Bock Water heaters 75-76SKG Service manual

WARNING
Improper installation, adjustment, alteration,
service or maintenance can cause serious injury
or property damage. Refer to this manual. For
assistance or additional information, consult a
qualified installer or service agency.
WARNING
If the information in these instructions is not
followed exactly, a fire or explosion may result
causing property damage, personal injury or
death.
WARNING
Install in accordance with all local codes.
In the absence of local codes, refer to ANSI
223.1/NFPA 54 and/or CSA B149.1.
CAUTION
The recommended temperature for normal
residential use is 120°F. The dial on the aquastat
does not always reflect the out-coming water
temperature and it could occasionally exceed
120°F. Variation in out-coming temperature
could be based on factors including but not
limited to usage patterns and type of instal-
lation. Test water at the tap nearest to the
water heater. See page 32 for measuring the
out-coming water temperature.
WARNING
Hotter water increases the risk of scald injury.
Before adjusting the water temperature setting,
read this instruction manual. Temperatures
at which injury occurs vary with the person’s
age and the length of exposure. The slower
reaction time of children, elderly or physically
or mentally challenged persons increases the
scalding hazard to them. It is recommended
that lower water temperatures be used where
these exposure hazards exist. Households
with small children or invalids may require
a temperature setting less than 120°F to
prevent accidental contact with hot water. To
produce less than 120°F, use point-of-use
temperature limiting devices.
If higher water temperature is needed in part
of the water system, automatic temperature
limiting devices must be used on all lines to
water taps.
WARNING
Flammable vapors may be drawn to this water
heater from other areas of the structure by air
currents. Do not store or use any flammable
liquids in the vicinity of this heater.
WARNING
Water heater blankets may restrict air flow to
the water heater and cause fire, asphyxiation,
personal injury or death.
THIS MANUAL HAS BEEN PREPARED TO
ACQUAINT YOU WITH THE INSTALLATION,
OPERATION, AND MAINTENANCE OF
YOUR WATER HEATER AND TO PROVIDE
IMPORTANT SAFETY INFORMATION.
Read all instructions thoroughly before
attempting installation or operation of your
water heater. Keep these instructions for future
reference.
Local plumbing and electrical codes must
be followed in the installation of this water
heater. In the absence of a local code use the
UNIFORM PLUMBING CODE and the NFPA
Code. Local codes may supersede instructions
in this installation manual.
These instructions are a guide for the correct
installation of the water heater. The manufac-
turer will not be liable for damages caused by
failure to comply with the installation and
operating instructions outlined on the
following pages.
Installation, testing, and replacement of gas
piping, appliances, or accessories, and repair
and servicing of equipment, shall be performed
only by a qualified agency.
FAILURE TO FOLLOW THESE INSTRUCTIONS
OR ALL APPLICABLE BUILDING CODES
AND REGULATIONS VOIDS THE WARRANTY
ON THIS WATER HEATER.
Warranty, Registration Card and Parts List are included.
Homeowner: Please remember to return the Registration Card!
To the Consumer:
Please read these and all component
instructions and keep for future reference.
To the Installer:
Please attach these instructions
next to the water heater.
Rev 4 4/21
Installation and Operation Instructions Manual
23419
Models: 75-76SKG, 100-76SKG
Solar Indirect Water Heater with
Power Direct Vent Gas Backup

Page 2
IMPORTANT SAFETY INSTRUCTIONS
FOR YOUR SAFETY!
- Do not store or use gasoline or other flammable vapors and liquids in the
vicinity of this or any other appliance.
- WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any phone in your
building.
• Immediately call your gas supplier from a neighbor’s phone.
Follow the gas supplier’s instructions.
• If you cannot reach your gas supplier, call the fire department.
- Installation and service must be performed by a qualified installer,
service agency or the gas supplier.
SAVE THESE INSTRUCTIONS
WARNING
If the information in these instructions is not followed exactly, a fire or
explosion may result causing property damage, personal injury or death.
DANGER
Water heaters utilizing Liquefied Petroleum gas (LP) are different from
natural gas models. A natural gas heater will not function safely on LP gas
and vice versa. To avoid possible equipment damage, personal injury or
fire: DO NOT connect this water heater to a fuel type not in accordance
with the rating label. These units are only certified for a single fuel type.
DANGER
Failure to properly install the vent and combustion air intake system as
outlined in this manual can result in unsafe operation of the water heater.
To avoid the risk of fire, explosion, or asphyxiation from carbon monoxide,
never operate this water heater unless it is properly vented and has
adequate air supply for combustion and dilution of flue gas. Be sure to
inspect the system for proper installation at initial start-up; and at least
annually thereafter. See the Maintenance section for more information.

Page 3
TABLE OF CONTENTS
Section I: Specifications .............................................4
Section II: General Information ........................................5
Section III: Pre-Installation ............................................7
Section IV: Installation ..............................................10
Section V: Operation ...............................................30
Section VI: Maintenance ............................................33
Section VII: Troubleshooting .........................................35
Section VIII: Parts List ...............................................37
Section IX: Warranty ...............................................39

