Lochinvar EW 150 User manual

DESIGNER’S GUIDE EFFICIENCY+®WATER HEATER
150,000 – 300,000 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 our 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
Lochinvar Corporation • 615-889-8900 / Fax: [phone]

Lochinvar DESIGNER’S GUIDE EFFICIENCY+ WATER HEATER 615-889-8900 1
Clearances . . . . . . . . . . . . . . . . . . . . . .3
Codes . . . . . . . . . . . . . . . . . . . . . . . . .2
Combustion & Ventilation Air . . . . . . . . .3
Contaminants . . . . . . . . . . . . . . . . . . . .5
Conventional Venting . . . . . . . . . . . . . .8
Direct Venting . . . . . . . . . . . . . . . . . . .11
Electrical Requirements . . . . . . . . . . . .17
Gas Supply . . . . . . . . . . . . . . . . . . . .15
General Venting . . . . . . . . . . . . . . . . .13
Location of Unit . . . . . . . . . . . . . . . . . .2
Low Water Temperature Delivery . . . . .16
Outdoor Installation . . . . . . . . . . . . . .14
Outdoor Use . . . . . . . . . . . . . . . . . . . .3
Pump Operation . . . . . . . . . . . . . . . . .16
Relief Valve . . . . . . . . . . . . . . . . . . . .17
Water Connections . . . . . . . . . . . . . . .16
Water Treatment . . . . . . . . . . . . . . . . .17
Water Velocity Control . . . . . . . . . . . .15
Figures & Tables Index
FIG. 1 Water Heater Equipment
and Control Orientation . . . . .3
FIG. 2-5 Combustion & Ventilation Air .4,5
FIG. 6 Barometric Damper
Installation . . . . . . . . . . . . . . .8
FIG. 7 Multiple Unit Barometric
Damper Installation . . . . . . . . .8
FIG. 8 E+ DirectAire Vent With
Sidewall Air Inlet . . . . . . . . .10
FIG. 9 E+ DirectAire Vent With
Rooftop Air Inlet . . . . . . . . . .10
FIG. 10 Horizontal Direct Vent . . . . . .12
FIG. 11 Horizontal Direct Vent Caps .12
FIG. 12 Multiple Sidewall
Direct Vent Caps . . . . . . . . .13
FIG. 13 Vertical Direct Vent . . . . . . . .13
FIG. 14 Outdoor Venting . . . . . . . . .14
TABLE A. Clearances From
Combustible Construction . . . .3
TABLE B. Conventional Venting,
Vent Connection Size . . . . . . .8
TABLE C. E+ DirectAire Vent Kits . . . . .10
TABLE D. Horizontal Direct Vent Kits . . .12
TABLE E. Vertical Direct Vent,
Flue And Air Inlet Sizes . . . . .13
TABLE F. Outdoor Vent Kits . . . . . . . . .14
TABLE G. Gas Supply Pipe Sizing . . . .15
TABLE H. Inlet Gas Pressure . . . . . . . . .15
TABLE I. Required Temperature Rise . .16
TABLE J. Required Pump Performance 17
TABLE K. Common Water
Manifold Size . . . . . . . . . . .17
TABLE L. Amp Draw Data . . . . . . . . . .17
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 w/Water Heaters
and Storage Tank . . . . . . . . . . . . . . . .A6
Table of Contents

2Lochinvar DESIGNER’S GUIDE EFFICIENCY+ WATER HEATER 615-889-8900
Lochinvar
CODES
The equipment MUST be installed in
accordance with those installation regulations
in effect in the local area where the installation
is to be made. These MUST be carefully
followed in all cases. Authorities having
jurisdiction MUST be consulted before
installations are made. In the absence of such
requirements, the installation MUST 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, No. (CSD-1). All boilers conform
to the latest edition of the ASME Boiler and
Pressure Vessel Code, Section IV. Where
required by the authority having jurisdiction,
the installation MUST comply with the
Canadian Gas 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 airflow. Under no circumstances
is the manufacturer to be held responsible
for water damage in connection with this
unit or any of its components.
•Water Velocity – Flow Rate
(See page 16 for Required
Temperature Degree Rise chart.)
•Factory Supplied
Pump Capacity
(See page 16 for Pump Operation.)
• Manifold Pipe Size
When using more than one heater
(See page 17 for Common Water
Manifold Size for Multiple Water
Heater Installation table.)
•Storage Tank Circulating
Tappings
(See page 17 for Manifold Pipe
Size.)
• Placement of Cold Water Inlet
and Building Return
(See Appendix A for Water Heater
Piping Diagrams.)
• Water Hardness
(See page 16 for Water Treatment
Information.)
In designing a hot
water heater system,
pay special attention to:
1.

