RBI LCD OMINATOR Series User manual

9/2021 Copyright 2014 Mestek, Inc.
LCD-I0M-10
82-0278
Boiler Manual
Installation and Operation
Instructions
is manual is intended only for use by a qualied heating installer/technician. Read and follow this manual, all supplements and related
instructional information provided with the boiler. Install, start and service the boiler only in the sequence and methods given in these
instructions. Failure to do so can result in severe personal injury, death or substantial property damage.
Do not use the boiler during construction. Construction dust and particulate, particularly drywall dust, will cause contamination
of the burner, resulting in possible severe personal injury, death or substantial property damage. e boiler can only be operated with
a dust-free air supply. Follow the instruction manual procedures to duct air to the boiler air intake. If the boiler has been contaminated
by operation with contaminated air, follow the instruction manual guidelines to clean, repair or replace the boiler if necessary.
Ax these instructions near to the boiler. Instruct the building owner to retain the instructions for future use by a qualied service
technician, and to follow all guidelines in the User’s Information Manual.
Finned Copper Tube
Gas Boilers (LB) &
Water Heaters (LW)

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
2
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 13
HORIZONTAL VENTING . . . . . . . . . . . . . . . PAGE 14
OUTDOOR VENTING . . . . . . . . . . . . . . . . PAGE 14
COMMON VENT SYSTEMS . . . . . . . . . . . . . PAGE 15
GENERAL PIPING REQUIREMENTS . . . . . . . . PAGE 16
HEATING SYSTEM PIPING . . . . . . . . . . . . . PAGE 17
DOMESTIC WATER SUPPLY PIPING . . . . . . . . PAGE 21
GAS SUPPLY PIPING . . . . . . . . . . . . . . . . PAGE 24
ELECTRICAL WIRING . . . . . . . . . . . . . . . . PAGE 25
GENERAL OPERATION . . . . . . . . . . . . . . . PAGE 25
OPERATING INSTRUCTIONS . . . . . . . . . . . . PAGE 29
CHECKING & ADJUSTMENTS. . . . . . . . . . . . PAGE 31
CONTROL DESCRIPTION . . . . . . . . . . . . . . PAGE 33
MAINTENANCE . . . . . . . . . . . . . . . . . . . PAGE 34
TROUBLESHOOTING . . . . . . . . . . . . . . . . PAGE 37
REPAIR PARTS . . . . . . . . . . . . . . . . . . . . PAGE 39
START UP SHEET . . . . . . . . . . . . . . . . . . PAGE 47
MASS. CODE . . . . . . . . . . . . . . . . . . . . . PAGE 49
WARRANTY . . . . . . . . . . . . . . . . . . . . . PAGE 50
BEFORE YOU START
is manual covers the application, installation, operation and
maintenance of a LCD Series nned copper heating boiler/water
heater.
To obtain the safe, dependable, ecient operation and long life for
whichthisheatingboiler/waterheaterwasdesigned,theseinstructions
must be read, understood and followed.
e LCD Series nned copper heating boiler/water heaters have
been design certied by CSA for use with natural andpropane gas
under the latest revision of ANSI-Z21.10.3/CSA 4.3, Gas Water
Heaters,andANSI-Z21.13/CSA4.9,Gas-FiredLowPressureSteam
and Hot Water Boilers. Each unit has been constructed and
hydrostatically tested foramaximumworking pressureof160 psi,
1103 kPa in accordance with SectionIVoftheA.S.M.E. Boilerand
PressureVesselCode.
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.
If the information in this manual is not followed
exactly, a fire or explosion may result causing property,
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 froma phone outside
the building. 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.
Assurez-vous de bien suivre les instructions données
dans cette notice pour réduire au minimum le risque
d’incendieoud’explosionoupourévitertoutdommoge
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 immédiatementvotre fournisseur degas 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.
Failure to properly vent this unit can cause excessive
amounts of carbon monoxide resulting in severe
personal injury or death!
DESIGNED AND TESTED ACCORDING TO A.S.M.E.
BOILER AND PRESSURE VESSEL CODE, SECTION
IV FOR A MAXIMUM ALLOWABLE WORKING PRES-
SURE OF 160 PSI, 1103 kPa WATER.
INSTALLER, THESE INSTRUCTIONS TO BE AFFIXED
ADJACENT TO THE HEATER.
CONSUMER, RETAIN THESE INSTRUCTIONS FOR
FUTURE REFERENCE PURPOSES.

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
3
In Canada, the installation must be in accordance with the
requirementsofCSAB149.1or.2,InstallationCodeforGasBurning
Appliances and Equipment.
If installed in the Commonwealth of Massachuses, you MUST
FOLLOW the additional instructions located in the back of this
manual (MACODE-3).
e 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 Cus-
tomer Service Department, 260 North Elm Street, Westeld, MA
01085forU.S.or7555TranmereDrive,Mississauga,ONTL5S1L4
for Canada. Always include the model and serial numbers from the
rating plate of the boiler/water heater in question.
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. e “Net AHRI 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. is 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
removalofjacketpanels.Allowtheminimumclearancesbetween
adjacent construction and the boiler/water heater as listed in
Table 1.
Service clearances are not mandatory, but are
recommended to ensure ease of service should it be
required.
Table 1
Clearance to
Combustibles
Service
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 oor is structurally sound and will support the
weight of the boiler/water heater.
e LCD may be installed directly on combustible
ooring, 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
restricttheintroductionofcombustionair intotheunitorsubject
the air inlet to a negative pressure, see “GENEL VENTING
GUIDELINES”.
Never store combustible materials, gasoline or any
product containing ammable vapors or liquids in the
vicinity of the boiler/water heater. Failure to comply
with this warning can result in an explosion or re
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 17.
Units installed outdoors MUST be protected from ice
and snow accumulation or the unit will be damaged
voiding the warranty!
COMBUSTION AIR & VENTILATION
is boiler/water heater must be supplied with
combustion air in accordance with Section 9.3, 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!

