Lochinvar COPPER-FIN CW 645 User manual

DESIGNER’S GUIDE COPPER-FIN®WAT ER HEAT ER
495,000 – 2,065,000 Btu/hr

Dear Specifier/Project Manager,
At Lochinvar, we have long recognized the importance of innovation to any
product or service. Those who enter into business must also accept the challenge
of meeting constantly changing needs.
The designer’s guide you are now holding has been designed to make it more
convenient for you to select the perfect Lochinvar water heater for your projects
and provide correct specifications for your teams.
All information has been organized and presented in a succinct, easy-to-use
manner, so you can use and share information confidently and with minimal
effort.
However, it is important to remember that this guide is not intended to replace our
installation manual. Installers should still refer to our installation manual for
specific installation instructions.
We hope this manual will make your work easier and more productive. As always,
we greatly appreciate your input on additional improvements for the future.
Thanks once again for specifying the Lochinvar family of quality standard
and custom-built water heaters and boilers.
Sincerely,
Lochinvar Corporation
Nashville, TN • 615-889-8900 • Fax: [phone]

Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900 1
Codes . . . . . . . . . . . . . . . . . . . . . . . . .2
Combustion & Ventilation Air . . . . . . . . .5
Contaminants . . . . . . . . . . . . . . . . . . . .6
Determining Total “Free Area” . . . . . . . .5
Electrical Requirements . . . . . . . . . . . .14
Gas Supply . . . . . . . . . . . . . . . . . . . .10
General Venting . . . . . . . . . . . . . . . . . .6
Location of Unit . . . . . . . . . . . . . . . . . .2
Low Water Temperature Delivery . . . . .12
Outdoor Use . . . . . . . . . . . . . . . . . . . .3
Outdoor Installation . . . . . . . . . . . . . . .9
Pump Operation . . . . . . . . . . . . . . . . .12
Relief Valve . . . . . . . . . . . . . . . . . . . .14
Venting Options . . . . . . . . . . . . . . . . . .8
Water Connections . . . . . . . . . . . . . . .11
Water Treatment . . . . . . . . . . . . . . . . .13
Water Velocity Control . . . . . . . . . . . .12
Figures & Tables Index
FIG. 1 Models CW 495-2066
Requirements For Installation
Over Combustible Floor . . . . .3
FIG. 2 Water Heater Equipment
& Control Orientation . . . . . . .4
FIG. 3-6 Combustion &
Ventilation Air . . . . . . . . . . .5,6
FIG. 7 Barometric Damper
Installation . . . . . . . . . . . . . . .8
FIG. 8 Multiple Unit Barometric
Damper Installation . . . . . . . .9
FIG. 9 Outdoor Venting . . . . . . . . . . .9
TABLE A. Clearances From
Combustible . . . . . . . . . . . . .3
TABLE B. Flue Sizes . . . . . . . . . . . . . . . .8
TABLE C. Outdoor Kits . . . . . . . . . . . .10
TABLE D. Gas Supply Pipe Sizing . . . .11
TABLE E. Inlet Gas Pressure . . . . . . . . .11
TABLE F. Required Temperature Rise . . .12
TABLE G. Required Pump Performance .13
TABLE H. Common Water
Manifold Sizes . . . . . . . . . . .14
TABLE I. Amp Draw . . . . . . . . . . . . . .14
Appendix A -
Water Heater Piping Diagrams
Single Heater – Single Tank . . . . . . . . .A1
Single Heater – Two Tanks . . . . . . . . .A2
Two Temperature Installation
Single Heater – Single Tank . . . . . . . . .A3
Two Heaters – Single Tank . . . . . . . . .A4
Two Heaters – Two Tanks . . . . . . . . . .A5
Multi-Stack Frame
Two Heaters – Single Tank . . . . . . . . .A6
Table of Contents