The indoor unit 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.)
Units located in a residential garage
MUST be installed so that burners and
ignition devices have a minimum clearance
of 18" (46 cm) above the floor. The units
shall be located or protected to prevent
physical damage by a moving vehicle.
The appliance MUST be installed on a
level floor. A combustible wood floor may
be used without additional bases or special
floor buildup. Maintain required clearances
from combustible surfaces.
The appliance MUST NOT be installed on
carpet or other combustible material other
than wood flooring.
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, in the
venting section on page 15.
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; or in Canada, the latest edition of
CGA Standard B149 Installation Code for
Gas Burning Appliances and Equipment; or
provisions of the local building codes.
3.
5.
4.
Lochinvar DESIGNER’S GUIDE EFFICIENCY+ WATER HEATER 615-889-8900 3
(TABLE A)
CLEARANCES FROM COMBUSTIBLE CONSTRUCTION
RIGHT SIDE 1”
REAR 1”
LEFT SIDE 6”(24”suggested for service)
FRONT 3”(24”suggested for service)
Suitable for closet installation
TOP 3”
*Allow sufficient space for servicing pipe connections, pump and other
auxiliary equipment, as well as the appliance.
(FIG. 1) WATER HEATER EQUIPMENT &
CONTROL ORIENTATION
FLUE PRODUCTS
VENT
HOT WATER
OUTLET
BURNER INSPECTION
PORT
GAS
CONNECTION
COLD WATER
INLET
BACK
TERMINAL STRIP
(INSIDE)
FRONT
DRAIN
120V ELECTRICAL
CONNECTION
AIR INLET
EW 150-300
LEFT SIDE
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 be sized to make
sure that it does not
cause drafts which
could lead to nuisance
operational problems
with the water heater.
2.

4Lochinvar DESIGNER’S GUIDE EFFICIENCY+ WATER HEATER 615-889-8900
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/hr 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/hr 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/hr
(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 per
1000 Btu/hr (22 cm2per kW) input, but
not less than 100 square inches (645 cm2).
Lochinvar
2.
(FIG. 4) COMBUSTION AIR FROM AN
INTERIOR SPACE
(FIG. 3) COMBUSTION AIR THROUGH
DUCTWORK
3.
(FIG. 2) COMBUSTION AIR DIRECT FROM
OUTSIDE
1.
EXAMPLE OF
SIZING FOR
COMBUSTION
& VENTILATION
AIR OPENINGS
(WATER HEATER
WITH 300,000
BTU/HR INPUT):
When combustion and
ventilated air is taken
from directly outside the
building (FIG. 2), divide
the total BTU’s by 4,000.
This yields 75 sq.in. of
“Free Area” without
restriction.
(300,000/4,000 =
75 sq.in.)
Since the air opening is
50% closed due to
screens and louvers, the
total opening MUST be
multiplied by 2.
(75 sq.in. x 2 =
150 sq.in.)
This project requires one
Ventilation Air Opening
of 150 square inches
with louver dimensions
of 12” x 15”= 180
sq.in. and one
Combustion Air Opening
of 150 square inches
with louver dimensions
of 12” x 15”.