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
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Combustion air contaminated with uorocarbons or
other halogenated compounds such as cleaning
solvents and refrigerants will result in the formation
of acids in the combustion chamber. ese acids will
cause premature failure of the boiler/water heater
voiding the warranty!
Iftheboiler/waterheaterisoperatedwhilethebuilding
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!
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.
Anybuildingutilizingothergasburningappliances,areplace,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.
NeveroperatetheLCDinanenvironmentsubjectedto
anegativepressureunless the air intakeisconnectedto
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
IftheLCDistobelocatedinaconnedspacetheminimumclearances
listedin Table1mustbe maintainedbetweenit andanycombustible
construction. When installed in a conned space without the
intake air option, Figures 1, 2 & 3, two permanent openings
communicating with an additional room(s) are required. e
combined volume of these spaces must have sucient volume to
meetthecombustionairrequirementsofallgasutilizationequipment.
Fireplaces,woodstovesor anytypeofexhaustfanmustbeconsidered
whenmakingthisdetermination.Eachopeningmusthaveaminimum
free area of 1 in2/1000 Btu/hr, 2200 mm2kW based on the total
input rating of ALL gas utilization equipment in the conned area.
Eachopeningmustbeno lessthan100in2,64,516 mm2insize.e
upper opening must be within 12 in, 305 mm of, but not less than
3 in, 76 mm from, the top of the enclosure. e boom opening
must be within 12 in, 305 mm of, but not less than 3 in, 76 mm
from, the boom of the enclosure.
Figure 1 Vertical venting with a metal chimney system and inside air
10 FT

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
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Figure 2 Vertical venting using a masonry chimney system and inside air
Figure 3 Horizontal venting using inside air
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
Table 2

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
6
All Air From Outside The Building
When installed in a conned 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
theoutdoorsmustbepresent.eupperopeningmustbewithin12
in, 305 mm of, but not less than 3 in, 76 mm from, the top of the
enclosure. e boom opening must be within 12 in, 305 mm of,
but not less than 3 in, 76 mm from, the boom of the enclosure.
Wheredirectlycommunicatingwiththeoutdoorsorcommunicating
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 eects 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
(MBH)
1/4 in 6.4 mm
Wire Screen
75% Free Area
Metal Louvers
25% Free Area
Wooden Louvers
in2cm2in2cm2in2cm2
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 naturalairowfromthe outdoorsfornatural
dra, partial fan-assisted, fan-assisted, or power dra-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
is conguration provides combustion air directly to the boiler/
waterheater’sair intakeusingadedicatedpipe toobtaincombustion
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.
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
exible 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. e 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
400 6152
600 - 750 8 203
1050 10 254
1200 - 2300 12 305
A combustion air damper interlocked with the unit
should be installed in the intake air pipe when the
inltration of sub-freezing air could occur, otherwise
the unit could freeze up voiding the warranty!
Intake Air Option - Horizontal Guidelines
e maximum equivalent length for the horizontal combustion
air pipe on installations that used the Direct Vent option is 35 ,
10.8 m. e maximum equivalent length for the horizontal
combustion air pipe on installations that use the Horizontal Vent
option is 100 , 30.5 m. Each 90° elbow and the combustion air
terminal are equal to 10 linear , 3.0 mof pipe. If horizontal runs
exceed 5 , 1.5 m they must be supported at 3 , 0.9 m intervals
with overhead hangers. e certied combustion air terminal from
RBI must be used and installed as shown in Figures 4 and 5.
Intake Air Option - Vertical Guidelines
e maximum length for the vertical combustion air pipe is 30 ,
9.1 m plus two 90° elbows. A listed, nonrestrictive combustion air
cap must be used. e combustion air cap must terminate as shown
in Figure 6. e penetration point in the roof must be properly
ashed and sealed.

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
7
Figure 4 Horizontal combustion air and venting for a single unit
Figure 5 Horizontal combustion air and venting for a 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 dierences due to prevailing winds. In cold climates, double-
wall or insulated inlet pipe recommended to prevent condensation.
1.5 FT 0.5 m
2 IN.5.0 cm
0
1
2
3
4
5
6
7
8
9
0510 15 20
Horizontal Distance, X
Y,ecnatsiDlacitreV
2000 & Larger
1201 To 2000
901 To 1200
200 To 900
1000 BTU'S
0
1
2
3
4
5
6
7
8
9
05101520
Horizontal Distance, X
Y,ecnatsiDlacitreV
2000 & Larger
1201 To 2000
901 To 1200
200 To 900
1000 BTU'S
400

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
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Figure 6 Vertical combustion air and venting, metal chimney system shown
Locate exhaust terminal downwind from air intake to reduce potential for flue gas recirculation.
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