Table 1: Dimensions
Page 4
SECTION I: SPECIFICATIONS
BOCK WATER HEATERS, INC.
110 S. DICKINSON ST. MADISON, WI 53703
SCALE: 1:24
SIZE DWG. NO.
A
REV.
MATERIAL
FINISH
--
xxxx
DO NOT SCALE DRAWING
DIMENSIONS ARE IN INCHES
TOLERANCES:
FRACTIONAL ±
ANGULAR: MACH ±BEND ±
TWO PLACE DECIMAL ±x.xx
THREE PLACE DECIMAL ±x.xxx
NAME DATE
DRAWN
CHECKED
ENG APPR.
MFG APPR.
Q.A.
SHEET 1 OF 1
WEIGHT:
COMMENTS:
THE INFORMATION CONTAINED IN THIS
DRAWING IS THE SOLE PROPERTY OF
BOCK WATER HEATERS, INC. ANY
REPRODUCTION IN PART OR AS A WHOLE
WITHOUT THE WRITTEN PERMISSION OF
BOCK WATER HEATERS, INC. IS
PROHIBITED.
PROPRIETARY AND CONFIDENTIAL
A
A
Figure 1 : All models
SKG Manual
Figure 1
2/21/11
xxxxx
MBS
0
F
D
E
A
B
C
H
I
Gas/Temp.
Control
T&P Relief
Valve
HOT
(Space heating supply)
COLD
(Space heating
return)
FROM SOLAR
TO SOLAR
Gas backup
temp. sensor & ECO
Solar sensor
immersion well
G
COLD
HOT
Anode
Figure 1: All Models
For LP models change suffix “N” to “LP”
Working Pressure: 150 PSI (1034 kPa)
Test Pressure: 300 PSI (2068 kPa)
For natural gas: Manifold pressure = 4” W.C. (1.00 kPa); Inlet pressure range 5-14” W.C. (1.25 - 3.49 kPa)
For propane gas: Manifold pressure = 10” W.C. (1.00 kPa); Inlet pressure range 11-14” W.C. (2.74 - 3.49 kPa)
T&P valve installed
All Bock products meet or exceed current ASHRAE standards.
These products are design certified by UL (Underwriters Laboratories) and meet ANSI Z21.10.3 / CSA 4.3 requirements for operation up to 180°F (82°C).
Approved for use as a direct vent automatic storage water heater.
WARNING: Installation shall be in accordance with all national and/or local codes. In the absense of local codes, refer to NFPA 54 and/or CSA B149.1.
CAUTION: The recommended maximum hot water temperature setting for normal residential use is 120°F (49°C). Bock recommends a
tempering valve or anti-scald valve be installed and used according to the manufacturer’s directions to prevent scalding.
Model
75-76SKGN
100-76SKGN
GAS-FIRED ONLY
SOLAR ONLY
2.76 (10.45) 14.14 (1.31) 0.6 32 (121) 98 (371)
2.76 (10.45) 14.14 (1.31) 0.6 32 (121) 121 (458)
Model
75-76SKGN
100-76SKGN
Coil Volume Coil Surface Area Coil Friction Loss Recovery*** 1st Hr. Delivery***
GAL (L) FT2(m2) @ 5 GPM @ 77°F rise @ 77°F rise
(feet w.c.) GAL/HR (L/HR) GAL (L)
***Input to coil: 140°F, 2 GPM
DIMENSIONS INCHES (cm)
Storage GAL (L)
Rated Input
BTU/HR (kW)
Recovery @ 77
o
F rise
GAL/HR (L/HR)
A
B
C
D
E
F
G H I
Outlet Conn. Dia.
(NPT)
Aux. Conn. Dia.
(NPT)
Gas Conn. Dia.
(NPT)
Shipping Weight
LBS (kg)
Inlet Conn. Dia.
(NPT)
1st Hr. Delivery @
77
o
F rise GAL (L)
73 76000 96 136 76.88 67.25 26.00 60.00 28.19 16.00 11.00 43.50 18.50 1.00 1.00 1.00 0.50 469
(276) (22.3) (363) (515) (195) (171) (68) (152) (72) (41) (28) (110) (47) (213)
98 76000 96 154 76.88 67.25 28.00 60.00 28.19 16.00 11.00 43.50 18.50 1.00 1.00 1.00 0.50 572
(371) (22.3) (363) (583) (195) (171) (71) (152) (72) (41) (28) (110) (47) (259)

Page 5
SECTION II: GENERAL INFORMATION
WHEN YOU RECEIVE YOUR NEW WATER HEATER
Check the new equipment to see if all components are in good condition. If damage is
observed or parts appear to be missing, contact your wholesaler.
WATER TREATMENT/FILTRATION
In areas where poor water conditions are suspected (i.e. lime, iron, and other minerals), it is
essential that the water be tested and appropriate action taken to prevent damage to the
water heater and ensure the quality of the water.
SOLAR WATER HEATER FUNCTION
The solar water heater is designed with an internal coil and gas burner for backup heating.
A heating medium is passed through the solar panels and internal coil as long as there is an
adequate temperature difference between the heating medium and stored water in the tank.
The internal coil is located as close to the bottom as possible to facilitate the transfer of heat
even at lower solar panel temperatures.
During periods of water flow through the water heater, hot water is drawn from the top of the
heater and cold water is delivered to the bottom of the tank (by a diptube). If the hot water
demand should exceed the solar heat output or there is an insufficient temperature difference
between the heating medium and stored water, the gas-fired backup thermostat will activate
the burner for backup heat.
Solar heat output from the internal coil will vary depending on outside conditions and the
temperature of the stored water. The temperature sensor for the gas backup is higher in the
tank to delay burner operation. To further limit the operation of backup heating, connect the
water heater to a programmable timer. Limiting the gas backup operation to off-peak solar
time can increase solar gain in the stored water.
TEMPERATURE CONTROL
The water heater is equipped with a combination gas valve, ignition control, and thermostat
to operate the gas backup system. For domestic hot water, the proper temperature setting is
120°F (i.e. “WARM” setting on control). For commercial applications, the maximum approved
temperature setting is 180°F (i.e. “F” setting on control).
A built-in, automatic reset Energy Cut-Off (ECO) is standard on all models. In the event
that the water temperature becomes excessive (195°F), the ECO will shut off all gas to the
water heater. If the ECO switch opens, it will automatically reset (or close) when the water
temperature drops to 120°F or below. The water heater thermostat will automatically reset
following a three minute standby period once the ECO switch closes.
The thermostat is factory set at 120°F. See Figure 21 for temperature and display settings.
If hotter water is required a tempering device or anti-scald device must be installed at the
domestic hot water outlet of the heater or at the point of use. Table 3 details the approximate
relationship of water temperature and time with regard to scald injury. It is important for the
user to understand the necessity of tempering or anti-scald devices when using hotter water in
domestic water heating systems.
CAUTION: Hot water in excess of 120°F can cause scalding!
Bock recommends a tempering valve or anti-scald valve be installed and used according to
the manufacturer’s directions to prevent scalding. Many state and local codes now require
installation of these devices. Point of use temperature may be hotter than the setting on the
water heater thermostat. The tempering valve or anti-scald valve will ensure potable
water temperatures at the desired set point with a higher degree of accuracy.