Lochinvar DESIGNER’S GUIDE EFFICIENCY+ WATER HEATER 615-889-8900 5
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/hr (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 and 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
Vent installations for connection to gas vents or
chimneys should 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, using the proper vent table.
The horizontal breaching of a vent MUST
have at least 1/4”rise per linear foot.
The horizontal portions shall 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 Type “B” double
wall vent (or equivalent) for conventional vent
applications.
When utilizing direct vent capabilities,
connections MUST be made with AL29-4C
stainless steel (or equivalent) vent material.
Material should be sized according to vent sizing tables
(FAN column) in the latest edition of the National Fuel
Gas Code.
4.
CAUTION! Under no circumstances should the
equipment room be under a negative pressure
when atmospheric combustion equipment is
installed in the room.
(FIG. 5) COMBUSTION AIR FROM A
SINGLE OPENING
NOTE:
The weight of the
venting system MUST
NOT rest on the water
heater. It should be
properly supported.
WARNING
Vent connectors serving
gas appliances, which
operate under a
negative vent pressure,
shall not be connected
into any portion of
mechanical draft
systems operating under
positive vent pressure.

6Lochinvar DESIGNER’S GUIDE EFFICIENCY+ WATER HEATER 615-889-8900
The vent materials and accessories, such as
firestop spacers, thimbles, caps, etc., MUST
be installed in accordance with the
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 the existing building should
be corrected when new equipment is installed,
so that the installation conforms to the latest
edition of the National Fuel Gas Code, ANSI
Z223.1.
The efficiency of this appliance allows its
products of combustion to be vented through a
smaller vent pipe when compared to units of
the same Btu/hr capacity. For this reason,
resizing common venting systems is
recommended for proper operation.
When resizing any portion of the common
venting system, it should be resized to
approach the minimum size as determined
using the appropriate tables (FAN column) in
the National Fuel Gas Code.
Failure to resize a common venting system
could lead to the formation of condensate and
premature deterioration of the vent material.
Flue gas condensate can freeze on exterior
walls or on the vent cap. Frozen condensate
on the vent cap can result in a blocked flue
condition. Some discoloration to exterior
building surfaces can be expected. Adjacent
brick or masonry surfaces should be protected
with a rust resistant sheet
metal plate.
Vent connectors serving appliances vented by
natural draft shall not be connected to
any portion of a mechanical draft system
operating under positive pressure.
Connection to a positive pressure stack may
cause flue products to be discharged into the
living space causing serious health injury.
Locate units as close as possible to a chimney
or gas vent.
VENT TERMINATIONS
When locating the vent cap, consider the
effects of snow, leaf dropping, etc., to insure
that no blockage occurs.
The distance of the vent terminal from adjacent
public walkways, adjacent buildings, windows
that open and building openings MUST
comply with the latest edition of the National
Fuel Gas Code, ANSI Z223.1.
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
within a 10 foot (3.05 m) radius of the
termination.
Lochinvar
IMPORTANT!
The vent cap should
have a minimum
clearance of 4 feet
horizontally from electric
meters, gas meters,
regulators, air inlets and
air relief equipment.
Additionally, the vent
cap should never be
located above or below
these items, unless a 4
foot horizontal distance
is maintained.