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
9
GENERAL VENTING GUIDELINES
e 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. See Figure A for added clarity.
Improperventingcanresultinexcessivelevelsofcarbon
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 re-
stops must be used where required.
Common vent systems must be properly engineered
and sized to provide a negative dra of 0.01 to 0.08
in, .25 to 2.0 mm WC at the ue 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!
Multi-story, common venting systems shall be in
accordance with the National Fuel Gas Code, ANSI
Z223.1/NFPA 54 and/or the CSA B149.1, Natural
GasandPropaneInstallationCode(CurrentEditions),
local codes and vent manufacturer's installation
instructions. Size the chimney and breeching using
generally accepted engineering practices. (Consult
factory for vertical heights beyond 60 .)
A single acting barometric damper must be
installed directly to the boiler/water heater ue
outlet to ensure proper operation. is does not apply
to outdoor units or direct vent positive pressure units.
Some venting applications may require the stop to be
removed for smooth operation. e barometric
damper should be located aer the ue collector, refer
to Figures 2, 7A and 8 for proper location. Carefully
follow the instructions provided with the barometric
damper. Check with local codes for specic
requirements.
In Canada, B149 (7.25 Dra Regulators) states the
damper shall be of double-acting type.
To avoid spillage into the room of dangerous ue gas
containing carbon monoxide, the opening in damper
must never face against the ow of ue gas.
Boiler/Water Heater shall not be connected to a
chimney ue serving a separate appliance designed
to burn solid fuel.
VENT SYSTEM OPTIONS
e 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 ue outlet when venting
vertically.SeeFigures6and7. isalsoappliestoanyfan-assisted
chimneys or vents.
2) Direct Vent, Positive Pressure, Category III - for
horizontal vent runs equivalent to 35 , 10.8 m or less.
A stainless steel vent system certied 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 ,
10.8 m (90° elbow equals 10 equivalent ). A dedicated wall
mounted power venter must be used. e 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° elbow = 10 equivalent
). If this is the case, a power venter must also be used.
4) Outdoor Installation -usesthe outdooroptionkit.Barometric
damper is not required.
All venting, combusiton air material supplied by
installer. All venting material must be approved for the
application. Consult the vent manufacturer’s product
literature.

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
10
Canadian Installations¹ US Installations²
A = Clearance above grade, veranda, porch,
deck, or balcony 12 in (30 cm) 12 in (30 cm)
B = Clearance to window or door that may
be opened
6 in (15 cm) for appliances < 10,000
Btuh (3 kW); 12 in (30 cm) for appliances
> 10,000 Btuh (3 kW) and < 100,000
Btuh (30 kW); 36 in (91 cm) for
appliances > 100,000 Btuh (30 kW)
6 in (15 cm) for appliances < 10,000 Btuh
(3 kW); 9 in (23 cm) for appliances >
10,000 Btuh (3 kW) and < 50,000 Btuh
(15 kW); 12 in (30 cm) for appliances >
50,000 Btuh (15 kW)
C = Clearance to permanently closed
window
D =
Vertical clearance to ventilated soffit
located above the terminal within a
horizontal distance of 2 ft (61 cm) from
the center line of the terminal.
E = Clearance to unventilated soffit
F = Clearance to outside corner
G = Clearance to inside corner
H =
Clearance to each side of center line
extended above meter / regulator
assembly
I = Clearance to service regulator
vent outlet 3 ft (91 cm)
J =
Clearance to nonmechanical air supply
inlet to building or the combustion air
inlet to any other appliance
6 in (15 cm) for appliances < 10,000
Btuh (3kW); 12 in (30 cm) for appliances
> 10,000 Btuh (3 kW) and < 100,000
Btuh (30 kW); 36 in (91 cm) for
appliances > 100,000 Btuh (30 kW)
6 in (15 cm) for appliances < 10,000 Btuh
(3kW); 9 in (23 cm) for appliances >
10,000 Btuh (3 kW) and < 50,000 Btuh (15
kW); 12 in (30 cm) for appliances > 50,000
Btuh (15 kW)
Torus Stainless Steel Condensing Boilers & Water Heaters – Installation Manual
Per local installation codes
Figure A- Direct Vent Terminal Clearances
3 ft (91 cm) within a height of 15 ft (4.6m)

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
11
K = Clearance to a mechanical air
supply inlet 6 ft (1.83 m) 3 ft (91 cm) above if within 10 ft (3 m) horizontally
L =
Clearance above paved sidewalk
or paved driveway located on
public property
7 ft (2.13 m)†
M = Clearance under veranda, porch,
deck, or balcony
12 in (30 cm)‡
†
‡
A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family
dwellings and serves both dwellings.
NOTES:
1) In accordance with the current CSA B149.1, Natural Gas and Propane Installation Code
2) In accordance with the current ANSI Z223.1/NFPA 54, National Fuel Gas Code
3) If locally adopted installation codes specify clearances different than those illustrated, then the most stringent clearances must prevail.
Torus Stainless Steel Condensing Boilers & Water Heaters – Installation Manual
Per local installation codes
Canadian Installations¹ US Installations²
A = Clearance above grade, veranda, porch,
deck, or balcony 12 in (30 cm) 12 in (30 cm)
B = Clearance to window or door that may
be opened
6 in (15 cm) for appliances < 10,000
Btuh (3 kW); 12 in (30 cm) for appliances
> 10,000 Btuh (3 kW) and < 100,000
Btuh (30 kW); 36 in (91 cm) for
appliances > 100,000 Btuh (30 kW)
4 ft (1.2 m) below or to side of opening;
1 ft (300 mm) above opening
C = Clearance to permanently closed
window
D =
Vertical clearance to ventilated soffit
located above the terminal within a
horizontal distance of 2 ft (61 cm)
from the center line of the terminal
E = Clearance to unventilated soffit
F = Clearance to outside corner
G = Clearance to inside corner
H =
Clearance to each side of center line
extended above meter/regulator
assembly
I = Clearance to service regulator vent
outlet 3 ft (91 cm)
Per local installation codes
Figure A- Other Than Direct Vent Terminal Clearances
Figure A- Direct Vent Terminal Clearances - Concluded
J =
Clearance to nonmechanical air supply
inlet to building or the combustion air
inlet to any other appliance
6 in (15 cm) for appliances < 10,000
Btuh (3kW); 12 in (30 cm) for appliances
> 10,000 Btuh (3 kW) and < 100,000
Btuh (30 kW); 36 in (91 cm) for
appliances > 100,000 Btuh (30 kW)
4 ft (1.2 m) below or to side of opening;
1 ft (300 mm) above opening
Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.
Vents for Category II and IV appliances
cannot be located above public walkways
or other areas where condensate or vapor
can cause a nuisance or hazard
3 ft (91 cm) within a height of 15 ft (4.6m)

