VWH0500N
Installation & Operation Manual
Models: 500 - 2000
Up To 4:1 Turndown
This manual supplies information for the
installation, operation, and servicing of the
appliance. It is strongly recommended that this
manual and the VF Series Service Manual be
reviewed completely before proceeding with an
installation. Perform steps in the order given.
Failure to comply could result in severe personal
injury, death, or substantial property damage.
WARNING:
Save this manual for future reference.
VFS-I-O Rev A
2
Hazard definitions
The following defined terms are used throughout this manual to bring attention to the presence of hazards of various risk levels
or to important information concerning the life of the product.
DANGER
WARNING
CAUTION
CAUTION
NOTICE
DANGER indicates an imminently hazardous situation which, if not avoided, will result in death or serious
injury.
WARNING indicates a potentially hazardous situation which, if not avoided, could result in death or serious
injury.
CAUTION indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate
injury.
CAUTION used without the safety alert symbol indicates a potentially hazardous situation which, if not
avoided, may result in property damage.
NOTICE indicates special instructions on installation, operation, or maintenance that are important but not
related to personal injury or property damage.
Contents
HAZARD DEFINITIONS .................................................... 2
PLEASE READ BEFORE PROCEEDING ..................... 3-4
RATINGS ........................................................................... 5
THE VF SERIES -- HOW IT WORKS ............................. 6-8
1. DETERMINE UNIT LOCATION
Location of Unit .................................................................. 9
Recommended Service Clearances ............................. 9
Combustion and Ventilation Air Requirements .......... 10-12
2. VENTING
Before You Begin ............................................................. 13
Venting Category Definitions .......................................13
Vent Materials ............................................................. 14
Condensing Vent Options: CAT II & IV ................ 15-18
Common Venting CAT II & IV Venting Information 19-20
Vertical Vent Options .................................................. 21
Horizontal Vent Options .............................................. 22
All Categories ........................................................ 23-26
3. GAS CONNECTIONS
Gas Supply ....................................................................... 27
Gas Pressure Test ............................................................27
Checking Manifold Gas Pressure .....................................27
Gas Connection ............................................................... 27
Gas Piping ........................................................................ 28
Checking Gas Supply Pressure ....................................... 29
High and Low Gas Pressure Switches ............................ 30
4. WATER CONNECTIONS
Inlet and Outlet Connections ............................................ 31
Water Heater Installations ........................................... 32-34
5. ELECTRICAL CONNECTIONS
Water Heater Operating Control Module ......................... 35
Line and Low Voltage Connections ............................ 35-36
EMS or Remote Thermostat Connection ......................... 36
Louver Proving Switch ................................................ 37
Water Heater Management System (BMS) ................ 37
Runtime Contacts ....................................................... 37
Alarm Contacts ............................................................37
Low Voltage Field Wiring Connections ..................38
6. CONDENSATE DISPOSAL.........................................39
7. START-UP
Check / Control Water Chemistry .................................... 40
Filling Hot Water Heater ................................................... 40
Check for Gas Leaks ........................................................40
Inspect / Fill Condensate System ..................................... 40
Check Vent and Air Piping ................................................ 40
Placing the Water Heater in Operation .............................41
Operating Instructions .......................................................42
8. OPERATING INFORMATION
General ............................................................................. 43
How the Appliance Operates ............................................43
How the Control Module Operates ....................................43
Control Inputs and Outputs ...............................................43
Temperature Control .........................................................43
Protection Features ......................................................43-44
Water Heater Temperature Regulation .............................44
Sequence of Operation .....................................................45
VF Series Control Module .................................................46
Status Display Screens ................................................47-48
9. DOMESTIC WATER HEATERS
Initial Setup of Maximum Water Flow ...............................49
Water Chemistry................................................................50
Pump Operation ................................................................55
Heat Exchanger ................................................................55
Thermostat Adjustment Procedure ................................... 56
Minimum Water Temperatures ..........................................56
Adjustable High Water Temperature Limit Control ...........57
Optional Relief Valve .........................................................57
Thermal Expansion ...........................................................57
Cathodic Protection ...........................................................57
10. MAINTENANCE
Maintenance and Annual Startup ................................ 58-63
11. CONNECTION DIAGRAM ..........................................64
12. LADDER DIAGRAM ................................................... 65
13. WARRANTY ...............................................................67
Revision Notes .................................................. Back Cover
3
Please read before proceeding
NOTICE
This is a gas appliance and should be installed
by a licensed electrician and/or certified gas
supplier. Service must be performed by a
qualified service installer, service agency or the
gas supplier.