CODES
The equipment shall be installed in
accordance with those installation
regulations in effect in the local area where
the installation is to be made. These shall
be carefully followed in all cases. Authorities
having jurisdiction shall be consulted before
installations are made.
In the absence of such requirements, the
installation shall conform to the latest edition of
the National Fuel Gas Code, ANSI Z223.1.
Where required by the authority having
jurisdiction, the installation must conform to
American Society of Mechanical Engineers
Safety Code for Controls and Safety Devices
for Automatically Fired Boilers, ASME CSD-1.
Where required by the authority having
jurisdiction, the installation must comply with
the Canadian Association Code, CAN/CGA-
B149.1 and/or B149.2 and/or local codes.
LOCATION OF UNIT
Locate the unit so that if water connections
should leak, water damage will not occur.
When such locations cannot be avoided, it
is recommended that a suitable drain pan,
adequately drained, be installed under the
unit. The pan must not restrict combustion
air flow.
2Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900
1.
Lochinvar
oWater Velocity
(See page 12 for Required Degree
Rise chart.)
oFactory Supplied Pump
Capacity
(See page 12 for Pump Operation.)
oManifold Pipe Size
When using more than one heater
(See page 14 for Common Water
Manifold Size for Multiple Water
Heater Installation Table.)
oStorage Tank Circulating
Tappings
(See page 14 for Manifold Pipe
Size.)
oPlacement of Cold Water
Inlet and Building Return
(See Appendix A for Water Heater
Piping Diagrams.)
o Water Hardness
(See page 13 for Water Treatment
Information.)
In designing
a water heater system,
pay special attention to:
Under no circumstances is the
manufacturer to be held responsible
for water damage in connection
with this unit or any of its
components.

The indoor units must be installed so that
the ignition system components are
protected from water (dripping, spraying,
rain, etc.) during appliance operation and
service (circulator replacement, control
replacement, etc.).
The appliance must be installed
on a level, non-combustible floor.
Concrete over wood is not considered a
non-combustible floor. Maintain required
clearances from combustible surfaces.
For installation on a combustible
floor only when installed on
special base: Units installed over a
combustible floor must use the Special
Combustible Floor Base. The unit must be
centered on the base as shown in FIG. 1.
• Provide a base of hollow clay tile or
concrete blocks from 8”to 12”thick
and extending 24”beyond the sides.
• The blocks must be placed in line so that
the holes line up horizontally to provide a
clear passage through the blocks.
• This procedure should also be
followed if electrical conduit or
radiant heat distribution piping
runs through the floor and
beneath the appliance.
• Ensure that combustible floor base
meets local fire code requirements.
Outdoor models require the installation of
an optional vent cap. Instructions for
placement of the vent cap are included in
the venting section.
Outdoor models must not be installed
directly on the ground. The outdoor unit
must be installed on a concrete brick,
block or other non-combustible pad.
SPECIAL LOCATION: OUTDOOR USE
Outdoor models have additional location
and clearance requirements. These
requirements must be adhered to carefully,
since wind, rain, snow and cold cannot be
controlled in outdoor applications. See
Outdoor Installation, on page 9.
2.
4.
3.
Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900 3
(FIG. 1) 495-2066 REQUIREMENTS FOR
INSTALLATION OVER COMBUSTIBLE FLOOR
5.
(TABLE A) – CLEARANCES FROM
COMBUSTIBLE CONSTRUCTION
CLEARANCES CW495-2066
Right Side 3"
Rear 3"
Left Side 3"
(24"for Service)
Front ALCOVE*
(30"for Service)
Top 3"
Flue 1"**
* Alcove is a closet without a door.
** Consult local codes and/or vent
material manufacturer.

4Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900
Lochinvar
(FIG. 2) WATER HEATER EQUIPMENT AND CONTROL ORIENTATION.
RIGHT SIDE
FLUE PRODUCTS VENT
TERMINAL
STRIP
HOT WATER
OUTLET
COLD WATER
INLET
BURNER INSPECTION PORT
FRONT
GAS
CONNECTION
HOT WATER
OUTLET
COLD WATER
INLET BURNER
INSPECTION PORT
FRONT
AIR
INLET
FRESH AIR
INLET
RIGHT SIDE FLUE PRODUCTS VENT
BACK
DRAIN LEFT SIDE
BACK
120V ELECTRICAL
CONNECTION
OPERATOR
ON/OFF SWITCH
OPERATOR
TERMINAL STRIP
ON/OFF SWITCH
LEFT SIDE
DRAIN
RELIEF VALVE
TAPPING
INLET GAS
CONNECTION
CW495-745
CW986-2066

Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900 5
COMBUSTION & VENTILATION AIR
Provisions for combustion and ventilation air
must be in accordance with Section 5.3,
Air for Combustion and Ventilation, of the
latest edition of the National Fuel Gas
Code, ANSI Z223.1; in Canada, the latest
edition of CGA Standard B149 Installation
Code for Gas Burning Appliances and
Equipment; or applicable provisions of the
local building codes.
The equipment room must be provided with
properly sized openings to assure adequate
combustion air and proper ventilation when
the unit is installed with conventional venting
or sidewall venting.
If air is taken directly from outside
the building with no duct, provide two
permanent openings:
A. Combustion air opening with a
minimum free area of one square inch per
4000 Btu input (5.5 cm2per kW).
This opening must be located within 12”
(30 cm) of the bottom of the enclosure.
B. Ventilation air opening with a minimum
free area of one square inch per 4000
Btu input (5.5 cm2per kW). This opening
must be located within 12”(30 cm) of the
top of the enclosure.
If combustion and ventilation air is
taken from the outdoors using a
duct to deliver the air to the
mechanical room, each of the two
openings should be sized based on a
minimum free area of one square inch
per 2000 Btu input (11 cm2per kW).
If air is taken from another interior
space, each of the two openings
specified above should have a net free
area of one square inch for each 1000
(FIG. 3) COMBUSTION AIR DIRECT FROM OUTSIDE
(FIG. 4) COMBUSTION AIR THROUGH DUCTWORK
(FIG. 5) COMBUSTION AIR FROM AN
INTERIOR SPACE
CAUTION: Under no circumstances should
the equipment room be under a negative
pressure when atmospheric combustion
equipment is installed in the room.
1.
2.
3.
EXAMPLE OF
SIZING FOR
COMBUSTION
& VENTILATION
AIR OPENINGS
(WATER HEATER
WITH 2,065,000
Btu/hr INPUT):
When combustion and
ventilated air is taken
from directly outside the
building (FIG. 4), divide
the total BTU’s by 4,000.
This yields 516.25 sq.in.
of “Free Area” without
restriction.
(2,065,000 ÷ 4000 =
516.25 sq.in.)
Since the air opening is
50% closed due to
screens and louvers, the
total opening must be
multiplied by 2.
(516.25 sq. in. x 2 =
1,032 sq.in.)
This project requires one
Ventilation Air Opening
with net “Area” of
1,032 square inches with
louver dimensions of 30”
x 35”and one
Combustion Air Opening
with net “Area” of
1,032 square inches with
louver dimensions
of 30”x 35”.

6Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900
Btu (22 cm2per kW) of input, but not less
than 100 square inches (645 cm2).
If a single combustion air opening
is provided to bring combustion
air in directly from the outdoors,
the opening must be sized based on a
minimum free area of one square inch
per 3000 Btu input (7 cm2per kW). This
opening must be located within 12”
(30 cm) of the top of the enclosure.
CONTAMINANTS
Combustion air drawn from an interior
or exterior space must be free of any
chemical fumes which could be corrosive to
the water heater.
Burning chemical fumes results in the
formation of corrosive acids which attack the
water heater, cause improper combustion
and premature failure of the water heater
and vent.
These fumes are often present in areas
where refrigerants, salts, and solvents are
used. Therefore, be aware of swimming
pool equipment, water softening, and
cooling system placement.
VENTING
General
Copper-Fin II Water Heaters are classified as
Category I appliances when tested to the
latest ANSI Standard. This classification
requires all conventionally vented
combustion products to be vented using
Category I listed vent pipe.
Additionally, it is recommended that this vent
material be double wall construction or
insulated in the field. A Category I
appliance operates with a non-positive static
vent pressure and with flue loss greater than
17 percent.
Vent installations for connection to gas vents
or chimneys must be in accordance with
Part 7, “Venting of Equipment,” of the latest
edition of the National Fuel Gas Code, ANSI
Z223.1, or applicable provisions of the local
building codes.
The connection from the appliance vent
to the stack must be as direct as possible
and sized correctly. The horizontal breeching
of a vent must have at least 1/4”rise per
linear foot. The horizontal portions should
also be supported for the design and weight
of the material employed to maintain
clearances, prevent physical damage and
separation of joints.
The connection from the appliance vent
to the stack or vent termination outside the
building must be made with listed
Lochinvar
4.
(FIG. 6) COMBUSTION AIR FROM OUTSIDE,
SINGLE OPENING
CAUTION!
EXHAUST FANS:
Any fan or equipment
which exhausts air
from the equipment
room may deplete the
combustion air supply
and/or cause a down
draft in the venting
system. If a fan is used
to supply combustion
air to the equipment
room, it must by sized
such to make sure that
it does not cause drafts
which could lead to
nuisance operational
problems with the
water heater.

