
If the LCD is to be located in a confined space the
minimum clearances listed in Table 1 must be
maintained between it and any combustible construction.
When installed in a confined space without the intake
air option, Figures 1, 2 & 3, two permanent openings
communicating with an additional room(s) are required.
The combined volume of these spaces must have
sufficient volume to meet the combustion air
requirements of all gas utilization equipment. Fireplaces,
wood stoves or any type of exhaust fan must be
considered when making this determination. Each
opening must have a minimum free area of 1 in2/1000
Btu/hr, 2200 mm2/kW based on the total input rating of
ALL gas utilization equipment in the confined area. Each
opening must be no less than 100 in2,64,516 mm2in
size. The upper opening must be within 12 in, 305 mm
of, but not less than 3 in, 76 mm from, the top of the
enclosure. The bottom opening must be within 12 in,
305 mm of, but not less than 3 in, 76 mm from, the
bottom of the enclosure.
Figure 1 - Vertical Venting with a Metal Chimney System and Inside Air
10 FT

LCD INSTALLATION AND OPERATION INSTRUCTIONS Page 5
Figure 2 - Vertical Venting using a Masonry Chimney and Inside Air
Figure 3 - Horizontal Venting using Inside Air
Table 2
305 TO 457
127 TO 254
VENT PIPE DIAMETER
5" TO 10"
12" TO 18"
MINIMUM VERTICAL RISE
OFF THE TOP OF UNIT "A"
IN. mm FT mm
12"
24"
305
610
1.5 FT 0.5 m
1/4 IN. PER F00T 20 mm/m

LCD INSTALLATION AND OPERATION INSTRUCTIONSPage 6
All Air From Outside The Building
When installed in a confined space without utilizing
the intake air option two permanent openings
communicating directly with, or by ducts to, the outdoors
or spaces that freely communicate with the outdoors must
be present. The upper opening must be within 12 in,
305 mm of, but not less than 3 in, 76 mm from, the top of
the enclosure.The bottom opening must be within 12 in,
305 mm of, but not less than 3 in, 76 mm from, the bottom
of the enclosure.
Where directly communicating with the outdoors
or communicating with the outdoors through vertical
ducts, each opening shall have a minimum free area
of 1 in2/4000 Btu/hr, 550 mm2/kW of the total input
rating of all of the equipment in the enclosure.
Where communicating with the outdoors through
horizontal ducts, each opening shall have a minimum
free area of 1 in2/2000 Btu/hr, 1100 mm2/kW of the total
input rating of all of the equipment in the enclosure.When
louvers and screens are used, they must have the same
cross-sectional area as the free area of the opening to
which they connect.
When calculating the free area necessary to meet
the make-up air requirements of the enclosure,
consideration must be given to the blockage effects
of louvers, grills and screens. Screens must have a
minimum mesh size of 1/4 in, 6.4mm. If the free area
through a louver or grill is not known, ducts should be
sized per Table 3.
Table 3 - Make-up Air Louver Sizing
Required Cross Sectional Area
Input 1/4 in 6.4 mm 75% Free Area 25% Free Area
(MBH) Wire Screen Metal Louvers Wooden Louvers
in2cm2 in2cm2 in2cm2
225 57 363 75 484 225 1452
300 75 484 100 645 300 1935
399 100 645 133 858 399 2573
600 150 968 200 1290 600 3870
750 190 1210 250 1613 750 4840
1050 263 1696 350 2258 1050 6773
1200 300 1936 400 2580 1200 7740
1480 370 2388 494 3182 1480 9546
1650 413 2662 550 3548 1650 10,643
1970 493 3179 657 4236 1970 12,707
2300 575 3711 767 4945 2300 14,835
Canadian installations must comply with CSA B149.1
when air supply is provided by natural air flow from the
outdoors for natural draft, partial fan-assisted, fan-
assisted, or power draft-assisted burners, there shall
be a permanent air supply opening(s) having a cross-
sectional area of not less than 1 in2per 7,000 Btuh
(310 mm2per kW) up to and including 1 million Btuh,
plus 1 in2per 14,000 Btuh (155 mm2per kW) in excess
of 1 million Btuh.