WARNING
If the information in these instructions is not
followed exactly, a fire or explosion may result
causing property damage, personal injury, or
death.
This appliance MUST NOT be installed in any
location where gasoline or flammable vapors
are likely to be present, unless the installation
is such to eliminate the probable ignition of
gasoline or flammable vapors.
What to do if you smell gas –
• Do not try to light any appliance.
• Do not touch any electric switch; do not use any
phone in your building.
• Immediately call your gas supplier from a neighbors 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.
Warranty –
Factory warranty (shipped with unit) does not apply to units
improperly installed or improperly operated.
Experience has shown that improper installation or system design,
rather than faulty equipment, is the cause of most operating
problems.
1. Excessive water hardness causing a lime/scale build-up in
the copper tube is not the fault of the equipment and is
not covered under the manufacturer’s warranty (see
Water Treatment and Water Chemistry).
2. Excessive pitting and erosion on the inside of the copper
tube may be caused by too much water velocity through
the tubes and is not covered by the manufacturer’s
warranty (see Flow Rates and Temperature Rise for
flow requirements).
Checking equipment –
Upon receiving equipment, check for signs of shipping
damage. Pay particular attention to parts accompanying the
appliances which may show signs of being hit or otherwise
being mishandled. Verify total number of pieces shown on
packing slip with those actually received. In case there is
damage or a shortage, immediately notify the carrier.
Do not use this appliance if any part has been under water.
The possible damage to a flooded appliance can be extensive
and present numerous safety hazards. Any appliance that
has been under water must be replaced.
WARNING
Improper installation, adjustment,
alteration, service or maintenance can
cause injury or property damage. Refer to
this manual for assistance or additional
information, consult a qualified installer,
service agency or the gas supplier.
Owner warning –
The information contained in this manual is intended for use
by qualified professional installers, service technicians, or gas
suppliers. Consult your local expert for proper installation
or service procedures.
NOTICE
Consult and follow all local Building and
Fire Regulations and other Safety Codes
that apply to this installation. Consult
local gas utility company to authorize and
inspect all gas and flue connections.
A gas appliance that draws combustion air from the
equipment room where it is installed must have a supply of
fresh air circulating around it during burner operation for
proper gas combustion and proper venting.
WARNING
Should overheating occur or the gas
supply fail to shut off, do not turn off
or disconnect the electrical supply to the
pump. Instead, shut off the gas supply at
a location external to the appliance.
Prevention of freezing –
Heat exchangers and headers damaged by freezing are not
covered by warranty.
See Section 7, Startup - Freeze Protection for more information.
3
Installation & Operation Manual
Installation & Operation Manual
4
Please read before proceeding
WARNING
To minimize the possibility of serious
personal injury, fire, or damage to your
appliance, never violate the following safety
rules:
1. Water heaters are heat producing
appliances. To avoid damage or injury,
do not store materials against the
appliance or the vent-air intake system.
Use proper care to avoid unnecessary
contact (especially children) with the
appliance and vent-air intake
components.
2. Never cover your appliance, lean
anything against it, store trash or debris
near it, stand on it or in any way block
the flow of fresh air to your appliance.
3. UNDER NO CIRCUMSTANCES must
flammable materials such as gasoline or
paint thinner be used or stored in the
vicinity of this appliance, vent-air intake
system or any location from which fumes
could reach the appliance or vent-air
intake system.
Codes –
The equipment shall be installed in accordance with those
installation regulations in force in the local area where the
installation is to be made. These shall be carefully followed in all
cases. Authorities having jurisdiction shall be consulted before
installations are made. In the absence of such requirements, the
installation shall conform to the latest edition of the National
Fuel Gas Code, ANSI Z223.1. All water heaters 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. This appliance meets the safe lighting performance
criteria with the gas manifold and control assembly provided,
as specified in the ANSI standards for gas water heaters, ANSI
Z21.10.3.