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
12
K = Clearance to a mechanical air supply
inlet 6 ft (1.83 m) 3 ft (91 cm) above if within 10 ft (3 m)
horizontally
L =
Clearance above paved sidewalk or
paved driveway located on public
property
7 ft (2.13 m)†
M = Clearance under veranda, porch, deck,
or balcony
12 in (30 cm)‡
†
‡
A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings
and serves both dwellings.
Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.
NOTES:
1) In accordance with the current CSA B149.1, Natural Gas and Propane Installation Code
2) In accordance with the current ANSI Z223.1/NFPA 54, National Fuel Gas Code
3) If locally adopted installation codes specify clearances different than those illustrated, then the most stringent clearances must prevail.
Per local installation codes
Torus Stainless Steel Condensing Boilers & Water Heaters – Installation Manual
Figure A- Other Than Direct Vent Terminal Clearances - Concluded
Vents for Category II and IV appliances
cannot be located above public walkways
or other areas where condensate or vapor
can cause a nuisance or hazard

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
13
VERTICAL/CHIMNEY VENTING
e 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. e chimney must provide a negative pressure
of 0.01 to 0.08 in, .25 to 2.0 mm WC at the boiler/water heater
ue collar with the unit running at full load. A barometric damper
must be installed between the ue collar and the vent connector.
Approved thimbles and re-stops must be used when combustible
construction is penetrated.
If an appliance using any type of a mechanical dra
system operating under positive pressure is connected
to a chimney ue, never connect any other appliances
to this ue. 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.Exteriormasonry chimneysshouldnotbeusedunlessproperly
lined to prevent condensation and dra problems. Table 5 lists the
mimimum riser diameter connections, negative pressure for the
boiler/water heater. When more than one appliance is connected
to the same chimney ue, the ue must be large enough to safely
vent the combined output of all of the appliances.
Table 5 Minimum Riser Connection, Negative Pressure (Category I)
Model Size Pipe Diameter
in mm
400 6152
600 7 178
750 8 203
1050 10 254
1200 - 1480 12 305
1650 - 2300 14 356
Note: Vent system must be sized per the tables contained in
NFPA 54 or an engineered system
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 , 1.5 m they must be
supported at 3 , 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 ue collar to connect the boiler/water
heater to a masonry chimney. When using an approved metal
chimney system use the appropriate vent connector. e vent
connector should be sloped up toward the chimney at a minimum
rate of 1/4 in/, 20 mm/m. On masonry chimneys the connector
must terminate ush with the inside of the chimney ue, Figure 2.
Fasten each single wall vent connection with at least 3 corrosion
resistant sheet metal screws.
Never install a vent pipe having a diameter dierent
than that of the boiler/water heater ue 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.
Failuretomaintainminimumclearancesbetweenvent
connectors and any combustible material can result
in a re causing extensive property damage, severe
personal injury or death!
DIRECT VENT, POSITIVE PRESSURE,
CATEGORY III
In this conguration the boiler/water heater blower is used to push
the ue products to the outdoors while drawing combustion air
fromtheoutdoors.eequivalentlengthofthe ventandcombustion
air systems must not exceed 35 , 10.7 m for each. e Intake
Air Option instructions under the “COMBUSTION AIR &
VENTILATION” section must be followed! e vent system ue
pipe diameter must be sized per Table 5a.
Horizontal Direct Vent Systems - Figures 4 & 5
e vent materials used in horizontal vent systems must be certied
to UL 1738 for installations in the United States, ULC S636 for
installations in Canada. e certied vent terminal from RBI must
also be used.
e maximum equivalent length for the horizontal vent and
combustion air pipes is 35 , 10.8 m for each. Each 90° elbow
and the intake air and vent terminals are equal to 10 , 3.1 m of
straight pipe. To maximize the performance of single wall sheet
metalventsystemslocate90° elbowsasfarfromtheboileraspossible
and from one another. For best results, horizontal vent systems
should be as straight as possible.
e 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.
Whenhorizontalventrunsexceed5,1.5 mtheymustbesupported
at 3 , 0.9 m intervals with overhead hangers. e vent system
must be pitched down, toward the vent terminal, 1/4 in/,
20 mm/m. If any part of a single wall metal vent system passes
throughanunheatedspace it mustbeinsulated with insulationrated
for 400°F, 204°C.