Intake Air Option - General Guidelines
This configuration provides combustion air directly to the
boiler/water heater’s air intake using a dedicated pipe
to obtain combustion air from the outdoors. Combustion
air can be drawn in horizontally through an outside wall
or vertically through the roof, see Figures 4, 5, 6 & 7.
WARNING: Common intake air systems may
be used to provide the common duct is sized
properly and an intake combustion air damper
is installed in the intake air pipe of each heater.
Improper installation can result in excessive
levels of carbon monoxide which can cause
severe personal injury or death!
Single wall galvanized smoke pipe, single wall aluminum
pipe or flexible aluminum pipe can be used for the
in-take air pipe. It must be sized per Table 4. All joints
in metal combustion air systems must be secured using
corrosion resistant fasteners and sealed using a suitable
Silicon caulk or tape. The combustion air system
MUST be supported by the building structure not
the boiler/water heater.
Table 4 - Combustion Air Pipe Sizing
Model Size Pipe Diameter
in mm
225 - 300 5 127
400 6 152
600 - 750 8203
1050 10 254
1200 - 2300 12 305
CAUTION: A stack damper interlocked with the unit
should be installed in the intake air pipe when the
infiltration of sub-freezing air could occur, otherwise
the unit could freeze up voiding the warranty!
Intake Air Option - Horizontal Guidelines
The maximum equivalent length for the horizontal
combustion air pipe on installations that used the Direct
Vent option is 35 ft, 10.8 m. The maximum equivalent
length for the horizontal combustion air pipe on
installations that use the Horizontal Vent option is 100 ft,
30.5 m. Each 90° elbow and the combustion air terminal
are equal to 10 linear ft, 3.0 mof pipe. If horizontal runs
exceed 5 ft, 1.5 m they must be supported at 3 ft, 0.9 m
intervals with overhead hangers.The certified combustion
air terminal from RBI must be used and installed as
shown in Figures 4 and 5.
Intake Air Option - Vertical Guidelines
The maximum length for the vertical combustion air
pipe is 30 ft, 9.1 m plus two 90° elbows. A listed,
nonrestrictive combustion air cap must be used. The
combustion air cap must terminate as shown in Figure
6. The penetration point in the roof must be properly
flashed and sealed.

LCD INSTALLATION AND OPERATION INSTRUCTIONS Page 7
Figure 4 - Horizontal Combustion Air and Venting for a Single Unit
Figure 5 - Horizontal Combustion Air and Venting for Multiple Units
When running horizontal combustion air and venting for single or multiple units, exhaust and combustion air terminals
must be installed on the same plane (outside wall) in order to prevent pressure differences due to prevailing winds.
In cold climates, double-wall or insulated inlet pipe recommended to prevent condensation.
16 FT 4.9 m
1/4 IN. PER FOOT
20 mm/m
1.5 FT 0.5 m
0
1
2
3
4
5
6
7
8
9
05101520
Horizontal Distance, X
Y
,
e
c
na
t
s
iD
lac
i
t
r
e
V
2000 & Larger
1201 To 2000
901 To 1200
200 To 900
1000 BTU'S
1.5 FT 0.5 m
2 IN. 5.0 cm

LCD INSTALLATION AND OPERATION INSTRUCTIONSPage 8
Figure 6 - Vertical Combustion Air and Venting, Metal Chimney System Shown
Figure 7 - Combination Air Intake And Venting, Masonry Chimney Shown
10 FT 3.1 m
4 FT
1.2 m
5 FT
1.5 m
1.5 FT
0.5 m
5 1/2 FT
1.7 m
1.5 FT .5m
10 FT 3.1 m
3 FT 1 m
Note: Locate exhaust terminal down wind to reduce flue gas recirculation.