Page 6
SECTION II: GENERAL INFORMATION (cont.)
TEMPERATURE CONTROL (cont.)
ANODE RODS
The anode rod is used as a sacrificial element within the volume of the storage tank. The purpose
of the magnesium anode rod is to protect the inside of the tank against corrosion. Anode rods
should be inspected twice in the first year and at least yearly once a time interval for inspection
has been developed. Water conditions can influence the consumption rate of the anode rods.
Please see the Maintenance section of this manual for instructions on how to change the anode
rods.
CAUTION
Hydrogen gas is produced in a hot water system served by the heater that has not been
used for a long period of time (2 weeks or more). Hydrogen gas is extremely flammable.
To reduce the risk of injury under these conditions, it is recommended that the hot water
faucet be opened for several minutes at the kitchen sink before using any electrical
appliance connected to the hot water system. When hydrogen is present, there will
probably be an unusual sound such as air escaping through the pipe as the water begins
to flow. There should be no smoking or open flame near the faucet at the time it is open.
TEMPERATURE AND PRESSURE RELIEF VALVE (T&P)
CAUTION
To reduce the risk of excessive pressures and temperatures in this water heater, install
temperature and pressure protective equipment required by local codes and no less
than a combination temperature and pressure relief valve certified by a nationally
recognized testing laboratory that maintains periodic inspection of production of listed
equipment or materials, as meeting the requirements for Relief Valves and Automatic
Gas Shutoff Devices for Hot Water Supply Systems, ANSI Z21.22. This valve must be
marked with a maximum set pressure not to exceed the marked maximum working
pressure of the water heater. Install the valve in an opening provided and marked for
this purpose in the water heater, and orient it or provide tubing so that any discharge
from the valve exits only within 6 inches above, or at any distance below, the structural
floor, and does not contact any live electrical part. The discharge opening must not be
blocked or reduced in size under any circumstances.
APPROXIMATE
TEMPERATURE/TIME
RELATIONSHIPS TO
SCALDING
120°F (49°C) More than 5 minutes
125°F (52°C) 1 1⁄2 to 2 minutes
130°F (54°C) About 30 seconds
135°F (57°C) About 10 seconds
140°F (60°C) Less than 5 seconds
145°F (63°C) Less than 3 seconds
150°F (66°C) About 1 1⁄2 seconds
155°F (68°C) About 1 second
Table 2: Scald Temperature/Time Relationships

Page 7
SECTION II: GENERAL INFORMATION (cont.)
TEMPERATURE AND PRESSURE RELIEF VALVE (T&P) (cont.)
CAUTION
Scalding injury and/or water damage can occur from either the manual lifting of the
lever or the normal operation of the T&P valve. If it is not piped to a proper drain.
If the valve fails to flow water or reseat, call your plumber.
The T&P valve is factory installed. A discharge drain tube must be installed (responsibility
of the installer) and shall terminate plain, not threaded, 6 inches above the floor drain.
The drain tube material must be approved for temperatures of 120o F or greater and a
pressure of 150 PSI or greater.
BACKFLOW PREVENTER (CLOSED SYSTEM)
Some local municipal codes and ordinances require the use of these devices on potable
(domestic) water lines. Where backflow preventers, check valves, or pressure regulating valves
are required, it will be necessary to install a thermal expansion tank (designed for use
with potable water) in order to prevent pressure build up in the water heater and associated
piping, which could cause the T&P valve to discharge. Follow the expansion tank manufactur-
er’s recommendations when selecting a tank for your hot water system. The expansion tank
pressure shall equal the water heater system pressure prior to initial warm up.
Note: Working pressure of the water heater is 150 PSI. Do not exceed 150 PSI.
CONDENSATION
In some installations condensation will occur in the venting (exhaust) system. It is important
to not allow condensate to collect around mechanical components and bare metal parts on
the water heater. Therefore, if condensation occurs in the venting system it must be routed
to a proper area for drainage. Horizontal sections of the vent system shall slope downward
away from the water heater a minimum of 1/8” per foot. When downward sloping of the vent
system is not possible or a vertical vent arrangement is used, the condensate drain kit must be
installed. See Section IV: Installation / Vent and Combustion Air Intake / Condensate Drain
Kit for installation details.
HIGH ALTITUDE
Refer to Section IV: Installation / Vent & Combustion Air Intake, Tables 4b and 5b for special
venting requirements for installations at altitudes greater than 2,000 feet. Expect a 2% input
rate reduction per 1,000 feet altitude. Installations at altitudes greater than 7,700 feet are not
permitted.
SECTION III: PRE-INSTALLATION
LOCATION
CAUTION
This water heater must be located in an area where leakage of the tank, water line
connections, or the temperature and pressure relief valve will not result in damage to the
area adjacent to the water heater or to lower floors of the structure. When such location
cannot be avoided, a suitable drain pan must be installed under the water heater. The
drain pan depth must be suitable for draining and collecting water. The drain pan can be
purchased from your plumbing professional. The drain pan must be piped to an adequate
drain and all drain piping must be at least 0.75” in diameter
and pitched for proper drainage.

Page 8
SECTION III: PRE-INSTALLATION (cont.)
CAUTION
DO NOT store or use gasoline or other flammable, combustible, or corrosive vapors
and/or liquids in the vicinity of the water heater or any other appliance.
IF YOU SMELL GAS:
• DO NOT try to light any appliance.
• DO NOT touch any electric switch; do not use any telephone in your building.
• Immediately call your gas supplier from a telephone in another building. Follow your
gas supplier’s instructions.
• If you cannot reach your gas supplier, call the fire department.
DO NOT OPERATE THE APPLIANCE UNTIL THE LEAKAGE IS CORRECTED!
CAUTION
Do not drop water heater or lay heater down on its side. Move the water heater into
position by sliding or using an appropriately sized hand truck.
CAUTION
If the water heater is installed directly on carpeting, the water heater shall be installed
on a metal or wood panel extending beyond the full width and depth of the water
heater by at least 3 inches (76.2 mm) in any direction or, if the water heater is installed
in an alcove or closet, the entire floor shall be covered by the panel. The panel must be
strong enough to carry the weight of the heater when full of water.
NOTE: Locate the heater so it is not subject to physical damage from moving vehicles or
flooding. Do not locate the water heater in a room where swimming pool chemicals or large
quantities of water softener salt are kept. Installing a water heater in this environment will
result in premature failure of tank and burner components due to corrosion caused by these
elements diffusing into the air.
The water heater can be installed on combustible or non-combustible flooring. Maintain
clearances specified in this manual and in accordance with the National Fuel Gas Code (NFPA
54, ANSI Z223.1) unless otherwise directed by state and local code requirements. Locate the
water heater such that plastic vent pipe lengths and the number of connection fittings are
minimized.
Minimum clearances from combustible construction are:
Table 3: Clearances
1) Measured from water heater jacket to wall. This clearance accommodates the air intake
boot.
2) Measured from jacket to closet door.
3) Measured from water heater top to ceiling.
This water heater is approved for installation in a closet or alcove with the clearances above.
SIDES BACK1FRONT2TOP3
0 in. (0 cm) 6 in. (15 cm) 24 in. (61 cm) 26 in. (66 cm)