The vertical termination MUST be a minimum
of 3 feet (0.9 m) above the point of exit in the
rooftop.
A vertical termination less than 10 feet
(3.05 m) from a parapet wall MUST be a
minimum of 2 feet (0.6 m) higher than the
parapet wall.
The vent cap shall terminate at least 3 feet
(0.9 m) above any forced air inlet within 10
feet (3.05 m). The vent shall terminate at least
4 feet (1.2 m) below, 4 feet (1.2 m)
horizontally from or 1 foot (0.30 m) above
any door, window, or gravity air inlet to the
building.
Do not terminate the vent in a window well, stairwell,
alcove, courtyard, or other recessed area. The vent
cannot terminate below grade.
MASONRY CHIMNEY
A masonry chimney MUST be properly sized
for the installation of a high efficiency gas fired
appliance. Venting of a high efficiency
appliance into a cold or oversized masonry
chimney can result in operational and safety
problems.
Exterior masonry chimneys, with one or more
sides exposed to cold outdoor
temperatures, are more likely to have
venting problems. For this reason, exterior
masonry chimneys are not generally
recommended to vent high efficiency gas
appliances.
An interior masonry chimney, which is not
exposed to the outdoors below the roofline,
may be used to vent high efficiency gas
appliances based on the results of careful
inspection, proper sizing and local code
approval. If there is any doubt about the sizing
or condition of a masonry chimney, it MUST
be relined with a properly sized and approved
chimney liner system.
An interior masonry chimney MUST be
carefully inspected to determine its suitability
for the venting of flue products.
A clay tile lined chimney MUST be structurally
sound, straight and free of misaligned tile,
gaps between liner sections, missing sections
of liner or any signs of condensate drainage at
the breeching or clean out. If there is any
doubt about the condition of a masonry
chimney, it MUST be relined.
Metallic liner systems (Type “B” double-wall,
flexible, or rigid metallic liners) are
recommended to line or reline an existing
masonry chimney. Consult with local code
officials to determine code requirements or
the advisability of using a lined masonry
chimney or relining of a masonry chimney.
Lochinvar DESIGNER’S GUIDE EFFICIENCY+ WATER HEATER 615-889-8900 7
NOTE:
An unlined masonry
chimney MUST NOT be
used to vent flue
products from this high
efficiency appliance.

8Lochinvar DESIGNER’S GUIDE EFFICIENCY+ WATER HEATER 615-889-8900
CONVENTIONAL VENTING –
NEGATIVE DRAFT
Size vent material according to the “FAN”
column of vent sizing tables in the latest edition
of the National Fuel Gas Code.
“FAN” applies to Category I fan-assisted
combustion appliances with natural draft.
Utilize Category I Type “B” vent material
for all conventional venting applications.
A bell increaser is provided and installed
directly on the water heater vent outlet.
The bell increases the water heater vent
size by 1 inch (25.4 mm) in diameter. The vent
connection is made directly to the bell
increaser on the top of the unit. No additional
draft diverter or barometric damper is
required.
When each unit is installed with an individual
vent, and the negative draft is higher than the
specified range of 0.02 to 0.05 inches of
water column, a barometric damper will be
necessary.
Multiple unit installations with combined
venting require barometric dampers to regulate
draft at each unit. The negative draft MUST
be within the range of 0.02 to 0.05 inches of
water column to ensure proper operation.
All draft readings are made while unit is in
stable operation (approximately 2 to 5
minutes).
Lochinvar
(FIG. 7) MULTIPLE UNIT BAROMETRIC
DAMPER INSTALLATION
WATER HEATER/BOILER
BAROMETRIC DAMPER ON SINGLE UNIT INSTALLATION
Lined
Chimney
WATER HEATER/BOILER
BAROMETRIC DAMPER ON SINGLE UNIT INSTALLATION
(FIG. 6) BAROMETRIC DAMPER INSTALLATION
(TABLE B)
CONVENTIONAL VENTING, VENT CONNECTION SIZE
MODEL DIAMETER
EW 150 5”
EW 200 5”
EW 250 6”
EW 300 6”
NOTE:
An unlined masonry
chimney MUST NOT be
used to vent flue
products from this high
efficiency appliance.