Category I double wall vent (or equivalent)
connectors and sized according to vent
sizing tables (FAN column) in the latest
edition of the National Fuel Gas Code.
The Category I vent and accessories, such as
firestop spacers, thimbles, caps, etc., must
be installed in accordance with the vent
manufacturer’s listing. The vent connector and
firestop must provide correct spacing to
combustible surfaces and seal to the vent
connector on the upper and lower sides of
each floor or ceiling through which the vent
connector passes.
Any improper operation of the common
venting system in an existing building should
be corrected when new equipment is
installed, so the installation conforms to the
latest edition of the National Fuel Gas Code,
ANSI Z223.1.
When resizing any portion of the common
venting system, it should be resized to
approach the minimum size as determined
using the appropriate tables in the National
Fuel Gas Code.
The weight of the venting system must not
rest on the water heater. The venting system
must be adequately supported in
compliance with local codes and other
applicable codes.
Vent Terminations
The vent terminal should be vertical and
exhaust outside the building at least 2 feet
(0.6 m) above the highest point of the roof
when within a 10 foot (3.05 m) radius.
Additionally, vertical terminations must be a
minimum of 3 feet (0.9 m) above the roof
line, and when less than 10 feet (3.05 m)
from a parapet wall must be a minimum of
2 feet (0.61 m) higher than the parapet wall.
Vent caps should have a minimum clearance
of 4 feet (1.2 m) horizontally from, and in no
case above or below [unless a 4 feet (1.2 m)
horizontal distance is maintained], electric
meters, gas meters, regulators and relief
equipment.
Maintain a distance of at least 3 feet
(0.9 m) above any forced air inlet within
10 feet (3.05 m) and a distance of at
least 4 feet (1.2 m) below, 4 feet (1.2 m)
horizontally from, or 1 foot (30 cm) above
any door, window or gravity air inlet.
Do not terminate the vent in a window well,
stairwell, alcove, courtyard or other recessed
area. The vent can not terminate
below grade. The bottom of the vent
terminal shall be located at least 12 inches
(30 cm) above grade and clear of snow,
ice, leaves or other debris.
The distance of the vent terminal from
adjacent public walkways, adjacent
buildings, windows, and building openings
Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900 7

8Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900
must be consistent with the National Fuel
Gas Code Z223.1 or in Canada, the latest
edition of CGA Standard B149 Installation
Code for Gas Burning Appliances and
Equipment.
VENTING OPTIONS
Conventional Venting
A conventional venting system utilizes
the natural buoyancy of the heated flue
products to generate a negative draft. This
draft forces flue products to rise vertically
through a rooftop flue termination. The vent
connection is made directly to the top of the
unit and combustion air supplied from the
mechanical room. Properly sizing vent
material and the use of a barometric
damper (when required) will lead to proper
vent operation.
The minimum flue pipe diameters for
Copper-Fin models, utilizing negative draft
venting are as follows:
Size vent material using the “FAN” category
of vent sizing tables in the latest edition of
the National Fuel Gas Code. “FAN” applies
to fan-assisted combustion appliances in
Category I.
Barometric Dampers
A barometric damper is required when draft
exceeds 0.08 inches of negative water
column. When installed and adjusted
properly, a barometric damper will maintain
draft between 0.02 and 0.08 inches of
negative water column ensuring proper
operation.
Multiple unit installations with combined
venting also require barometric dampers to
regulate draft at each unit. Again, the
negative draft must be within the range of
0.02 to 0.08 inches of negative water
column to ensure proper operation.
Lochinvar
(FIG. 7) BAROMETRIC DAMPER INSTALLATION
(TABLE B)
FLUE SIZES AND COMBUSTION AIR PIPE SIZES
MODEL FLUE SIZE
NUMBER
CW 495 6"
CW 645 8"
CW 745 8"
CW 986 10"
CW 1256 12"
CW 1436 12"
CW 1796 14"
CW 2066 14"
NOTE:
A vent system should
never be sized based
only on the vent
connection diameter of
the appliance. For proper
vent design and sizing,
please consult the
National Fuel Gas Code
(ANSI Z223.1).