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
14
Table 5a Category III Vent Pipe Diameter
Model Size Pipe Diameter
in mm
400 6152
600 - 750 8 203
1050 10 254
1200 - 1480 12 305
1650 - 2300 14 356
Note: Diameters based on a maximum 35 equivalent feet.
Horizontal vent systems shall terminate at least 4 , 1.2 m below,
4 ,1.2 mhorizontallyfromor1 ,0.23 maboveanydoor,window
or gravity air inlet into any building. It must not terminate less than
4 , 1.2 m horizontally from, and in no case above or below, unless
a 4 , 1.2 m horizontal distance is maintained, from electric meters,
gas meters, regulators and relief equipment and not less than 7 ,
2.1 m from any adjacent public walkway. e boom of the vent
terminal(s) shall be located at least 5 , 1.5 m above the air intake
terminal(s)unlessthereisaminimum5,1.5 mhorizontalseparation
betweenthem.Avoidterminallocationslikelytobeaectedbywinds,
snowdris,peopleandpets.Protectbuildingmaterialsandvegetation
from degradation caused by the ue gases.
Vertical Direct Vent Systems - Figure 6
e maximum length for the vertical vent and combustion air pipes
is 35 , 10.7 m plus two 90° elbows. 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. Structural
penetrations must be made using approved re-stops.
A listed, nonrestrictive vent cap must be used. e top of a vertical
vent system must extend at least 5 1/2 , 1.7 m above the roof
surface that it passes through, 4 , 1.2 m above the intake air cap,
see Figure 6.
HORIZONTAL VENT, NEGATIVE PRESSURE,
CATEGORY I
In this conguration a wall-mounted power venter must be used
to pull the ue products horizontally from the unit and vent them
to the outdoors, see Figures 3, 4 & 5. e air for combustion is
taken from the space in which the unit is installed, or from the
outdoors. e applicable instructions under the “COMBUSTION
AIR & VENTILATION” section must be followed!
To maximizetheperformanceofsinglewallsheetmetalventsystems
locate 90° elbows as far from the boiler as possible and from one
another. For best results, horizontal vent systems should be as short
and straight as possible.
Whenhorizontalventrunsexceed5,1.5 mtheymustbesupported
at 3 , 0.9 m intervals with overhead hangers. e vent system must
be pitched down, toward the vent terminal, 1/4 in/, 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 for400°F,
204°C.
Horizontal vent systems shall terminate at least 4 , 1.2 m below,
4 , 1.2 m horizontally from or 1 , 0.23 m above any door,
window or gravity air inlet into any building. It must not terminate
less than 4 , 1.2 m horizontally from, and in no case above
or below, unless a 4 , 1.2 m horizontal distance is maintained,
from electric meters, gas meters, regulators and relief equipment
and not less than 7 , 2.3 m from any adjacent public walkway.
e boom of the vent terminal(s) shall be located at least 5 ,
1.5 m above the air intake terminal(s) unless there is a minimum
5 , 1.5 m horizontal separation between them. Avoid terminal
locations likely to be aected by winds, snowdris, people and pets.
Protect building materials and vegetation from degradation caused
by the ue gases.
To determine the appropriate power venter for the boiler/water
heater, see Table 6. Follow the power venter manufacturer’s
installation instructions.
Table 6 Power Venter Sizes
LCD Power Venter Max. Pipe Length
Model Model ft mm
400 HS-2 100 31.0
600 HS-2 67** 20.8
750 HS-3 100 31.0
1050-1200 HS-4 100 31.0
1480-2300 HS-5 100 31.0
**Choose HS-3 for 100 ft, 31 m, Max. Pipe Length
OUTDOOR VENTING
When installed outdoors the LCD must be ed with the factory
supplied outdoor vent hood and air intake hood, see Figure 8.
Multiple units must be spaced per Figure 9.
e boiler/water heater must be at least 10 , 3.1 m from any
door, window or gravity air inlet into any building and at least
3 , 0.9 m from any overhang unless local codes dictate dierently.
Avoidlocationswherewinddeectionoofadjacentwalls, buildings
orshrubbery mightcauseadowndra.eunit(s)shouldbelocated
at least 3 , 0.9 m from structures. Outdoor installations are not
recommended in areas where the danger of snow blockage exists.
Do not place the boiler/water heater in a location that
would subject it to runo from adjacent buildings or
damage may occur voiding the warranty!

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
15
Figure 8 Outdoor venting
Figure 9 Multiple outdoor units
COMMON VENT SYSTEMS
Ifanexistingboiler/waterheateris removedfroma common venting
system, the common venting system may then be too large for the
proper venting of the remaining appliances connected to it. At the
time of removal of an existing boiler/water heater, the following
steps shall be followed with each appliance remaining connected
to the common venting system placed in operation, while the other
appliances remaining connected to the common venting system
are not in operation.
Aumomentduretraitd'unechaudièreexistante,lesmesuressuivantes
doiventêtreprisespourchaqueappareiltoujoursraccordéausystème
d'évacuation commun et qui fonctionne alors que d'autres appareils
toujours raccordés au système d'évacuation ne fonction-nent pas:
système d'évacuation
a) Seal any unused openings in the common venting system.
Sceller toutes les ouvertures non utilisées du sys-tème d'évacuation.
b) Visuallyinspect theventingsystemforpropersizeandhorizontal
pitchanddetermineifthereis no blockageorrestriction,leakage,
corrosion and other deciencies which could cause an unsafe
condition.
Inspecter de façon visuelle le système d'évacu-ation pour
déterminerlagrosseretl'inclinaisonhorizontalequiconviennent
ets'assurerquelesystèmeestexemptd'obstruction,d'étranglement
de fruite, de corrosion et autres défaillances qui pourraient
présenter des risques.
c) Insofar as is practical, close all building doors and windows and
all doors between the space in which the appliances remaining
connected to the common venting system are located and other
spaces of the building. Turn on clothes dryers and any appliance
not connected to the common venting system. Turn on any
exhaust fans, such as range hoods and bathroom exhaust, so
they will operate at maximum speed. Do not operate a summer
exhaust fan for a boiler installation. Close replace dampers.
Danslamesuredu possible,fermertouteslesportesetlesfenêtres
du bâtiment et toutes les portes entre l'espace où les appareils
toujours raccordés du système d'évacuation sont installés et
les autres espaces du bâtiment. Mere en marche les sécheuses,
touslesappareilsnonraccordésausystèmed'évacuationcommun
ettouslesventilateursd'extractioncommeleshoesde cuisinère
etlesventilateurs des salles debain.S'assurerquecesventilateurs
fonctionnent à la vitesse maximale. Ne pas faire fonctionner les
ventilateurs d'été. Fermer les registres des cheminées.
d) Place in operation the appliance being inspected. Follow the
lightinginstructions.Adjustthermostatsoappliancewilloperate
continuously.
Mere l'appareil inspecté en marche. Suivre les instructions
d'allumage. Régler le thermostat de façon que l'appareil
fonctionne de façon continue.