Installation & Operation Manual
Ratings
HLW
Notes:
1. The ratings are based on standard test procedures prescribed
by the United States Department of Energy.
2. The VF Series requires special gas venting. Use only the
vent materials and methods specified in the VF Series
Installation and Operation Manual.
Maximum allowed working pressure is located on the rating plate.
NOTICE
3. The VF Series is equipped for operation up to 2000 feet, and
including up to 4000 feet, with no field adjustments. The
appliance output ratings up to 4000 feet shall be reduced by
4% for each 1000 feet above sea level. For operation above
4000 feet, consult the factory.
VF Series
AHRI Rating
Model Number
Note: Change “N” to
“L” for L.P. gas models
.
Input
MBH
(Note 3)
Min Max
Gross
Output
MBH
(Note 1)
Net
AHRI
Ratings
Water,
MBH
VWH0500N 125 500 425 370
VWH0750N 188 750 637 554
VWH1000N 250 1000 850 739
VWH1500N 375 1500 1275 1109
VWH2000N 500 2000 1700 1478
Other Specifications
Appliance
Water
Content
Gallons
Water
Connections
Gas
Connections
Air / Vent
Sizes
(Note 2)
3.50 2.5” 1” 5” - 4”
4.00 2.5” 1 1/4” 5” - 5”
4.50 2.5” 1 1/4” 6” - 6”
5.50 2.5” 1 1/2” 6” - 6”
6.13 2.5” 1 1/2” 8” - 8”
5
The VF Series - How it works...
1. Heat exchanger
The heat exchanger allows system water to flow through specially
designed tubes for maximum heat transfer. The glass lined
headers and copper finned tubing are encased in a jacket that
contains the combustion process.
2. Heat exchanger access cover
The heat exchanger access cover is a stainless steel door which
allows access for service, maintenance, and removal of the heat
exchanger from inside the combustion chamber.
3. Blower
The blower pulls in air and gas through the venturi (see item 5)
and injects the fuel/air mixture into the burner, where they burn
inside the combustion chamber.
4. Gas valve
The gas valve allows the proper amount of gas to pass into the
burner for combustion. The gas valve on the
VF Series works
under a negative pressure so gas should only be pulled through the
valve when the blower is in operation.
5. Venturi
The venturi attaches to the inlet (or suction) side of the blower
and generates the negative pressure needed by the gas valve.
6. Flue sensor (not shown)
The flue sensor is mounted in the exhaust collar of the unit and
monitors the flue gas temperature. If the temperature in the stack
exceeds the maximum temperature the unit will shut down to
prevent a hazardous condition.
7. Outlet temperature sensor
This sensor monitors the outlet water temperature. If selected
as the controlling sensor, the appliance will maintain set point by
adjusting the firing rate of the unit according to this sensor.
8. Inlet temperature sensor
This sensor monitors inlet water temperature. If selected as the
controlling sensor, the appliance will maintain set point by
adjusting the firing rate of the unit according to this sensor.
9. Electronic display
The electronic display consists of 7 buttons and a dual line
32-character liquid crystal display used to monitor the operation
of the heater as well as enter and view the programming of the
main control board.
10. Burner (not shown)
The burner is made of a woven fabric over steel screen construction.
The burner uses pre-mixed air and gas and provides a wide range
of firing rates.
11. Water outlet (system supply)
The water outlet is a 2 1/2" pipe connection that supplies water to
the system with connections for a flow switch (see #28) and a relief
valve (see #25).
12. Water inlet (system return)
The water inlet is a 2 1/2" pipe connection that receives water from
the system and delivers it to the heat exchanger.
13. Gas connection pipe
The gas pipe connection on this appliance is 1", 1 1/4", or 1 1/2"
NPT. To deliver the correct amount of gas volume to the appliance
it may be necessary to have a larger gas line reduced to 1 1/4" at the
appliance. Please reference the National Fuel Gas Code charts for
more details.
14. Control module
The control module is the main control for the appliance. This
module contains the programming that operates the blower, gas
valve, and pumps in addition to other programmable features.
