RBI DOMINATOR Series User manual

03/16 Copyright 2014 Mestek, Inc.
DOM-I0M-11
82-0262
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 (DB) &
Water Heaters (DW)

Finned copper tube gas boilers & water heaters – Boiler Manual
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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 10
OUTDOOR VENTING . . . . . . . . . . . . . . . . PAGE 11
COMMON VENT SYSTEMS . . . . . . . . . . . . . PAGE 12
GENERAL PIPING REQUIREMENTS . . . . . . . . PAGE 13
HEATING SYSTEM PIPING . . . . . . . . . . . . . PAGE 15
DOMESTIC WATER SUPPLY PIPING . . . . . . . . PAGE 18
GAS SUPPLY PIPING . . . . . . . . . . . . . . . . PAGE 21
ELECTRICAL WIRING . . . . . . . . . . . . . . . . PAGE 22
GENERAL OPERATION . . . . . . . . . . . . . . . PAGE 22
BOILER/WATER HEATER OPERATION . . . . . . . PAGE 23
OPERATING INSTRUCTIONS . . . . . . . . . . . . PAGE 27
CHECKING & ADJUSTMENTS. . . . . . . . . . . . PAGE 30
CONTROL DESCRIPTION . . . . . . . . . . . . . . PAGE 31
MAINTENANCE . . . . . . . . . . . . . . . . . . . PAGE 33
TROUBLE-SHOOTING . . . . . . . . . . . . . . . . PAGE 36
REPAIR PARTS . . . . . . . . . . . . . . . . . . . . PAGE 38
START UP FORM. . . . . . . . . . . . . . . . . . . PAGE 45
BEFORE YOU START
This manual covers the application, installation, operation and
maintenance of a Dominator Series finned copper heating boiler/
water heater/(pool heater-Canada only).
To obtain the safe, dependable, efficient operation and long life for
which this heating boiler/water heater was designed, these instruc-
tions must be read, understood and followed.
The Dominator 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 ANSI-Z21.56/CSA 4.7 Gas Fired Pool
Heaters (Canada only) and CAN 1-3.1 Industrial and Commercial
Gas Fired Packaged 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
Pressure Vessel 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.
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 applianc
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 immédiatement votre fournisseurde 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.
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.

Finned copper tube gas boilers & water heaters – Boiler Manual
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In Canada, the installation must be in accordance with the
requirementsofCSAB149.1 or .2, InstallationCodeforGasBurning
Appliances and Equipment.
If installed in the Commonwealth of Massachusetts, you MUST
FOLLOW the additional instructions contained 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
RBICustomerServiceDepartment,260NorthElmStreet,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.
RATINGS & CAPACITIES
Before undertaking the installation of the Dominator Series
boiler/water heater check the rating plate to ensure that the unit
has been sized properly for the job. The "Net Ratings" specify
the equivalent amount of direct copper 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.Otherimportantconsiderationsaretheavailabilityofanadequate
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
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
alocationthatwouldsubjectanyof thegas 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.
The Dominator may be installed directly on combus-
tible 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 NOTplacethis boiler/waterheaterin alocationthatwould
restricttheintroductionofcombustionair intotheunitorsubject
the air inlet to a negative pressure, see “GENERAL VENTING
GUIDELINES”.
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 13.
Units installed outdoors MUST be protected from ice
and snow accumulation or the unit may be damaged
voiding the warranty!
COMBUSTION AIR & VENTILATION
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
buildingcodes.Failuretoprovideadequatecombustion
air for this boiler/water heater can result in excessive
levels of carbon monoxide which can result in severe
personal injury or death!

Finned copper tube gas boilers & water heaters – Boiler Manual
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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!
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!
Iftheboiler/waterheateris operatedwhile thebuilding
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 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.
Never operate the Dominator 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 Dominator 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 Figure 1 - Vertical Venting with a Metal Chimney System and Inside Air
10 FT

Finned copper tube gas boilers & water heaters – Boiler Manual
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Figure 2 Vertical Venting using a Masonry Chimney and Inside Air
Figure 3 Horizontal Venting using Inside Air
1.5 FT 0.5 m
1/4 IN. PER F00T 20 mm/m
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 IN mm
12
24
305
610
Table 2