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 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”.
CONVENTIONAL VENTING WITH DIRECT
COMBUSTION AIR INTAKE (E+ DIRECTAIRE VENT)
This vent system uses two pipes, one vertical
pipe with a roof top termination for the flue
products and one pipe for combustion air. The
combustion air pipe may terminate horizontally
with a sidewall air inlet or vertically with a roof
top air inlet. All instructions for “Conventional
Venting Negative Draft” apply to
“Conventional Venting with Direct Combustion
Air”. The flue may be combined with the vent
from any other negative draft, Category I
appliances. Utilize Category I Type “B” vent
material for venting flue products.
The sidewall or vertical roof top E+ DirectAire
Vent combustion air supply system has specific
vent material and installation requirements.
The air inlet pipe connects directly to the water
heater to supply combustion air. In most
installations, the combustion air inlet pipe will
be a dedicated system with one air inlet pipe
per water heater. Multiple air inlets may be
combined if the guidelines in “Combined Air
Inlet Points” are followed. The air inlet pipe will
be connected to a combustion air inlet cap as
specified in this section. Combustion air
supplied from outdoors MUST be free of
contaminants. The air inlet pipe(s) MUST be
sealed. Select air inlet pipe material from the
following specified materials:
• PVC, CPVC or ABS (3”, 4”, 5”or 6”I.D.).
• Dryer vent (not recommended for roof top
air inlet).
• Galvanized steel vent pipe with joints and
seams sealed.
• Type “B” double wall vent with joints and
seams sealed.
The total equivalent length of the sidewall or
vertical roof top E+ DirectAire Vent combustion
air inlet pipe MUST NOT exceed a maximum
of 50 (15.2 m) equivalent feet in length.
Subtract 5 feet (1.5 m) for each elbow in the
air intake system.
Lochinvar DESIGNER’S GUIDE EFFICIENCY+ WATER HEATER 615-889-8900 9

10 Lochinvar DESIGNER’S GUIDE EFFICIENCY+ WATER HEATER 615-889-8900
SIDEWALL AIR INLET
The sidewall air inlet cap is supplied in the
E+ DirectAire Sidewall Vent Kit. Each kit
includes a sidewall combustion air inlet cap to
supply air to a single water heater and
instructions for proper installation. The part
number for each kit is listed by unit size.
Locate units as close as possible to sidewall
where the combustion air supply system will be
installed.
To prevent recirculation of flue products from
an adjacent vent cap into the combustion air
inlet, follow all applicable clearance
requirements in the latest edition of the
National Fuel Gas Code and instructions in
this guide.
The combustion air inlet cap MUST be placed
at least one foot (0.3 m) above ground level
and above normal snow levels.
ROOFTOP AIR INLET
The air inlet cap for the vertical roof top air
inlet is assembled from components purchased
locally. The air inlet cap consists of two 90°
elbows installed at the point of termination for
the air inlet pipe.
The point of termination for the combustion air
inlet cap MUST be at least 2 feet (0.6 m)
below the point of flue gas termination (vent
cap), if it’s located within 10 feet (3.05 m) of
the flue outlet.
The termination ell on the air inlet MUST be
located a minimum of 12”(0.30 m) above the
roof or above normal levels of snow
accumulation. It MUST NOT be placed closer
than 10 feet (3.05 m) from an inside corner of
an L-shaped structure.
Incorrect location of the air inlet cap can allow
the discharge of flue products to be drawn into
the combustion process of the water heater.
Lochinvar
(FIG. 9) E+ DIRECTAIRE VENT WITH VERTICAL AIR INLET
(FIG. 8) E+ DIRETAIRE VENT WITH SIDEWALL AIR INLET
(TABLE C)
E+ DIRECTAIRE VENT SIDEWALL AIR KIT PART NUMBERS
CONVENTIONAL VENT AIR VENT KIT
MODEL NUMBER FLUE SIZE* INLET SIZE PART NUMBER
EW 150 5”4”SVK 3020
EW 200 5”4”SVK 3020
EW 250 6”5”SVK 3021
EW 300 6”5”SVK 3021
NOTE:
The use of double wall
vent material
for the combustion air
inlet pipe is
recommended in cold
climates to prevent the
condensation of airborne
moisture
in the incoming
combustion air.
*Vent size with 1” increaser installed for conventional negative
draft venting.