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
16
e) Test for spillage at the dra hood relief opening aer 5 minutes
of main burner operation. Use the ame of a match or candle,
or smoke from a cigaree, cigar or pipe.
Faire fonctionner le brûleur principal pendant 5 min ensuite,
déterminer si le coupe-tirage déborde à l'ouverture de décharge.
Utiliser la amme d'une allunee ou d'une chandelle ou la
fumée d'une cigaree, d'un cigare ou d'une pipe.
f) Aer it has been determined that each appliance remaining
connected to the common venting system properly vents when
tested as outlined above, return doors, windows, exhaust fans,
replace dampers and any other gas-burning appliance to their
previous condition of use.
Une fois qu'il a été d éterminé, selon la métode indiquée ci-
dessus, que chaque appareil raccordé au système d'évacuation
est mis à l'air libre de façor adéquate. Remere les portes et les
fenêtres,lesventilateurs,lesregistresdecheminéeset lesappareils
au gaz à leur position originale.
g) Any improper operation of the common venting system should
be corrected so the installation conforms with the National Fuel
Gas Code, ANSI Z223.1/NFPA 54. When resizing any portion
of the common venting system, the common venting system
should be resized to approach the minimum size as determined
using the appropriate tables in Appendix F in the National Fuel
Gas Code, ANSI Z223.1/NFPA 54 and or CAN/CGA-B149
Installation Codes.
Tout mauvaisfonctionnementdusystémed'évacu-tioncommun
devrait étré corrigé de façor que l'installation soit conforme au
National Fue Gas Code, ANSI Z223.1/NFPA 54 et (ou) aux
codesd'installationCAN/CGA-B149.Silagrosseurd'unesection
du système d' évacuation doit étré modiée, le système devrait
étré modié pour respecter les valeurs minimales des tableaux
pertinents de l'appendice F du National Fuel Gas Code, ANSI
Z223.1/ NFPA 54 et (ou) des codes d'installation CAN/
CGA-B149.
GENERAL PIPING REQUIREMENTS
Improper piping of this boiler/water heater will void
themanufacturer's warrantyandcancauseboilerfailure
resulting in ooding and extensive property damage!
Excessive water hardness causing scaling in the copper
heat exchanger tubes is NOT covered under the
manufacturer’s warranty.Excessivepiinganderosion
of the internal surface of the copper heat exchanger
tubes is NOT covered under the manufacturer’s
warranty if the result of high water ow rates, see Table
7. Return water temperatures below 125°F, 52°C will
result in heat exchanger damage from excessive
condensationvoidingthemanufacturer’s warranty, see
Primary/Secondary Piping Figure 11.
Shut o valves and unions should be installed at the
inletand outlet connections of the boiler/water heater
to provide for isolation of the unit should servicing
be necessary.
Table 7 Temperature Rise Table
∆T = 15°F ∆T = 8.3°C
Model Flow Rate Pres. Drop Flow Rate Pres. Drop
Number GPM Ft L/s kPa
400 43.7 0.70 2.8 2.1
600 65.6 1.84 4.1 5.4
750 82.0 3.32 5.2 9.8
∆T = 20°F ∆T = 11.1°C
Model Flow Rate Pres. Drop Flow Rate Pres. Drop
Number GPM Ft L/s kPa
400 32.8 0.41 2.1 1.2
600 49.2 1.08 3.1 3.2
750 61.5 1.95 3.9 5.7
1050 86.1 5.16 5.4 15.2
1200 98.4* 8.14 6.2 24.0
1480 121.4* 7.94 7.7 23.4
∆T = 25°F ∆T = 13.9°C
Model Flow Rate Pres. Drop Flow Rate Pres. Drop
Number GPM Ft L/s kPa
400 26.2 0.27 1.7 0.8
600 39.4 0.71 2.5 2.1
750 49.2 1.29 3.1 3.8
1050 68.9 3.41 4.3 10.1
1200 78.7 5.38 5.0 15.9
1480 97.1 5.25 6.1 15.5
1650 108.2 7.02 6.8 20.7
∆T = 30°F ∆T = 16.7°C
Model Flow Rate Pres. Drop Flow Rate Pres. Drop
Number GPM Ft L/s kPa
600 32.8 0.51 2.1 1.5
750 41.0 0.92 2.6 2.7
1050 57.4 2.44 3.6 7.2
1200 65.6 3.84 4.1 11.3
1480 80.9 3.75 5.1 11.0
1650 90.2 5.01 5.7 14.8
1970 107.7 8.75 6.8 25.8
2300 125.7* 12.45 7.9 36.7
∆T = 35°F ∆T = 19.4°C
Model Flow Rate Pres. Drop Flow Rate Pres. Drop
Number GPM Ft L/s kPa
600 28.1 0.38 1.8 1.1
750 35.1 0.69 2.2 2.0
1050 49.2 1.83 3.1 5.4
1200 56.2 2.89 3.5 8.5
1480 69.3 2.82 4.4 8.3
1650 77.3 3.77 4.9 11.1
1970 92.3 6.58 5.8 19.4
2300 107.8 9.36 6.8 27.6
**Flow exceeds recommended maximum use a greater temperature
rise or consult manufacturer. Cupro-nickel heat exchanger should be
considered.