Page 9
SECTION III: PRE-INSTALLATION (cont.)
COMBUSTION AND VENTILATION AIR
The water heater can be installed to utilize combustion air from either inside or outside the
building. Refer to “Section IV: Installation” for detailed venting specifications. If indoor air is
used for combustion air it is imperative that the room has an adequate air supply. Inadequate
air supplies may lead to unsafe levels of carbon monoxide (CO), condensation of flue gases,
and excessive levels of soot. See NFPA 54 or the discussions of “Unconfined Space” and
“Confined Space” below. In addition, poor ventilation will also result in hot spots around the
heater. Temperatures over 90°F near the water heater generally indicate a lack of ventilation.
UNCONFINED SPACE
Unconfined space is defined by NFPA 54 as a space with a volume greater than 50 cubic feet
(during typical use) per 1000 BTUH of the total combined input of all fuel burning appliances
in the space. Rooms leading directly to the installation space through doors that cannot
be closed can be considered part of the space. Exception: Buildings with full vapor barriers,
tight doors and windows or air infiltration rates of less than 0.35 air changes per hour will be
considered a confined space and require additional air supplies.
CONFINED SPACE
Confined space is defined by NFPA 54 as a space with a volume less than 50 cubic feet (during
typical use) per 1000 BTUH of the total combined input of all fuel burning appliances in the
space. Buildings or rooms of unusually tight construction are also considered a confined space.
See “Unconfined Space: Exception”.
When installing fuel burning appliances in a confined space, air must be supplied to that
space from either inside or outside of the building as conditions allow.
A. Inside Air Supply: A confined space shall be provided with two permanent openings; one
within 12 inches of the top and one within 12 inches of the bottom of the enclosure. These
openings shall lead directly to room(s) of sufficient volume so that the combined volume of
all the space meets the criteria for unconfined space. Each opening shall have a minimum
free area of 1 square inch per 1000 Btu/hr of the combined total input of all fuel burning
appliances in the space. Each opening shall have an area of not less than 100 square inches or
a minimum dimension of not less than 3 inches.
B. Outside Air Supply: Confined spaces shall be provided with two permanent openings; one
within 12 inches of the top and one within 12 inches of the bottom of the enclosure. These
openings shall communicate directly, or by ducts, with the outdoors or spaces that
communicate with the outdoors.
1.) Leading directly to the outside or through vertical ducts: Each opening shall have a
minimum free area of one square inch per 4000 Btu/hr of total input rating of all equipment
in the enclosure.
2.) Leading to outside through horizontal ducts: Each opening shall have a minimum free
area of one square inch per 2000 Btu/hr of total input rating of all equipment in the enclosure.
Note: All ducts shall have the same cross sectional area as the free area of each opening to
which they connect. The minimum dimensions of all ducts shall not be less than three inches.
Powered combustion air supplies are also commercially available and may be used.
LOUVERS & GRILLES
In calculating the free area of an opening, consideration must be given to the blocking effects
of louvers or grilles protecting the opening. Any screens used must be no finer than 1⁄4inch
mesh. If the free area of a louver or grille is known, this should be used in calculating the size
of opening required. If free area is unknown, it may be assumed that wood louvers will have
20 to 25% free area and metal louvers and grilles will have 60 to 75% free area. Louvers and
grilles should be fixed in the open position or interlocked with the equipment so that they
open automatically during equipment operation.

SECTION IV: INSTALLATION
VENT & COMBUSTION AIR INTAKE
DANGER
Failure to properly install the vent and combustion air intake system as outlined in this
manual can result in unsafe operation of the water heater. To avoid the risk of fire,
explosion, or asphyxiation from carbon monoxide, never operate this water heater
unless it is properly vented and has adequate air supply for combustion and dilution of
flue gas. Be sure to inspect the system for proper installation at initial start-up; and at
least annually thereafter. See the Maintenance section for more information.
The water heater venting and combustion air intake shall be installed in accordance with
these instructions and can be installed as a power direct vent system (combustion air
from outside the building, i.e. “two-pipe”) or power vent system (combustion air from
inside the building, i.e. “one-pipe”). If applicable, installation must also comply with the
venting system manufacturer’s instructions. Vertical or horizontal (side-wall) configura-
tions may be used with a one-pipe, two-pipe, or concentric vent termination.
Note: If air from inside the building will be used for combustion air, the require-
ments in Section III, “Unconfined Space” must be met.
The water heater is supplied with a rubber coupling (with clamps) that connects to the
blower assembly outlet. The air intake piping is preassembled to route dilution air to the
blower assembly and combustion air to the burner chamber. All vent length measure-
ments specified in this manual are in addition to the preassembled piping supplied with
the water heater. Equivalent pipe run lengths shall not be greater than the maximum
lengths (or less than minimums) given in Tables 4 and 5.
Note: DO NOT connect the water heater to an existing vent or chimney. It must
be vented separately from all other appliances.
The following materials are approved for use as the vent and combustion air intake
piping:
• PVC (DWV, ASTM-D2665 or CSA B181.2)
• PVC (Schedule 40, ASTM-D1785 or CSA B137.3)
• PVC (SDR Series, ASTM-D2241 or CSA B137.3)
• CPVC (Schedule 40, ASTM-F441 or CSA B137.3)
• CPVC (SDR Series, ASTM-F442)
• ABS (Schedule 40, DWV, ASTM-D2661 or CSA B181.1)
• AL29-4C Stainless Steel
• PVC IPEX 1738 (UL 1738, ASTM D2665)
In Canada, check local codes to ensure that SDR series is approved for use. SDR is
not approved for all installations in Canada.
The following materials are approved for use for the fittings in the vent and combustion
air intake systems:
• PVC (Schedule 40 DWV, ASTM D2665)
• CPVC (Schedule 40, ASTM F438)
• ABS (Schedule 40 DWV, ASTM D2661)
• AL29-4C Stainless Steel
• PVC IPEX 1738 (UL 1738, ASTM D2665)
The use of cellular core PVC (ASTM F891), cellular core CPVC, or Radel® (polyphenylsulfone) in
non-metallic vent pipe and systems is prohibited. Covering non-metallic vent pipe and fittings
with thermal insulation is prohibited.
Page 10