This can result in incomplete combustion and
potentially hazardous levels of carbon
monoxide in the flue products.
COMBINED AIR INLET POINTS
The air inlet pipes from multiple water heaters
can be combined into a single common
connection, if the common air inlet pipe has a
cross sectional area equal to or larger than the
total area of all air inlet pipes connected to the
common air inlet pipe.
The air inlet point for multiple water heater air
inlets MUST be provided with an exterior
opening which has a free area equal to or
greater than the total area of all air inlet pipes
connected to the common air inlet. This
exterior opening for combustion air
MUST connect directly to the outdoors.
The total length of the combined air inlet pipe
MUST NOT exceed a maximum of 50 feet
equivalent feet (15.2 m). Deduct the restriction
in area provided by any screens, grills or
louvers installed in the common air inlet point.
Screens, grills, or louvers installed in the
common air inlet can reduce the free area of
the opening from 25% to 75% based on the
materials used.
The air inlet cap for the combined air supply from
multiple water heaters MUST be purchased or
fabricated in the field.
DIRECT VENTING
POSITIVE PRESSURE
A direct vent water heater uses a two pipe
system, one pipe for the flue products and one
pipe for the combustion air supply. The flue
CANNOT be combined with any other appliance
vent or common vent from multiple water heaters.
The vent on a direct vent system will have a
positive pressure in the flue, which requires all
vent joints and seams to be sealed gas-tight. The
flue from a direct vent system MUST have a
condensate drain with provisions to properly
collect and dispose of any condensate that may
occur in the venting system. Direct vent systems
require Category IV vent material with AL29-4C
approved stainless steel.
The air inlet pipe connects directly to the water
heater to supply combustion air. The air inlet pipe
MUST be sealed. Choose acceptable
combustion air pipe materials from those
specified in this section.
Approved material for air inlet pipes include:
PVC, CPVC or ABS (4”, 5”or 6”I.D.), dryer
vent, and galvanized steel vent pipe with joints
and seams sealed.
The total equivalent length of the direct vent flue
pipe or the air inlet pipe MUST NOT exceed a
maximum of 50 equivalent feet (15.2 m) in length
for each pipe. Subtract 5 feet (1.5 m) for each
elbow in the vent pipe or air intake system.
EXAMPLE OF
COMBINED AIR
INLET SIZING
Two 5”air inlet pipes
(19.6 in2area each) have
a total area of 39.2 in2
requiring an 8”(50.3 in2
area) common air inlet
pipe.
Lochinvar DESIGNER’S GUIDE EFFICIENCY+ WATER HEATER 615-889-8900 11

HORIZONTAL DIRECT VENT
Horizontal direct vent applications require
a vent kit which MUST be supplied by
Lochinvar to guarantee proper operation.
The part number for each kit is listed by unit
size. Each kit includes a sidewall vent cap for
flue products, a firestop, a combustion air inlet
cap and instructions for proper installation.
It is important to be careful in the placement of
the horizontal direct vent caps. Combustion air
supplied from outdoors MUST be free of
contaminants.
To prevent recirculation of flue products into the
combustion air inlet:
The combustion air inlet cap MUST NOT
be installed above the flue outlet cap.
Maintain a minimum 3 foot (0.9 m) radius
clearance between the combustion air inlet
cap and the flue outlet cap.
The combustion air inlet cap and vent cap
for flue outlet MUST be located on the same
sidewall and in the same pressure zone.
DO NOT place the combustion air inlet
cap closer than 10 feet (3.0 m) from an
inside corner of an L-shaped structure.
Place the combustion air inlet cap at least
1 foot (0.3 m) above ground level and
above normal snow levels.
MULTIPLE UNIT APPLICATIONS
Horizontal Direct Vent
The combustion air inlet caps for multiple unit
installations MUST maintain the minimum 3
foot (0.9 m) radius clearance below or
horizontally from the closest flue outlet.
Lochinvar
12 Lochinvar DESIGNER’S GUIDE EFFICIENCY+ WATER HEATER 615-889-8900
CAUTION!
Water heaters which
are shut down or will
not operate may
experience freezing due
to convective air flow in
the air inlet pipe
connected to the unit.
Proper freeze
protection MUST be
provided.
(TABLE D)
–
HORIZONTAL DIRECT VENT KITS
MODEL DIRECT VENT AIR INLET HORIZONTAL DIRECT
NUMBER FLUE SIZE* PIPE* VENT KIT
EW 150 4”4”HDK3013
EW 200 4”4”HDK3013
EW 250 5”5”HDK3013
EW 300 5”5”HDK3014
1.
5.
4.
2.
3.
(FIG. 10) HORIZONTAL DIRECT VENT
(FIG. 11) HORIZONTAL DIRECT VENT CAPS
NOTE:
The use of double wall
vent material for the
combustion air inlet pipe
is recommended in cold
climates to prevent the
accumulation of
condensation on the pipe
exterior.
*Minimum diameter, installer may increase diameter one pipe
size for ease of installation if needed.