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
17
Freeze Protection
is boiler/water heater is CSA designed certied for outdoor
installation. Outdoor installations in areas where the danger of
freezingexistsarenotrecommendedunlessproperfreezeprotection
is provided. If the unit is to be installed in such an area the following
precautions MUST be observed:
1. A continuous ow of water through the boiler/water heater
MUST be maintained! e pump responsible for ow through
the boiler/water heater must run continuously!
2. A propylene glycol/water mixture suitable for the minimum
temperature that the unit will be exposed to must be used. e
pump must be capable of producing 15% more ow and
overcominga20%increaseinheadloss.Domesticwatersystems
must be isolated from the water heater by the use of a heat
exchanger or other approved method.
3. If the boiler/water heater must be shut o for any reason the
electric, gas and water supplies MUST be shut o and the unit
and its pump completely drained.
Improperoutdoorinstallationofthisboiler/waterheater
can cause boiler failure voiding the manufacturer's
warranty!
Relief Valve
Pipe the discharge of the pressure relief valve to prevent scalding in
the event of a discharge, see Figure 10. e discharge piping must be
sizedthesameasthepressurereliefvalveoutletandinstalledtoallow
complete drainage of both the relief valve and the discharge piping.
Figure 10 Relief valve piping
Never install any type of valve between the boiler/
waterheater and thereliefvalveoranexplosioncausing
extensive property damage, severe personal injury or
death may occur!
Flow Switch
eowswitchsuppliedwith the boiler/waterheatermustbe wired
to the terminal strip in the control panel to prevent the boiler from
ring unless there’s adequate water ow through the unit. e ow
switch must be installed in the supply piping adjacent to the boiler
outlet connection.
Failure to properly install the ow switch may result
in damage to the boiler/water heater heat exchanger
voiding the warranty!
HEATING SYSTEM PIPING
General Piping Requirements
All heating system piping must be installed by a qualied technician
in accordance with the latest revision of the ANSI/ASME Boiler
and Pressure Vessel Code, Section IV, and when required, ANSI/
ASME CSD-1, Standard for Controls and Safety Devices for
AutomaticallyFiredBoilers.Allapplicablelocalcodesandordinances
must also be followed. A minimum clearance of 1 in, 25 mm must
be maintained between heating system pipes and all combustible
construction.All heatingsystempipingmustbesupportedbysuitable
hangers not the boiler.
e thermal expansion of the system must be considered when
supporting the system. A minimum system pressure of 12 psig,
82.7 kPa must be maintained.
Heating Boiler Piping Connections
e supply and return piping should be sized to suit the system.
e supply and return connection sizes are listed in Table 8.
Table 8 Supply & return connection sizes
Model Size Supply Size Return Size
400 thru 2300 2 1/2” NPT 2 1/2” NPT

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
18
Pump Requirements (Primary/Secondary)
is low mass boiler requires a continuous minimum water ow
for proper operation. e boiler pump must be sized to overcome
the head loss of the boiler and the near piping in order to achieve
the required temperature rise. Table 7 provides the heat exchanger
pressure drop and temperature rise gures. e temperature rise
across the boiler must never exceed 35°F, 19.4°C.
A temperature rise outside of the range listed in Table
7indicates thattheowratethroughtheheatexchanger
is incorrect which will damage the heat exchanger
voiding the warranty! e maximum allowable
temperature rise is 35°F, 19.4°C.
e maximum allowable ow rate through a LCD
boiler with copper heat exchanger is 92 GPM,
5.8 L/s on 400-1200 models and 115 GPM,
7.3 L/s on 1480 to 2300 models. e cupro-nickel
heat exchanger allows for 100 GPM, 6.3 L/s on 400
to 1200 models and 125 GPM, 7.9 L/s on 1480 to
2300 models.
Low Water Cuto
If a boiler is installed above any radiation elements it must be ed
with a low water cuto device.
Refer to wiring diagram supplied with the boiler/water heater for
proper wiring connections.
Expansion Tank & Air Separator
An expansion tank or other means to control thermal expansion
must be installed in the heating system. An expansion tank must
be installed close to the boiler on the suction side of the pump. An
air scoop and automatic air vent must also be installed to eliminate
air trapped in the system.
Primary/Secondary Piping
Boilers connectedtoheatingsystemsusingzone valves, zonepumps,
orsystemsthathaveexcessiveowratesorreturnwatertemperatures
less than 125°F, 52°C must be isolated from these systems to protect
the boiler. Figure 11, shows a typical primary/secondary piping
system. A dedicated pump is used to maintain a constant water
ow through the boiler. is boiler pump is sized to overcome the
headlossoftheboilerandnear-boilerpipingsystemwhilesupplying
theowraterequiredtomaintainthedesiredtemperatureriseacross
the boiler heat exchanger. e system pump is sized to provide the
required ow to the heating system. e boiler piping connections
tothe heatingsystempipingmustbeamaximum10Xpipediameters
between centers to ensure zero pressure drop in the primary system.
Flow must be properly accounted for in the design of primary/
secondary systems. In order to prevent boiler(s) short cycling the
system ow must be equal to or higher than the boiler(s) local ow.
Low Return Water Temperatures
To prevent the problems associated with condensation of the
products of combustion due to low return water temperatures a
primary/secondary piping system with a bypass and bypass valve
must be installed, see Figure 12 and 12A. e bypass and bypass
valve must be sized the same as the secondary piping. A balancing
valve must also be installed in the supply side of the secondary
piping downstream of the bypass. e balancing valve should be
adjusted to divert some of the heated discharge water into the return
water until the required inlet water temperature is achieved. e
primaryandsecondarypumpsshouldbesizedtoprovidetherequired
ow through each system. e secondary piping connections to
theprimarysystempipingmustnotbemorethan10Xpipediameters
apart to ensure zero pressure drop in the primary system, see Figure
12 and 12A.
Multiple Boiler Systems
Systemsusingmultipleboilers can also beinstalledusingaprimary/
secondary manifold system, Figure 13.
Piping For Use With Cooling Units
e boiler, when used in connection with a refrigeration system,
must be installed so the chilled medium is piped in parallel with
the boiler. Appropriate valves must be used to prevent the chilled
water from entering the boiler.
When a boiler is connected to a heating coil that may be exposed
to refrigerated air from an air handling device, the piping system
must be equipped with ow-control valves or some other automatic
means of preventing gravity circulation of the boiler water during
the cooling cycle.