SECTION IV: INSTALLATION (cont.)
VENT & COMBUSTION AIR INTAKE (cont.)
NOTICE
Installations in Canada must conform to the requirements of CSA B149 code. Plastic
vent systems must be assembled with pipe, fittings, cements, and primers listed to
ULC S636. Components of this listed system shall not be interchanged with other vent
systems or unlisted pipe/fittings. In Canada, the primer and cement must be of the
same manufacturer as the vent system; do not mix primers and cements from one
manufacturer with a vent system from a different manufacturer. The supplied plastic
pipe/fittings are certified as part of the water heater.
Minimum and Maximum System Lengths
The water heater should be located such that plastic vent pipe lengths and the number of
connection fittings are minimized. Minimum and maximum equivalent pipe lengths for
the vent and combustion air intake systems are given in Tables 4(a, b) and 5(a, b). Either
3 in. or 4 in. plastic piping may be used, where applicable. The water heater is provided
with fittings that readily adapt to 3 in. plastic pipe. DO NOT use less than 3 in. diameter
plastic pipe and DO NOT use unequal sizes except as shown to increase from 3 in. to 4 in.
diameter at the point of connection to the water heater.
NOTE: The equivalent straight pipe length of a 90°, 1/4 inch standard bend elbow
and a 45°, 1/8 inch standard bend elbow is 5 feet and 2.5 feet, respectively. The
concentric vent termination is equivalent to 10 feet of straight pipe. DO NOT use
short bend elbows.
NOTE: Elbows used as termination fittings must be included when determining
the total number of elbows.
Table 4a: Min and Max Vent and Air Intake Pipe Lengths (Two-Pipe Terminations) - 0-2,000 FT Elevation
Table 4b: Min and Max Vent and Air Intake Pipe Lengths (Two-Pipe Terminations) - 2,000 - 7,700 FT Elevation
Table 5a: Min and Max Vent and Air Intake Pipe Lengths (Concentric Termination) - 0-2,000 FT Elevation
Table 5b: Min and Max Vent and Air Intake Pipe Lengths (Concentric Termination) - 2,000 - 7,700 FT Elevation
Page 11
Model(s) Pipe Ø (in)
Minimum Equivalent Pipe Length
(per pipe run)
Maximum Equivalent Pipe Length
(per pipe run)
Air Intake
Ft (m)
Vent
Ft (m)
Air Intake
Ft (m)
Vent
Ft (m)
75-76SKG,
100-76SKG
3 5 (1.52) 12 (3.66) 45 (13.72) 45 (13.72)
4 5 (1.52) 12 (3.66) 75 (22.86) 75 (22.86)
Model(s) Pipe Ø (in)
Minimum Equivalent Pipe Length
(per pipe run)
Maximum Equivalent Pipe Length
(per pipe run)
Air Intake
Ft (m)
Vent
Ft (m)
Air Intake
Ft (m)
Vent
Ft (m)
75-76SKG,
100-76SKG
3 5 (1.52) 12 (3.66) 55 (16.76) 55 (16.76)
4 5 (1.52) 12 (3.66) 85 (25.91) 85 (25.91)
Model(s) Pipe Ø (in)
Minimum Equivalent Pipe Length
(per pipe run)
Maximum Equivalent Pipe Length
(per pipe run)
Air Intake
Ft (m)
Vent
Ft (m)
Air Intake
Ft (m)
Vent
Ft (m)
75-76SKG,
100-76SKG 4 5 (1.52) 12 (3.66) 55 (16.76) 55 (16.76)
Model(s) Pipe Ø (in)
Minimum Equivalent Pipe Length
(per pipe run)
Maximum Equivalent Pipe Length
(per pipe run)
Air Intake
Ft (m)
Vent
Ft (m)
Air Intake
Ft (m)
Vent
Ft (m)
75-76SKG,
100-76SKG 4 5 (1.52) 12 (3.66) 45 (13.72) 45 (13.72)

For quick reference, Tables 6 and 7 give the maximum allowable length of straight pipe
based on the total number of elbows per pipe run.
Table 6: Maximum Pipe Lengths Quick Reference (Two-Pipe Terminations)
Table 7: Maximum Pipe Lengths Quick Reference (Concentric Termination)
Page 12
Model(s) Pipe Ø (in)
# of 90° Elbows per
pipe run
(including termination fittings)
Maximum Equivalent Pipe
Length (per pipe run)
Air Intake
Ft (m)
Vent
Ft (m)
75-76SKG,
100-76SKG
3 0 55 (16.76) 55 (16.76)
3 1 50 (15.24) 50 (15.24)
3 2 45 (13.72) 45 (13.72)
3 3 40 (12.19) 40 (12.19)
3 4 35 (10.67) 35 (10.67)
3 5 30 (9.14) 30 (9.14)
3 6 25 (7.62) 25 (7.62)
4 0 85 (25.91) 85 (25.91)
4 1 80 (24.38) 80 (24.38)
4 2 75 (22.86) 75 (22.86)
4 3 70 (21.34) 70 (21.34)
4 4 65 (19.81) 65 (19.81)
4 5 60 (18.29) 60 (18.29)
4 6 55 (16.76) 55 (16.76)
Model(s) Pipe Ø (in)
# of 90° Elbows per
pipe run
(including termination fittings)
Maximum Equivalent Pipe
Length (per pipe run)
Air Intake
Ft (m)
Vent
Ft (m)
75-76SKG,
100-76SKG
3 0 45 (13.72) 45 (13.72)
3 1 40 (12.19) 40 (12.19)
3 2 35 (10.67) 35 (10.67)
3 3 30 (9.14) 30 (9.14)
3 4 25 (7.62) 25 (7.62)
3 5 20 (6.10) 20 (6.10)
3 6 15 (4.57) 15 (4.57)
4 0 75 (22.86) 75 (22.86)
4 1 70 (21.34) 70 (21.34)
4 2 65 (19.81) 65 (19.81)
4 3 60 (18.29) 60 (18.29)
4 4 55 (16.76) 55 (16.76)
4 5 50 (15.24) 50 (15.24)
4 6 45 (13.72) 45 (13.72)
SECTION IV: INSTALLATION (cont.)
VENT & COMBUSTION AIR INTAKE (cont.)

The vent and combustion air intake systems must be sufficiently supported along
vertical and horizontal sections. At minimum, it is recommended that a support is placed
along the vent or air intake piping every 4 feet. For horizontal systems, the first support shall
be located immediately adjacent to the first 90-deg. elbow following the vertical section
connected to the water heater. The support method should act to isolate the vent and
combustion air intake piping from floor joists or other structural members to reduce transmis-
sion of noise and vibration.
NOTE: Do not support, pin, or secure the vent and combustion air intake pipe in a
way that restricts the normal thermal expansion and contraction of the venting
material.
For replacement installations, thoroughly inspect the existing vent and combustion air intake
systems prior to installing the new water heater. The following steps shall be taken to properly
inspect the existing vent system:
• Verify that the materials as specified in this manual have been used.
• Verify the maximum and minimum vent and combustion air intake equivalent lengths and
terminal clearances meet the specifications in this manual.
• Inspect the vent and combustion air intake systems for cracking. Pay close attention to joints
between elbows and straight pipe.
• Inspect the system for misalignment of components. This may lead to sagging and unwanted
stresses in the joints.
If any corrections are required they must be computed before installing the replacement water
heater.
Horizontal Venting, Direct Vent 2-pipe termination
This water heater may be vented horizontally (through a sidewall) with a two-pipe
termination. Two holes through an exterior wall are required for the vent and
combustion air intake pipes. Minimum clearances between the terminals must be met as
specified in Figure 3. All clearances must comply with local codes or the latest edition of
NFPA 54/ANSI Z223.1 or CSA B149. See Figure 2 and Table 8 for terminal clearances.
Page 13
SECTION IV: INSTALLATION (cont.)
VENT & COMBUSTION AIR INTAKE (cont.)
Figure 2: Terminal Clearances