LCD INSTALLATION AND OPERATION INSTRUCTIONS Page 9
VENT SYSTEM OPTIONS
The LCD may be vented the following ways:
1) Vertical/Chimney Venting, Negative Pressure,
Category I - uses an approved metal chimney system
or properly lined masonry chimney. Combustion air is
obtained from the space in which the unit is installed or
from outdoors. A barometric damper must be installed
near the flue outlet when venting vertically. See Figures
6 and 7. This also applies to any fan-assisted chimneys
or vents.
2) Direct Vent, Positive Pressure, Category III - for
horizontal vent runs equivalent to 35 ft, 10.8 m or less.
A stainless steel vent system certified to UL 1738 for
installations in the United States. ULC S636 for
installations in Canada must be used when combustion
air is ducted from outdoors, from the same wall.
3) Horizontal Vent, Negative Pressure, Category I -
for horizontal vent runs equivalent to more than 35 ft,
10.8 m (90 degree elbow equals 10 equivalent feet). A
dedicated wall mounted power venter must be used. The
vent system can be single wall galvanized steel or type
B vent pipe. Combustion air is obtained from the space
in which the unit is installed or from the outdoors.
A barometric damper must be installed when the
horzontal run is longer than 35 equivalent feet. (90 degree
elbow = 10 equivalent feet). If this is the case, a power
venter must also be used.
If horizontal run is less than 35 equivalent feet, do not
use a barometric damper. Follow applicable instructions
under the “COMBUSTION AIR & VENTILATION” section.
4) Outdoor Installation - uses the outdoor option kit.
Barometric damper is not required.
NOTE: All venting, combusiton air material supplied
by installer. All venting material must be approved
for the application. Consult the vent manufacturer’s
product literature
GENERAL VENTING GUIDELINES
WARNING: The vent installation must be in
accordance with Part 7, Venting of Equipment,
of the National Fuel Gas Code, ANSI Z223.1/
NFPA 54-latest revision or applicable provisions
of the local building codes. Canadian
installations must comply with CSA B149.1 or
.2 Installation Code. Improper venting can result
in excessive levels of carbon monoxide which
can result in severe personal injury or death!
All vent systems must be fully supported by the building
structure and not by the boiler/water heater. Appropriate
thimbles and fire-stops must be used where required.
WARNING: Common vent systems must be
properly engineered and sized to provide a
negative draft of 0.01 to 0.08 in, .25 to 2.0 mm
W.C. at the flue outlet! Common positive
pressure vent systems are not to be used.
Improper installation can result in excessive
levels of carbon monoxide which can cause
severe personal injury or death!
NOTE: A single acting barometric damper must be
installed directly to the boiler/water heater flue
outlet to ensure proper operation. This does not
apply to outdoor units or direct vent positive
pressure units.
NOTE: Some venting applications may require the stop
to be removed for smooth operation. The barometric
damper should be located after the flue collector, refer
to Figures 2, 7A and 8 for proper location. Be sure that
the damper is mounted horizontally (never vertically).
Carefully follow the instructions provided with the
barometric damper. Check with local codes for specific
requirements.
In Canada, B149 (7.25 Draft Regulators) states the
damper shall be of double-acting type.
WARNING: To avoid spillage into the room of
dangerous flue gas containing carbon monoxide,
the opening in damper must never face against the
flow of flue gas.

LCD INSTALLATION AND OPERATION INSTRUCTIONSPage 10
VERTICAL/CHIMNEY VENTING
The LCD is listed as a Category I appliance when vented
vertically into a metal chimney system or properly sized
masonry chimney, Figures 1, 2, 6 & 7. The chimney must
provide a negative pressure of 0.01 to 0.08 in, .25
to 2.0 mm W.C. at the boiler/water heater flue collar
with the unit running at full load. A barometric damper
must be installed between the flue collar and the vent
connector. Approved thimbles and fire-stops must be
used when combustible construction is penetrated.