Multiple flue outlet caps may be installed side
by side, and multiple air inlet caps may be
installed side by side, but the 3 foot (0.9 m)
radius minimum clearance between air inlet
and flue outlet MUST be maintained.
All clearance and installation requirements in
this section and the applicable portions of the
general venting section MUST be maintained
on multiple unit installations.
VERTICAL DIRECT VENT
Vertical direct vent applications do not
require a vent kit to be supplied by Lochinvar.
The vent cap and air inlet cap for vertical
direct vent applications are fabricated or
purchased in the field. A vertical vent cap, as
specified by the vent material manufacturer, is
used to vent the flue products to the outdoors.
The air inlet cap consists of two 90° elbows
installed at the point of termination for the air
inlet pipe. The termination ell on the air inlet
MUST be located a minimum of 12”(15.2 cm)
above the roof or above normal levels of snow
accumulation. The point of termination for the
air inlet MUST be 24”(0.6m) lower than the
point of flue gas termination, if it is located
within 10 feet (3.05 m) of the flue outlet.
Incorrect installation and/or location of the air
inlet cap can allow the discharge of flue
products to be drawn into the combustion
process on the water heater. This can result in
incomplete combustion and potentially
hazardous levels of carbon monoxide in the
flue products.
MULTIPLE UNIT APPLICATIONS
Vertical Direct Vent
The combustion air inlet caps for multiple unit
installations MUST maintain the minimum 2 foot
(0.6 m) clearance below the closest vertical flue
outlet if within 10 feet (3.05 m).
Multiple flue outlet caps may be installed side
by side and multiple air inlet caps may be
installed side by side, but the air inlet MUST
always be at least 2 feet (0.6 m) below the
closest flue outlet if the outlet is within 10 feet
(3.05 m).
Lochinvar DESIGNER’S GUIDE EFFICIENCY+ WATER HEATER 615-889-8900 13
(FIG. 13) VERTICAL DIRECT VENT
(TABLE E) – VERTICAL DIRECT VENT,
FLUE AND AIR INLET SIZES
MODEL DIRECT VENT AIR INLET
NUMBER FLUE SIZE PIPE
EW 150 4”4”
EW 200 4”4”
EW 250 5”5”
EW 300 5”5”
(FIG. 12) MULTIPLE SIDEWALL DIRECT VENT CAPS
AIR INLETS
AIR INLETS
3’MIN.
3’MIN.
FLUE OUTLETS

14 Lochinvar DESIGNER’S GUIDE EFFICIENCY+ WATER HEATER 615-889-8900
OUTDOOR INSTALLATION
Units are self venting and can be used outdoors
when installed with the optional Outdoor Vent
Kit. This kit includes a one piece top cover
which replaces the standard two piece cover,
air inlet cap, exhaust cap and gas valve cover.
The 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" (76mm) to combustible surfaces
and a minimum of 3" (76 mm) clearance to the
air inlet. 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"
(1.22m) clearance between each vent cap. The
outdoor cap must be located 4 feet (1.22m)
below and 4 feet (1.22m) 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 (0.30m) above
grade and above normal snow levels. The
water heater must be at least 10 feet (3.05m)
away from any forced air inlet and at least 3
feet (0.91m) 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, gas valve cover,
piece unit top 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.
Lochinvar
(FIG. 14) OUTDOOR VENTING
(TABLE F)
–
OUTDOOR VENT KITS
MODEL OUTDOOR
NUMBER VENT KIT
EW150 ODK3062
EW200 ODK3063
EW250 ODK3067
EW300 ODK3068
*Minimum diameter, installer may increase diameter one pipe
size for ease of installation if needed.