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
19
H-1 Rev 4
NOTES:
1. Boiler circuit piping must be sized
large enough to handle maximum
ow through unit.
2. Boiler pump sized to boiler design
ow requirements.
3. All boilers furnished with factory
mounted outlet water temperature
gauge.
4. Boiler pump purging required.
Use terminals supplied.
Notice: These drawings show suggested
piping conguration and valving.
Check with local codes and ordinances for
specic requirements.
Adjustment Procedure To Maintain Inlet Temperature
Above Dew Point
T1-Temp-Min=110°F For Atmospheric
T1-Temp-Min=125°F Sealed Combusion
1. Turn heater on and open valves A & B.
2. After steady-state operation, if T1 is less than Temp-Min
slowly close valve B until T1 climbs to desired operating
temperature above Temp-Min.
3. If T1 is greater than desired operating temperature, slowly
close valve A to adjust to lower desired temperature above
Temp-Min.
4. Check after system operating temperature has stabilized.
Make nal adjustments.
5. Follow same adjustment procedure for sealed combustion.
H-3 Rev 6
NOTES:
1. Boiler circuit piping must be sized large enough to handle
maximum ow through unit.
2. Boiler pump sized to boiler design ow requirements.
3. All boilers furnished with factory mounted outlet water
temperature gauge.
4. Boiler pump purging required. Use terminals supplied.
Notice: These drawings show suggested piping conguration and valving.
Check with local codes and ordinances for specic requirements.
Figure 11 Typical primary/secondary piping system
(See notes)
Figure 12 Low temperature piping
(See notes and adjustment procedures)
Operated Valve
Air Vent
Pressure Switch
Aquastat Union
Gas Pressure
Regulator
Automatic
Thermometer
Flow Switch
Pressure
Relief Valve
Reducing Valve
Self-Operated
Check Valve
Pressure
Va lve
Pump
Motorized Valve
Solenoid
Ball Valve
Bufferfly Valve
Angle Valve
Gate Valve
Globe Valve
Balance Valve
Backflow-
Prevention
Device
3-Way Valve
Expansion
Tank

LCD Series Finned Copper Tube Gas Boilers & Water Heaters – Boiler Manual
20
H-18 Rev 3
NOTES:
1. For pump selection consult factory.
2. Boiler pump sized to boiler and
thermostatic 3-way valve design ow
requirements.
3. Boiler circuit piping must be sized
large enough to handle maximum
ow through unit.
4. All boilers furnished with factory
mounted outlet water temperature
gauge.
5. Boiler pump purging required. Use
terminals supplied.
6. Valve is precalibrated for 140°F
return temperature.
Notice: These drawings show
suggested piping conguration and
valving. Check with local codes and
ordinances for specic requirements.
H-15 Rev 5
NOTES:
1. Boiler circuit piping must be sized large enough to handle
maximum ow through unit.
2. Boiler pump sized to boiler design ow requirements.
3. All boilers furnished with factory mounted outlet water
temperature gauge.
4. Boiler pump purging required. Use terminals supplied.
5. Secondary loop pipe diameter must be sized large enough to
handle maximum ow through all units.
Notice: These drawings show suggested piping conguration and valving.
Check with local codes and ordinances for specic requirements.
Figure 12A Low temperature piping with thermostatic valve
(See notes and adjustment procedures)
Figure 13 Multiple Boiler Piping
(See Notes)
Operated Valve
Air Vent
Pressure Switch
Aquastat Union
Gas Pressure
Regulator
Automatic
Thermometer
Flow Switch
Pressure
Relief Valve
Reducing Valve
Self-Operated
Check Valve
Pressure
Va lve
Pump
Motorized Valve
Solenoid
Ball Valve
Bufferfly Valve
Angle Valve
Gate Valve
Globe Valve
Balance Valve
Backflow-
Prevention
Device
3-Way Valve
Expansion
Tank