15. Air intake
The air intake pipe allows fresh air to flow directly to the
appliance. The air inlet is part of the filter box assembly where air
filtration is accomplished with a standard filter.
16. Line voltage terminal strip
The line voltage terminal strip provides a location to connect all of
the line voltage (120 VAC) contact points to the unit.
17. Low voltage connection board
The low voltage connection board provides a location to tie in
all of the low voltage contacts to the appliance. This is where most
of the external safety devices are connected to the unit such as the
louver proving switch.
18. Condensate trap
The condensate trap is designed to prevent flue gases from
escaping the appliance through the combustion chamber drain.
19. Access cover - front
The front access cover provides access to the gas train as well as the
blower and other key components for service and maintenance.
20. Hot surface igniter (HSI)
The hot surface igniter is a device that is used to ignite the air/
gas mixture as well as monitor the performance of the flame
during operation. This device acts as a flame sense electrode.
21. Flame inspection window (sight glass)
(not shown on Models 500 - 1000)
The flame inspection window is a quartz glass window that
allows a visual inspection of the burner and flame during
operation.
22. Gas shut off valve (downstream test cock)
The downstream test cock is provided in the gas train to ensure
complete shut off of the gas to the burner in case of
maintenance, inspection, or testing of the valve.
23. Manual reset high limit sensor
Device that monitors the outlet water temperature to ensure
safe operation. If the temperature exceeds its setting (field
adjustable), it will break the control circuit, shutting the
appliance down.
24. Relief valve
The relief valve is a safety device that ensures the maximum
pressure of the appliance is not exceeded. Water heaters operate
on temperature and pressure and are shipped standard as 125 PSI
and 210°F (98.9°C).
25. Power switch
The power switch is used to engage and disengage power to the
appliance on the 120 VAC circuit.
26. Air pressure switch
The air pressure switch is a safety device which ensures proper
blower operation. The air pressure switch is wired in series with
the low voltage control circuit in such a way that if the fan does not
engage or shuts down prematurely the device will break the
control circuit and the unit will shut down.
27. Flow switch
The flow switch is a safety device that ensures flow through the
heat exchanger during operation. This appliance is low mass and
should never be operated without flow. The flow switch makes
contact when flow is detected and allows the unit to operate. If
flow is discontinued during operation for any reason the flow
switch will break the control circuit and the unit will shut down.
6
Installation & Operation Manual
28. Drain port(s)
Location from which the heat exchanger can be drained.
29. Auto reset high limit switch
The auto reset high limit is fixed at 200°F (93°C) preventing the
outlet water temperature from exceeding 210°F (98.9°C).
30. Ventilation fan
Provides air circulation around the controls inside the unit.
31. Manual shutoff valve
Manual valve used to isolate the unit from the gas supply.
Models 500 - 1000 Front View
Models 500 - 1000 Right Side (inside unit)
Models 500 - 1000 Rear View
7
The VF Series - How it works... (continued)
Installation & Operation Manual
Models 500 - 1000 Left Side (inside unit)
IMG00611
19
25
9
30
IMG00613
23
1
3
5
4
22
26
20
IMG00614
8
14
7
2
29
IMG00612
13
12
17
16
31
24
11
18
28
27
15
Installation & Operation Manual
8
Models 1500 - 2000 Left Side (inside unit)
Models 1500 - 2000 Right Side (inside unit)
Models 1500 - 2000 Rear View
Models 1500 - 2000 Front View
The VF Series - How it works...
IMG00615
19
25
9
30
IMG00617
23
1
3
5
4
22
26
20
21
IMG00616
13
12
17
16
31
24
11
18
28
27
15
IMG00618
8
14
7
2
29
Installation & Operation Manual
9
1 Determine unit location
NOTICE
Clearances from combustible construction are
noted on the appliance rating plate.
Location of unit
1. Locate the appliance 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.
2. The appliance 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.,).
3. Appliances located in a residential garage and in
adjacent spaces that open to the garage and are not
part of the living space of a dwelling unit must be
installed so that all burners and burner ignition
devices have a minimum clearance of not less than
18" (46 cm) above the floor. The appliance must
be located or protected so that it is not subject to
physical damage by a moving vehicle.