Finned copper tube gas boilers & water heaters – Boiler Manual
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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.
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.
Wherecommunicatingwith the outdoorsthroughhorizontalducts,
eachopeningshallhaveaminimumfreeareaof1 in2/2000 Btu/hr,
1100 mm2/kW of the totalinput ratingof allof the equipmentinthe
enclosure. When ducts are used, they must have the same cross-
sectionalareaasthefreeareaoftheopeningtowhich 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
(MBH)
1/4 in 6.4 mm
Wire Screen
75% Free Area
Metal Louvers
25% Free Area
Wooden Louvers
in2cm2in2cm2in2cm2
300 75 484 100 645 300 1935
400 100 645 133 860 400 2581
600 150 968 200 1290 600 3871
750 188 1210 250 1613 750 4839
900 225 1452 300 1935 900 5806
1050 263 1694 350 2258 1050 6774
1350 338 2177 450 2903 1350 8710
1500 375 2419 500 3226 1500 9677
1950 488 3145 650 4194 1950 12,581
2100 525 3387 700 4516 2100 13,548
Canadian installations must comply with CSA B149.1 when air
supply is providedbynaturalairflowfromtheoutdoorsfor 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
1in2per 14,000 Btuh(155 mm2per kW)in excess of 1million
Btuh.
Intake Air Option - General Guidelines
This configuration provides combustion air directly to the boiler/
waterheater's air intake usinga dedicatedpipe toobtaincombustion
air from the outdoors. Combustion air can be drawn in horizontally
throughthe sameoutsidewall whichterminatesthe exhaustgasesor
vertically through the roof, see Figures 4, 5, 6 & 7.
Common intake air systems may be used provided
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 intake air pipe. It must be
sized per Table 4. All joints in metal combustion air systems must be
securedusingcorrosionresistantfastenersandsealedusingasuitable
Siliconecaulk.ThecombustionairsystemMUSTbesupported
by the building structure not the boiler/water heater.
Table 4 Intake Air Pipe Sizing
Model Size Pipe Diameter
in mm
300 & 400 6152
600 & 750 8203
900 & 1050 10 254
1350 - 2100 12 305
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,
10.8m. The maximum equivalent length for the horizontal
combustion air pipe on installations that use the Horizontal Power
Vent option is 100 ft, 30.5 m. Each 90° elbow and the combustion
air terminal are equal to 10 linear ft, 3.0 m of pipe. If horizontal
runs exceed 5 ft, 1.5 m theymustbesupportedat3 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 mplustwo90°elbows.Alisted,nonrestrictivecombustionaircap
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.

Finned copper tube gas boilers & water heaters – Boiler Manual
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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.
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
0510 15 20
Horizontal Distance, X
Y,ecnatsiDlacitreV
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
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

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 ue gas recirculation.
Figure 7 Combination Air Intake and Venting, Masonary 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

Finned copper tube gas boilers & water heaters – Boiler Manual
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GENERAL VENTING GUIDELINES
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.
Common vent systems must be properly engineered
and sized to provide a negative draft of .01 to 0.08 in,
.25 to 2.0 mmWCattheflueoutlet!Commonpositive
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!
A single acting barometric damper must be installed
directly to the boiler/water heater flue outlet to ensure
properoperation.Thisdoesnotapplytooutdoorunits
or direct vent positive pressure units.
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, 3 and 7 for proper location. Be sure that
thedamper is mountedhorizontally (neververtically).
Carefully follow the instructions provided with the
barometricdamper.Checkwith local codes for specific
requirements.
In Canada, B149 (7.25 Draft Regulators) states the
damper shall be of double-acting type.
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.
VENT SYSTEM OPTIONS
The Dominator 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 the outdoors. A barometric
damper must be installed near the flue outlet when venting
vertically.SeeFigures6and7. Thisalsoappliestoanyfan-assisted
chimneys or vents.
2) Direct Vent, Positive Pressure, Category III - for horizontal
ventrunsequivalentto35 ft, 10.7 m orless.Astainlesssteelvent
systemcertifiedtoUL 1738 forinstallationsin the UnitedStates,
ULS636 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, 10.7 m (90°
elbowequals 10 equivalentft). A dedicatedwall mountedpower
venter and barometric damper must be used. The vent system
canbesinglewallgalvanizedsteelortypeBventpipe.Combustion
airisobtainedfromthespaceinwhichtheunitisinstalledorfrom
the outdoors.
A barometric damper must be installed when the horizontal run
is longer than 35 equivalent ft. (90° elbow = 10 equivalent ft). If
this is the case, a power venter must also be used.
If horizontal run is less than 35 equivalent ft, 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.
All venting, combusiton air material supplied by
installer. All venting material must be approved for
the application. Consult the vent manufacturer’s
productliterature.