For this type of installation, it is best to use a
draft control for each water heater located
on the riser between the vent outlet and the
breeching - Location “A”. When this riser is
too short to permit the installation of a draft
control, locate a separate control for each
water heater on the main breeching as
illustrated in Location “B”. If, because of
general crowding or other reasons, neither
of these locations are possible, use a single
large control in the breeching between the
water heater nearest the chimney and the
chimney, as shown in Location “C”.
All draft readings are made while unit is in
stable operation (approximately 5 minutes
running time).
Masonry Chimney
A masonry chimney must be properly sized
for the installation of a high efficiency gas
fired appliance. Exterior masonry chimneys,
with one or more sides exposed to cold
outdoor temperatures, are more likely to
have venting problems. The temperature of
the flue products from a high efficiency
appliance may not be able to sufficiently
heat the masonry structure of the chimney to
generate proper draft. This will result in
condensing of flue products, damage of the
masonry flue/tile, insufficient draft and
possible spillage of flue products into an
occupied living space.
Carefully inspect all chimney systems during
the project design phase. If there is any doubt
about the sizing or condition of a masonry
chimney, it is prudent to reline the chimney
with a properly sized and approved chimney
liner system. Metallic liner systems (Type “B”
doublewall or flexible or rigid metallic liners)
are recommended. Consult with local code
officials to determine code requirements or the
advisability of using or relining a masonry
chimney.
OUTDOOR INSTALLATION
Units are self venting and can be used
outdoors when installed with the optional
Outdoor Cap. This cap mounts directly to
the top of the water heater and covers the
flue outlet and combustion air inlet openings
on the jacket. No additional vent piping is
required. Maintain a minimum clearance of
3”(76 mm) to combustible surfaces and a
minimum of 3”(76 mm) clearance to the air
inlet.
Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900 9
NOTE:
Common venting
systems may be too
large when an existing
unit is removed. Be
careful to resize any
common venting system
when new appliances
are installed or existing
appliances are replaced.
NOTE:
Flue gases will form a
white plume in winter.
Plume could obstruct
window view. Flue gas
condensate can freeze
on exterior surfaces or
on the vent cap. Flue
gas condensate can
cause discoloration of
exterior building
surfaces. Adjacent brick
or masonry surfaces
should be protected with
a rust resistant sheet
metal plate.
(FIG. 8) MULTIPLE UNIT BAROMETRIC
DAMPER INSTALLATION
(FIG. 9) OUTDOOR VENTING
NOTE:
Venting of a high
efficiency appliance into
a cold or oversized
masonry chimney can
result in operational and
safety problems.

10 Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900
An outdoor unit should not be located so
that high winds can deflect off of adjacent
walls, buildings or shrubbery causing
recirculation. Recirculation of flue products
may cause operational problems, bad
combustion or damage to controls. The unit
should be located at least 3 feet (0.91m)
from any wall or vertical surface to prevent
adverse wind conditions from affecting
performance.
Multiple unit outdoor installations require
48”(1.22 m) clearance between each vent
cap. The outdoor cap must be located 4
feet (1.22 m) below and 4 feet (1.22 m)
horizontally from any window, door,
walkway or gravity air intake.
The combustion air inlet of the outdoor cap
must be located at least one foot (0.30 m)
above grade and above normal snow
levels. The water heater must be at least 10
feet (3.05 m) away from any forced air inlet
and at least 3 feet (0.91 m) outside any
overhang.
Do not install in locations where rain from
building runoff drains will spill onto the
water heater.
Lochinvar must furnish an outdoor vent kit
in accordance with CSA international
requirements. Each kit includes the flue
outlet/combustion air inlet, assembly, gasket
and pump cover.
Freeze Protection-
Outdoor Installation
A snow screen should be installed to prevent
snow and ice accumulation around the
appliance or its venting system.
If for any reason the unit is to be shut off:
(a.) Shut off water supply.
(b.) Drain unit completely.
(c.) Drain pump and piping.
If freeze protection is not provided for the
system, a low ambient temperature alarm or
automatic drain system is recommended.
GAS SUPPLY
The gas pressure regulator supplied is for
low pressure service. If upstream pressure
exceeds 6 oz. (10.5" water column), an
intermediate gas pressure regulator, of the
lock up type, must be installed.
The gas line should be a separate line
direct from meter, unless the existing
gas line is of sufficient capacity. Verify
pipe size with your gas supplier.
A trap (drip leg) should be provided in the
inlet gas connection to the water heater.
Lochinvar
(TABLE C) - OUTDOOR VENT KIT PART NUMBERS
MODEL
NUMBER PART NUMBER
CW 495 ODK3023
CW 645 ODK3024
CW 745 ODK3024
CW 986 ODK3046
CW 1256 ODK3047
CW 1436 ODK3047
CW 1796 ODK3048
CW 2066 ODK3048
1.
2.
3.