1) In accordance with the current CSA B149.1 Natural Gas and Propane Installation Code.
2) In accordance with the current ANSI Z223.1 / NFPA 54 National Fuel Gas Code.
3) If locally adopted installation codes specify clearances different than those illustrated, then the most stringent clearance shall prevail.
† A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves
both dwellings.
‡ Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.
* Manufacturer’s recommendation. Must be in accordance with local installation codes and requirements of the gas supplier.
In addition to the clearances specified, the following items shall be accounted for during installation:
• Do not terminate near soffit vents or crawl space or other area where condensate or vapor could create a
nuisance hazard or cause property damage.
• Do not locate the exhaust vent terminal where condensate or vapor could cause damage or could be
detrimental to the operation of regulators, relief valves, or other equipment.
• Do not locate the exhaust vent terminal over public area or walkways where condensate or vapor can
cause nuisance or hazard.
• Do not locate the vent terminal in proximity to plants/shrubs.
• The vent and air intake shall terminate a minimum of 12 ” (30.5 cm) above expected snowfall level to
prevent blockage.
CAUTION
Never install air intake terminal above vent (exhaust) terminal.
Page 14
SECTION IV: INSTALLATION (cont.)
VENT & COMBUSTION AIR INTAKE (cont.)
Table 8: Direct Vent Terminal Clearances
Canadian Installations1US Installations2
A = Clearance above grade, veranda,
porch, deck, or balcony 12 inches (30 cm) 12 inches (30 cm)
B = Clearance to window or door that
may be opened
6 in (15 cm) for appliances ≤10,000
Btuh (3 kW), 12 in (30 cm) for
appliances > 10,000 Btuh (3 kW) and
≤100,000 Btuh (30 kW), 36 in (91
cm) for appliances > 100,000 Btuh
(30 kW)
6 in (15 cm) for appliances ≤10,000
Btuh (3 kW), 9 in (23 cm) for
appliances > 10,000 Btuh (3 kW) and
≤50,000 Btuh (15 kW), 12 in (30 cm)
for appliances > 50,000 Btuh (15 kW)
C = Clearance to permanently closed
window 12 inches (30 cm)*12 inches (30 cm)*
D = Vertical clearance to ventilated
soffit located above the terminal within
a horizontal distance of 2 feet (61 cm)
from the centerline of the terminal
12 inches (30 cm)*12 inches (30 cm)*
E = Clearance to unventilated soffit 12 inches (30 cm)*12 inches (30 cm)*
F = Clearance to outside corner 2 ft (60 cm)*2 ft (60cm)*
G = Clearance to inside corner 18 in (45 cm)*18 in (45 cm)*
H = Clearance to each side of centerline
extended above meter/regulator
assembly
3 ft (91 cm) within a height
of 15 ft (4.6 m)*
Clearance in accordance with local
installation codes and the require-
ments of the gas supplier.
I = Clearance to service regulator vent
outlet 3 ft (91 cm)
Clearance in accordance with local
installation codes and the require-
ments of the gas supplier.
J = Clearance to non-mechanical
air supply inlet to building or the
combustion air inlet to any other
appliance
6 in (15 cm) for appliances ≤10,000
Btuh (3 kW), 12 in (30 cm) for
appliances > 10,000 Btuh (3 kW) and
≤100,000 Btuh (30 kW), 36 in (91
cm) for appliances > 100,000 Btuh
(30 kW)
6 in (15 cm) for appliances ≤10,000
Btuh (3 kW), 9 in (23 cm) for
appliances > 10,000 Btuh (3 kW) and
≤50,000 Btuh (15 kW), 12 in (30 cm)
for appliances > 50,000 Btuh (15 kW)
K = Clearance to a mechanical air
supply inlet 6 feet (1.83 m) 3 feet (91 cm) above if within
10 feet (3 m) horizontally
L = Clearance above paved sidewalk
or paved driveway located on public
property
7 feet (2.13 m)†
Cannot be located above public
walkways or other areas where
condensate or vapor can cause
nuisance or hazard.
M = Clearance under veranda, porch,
deck, or balcony 12 inches (30 cm) ‡ 12 inches (30 cm) ‡