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VERTICAL/CHIMNEY VENTING
The Dominator 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 .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.
If an appliance using any type of a mechanical draft
system operating under positivepressure 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 toensurethatthe chimney isclean,properlyconstructed,
linedandsized.Exteriormasonrychimneysshouldnotbeusedunless
properly lined to prevent condensation and draft problems. Table 5
lists the equivalent breeching and flue sizes required for the boiler/
waterheater.Whenmorethanoneapplianceisconnectedtothesame
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 (Category I)
Model Size Pipe Diameter
in mm
300 - 400 6152
600 7178
750 8 203
900 - 1050 10 254
1350 12 305
1500 - 2100 14 356
Note: These sizes are based on 20 ft, 6.1 m 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.
Neverinstallaventpipehavingadiameterdifferentthan
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.
Failuretomaintainminimumclearancesbetweenvent
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 system must not
exceed 35 ft, 10.7 m. The Intake Air Option instructions under the
“COMBUSTION AIR & VENTILATION” section must be
followed! The vent system flue pipe diameter must be sized per Table
5a.
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, ULS636 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, 10.7 m for each. Each 90° elbow and
the vent and intake air 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
fromone another.Forbestresults,horizontalventsystemsshould be
as straight as possible.
Theventsystemmustbeboth gastightandwatertight.Allseamsand
joints in metal pipes must be joined and sealed in accordance with
the vent system manufacturer’s instructions.
Whenhorizontalventrunsexceed5 ft,1.5 m theymustbesupported
at 3 ft, 0.9 m intervals with overheadhangers.Theventsystemmust
be pitched down, toward the vent terminal, 1/4 in/ft, 21 mm/m. If
anypartof a singlewallmetalventsystempassesthroughanunheated
space it must be insulated with insulation rated for 400°F, 204°C.