GAS SUPPLY
Safe operation of unit requires properly
sized gas supply piping (See TABLE F).
Gas pipe size may be larger than the
heater connection.
An internal gas pressure regulator is required
if upstream pressure exceeds 6 oz. (10.5"
water column), an intermediate gas
pressure regulator, of the lockup type,
MUST be installed.
Installation of a union is suggested for ease
of service.
Install a manual main gas shutoff valve with
test plug, outside the appliance gas
connection and before the gas valve, when
local codes require.
A trap (drip leg) should be provided in the
inlet of the gas connection to the unit.
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
Lochinvar DESIGNER’S GUIDE EFFICIENCY+ WATER HEATER 615-889-8900 15
(TABLE H) – INLET GAS PRESSURE REQUIREMENTS
NAT. GAS LPG
MAX. (INCHES-WATER COLUMN) 10.5”w.c. 13”w.c.
MIN. (INCHES-WATER COLUMN) 4.7”w.c. 8”w.c.
EXAMPLE OF
HIGH ALTITUDE
APPLICATIONS
For example, if a unit’s
input is 200,000 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.
[200,000][1.00 -
(4000 ft./1000 ft. x
0.04)] = Btu/hr Input
4000 ft. elevation.
[200,000][0.84] =
168,000 Btu/hr Input
at 4000 ft. elevation.
(TABLE G) – 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
2.
3.
4.
5.
6.
1.

16 Lochinvar DESIGNER’S GUIDE EFFICIENCY+ WATER HEATER 615-889-8900
Lochinvar
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 Water Heater Piping diagrams).
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 I), you may be assured of
the proper velocity in the tubes and long life and
economical operation from the water heater.
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.)
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.
Pump is sized to heater input and water
hardness. Should water hardness exceed 25
grains/350 TDS per gallon, consult factory
for pump sizing.
The pump chart (Table J) is based on the
following fittings:
6-90° elbows
2 unions
2 ball valves
1 cold water supply tee
Due to pump capacity the following specifications cannot
be exceeded when using the standard pump:
•Not more than 45 feet of straight pipe
1.
2.
NOTE:
A larger pump
MUST be utilized in
situations where the
distance between the
water heater and tank
exceed those specified.
(TABLE I) – REQUIRED TEMPERATURE RISE
MODEL NUMBER TEMPERATURE RISE °F
EW 150 4.6
EW 200 6.2
EW 250 7.7
EW 300 9.3
NOTE:
Care should be
taken to measure
temperature rise
and maintain proper
water velocity in the
heat exchanger.

NOTE:
When the unit is installed
in Canada, it MUST
conform to the CSA
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.
See installation
drawings provided with
the unit for correct
piping. Higher water
temperatures reduce
condensate formation.
Refer to drawings
in Appendix.
•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 EW 150 through EW 300.
The flow switch is installed in the outlet piping from
the water heater and wired in series with the
ignition system safety controls. 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.
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.
(TABLE K)
COMMON WATER MANIFOLD PIPE SIZE FOR MULTIPLE WATER HEATER
INSTALLATIONS
NUMBER COMMON MANIFOLD PIPE SIZE (MINIMUM)
OF UNITS EW 100 EW 150-300
11
1/2”2”
22”3”
32
1/2”3 1/2”
43”4”
53
1/2”5”
63
1/2”5”
(TABLE L) – AMP DRAW DATA
MODEL FAN CONTROLS PUMP APPROXIMATE
NUMBER TOTAL AMPS
@ 120 VAC
EW 150-300 1.2 4.0 5.8 11.0
1.
2.
3.
Lochinvar DESIGNER’S GUIDE EFFICIENCY+ WATER HEATER 615-889-8900 17
(TABLE J)
REQUIRED PUMP PERFORMANCE FOR WATER HARDNESS OF 5
TO 25 GRAINS
MODEL GPM FT. HD. AMP HORSE VOLTAGE/
DRAW POWER PHASE
EW 150-300 55 10 5.8 1/4 120/1

EFFICIENCY+®WATER HEATER
PIPING DIAGRAMS