Install piping through the wall as shown in Figure 3. Adequate length of pipe must protrude
beyond the exterior wall for attachment of the termination fitting. The recommended
distance between the terminal fitting and the exterior wall is 1 in. (2.5 cm). Directions for
cementing joints (such as the terminal fittings to the straight pipe) can be found on page 24.
Two 45° elbows are provided with the water heater for termination fittings. If other fittings
are required (i.e. 90° elbows) they must be purchased separately. Install a screen inside the air
intake termination fitting to prevent items from entering the system. Complete the instal-
lation of the remainder of the vent and air intake system and attach to the water heater as
shown in Figure 4. It is recommended that horizontal sections of piping slope downward
away from the water heater a minimum of 1/8 inch per foot (10mm per meter) to prevent
condensate from flowing back towards the water heater.
CAUTION
Annular spaces around vent pipe wall penetrations shall be permanently sealed using
approved materials to prevent entry of combustion products into the building.
Page 15
SECTION IV: INSTALLATION (cont.)
VENT & COMBUSTION AIR INTAKE (cont.)
Vent Terminal
From
Water
Heater
Wall
Outside of
Building
Inside of
Building
Vent Pipe
12" (30 cm)
or greater
Ground Level
Wall Section View Outside View
CAUTION-NEVER INSTALL AIR INTAKE ABOVE VENT
(EXHAUST) TERMINAL
12" (30 cm)
MIN.
(center-to-center)
Vent
(Exhaust)
Terminal
Combustion
Air
Intake
Terminal
(w/
protective
screen)
Figure 3: Horizontal Venting, 2-pipe termination
Figure 3: Horizontal Venting, 2-pipe termination
BOCK WATER HEATERS, INC.
110 S. DICKINSON ST. MADISON, WI 53703
SCALE: 1:24
SIZE DWG. NO.
A
REV.
MATERIAL
FINISH
--
xxxx
DO NOT SCALE DRAWING
DIMENSIONS ARE IN INCHES
TOLERANCES:
FRACTIONAL ±
ANGULAR: MACH ±BEND ±
TWO PLACE DECIMAL ±x.xx
THREE PLACE DECIMAL ±x.xxx
NAME DATE
DRAWN
CHECKED
ENG APPR.
MFG APPR.
Q.A.
SHEET 1 OF 1
WEIGHT:
COMMENTS:
THE INFORMATION CONTAINED IN THIS
DRAWING IS THE SOLE PROPERTY OF
BOCK WATER HEATERS, INC. ANY
REPRODUCTION IN PART OR AS A WHOLE
WITHOUT THE WRITTEN PERMISSION OF
BOCK WATER HEATERS, INC. IS
PROHIBITED.
PROPRIETARY AND CONFIDENTIAL
A
A
B
B
D
E
Before Elbow
4" MIN
Vertical Length
Vent (To Outside)
Air Intake
(From Outside)
3" Pipe
3" Pipe
Figure 4 : Horizontal Direct Vent Connections to Water Heater (3" and 4" pipe systems)
Air Intake
(From Outside)
Vent (To Outside)
3" pipe systems 4" pipe systems
Exhaust
Adapter
Before Elbow
4" MIN
Vertical Length
3" Pipe
3" Pipe 4" x 3"
Reducing Coupling
4" Pipe
Exhaust
Adapter
EZ PDV Manual
Horizontal Venting, 2-pipe to
Water Heater
1/4/11
xxxxx
MBS
0
HOT COLD
10°
SECTION B-B
Figure 4: Horizontal Direct Vent Connections to Water Heater

Page 16
Horizontal Venting, Power Vent 1-pipe termination
This water heater may be vented horizontally (through a sidewall) with a one-pipe
termination. In this case, the water heater will be utilizing air from inside the building for
combustion air. A single hole through the exterior of the building is required for the vent
pipe.
Note: If air from inside the building will be used for combustion air, the require-
ments in Section III, “Unconfined Space” must be met.
All clearances must comply with local codes or the latest edition of NFPA 54/ANSI Z223.1
or CSA B149. See Figure 5 and Table 9 for vent terminal clearances.
SECTION IV: INSTALLATION (cont.)
VENT & COMBUSTION AIR INTAKE (cont.)
Figure 5: Terminal Clearances

Page 17
SECTION IV: INSTALLATION (cont.)
VENT & COMBUSTION AIR INTAKE (cont.)
Table 9: Power Vent Terminal Clearances
1) In accordance with the current CSA B149.1 Natural Gas and Propane Installation Code.
2) In accordance with the current ANSI Z223.1 / NFPA 54 National Fuel Gas Code.
3) If locally adopted installation codes specify clearances different than those illustrated, then the most stringent clearance shall prevail.
† A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves
both dwellings.
‡ Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.
* Manufacturer’s recommendation. Must be in accordance with local installation codes and requirements of the gas supplier.
In addition to the clearances specified, the following items shall be accounted for during installation:
• Do not terminate near soffit vents or crawl space or other area where condensate or vapor could create a
nuisance hazard or cause property damage.
• Do not locate the exhaust vent terminal where condensate or vapor could cause damage or could be
detrimental to the operation of regulators, relief valves, or other equipment.
• Do not locate the exhaust vent terminal over public area or walkways where condensate or vapor can cause
nuisance or hazard.
• Do not locate the vent terminal in proximity to plants/shrubs.
• The vent and air intake shall terminate a minimum of 12 ” (25.4 cm) above expected snowfall level to prevent
blockage.
CAUTION
Never install air intake terminal above vent (exhaust) terminal.
Canadian Installations1US Installations2
A = Clearance above grade, veranda,
porch, deck, or balcony 12 inches (30 cm) 12 inches (30 cm)
B = Clearance to window or door that
may be opened
6 in (15 cm) for appliances ≤10,000
Btuh (3 kW), 12 in (30 cm) for
appliances > 10,000 Btuh (3 kW) and
≤100,000 Btuh (30 kW), 36 in (91
cm) for appliances > 100,000 Btuh
(30 kW)
4 feet (1.2 m) below or to side
of opening; 1 foot (300 mm)
above opening
C = Clearance to permanently closed
window 12 inches (30 cm)*12 inches (30 cm)*
D = Vertical clearance to ventilated
soffit located above the terminal within
a horizontal distance of 2 feet (61 cm)
from the centerline of the terminal
12 inches (30 cm)*12 inches (30 cm)*
E = Clearance to unventilated soffit 12 inches (30 cm)*12 inches (30 cm)*
F = Clearance to outside corner 2 ft (60 cm)*2 ft (60 cm)*
G = Clearance to inside corner 18 in (45 cm)*18 in (45 cm)*
H = Clearance to each side of centerline
extended above meter/regulator
assembly
3 ft (91 cm) within a height
of 15 ft (4.6 m)*
Clearance in accordance with local
installation codes and the require-
ments of the gas supplier.
I = Clearance to service regulator vent
outlet 3 ft (91 cm)
Clearance in accordance with local
installation codes and the require-
ments of the gas supplier.
J = Clearance to non-mechanical
air supply inlet to building or the
combustion air inlet to any other
appliance
6 in (15 cm) for appliances ≤10,000
Btuh (3 kW), 12 in (30 cm) for
appliances > 10,000 Btuh (3 kW) and
≤100,000 Btuh (30 kW), 36 in (91
cm) for appliances > 100,000 Btuh
(30 kW)
4 feet (1.2 m) below or to side
of opening; 1 foot (300 mm)
above opening
K = Clearance to a mechanical air
supply inlet 6 feet (1.83 m) 3 feet (91 cm) above if within
10 feet (3 m) horizontally
L = Clearance above paved sidewalk
or paved driveway located on public
property
7 feet (2.13 m)†
Cannot be located above public
walkways or other areas where
condensate or vapor can cause
nuisance or hazard.
M = Clearance under veranda, porch,
deck, or balcony 12 inches (30 cm) ‡ 12 inches (30 cm) ‡