Finned copper tube gas boilers & water heaters – Boiler Manual
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Table 5a Category III Vent Pipe Diameter
Horizontal vent systems shall terminate at least 4 ft, 1.2 m below,
4 ft, 1.2 m horizontally from or 1 ft, 0.3 m above any door, window
or gravity air inlet into any building. It must not terminate less than
4 ft, 1.2 m horizontally from, and in no case above or below, unless
a 4 ft, 1.2 m horizontal distance is maintained, from electric meters,
gas meters, regulators and relief equipment and not less than 7 ft,
2.1 m from any adjacent public walkway. The bottom of the vent
terminal(s) shall be located at least 5 ft, 1.5 m above the air intake
terminal(s) unless there is a minimum 5 ft, 1.5 m horizontal
separation between them. Avoid terminal locations likely to be
affected by winds, snow drifts, people and pets. Protect building
materials and vegetation from degradation caused by the flue gases.
Vertical Direct Vent Systems - See Figure 6
The maximum length for the vertical vent and combustion air
pipes is 35 ft, 10.7 m plus two 90° elbows for each. 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. Structual
penetrations must be made using approved fire-stops.
A listed, nonrestrictive vent cap must be used. The top of a vertical
vent system must extend at least 51/2ft,1.7 m above the roof
surface that it passes through, 4 ft, 1.2 m above the intake air cap,
see Figure 6.
HORIZONTALVENT, NEGATIVE PRESSURE,
CATEGORY I
In this configuration a wall-mounted power venter must be used
to pull the flue products horizontally from the unit and vent them
to the outdoors, see Figures 3, 4 & 5. The air for combustion is taken
from the space in which the unit is installed, or from the outdoors.
The applicable instructions under the “COMBUSTION AIR &
VENTILATION” section must be followed!
To maximize the performace 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 short
and straight as possible.
Whenhorizontalventrunsexceed5 ft,1.5 m theymustbesupported
at 3 ft, 0.9 m intervals with overheadhangers.Theventsystemmust
be pitched down, toward the vent terminal, 1/4 in/ft, 20 mm/m. If
anypartof a singlewallmetalventsystempassesthroughanunheated
space it must be insulated with insulation rated for 400°F, 204°C.
Horizontal vent systems shall terminate at least 4 ft, 1.2 m below,
4 ft, 1.2 m horizontally from or 1 ft, 0.3 m above any door, window
or gravity air inlet into any building. It must not terminate less than
4 ft, 1.2 m horizontally from, and in no case above or below, unless
a 4 ft, 1.2 m horizontal distance is maintained, from electric meters,
gas meters, regulators and relief equipment and not less than 7 ft,
2.1 m from any adjacent public walkway. The bottom of the vent
terminal(s) shall be located at least 5 ft, 1.5 m above the air intake
terminal(s) unless there is a minimum 5 ft, 1.5 m, horizontal
separation between them. Avoid terminal locations likely to be
affected by winds, snowdrifts, people and pets. Protect building
materials and vegatation from degradation caused by the flue gases.
To determine the appropriate power venter for the boiler/water
heater, see Table 6, Power Venter Sizes. Follow the power venter
manufacturer’s installation instructions.
Table 6 Power Venter Sizes
Dominator Power Venter Max. Pipe Length
Model Model ft mm
300 HS-1 30* 9
400 HS-2 100 31
600 HS-2 67** 21
750-900 HS-3 100 31
1050-1350 HS-4 100 31
1500-2100 HS-5 100 31
*Choose HS-2 100 ft, 31 m, Max. Pipe Length.
**Choose HS-3 for 100 ft, 31 m, Max. Pipe Length.
OUTDOOR VENTING
When installed outdoors the Dominator must be fitted with the
factory supplied outdoor vent hood and air intake hood, see Figure
8. Multiple units must be spaced per Figure 9.
The boiler/water heater must be at least 10 ft, 3.0 m from any door,
window or gravity air inlet into any building and at least 3 ft, 0.9 m
from any overhang unless local codes dictate differently.
Avoidlocationswherewind deflectionoff of adjacentwalls,buildings
or shrubbery might cause a down draft. The unit(s) should be
located at least 3 ft, 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!
Model Size Pipe Diameter
in mm
300 - 400 6152
600 - 750 8203
900 - 1050 10 254
1350 12 305
1500 - 2100 14 356
Note: Diameters based on a maximum 35 equivalent feet.

Finned copper tube gas boilers & water heaters – Boiler Manual
12
Figure 8 Outdoor Venting
Figure 9 Multiple outdoor Units
COMMON VENT SYSTEMS
Ifanexistingboiler/waterheater is removedfromacommon 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 système d'évacuation.
b) Visuallyinspectthe ventingsystemforpropersizeandhorizontal
pitch and determine there is no blockage or restriction, 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.
Danslamesuredupossible,fermertoutesles portesetles fenêtres
du bâtiment et toutes les portes entre l'espace où les appareils
toujours raccordés du système d'évacuation sont installés et les
autresespacesdu bâtiment.Mereenmarchelessécheuses,tous
les appareils non raccordés au système d'évacuation commun et
tous les ventilateurs d'extraction comme les hoes de cuisinère
etlesventilateursdessalles de bain.S'assurerque ces ventilateurs
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. Adjustthermostatsoappliancewill operate
continuously.
Mere l'appareil inspecté en marche. Suivre les instructions
d'allumage.Réglerlethermostatdefaçonquel'appareilfonctionne
de façon continue.

Finned copper tube gas boilers & water heaters – Boiler Manual
13
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.
Utiliserlaammed'unealluneeou d'unechandelleoulafumée
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.
Unefoisqu'ila étédéterminé,selonlamétodeindiquéecidessus,
que chaque appareil raccordé au système d'évacuation est mis à
l'air libredefaçoradéquate.Remerelesportesetlesfenêtres,les
ventilateurs, les registres de cheminées et les appareils 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
codes d'installation CSA-B149. Si la grosseur d'une section
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 warranty andcancauseboilerfailure
resulting in ooding and extensive property damage!
Excessive water hardness causing scaling in the copper
heat exchanger tubes is NOT covered under the
manufacturer'swarranty.Excessivepiingand erosion
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 connectionsof the boiler/waterheater
to provide for isolation of the unit should servicing
be necessary.
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 respon-sible for ow through
the boiler/water heater must run continuously!
2. An ethylene 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 a minimum of 15% more
ow and overcoming a 20% increase in head loss. Domestic
water systems 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!