A manual main gas shutoff valve is
provided outside the jacket, upstream
of the main gas valve.
In Canada, derated10% from 2,000 -
4,500 ft., over 4,500 ft. derate must be
in accordance with local authorities.
Consult factory for installations at
higher elevations.
High Altitude Applications
Atmospheric pressure decreases as the
height above sea level increases. At any
altitude above sea level, a cubic foot will
contain less gas than a cubic foot at sea
level. Thus, the heating value of a cubic foot
of fuel gas will decrease as height above
sea level increases.
Specific gravity of a gas with respect to sea
level also decreases with altitude. These
changes in heating value and specific
gravity tend to offset each other.
However, as elevation above sea level is
increased, there is less oxygen per cubic foot
of air. Therefore, heat input rate should be
reduced in an appliance above 2000 feet.
Ratings should be reduced at the rate of 4
percent for each 1000 feet above sea level.
WATER CONNECTIONS
Inlet and Outlet Water Connections
For ease of service, install unions on inlet and
outlet of the water heater.
The connection on the unit marked “Inlet”
should be used for return water from the
storage tank. The connection on the header
marked “Outlet” should be connected to the
inlet of the storage tank. (See Appendix A for
Water Heater Piping Diagrams).
Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900 11
4.
5.
(TABLE D) – GAS SUPPLY PIPE SIZING
Length of Pipe In Straight Feet
Nominal Iron
Pipe Size, Inches 10 20 30 40 50 60 70 80 90 100 125 150 175 200
369 256 205 174 155 141 128 121 113 106 95 86 79 74
697 477 384 328 292 267 256 246 210 200 179 164 149 138
1,400 974 789 677 595 543 502 472 441 410 369 333 308 287
2,150 1,500 1,210 1,020 923 830 769 707 666 636 564 513 472 441
4,100 2,820 2,260 1,950 1,720 1,560 1,440 1,330 1,250 1,180 1,100 974 871 820
6,460 4,460 3,610 3,100 2,720 2,460 2,310 2,100 2,000 1,900 1,700 1,540 1,400 1,300
11,200 7,900 6,400 5,400 4,870 4,410 4,000 3,800 3,540 3,300 3,000 2,720 2,500 2,340
23,500 16,100 13,100 11,100 10,000 9,000 8,300 7,690 7,380 6,870 6,150 5,640 5,130 4,720
Maximum capacity of pipe in thousands of BTU’s per hour for gas pressures of 14” Inches Water Column (0.5 PSIG) or less and a total
system pressure drop of 0.05 Inch Water Column (Based on NAT GAS, 1025 BTU’s per Cubic Foot of Gas and 0.60 Specific Gravity).
11 /4
3
/4
11 /2
1
21
/2
31 /2
3
2
(TABLE E) – INLET GAS PRESSURE
MODELS NAT. GAS LP GAS
CW 495-745
Minimum Allowable 4”8”
Maximum Allowable 10.5”13”
CW 986-2066
Minimum Allowable 4.5”8”
Maximum Allowable 10.5”13”
EXAMPLE OF
HIGH ALTITUDE
APPLICATIONS
For example, if a unit’s
input is 100,000 Btu/hr
at sea level, the rated
input at 4000 feet of
elevation can be calculated
by derating input 4% per
1000 feet above sea
level.
[Btu/hr Input]
[1.00 - (Elevation/ 1000
ft. x 0.04)] = Btu/hr
Input at specified
elevation.
[100,000][1.00 - (4000
ft. /1000 ft. x 0.04)]
= Btu/hr Input 4000’
elevation.
[100,000][0.84] =
84,000 Btu/hr Input at
4000 ft. elevation.

LOW WATER
TEMPERATURE DELIVERY
A number of water heating applications may
require delivered water temperature in a
system below 140°F. Systems such as nursing
homes and hospitals would be examples of
this type of system.
A water heating system that will be operated
at less than 140°F must use a mixing valve
on the outlet side of the storage tank in order
to ensure that the products of combustion do
not condense inside the combustion chamber
of the water heater.
The mixing valve allows the water heater to
operate above 140°F to protect from
condensation, while still allowing a delivery of
colder water to the system fixtures. Also
inherent in this design is the protection of
occupants from water containing bacteria
such as Legionella. Legionella can be
significantly reduced in the water storage
vessel by heating the water to a minimum of
140°F. (See Appendix A for piping details.)
WATER VELOCITY CONTROL
IMPORTANT
To ensure proper velocity through the heat
exchanger, it is necessary to regulate the
temperature rise across the heat exchanger
from inlet to outlet. (This must be done on
initial installation and periodically rechecked).
With the correct temperature rise across the
heat exchanger (See TABLE F), you may be
assured of the proper velocity in the tubes
and long life and economical operation from
the water heater.
PUMP OPERATION
The water heater MUST be connected
with a properly sized and installed,
intermittent operating, all bronze pump
that circulates water between heater
and storage tank.
The pump is sized to heater input and
water hardness. Should water hardness
exceed 25 grains/350 TDS, consult
factory for pump sizing.
The pump chart (TABLE H) is based on the
following fittings:
6-90° elbows 2 ball valves
2 unions 1 cold water supply tee
Lochinvar
12 Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900
(TABLE F) - REQUIRED TEMPERATURE RISE
MODEL NUMBER TEMPERATURE RISE °F
CW 495 15
CW 645 19
CW 745 22
CW 986 19
CW 1256 24
CW 1436 27
CW 1796 34
CW 2066 39
1.
2.