WARNING : If an appliance using any type of a
mechanical draft system operating under
positive pressure is connected to a chimney
flue, never connect any other appliances to this
flue. Doing so can result in excessive levels of
carbon monoxide which can cause severe
personal injury or death!
Chimney Inspection & Sizing
A thorough inspection of the masonry chimney must be
performed to ensure that the chimney is clean, properly
constructed, lined and sized. Exterior masonry chimneys
should not be used unless properly lined to prevent
condensation and draft problems. Table 5 lists the
equivalent breeching and flue sizes required for the
boiler/water heater. When more than one appliance is
connected to the same chimney flue, the flue must be
large enough to safely vent the combined output of all
of the appliances.
Table 5 - Equivalent Breeching & Chimney Size
Model Size Pipe Diameter
in mm
225 5 127
300 - 400 6152
600 - 750 8 203
1050 10 254
1200 - 1480 12 305
1650 - 2300 14 356
Note: These sizes are based on a 20 ft, 6.1m chimney height.
Vent Connections
Locate the boiler/water heater as close to the chimney
as possible. Use the shortest, straightest vent connector
possible for the installation. If horizontal runs exceed
5 ft, 1.5 m they must be supported at 3 ft, 0.9 m
intervals with overhead hangers. Use a type B, single
wall stainless or single wall galvanized steel vent pipe
the same diameter as the flue collar to connect the
boiler/water heater to a masonry chimney. When using
an approved metal chimney system use the appropriate
vent connector. The vent connector should be sloped up
toward the chimney at a minimum rate of 1/4 in/ft,
20 mm/m. On masonry chimneys the connector must
terminate flush with the inside of the chimney flue,
Figure 2. Fasten each single wall vent connection with
at least 3 corrosion resistant sheet metal screws.
WARNING: Never install a vent pipe having a
diameter different than that of the boiler/water
heater flue collar. Failure to comply with this
warning can result in excessive levels of carbon
monoxide which can cause severe personal
injury or death.
Always provide a minimum clearance of 6 in, 152 mm
between single wall vent pipe and any combustible
materials. Type B1 vent may be used, clearance between
it and any combustible material must be as listed.
WARNING: Failure to maintain minimum
clearances between vent connectors and any
combustible material can result in a fire causing
extensive property damage, severe personal
injury or death!
DIRECT VENT,
POSITIVE PRESSURE, CATEGORY III
In this configuration the boiler/water heater blower is
used to push the flue products to the outdoors while
drawing combustion air from the outdoors.The equivalent
length of the vent and combustion air systems must not
exceed 35 ft, 10.7 m for each. The Intake Air Option
instructions under the “COMBUSTION AIR &
VENTILATION” section must be followed! The vent
system must be sized per Table 4.
Horizontal Direct Vent Systems - Figures 4 & 5
The vent materials used in horizontal vent systems
must be certified to UL 1738 for installations in the
United States, ULC S636 for installations in Canada. The
certified vent terminal from RBI must also be used.
The maximum equivalent length for the horizontal vent
and combustion air pipes is 35 ft, 10.8 m for each. Each
90˚ elbow and the intake air and vent terminals are
equal to 10 ft, 3.1 m of straight pipe. To maximize the
performance of single wall sheet metal vent systems
locate 90˚ elbows as far from the boiler as possible and
from one another. For best results, horizontal vent
systems should be as straight as possible.
The vent system must be both gas tight and watertight.
All seams and joints in metal pipes must be joined
and sealed in accordance with the vent system
manufacturer’s instructions.
When horizontal vent runs exceed 5 ft, 1.5 m they
must be supported at 3 ft, 0.9 m intervals with overhead
hangers.The vent system must be pitched down, toward
the vent terminal, 1/4 in/ft, 20 mm/m. If any part of a
single wall metal vent system passes through an
unheated space it must be insulated with insulation
rated for 400˚F, 204˚C.