Finned copper tube gas boilers & water heaters – Boiler Manual
14
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
sized the same as the pressure relief valve outlet and installed to allow
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/
waterheaterandthereliefvalveoranexplosioncausing
extensive property damage, severe personal injury or
death may occur!
Flow Switch
eowswitchsuppliedwiththe 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!
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
300 33.4 0.21 2.1 0.6
400 45.4 0.49 2.9 1.5
600 68.1 1.30 4.3 3.8
750 85.1 2.35 5.4 6.9
900 102.1 3.84 6.4 11.3
1050 119.1* 6.23 7.5 18.4
∆T = 20°F ∆T = 11.1°C
Model Flow Rate Pres. Drop Flow Rate Pres. Drop
Number GPM Ft L/s kPa
300 25.1 0.12 1.6 0.4
400 34.0 0.29 2.1 0.9
600 51.1 0.76 3.2 2.3
750 63.8 1.38 4.0 4.1
900 76.6 2.25 4.8 6.6
1050 89.4 3.66 5.6 10.8
1350 114.9* 7.17 7.2 21.1
∆T = 25°F ∆T = 13.9°C
Model Flow Rate Pres. Drop Flow Rate Pres. Drop
Number GPM Ft L/s kPa
300 20.0 0.08 1.3 0.2
400 27.2 0.19 1.7 0.6
600 40.8 0.51 2.6 1.5
750 51.0 0.91 3.2 2.7
900 61.3 1.49 3.9 4.4
1050 71.5 2.42 4.5 7.1
1350 91.9 4.74 5.8 14.0
1500 102.1 6.31 6.4 18.6
∆T = 30°F ∆T = 16.7°C
Model Flow Rate Pres. Drop Flow Rate Pres. Drop
Number GPM Ft L/s kPa
600 34.0 0.36 2.1 1.1
750 42.6 0.65 2.7 1.9
900 51.1 1.06 3.2 3.1
1050 59.6 1.73 3.8 5.1
1350 76.6 3.38 4.8 10.0
1500 85.1 4.50 5.4 13.3
1950 110.6* 9.20 7.0 27.1
2100 119.1* 11.27 7.5 33.2
∆T = 35°F ∆T = 19.4°C
Model Flow Rate Pres. Drop Flow Rate Pres. Drop
Number GPM Ft L/s kPa
750 36.5 0.49 2.3 1.4
900 43.8 0.80 2.8 2.4
1050 51.1 1.30 3.2 3.8
1350 65.6 2.54 4.1 7.5
1500 72.9 3.38 4.6 10.0
1950 94.8 6.91 6.0 20.4
2100 102.1 8.47 6.4 25.0
**Flow exceeds recommended maximum use a greater temperature
rise or consult manufacturer. Cupro-nickel heat exchanger should be
considered.

Finned copper tube gas boilers & water heaters – Boiler Manual
15
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.Allheatingsystempipingmustbe supportedbysuitable
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
300 thru 2100 2 1/2” NPT 2 1/2” NPT
Pump Requirements
is low mass boiler requires a continuous minimum water ow
for proper operation. e system pump must be sized to overcome
the head loss of the boiler and the heating system 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 7 indicates that the ow rate through the
heat exchanger 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 Dominator
boiler with copper heat exchanger is 105 GPM, 6.6 L/s.
e cupro-nickel heat exchanger allows for 120 GPM,
7.6 L/s.
An adjustable pump delay is available as a feature of the staging
controller.e pump delayestablisheswaterowthroughtheboiler
and heating system before the appliance starts. Consult the staging
controller manual for further details.
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 connected to heating systems using zone valves, zone pumps,
orsystemsthathaveexcessiveow ratesor returnwatertemperatures
less than 125°F, 52°C must be isolated from these systems to protect
the boiler.
Variable Water Flows
Figure 11 shows a typical primary/secondary piping system. A
dedicated pump is used to maintain a constant water ow through
the boiler. is secondary pump is sized to overcome the head loss
of the boiler and secondary piping system while supplying the ow
rate required to maintain the desired temperature rise across the
boiler. e primary pump is sized to provide the required ow to
theheatingsystem.esecondarypipingconnectionstotheprimary
system piping must not be more than 6 pipe diameters apart to
ensure zero pressure drop in the primary system, see Figure 11.
Low Return Water Temperatures
Topreventtheproblemsassociatedwithcondensationoftheproducts
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
alsobeinstalledinthesupplysideofthesecondarypipingdownstream
of the bypass. e balancing valve should be adjusted to divert some
ofthe heateddischargewaterintothe returnwateruntil therequired
inlet water temperature is achieved. e primary and secondary
pumps should be sized to provide the required ow through each
system. e secondary piping connections to the primary system
piping must not be more than 6 pipe diameters apart to ensure zero
pressure drop in the primary system, see Figure 12 and 12A.
Multiple Boiler Systems
Systemsusingmultiple boilers can also beinstalled usinga primary/
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.