Due to pump capacity the following
specifications cannot be exceeded
when using the standard pump:
• Not more than 45 feet of straight pipe.
• For every elbow and tee in excess of
those shown above, DEDUCT 5 FEET
from maximum allowable straight pipe
in heater-to-tank circulating loop.
WATER TREATMENT
In hard water areas, water treatment
should be used to reduce introduction
of minerals into the system. Minerals
in the water can collect in the heat
exchanger tubes causing noise and
inefficient operation. Excessive build-up
of materials in the heat exchanger can
cause a non-warrantable failure.
Acceptable Water Quality Levels
Maximum Water Hardness = 25 Grains
Minimum Water Hardness = 5 Grains
Maximum Total Dissolved Solids = 350 PPM
Range of Acceptable pH = 7.2 to 7.8
Standard production Lochinvar water heaters
are designed to operate free of impurity
build-up in the heat exchanger when
properly installed and operated under the
specified water quality conditions.
For installation in areas outside these
parameters, please consult the factory.
Water Flow Switch
Due to the low water content (between 1
and 6 gallons) of the copper finned tube
heat exchanger, a flow switch is factory
installed as a low water cutoff device on
models CW495 thru CW2066.
The flow switch is installed in the outlet
piping from the water heater and wired in
series with the ignition system safety controls.
In most localities, a flow switch is acceptable
as a low water cutoff device on water
heaters requiring forced circulation. It is
prudent to verify acceptance with the local
code official.
If the local water quality levels are slightly
higher than recommended, it may be
possible to use a copper-nickel heat
exchanger. With copper-nickel being a
harder alloy, flow rates can be safely
increased to keep the greater water
hardness and TDS in suspension. The flow
rate can be increased up to 25% faster than
the flow rates listed above.
Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900 13
NOTE:
Care should be taken to
measure temperature
rise and maintain proper
water velocity in the
heat exchanger.
NOTE:
A larger pump must be
utilized in situations
when the distance
between the water
and tank exceed
those specified.
NOTE:
If a pressure reducing
valve or check valve is
in the system a properly
sized expansion tank
may be required.
(TABLE G) – REQUIRED PUMP
PERFORMANCE FOR WATER HARDNESS
OF 5 TO 25 GRAINS
MODEL GPM FT. HD AMP DRAW HORSE VOLTAGE/
POWER PHASE
CW 495-745 60 10 5.8 1/4 120/1
CW 986-2066 90 15 7.4 1/2 120/1

14 Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900
Relief Valve
This water heater is supplied with
temperature and pressure relief valve(s)
sized in accordance with ASME Boiler and
Pressure Vessel Code, Section IV “Heating
Boilers.”
ELECTRICAL REQUIREMENTS
(North America)
The appliance is wired for 120 volts.
All wiring between the unit and field
installed devices shall be made of type
T wire [63°F (35°C) rise].
The pump must be wired to run
continuously when unit is firing.
It is recommended that the water heater
and pump be wired on separate circuits
with properly sized breakers.
Lochinvar
NOTE:
When the unit is
installed in Canada, it
must conform to the
CAE C22.1, Canadian
Electrical Code, Part 1,
and/or local Electrical
Codes.
NOTE:
Incorrect piping
of the cold water
supply to the
system will result
in condensate formation
on the heat exchanger
and operational
problems. Higher water
temperatures reduce
condensate formation.
Refer to drawings in
Appendix A.
(TABLE H) – COMMON WATER MANIFOLD
SIZE FOR MULTIPLE WATER HEATER
INSTALLATION
Pipe sizing chart provides minimum pipe size for
common manifold piping to ensure adequate flow.
NUMBER OF COMMON MANIFOLD SIZE
UNITS (Min.)
CW 495 thru 745
12”
23”
33
1/2”
44”
55”
65”
CW 986 thru 2066
12
1/2”
24”
34”
45”
56”
66”
2.
1.
3.
(TABLE I) – AMP DRAW DATA
MODEL FAN(S) CONTROLS PUMP TOTAL AMPS
NUMBER w/PUMP
CW 495-745 3.4 4.6 5.8 13.8
CW 986-1256 3.4 4.6 7.4 15.4
CW 1436-2066 3.8 4.6 7.4 15.8

Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900 A1
WATER HEATER PIPING DIAGRAMS
APPENDIX A
PIPING DIAGRAM SINGLE HEATER - SINGLE TANK
BUILDING HOT
WATER SUPPLY
RELIEF
VALVE
LOCK-TEMP
STORAGE
TANK
DRAIN
FULL PORT
BALL VALVE SYSTEM PUMP SYSTEM RELIEF VALVE TEE ELBOW UNION EXPANSION TANK CHECK VALVE THERMOMETER
COLD WATER SUPPLY
BUILDING RETURN
INLET
OUTLET
LOCHINVAR
WATER HEATER
LEGEND
LIT0133
This illustration is for concept only and should not be used for any actual installation without engineering
or technical advice from a licensed engineer. All necessary equipment may not be illustrated.

A2 Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900
PIPING DIAGRAM SINGLE HEATER - TWO TANK
FULL PORT
BALL VALVE SYSTEM PUMP SYSTEM RELIEF VALVE TEE ELBOW UNION EXPANSION TANK CHECK VALVE THERMOMETER
LEGEND
BUILDING HOT
WATER SUPPLY
LOCHINVAR WATER
HEATER
COLD WATER
SUPPLY
BUILDING
RETURN
LOCK-TEMP
STORAGE TANK
RELIEF VALVE
DRAIN
OUTLET
INLET
LIT0135
This illustration is for concept only and should not be used for any actual installation without engineering
or technical advice from a licensed engineer. All necessary equipment may not be illustrated.

FULL PORT
BALL VALVE SYSTEM PUMP SYSTEM RELIEF VALVE TEE ELBOW UNION EXPANSION TANK CHECK VALVE THERMOMETER
LEGEND
PIPING DIAGRAM TWO TEMPERATURE INSTALLATION - SINGLE HEATER-SINGLE TANK
HIGH TEMPERATURE
BUILDING RETURN
LOW TEMPERATURE
BUILDING RETURN
DRAIN
INLET
RELIEF
VALVE
OUTLET
COLD WATER
SUPPLY
140
0
F HOT WATER
SUPPLY
180
0
F HOT WATER
SUPPLY
LOCK-TEMP
STORAGE TANK LOCHINVAR
WATER HEATER
MIXING
VALVE
CHECK VALVE
LIT0136
This illustration is for concept only and should not be used for any actual installation without engineering
or technical advice from a licensed engineer. All necessary equipment may not be illustrated.
Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900 A3

A4 Lochinvar DESIGNER’S GUIDE COPPER-FIN WATER HEATER 615-889-8900
PIPING DIAGRAM TWO HEATERS-SINGLE TANK
FULL PORT
BALL VALVE SYSTEM PUMP
SYSTEM
RELIEF VALVE TEE ELBOW UNION EXPANSION
TANK CHECK VALVE
THERMOMETER REDUCING
TEE REDUCING TEE
LEGEND
LOCHINVAR
WATER HEATERS
INLET
INLET
OUTLET
RELIEF
VALVE
OUTLET
BUILDING RETURN
DRAIN
LOCK-TEMP
STORAGE TANK
COLD WATER
SUPPLY
BUILDING
HOT WATER
SUPPLY
LIT0138
This illustration is for concept only and should not be used for any actual installation without engineering
or technical advice from a licensed engineer. All necessary equipment may not be illustrated.
COMMON WATER MANIFOLD SIZE FOR MULTIPLE WATER HEATER INSTALLATION
Pipe sizing chart provides minimum pipe size for common manifold piping to ensure adequate flow.
NUMBER OF COMMON MANIFOLD SIZE NUMBER OF COMMON MANIFOLD SIZE
UNITS (Min.) UNITS (Min.)
CW 495-745 CW 986-2066
1 2” 1 2-1/2”
23”2 4”
3 3-1/2” 3 4”
44”4 5”
55”5 6”
65”6 6”
Gray shaded area represents common manifold piping.