Page 18
Install piping through the wall as shown in Figure 6. Adequate length of pipe must protrude
beyond the exterior wall for attachment of the termination fitting. The recommended
distance between the terminal fitting and the exterior wall is 1 in. (2.5 cm). Directions for
cementing joints (such as the terminal fittings to the straight pipe) can be found on page 24.
Two 45° elbows are provided with the water heater for termination fittings. If other fittings
are required (i.e. 90° elbows) they must be purchased separately. Install a screen inside the air
intake termination fitting to prevent items from entering the system. Complete the instal-
lation of the remainder of the vent and air intake system and attach to the water heater as
shown in Figure 7. It is recommended that horizontal sections of piping slope downward
away from the water heater a minimum of 1/8 inch per foot (10 mm per meter) to prevent
condensate from flowing back towards the water heater.
CAUTION
Annular spaces around vent pipe wall penetrations shall be permanently sealed using
approved materials to prevent entry of combustion products into the building.
SECTION IV: INSTALLATION (cont.)
VENT & COMBUSTION AIR INTAKE (cont.)
Vent Terminal
From
Water
Heater
Wall
Outside of
Building
Inside of
Building
Vent Pipe
12" (30 cm)
or greater
Ground Level
Wall Section View
Figure 6: Horizontal Venting, 1-pipe termination
Figure 6: Horizontal Venting, 1-pipe termination
BOCK WATER HEATERS, INC.
110 S. DICKINSON ST. MADISON, WI 53703
SCALE: 1:24
SIZE DWG. NO.
A
REV.
MATERIAL
FINISH
--
xxxx
DO NOT SCALE DRAWING
DIMENSIONS ARE IN INCHES
TOLERANCES:
FRACTIONAL ±
ANGULAR: MACH ±BEND ±
TWO PLACE DECIMAL ±x.xx
THREE PLACE DECIMAL ±x.xxx
NAME DATE
DRAWN
CHECKED
ENG APPR.
MFG APPR.
Q.A.
SHEET 1 OF 1
WEIGHT:
COMMENTS:
THE INFORMATION CONTAINED IN THIS
DRAWING IS THE SOLE PROPERTY OF
BOCK WATER HEATERS, INC. ANY
REPRODUCTION IN PART OR AS A WHOLE
WITHOUT THE WRITTEN PERMISSION OF
BOCK WATER HEATERS, INC. IS
PROHIBITED.
PROPRIETARY AND CONFIDENTIAL
A
A
B
B
D
E
Before Elbow
4" MIN
Vertical Length
Vent (To Outside)
Air Intake
(From Inside)
3" Pipe
3" Pipe
Figure 7 : Horizontal Power Vent Connections to Water Heater (3" and 4" vent pipe systems)
Air Intake
(From Inside)
Vent (To Outside)
3" pipe systems 4" pipe systems
Exhaust
Adapter
Fitting w/ protective
screen
Fitting w/ protective
screen
Before Elbow
4" MIN
Vertical Length
3" Pipe
3" Pipe
4" x 3"
Reducing Coupling
4" Pipe
Exhaust
Adapter
EZ PDV Manual
Horizontal Venting, 1-pipe to
Water Heater
1/4/11
xxxxx
MBS
0
HOT COLD
10°
SECTION B-B
Figure 7: Horizontal Power Vent Connections to Water Heater

Page 19
Horizontal Venting, Direct Vent Concentric termination
This water heater may be vented horizontally (through a sidewall) with a concentric
vent termination kit. One hole through an exterior wall is required for the concentric
vent. Both combustion air intake and vent pipes must be attached to the concentric vent
termination.
All clearances must comply with local codes or the latest edition of NFPA 54/ANSI Z223.1
or CSA B149. See Figure 2 and Table 8 for terminal clearances. See Figure 8 for additional
information.
Cut a 5 in. diameter hole through an exterior wall. Make sure the wye concentric fitting
is cemented to the large diameter pipe and that the rain cap is cemented to the small
diameter pipe. Install the wye concentric fitting and large pipe assembly through the 5 in.
diameter hole in the wall. See Figure 9 for wall attachment details.
CAUTION
Annular spaces around vent pipe wall penetrations shall be permanently sealed using
approved materials to prevent entry of combustion products into the building.
Note: Do not allow insulation or other materials to accumulate inside pipe assembly
when installing through the wall.
SECTION IV: INSTALLATION (cont.)
VENT & COMBUSTION AIR INTAKE (cont.)
Figure 8: Concentric Vent Wall Clearances
Figure 9: Concentric Vent Wall Installation

Page 20
Install the rain cap and small pipe assembly into the wye concentric fitting and large pipe
assembly. Ensure small diameter pipe is bottomed and cemented in wye concentric fitting.
Complete indoor piping runs and connect piping to the water heater. See Figure 4, 3” pipe
systems, for connection details. It is recommended that horizontal sections of piping slope
downward away from the water heater a minimum of 1/8 inch per foot (10 mm per meter) to
prevent condensate from flowing back towards the water heater. Piping must be sufficient-
ly supported. At minimum, it is recommended that a support is placed along the vent or air
intake piping every 4 feet. For additional information, see installation instructions supplied
with concentric vent kit.
Vertical Venting, Direct Vent 2-pipe termination
This water heater may be vented vertically (through a roof) with a two-pipe termination.
Two holes through the roof are required for the vent and combustion air intake pipes. All
clearances must comply with local codes or the latest edition of NFPA 54/ANSI Z223.1 or CSA
B149. As a basic guide, the following minimum clearances shall be used:
• Minimum 12 inches (30 cm) above roof.
• Minimum 12 inches (30 cm) above anticipated snow level.
• Maximum 24 inches (61 cm) above roof level without additional support for vent.
• 4 feet (1.2 m) from any gable, dormer or other roof structure with building interior access
(e.g. vent or window).
• 10 feet (3 m) from any forced air inlet to the building. Any fresh or make-up air inlet such as
a dryer or furnace area is considered to be a forced air inlet.
• Minimum 12 inches (30 cm) between the vent and combustion air intake terminal
centerlines.
CAUTION
Never install air intake terminal above vent (exhaust) terminal.
SECTION IV: INSTALLATION (cont.)
VENT & COMBUSTION AIR INTAKE (cont.)
Figure 10: Vertical Venting, 2-pipe termination
Vent
Terminal
Combustion
Air Intake
Terminal
(w/ protective
screen)
From
Water
Heater
To
Water
Heater
Dim Y
Dim Y Requirements
1) Minimum 12 in. (30 cm) above roof.
2) Minimum 12 in. (30 cm) above
anticipated snow level.
3) Maximum 24 in. (61 cm) above roof
without additional support.
Support
Bracket
Support
Bracket
Figure 10: Vertical Venting, 2-pipe termination
CAUTION - NEVER INSTALL AIR INTAKE ABOVE VENT
(EXHAUST) TERMINAL
12" (30 cm) MIN
(center-to-center)