Finned copper tube gas boilers & water heaters – Boiler Manual
16
Figure 11 Typical Primary/Secondary Piping
(See Notes)
Figure 12 Low Temperature Piping with Thermostatic Valve
(See Notes)
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 pip-
ing conguration and valving.
Check with local codes and ordinances for
specic requirements.
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.
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

Finned copper tube gas boilers & water heaters – Boiler Manual
17
Figure 12A Low Temperature Piping
(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
Expansion
Tank
H-15 Rev 5
NOTES:
1. Boiler circuit piping must be 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.
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.

Finned copper tube gas boilers & water heaters – Boiler Manual
18
DOMESTIC WATER SUPPLY PIPING
Proper control seings must be used to prevent water
suppliedfordomesticusefromexceeding 130°F,54°C
or a scald injury will occur! When higher water
temperatures are required for appliances such as a
dishwasher, a mixing valve or some other tempering
means must be installed. Households with small
children may require water temperatures less than
120°F,49°C.Localcodesmustbe complied with!
General Piping Requirements
Ensure that the water heater is equipped with bronze headers. Piping
andcomponentsconnectedtothewaterheatermustbe suitableforuse
with potable water. e water heater must not be connected to any
heating system piping or components previously used with a non-
potablewaterheatingappliance.Notoxic chemicals,suchasthoseused
for boiler treatment, are to be introduced into the potable water used
forspaceheating.Ifahotwaterstorage tankisusedinthe systemitmust
beequipped withatemperatureandpressure reliefvalvethatcomplies
with ANSI Z21.22 or CAN-4.4 and CAN-4.6.
e storage tank must be located as close to the water
heater as possible to prevent excessive head loss which
will reduce ow.
Water Chemistry
e required temperature rise across the water heater is based on
water having a hardness between 8 and 18 grains per gallon with a
level of dissolved solids not exceeding 350 ppm. Water having a
hardness less than 8 grains can cause excessive errosion of the heat
exchanger. Waterthathasahardnessgreaterthan18 grainspergallon
and/or a level of dissolved solids exceeding 350 ppm will require a
recalculation of the pump size and temperature rise.
Acupro-nickelheatexchangermayalsoberequired.emanufacturer
should be consulted when these water conditions are encountered.
See Table 8A.
e maximum allowable ow rate through a Dominator
water heater with copper heat exchanger is 105 GPM,
6.6 L/s. e cupro-nickel heat exchanger allows for
120 GPM, 7.6 L/s, see Table 8B.
RBI water heaters are designed to run scale free. Due to the extreme
variables of water conditions world wide it is necessary to consider
pH values and water hardness in relationship to scaling. It is crucial
to consider these two variables when making heat exchanger and
pump selection. If local water conditions are extreme follow the
guidelines in the HeatExchangerSelectionTable(Table8A)andthe
PumpingPerformanceTable(Table 8B). Scalefreeoperationcan be
achieved by using water with a hardness between 8 and 18 and by
maintaining the pH between 5 and 9. Follow the conditions listed
underNORMALinthetable.Insomeareasofthecountryadditional
precautions must be observed due to unusual characteristics of the
local water supply. Call the nearest RBI representative for details.
To properlysizethepumpa grainhardnessandpHtestmustbetaken
at the installation site before the order is placed. Proper pump sizing
will improve heater performance and help ensure heater longevity.
Expansion Tank
An expansion tank or other means to control thermal expansion
must be installed in the water heating system if back ow preven-
tion devices are installed.
Cold Water Supply
ecoldwatersupplymustbepipedtothewaterheater'soutletpiping
between the water heater and the hot water storage tank. is will
prevent untempered water from entering the water heater, see the
Temperature Rise Control section below. A typical water heating
system is shown in Figure 14 and 15.
Pump Requirements
is low-mass water heater requires a continuous mini-mum water
owforproperoperation.elowwaterowswitchprovided forthis
unit will shut down the water heater if ow falls below the required
minimum level. Table 8B provides the heat exchanger pressure drop
chart and temperature rise table. e temperature rise across
the water heater must never exceed 35°F, 19°C.
Temperature Rise Control
Waterreturnedtothewaterheaterinlet mustnotbelessthan125°F,
52°C or excessive condensation of the products of combustion will
damage the water heater voiding the warranty. e method outlined
below can be employed to prevent this condition from occurring.
A balancing valve should be installed on the outlet side of the water
heater for purposes of adjusting the ow rate through the heat
exchanger. ermometers are installed on both the inlet and outlet
of the water heater for determining the temperature rise through the
unit. epropervelocitythroughthewaterheatermustbe maintained
in accordance with Table 8B for ecient operation and long life. If
the temperature rise through the water heater is lower than
recommended the water velocity is too high. Premature erosion of
the heat exchanger will occur. Conversely, if the temperature rise is
higherthanrecommended in Table 8B the owrateis toolow. Scaling
and soening of the heat exchanger will occur.
Thermostatic Mixing Valve -
Water Above 140°F, 60°C
Water can be stored at temperatures above 140°F, 60°C provided
that a thermostatically controlled mixing valve is used to temper
the hot water to an acceptable temperature before it's supplied for
domestic use.
e mixing valve MUST be set to prevent a scald injury from
occurring, see the caution against scalding above.
Storage of water for domestic use above 140°F, 60°C will provide
anincreasedquantityoftemperedwaterandhelp preventthegrowth
of water born bacteria.

Finned copper tube gas boilers & water heaters – Boiler Manual
19
Table 8A Dominator Heat Exchanger Selection Graph
Table 8B Dominator Pumping Performance Requirement

Finned copper tube gas boilers & water heaters – Boiler Manual
20
Figure 14 Typical Water Heating Piping (DW Models only)
(See Notes)
Figure 15 Multiple Water Heating Piping (DW Models only)
(See Notes)
D-4 Rev 6
D-1 Rev 6
NOTES:
1. Optional cold water make up and recirculation line location.
2. When using intermittent pump and pump delay, locate remote aquastat
well in lower 1/3 of tank. Install aquastat with heat sensing compound.
3. Thermal expansion tank may be required, check local codes.
4. When using optional factory mounted pump, max pipe length 30’ total, 6-90° elbows, full pipe size.
5. CAUTION: MEASURE WATER HARDNESS AND pH AT JOB SITE.
The pH and water hardness must be measured before selecting heat exchanger and pump.
Consult the Heat Exchanger Graph and Pumping Performance Table before making selection.
6. Common piping must be sized for maximum combined heater ow.
7. Hot water tanks should be equipped with a combination temperature & pressure relief valve.
8. MA Code requires an 1/8”hole in check valve to compensate for thermal expansion.
Notice: These drawings show suggested piping conguration and valving.
Check with local codes and ordinances for specic requirements.
SELF BALANCING DOUBLE REVERSE
RETURN MAKE-UP & SUPPLY, CIRCULATION
1
2
3
2
7
7
6
68
4
4
Attention:
Not all RBI stock storage tanks
incorporate this tapping: See Note 1.
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
Valve
Pump
Motorized Valv
e
Solenoid
Ball Valve
Bufferfly Valve
Angle Valve
Valve
Globe Valve
Balance Valve
Vacuum
Relief Valve
Temperature &
Pressure
Relief Valve
Drain Valve
(Typ.)
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
Valve
Pump
Motorized Valve
Solenoid
Ball Valve
Bufferfly Valve
Angle Valve
Valve
Globe Valve
Balance Valve
Vacuum
Relief Valve
Temperatu
re &
Pressure
Relief Valve
Drain Valve
(Typ.)
2
3
1
4
7
8
Attention:
Not all RBI stock storage tanks
incorporate this tapping: See Note 1.