4. DO NOT install this appliance in any location
where gasoline or flammable vapors are likely to be
present.
5. The appliance must be installed on a level floor.
Combustible floor locations may be used. Maintain
required clearances from combustible surfaces.
6. The appliance must not be installed on carpet.
7. The appliance must be installed indoors where it is
protected from exposure to wind, rain, and weather.
8. This appliance may condense the products of
combustion when operating at water temperatures
below 140°F (60°C). Ensure that the appliance is
located near an acceptable drain where condensate
that may form in the venting system may be properly
collected and disposed.
9. Access to rear of appliance MUST be maintained.
IMG00619
24"
MIN
TOP
24"
MIN
FRONT
24"
MIN
REAR
FROM
PIPING
0"
RIGHT
SIDE
0"
LEFT
SIDE
Figure 1-1_Recommended Service Clearances
Recommended service clearances
TABLE - 1A
CLEARANCES FROM COMBUSTIBLE CONSTRUCTION
Location Clearances
Right Side 0"
Rear
6" (15cm) (Minimum 24" (0.61m) suggested
for service to pump and components)
Left Side 0"
Front - Alcove* (Minimum 24" (0.61m) suggested for service)
Top
6" (15cm) (Minimum 24" (0.61m) suggested
for service)
Flue 2" (51mm)
Hot Water Pipes 1" (25.4mm)
*An Alcove is a closet without a door.
Installation & Operation Manual
10
1 Determine unit location
IMG00620
Figure 1-2_Combustion Air Direct from Outside
Combustion and ventilation air
requirements for appliances drawing air
from the equipment room
Provisions for combustion and ventilation air must be in
accordance with Air for Combustion and Ventilation, of the
latest edition of the National Fuel Gas Code, ANSI Z223.1, in
Canada, the latest edition of CGA Standard B149 Installation
Code for Gas Burning Appliances and Equipment, or applicable
provisions of the local building codes.
The equipment room MUST be provided with properly sized
openings to assure adequate combustion air and proper
ventilation.
Maintain minimum specified clearances for adequate operation.
All installations must allow sufficient space for servicing the
vent connections, water pipe connections, piping and other
auxiliary equipment, as well as the appliance. The clearance
labels on each appliance note the same service and combustible
clearance requirements as shown above.
Multiple appliances may be installed in a modular water heater
installation. Multiple appliances may be installed side by side
with no clearance between adjacent appliances because this
appliance is approved for zero clearance from combustible
surfaces and no service access is required from the sides.
Consult the Venting section of this manual for specific
installation instructions for the appropriate type of venting
system that you will be using. Direct Vent and Vent/Air
venting systems require installation with Category IV flue pipe,
sealed air inlet pipe, and air inlet caps, which must meet the
manufacturer’s specifications.
1. If air is taken directly from outside the building with no
duct, provide two permanent openings to the equipment
room (see FIG. 1-2):
(a) Combustion air opening, with a minimum free area of
one square inch per 4000 Btu/hr input (5.5 cm
2
per
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 cm
2
per
kW). This opening must be located within 12" (30 cm)
of the top of the enclosure.
IMG00621
Figure 1-3_Combustion Air Through Ducts
Installation & Operation Manual
1 Determine unit location (continued)
11
2. If combustion and ventilation air is taken from the
outdoors using a duct to deliver the air to the
equipment room, each of the two openings should be
sized based on a minimum free area of one square inch
per 2000 Btu/hr (11 cm
2
per kW) of input (see FIG. 1-3).
IMG00623
Figure 1-5_Combustion Air from Outside - Single
Opening
3. If air is taken from another interior space, each of the
two openings specified above should have a net free
area of one square inch for each 1000 Btu/hr (22 cm
2
per kW) of input, but not less than 100 square inches
(645 cm
2
) (see FIG. 1-4).
4. 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 cm
2
per kW). This opening must
be located within 12" (30 cm) of the top of the enclosure
(see FIG. 1-5).
IMG00622
Figure 1-4_Combustion Air from Interior Space
TABLE - 1B
MINIMUM RECOMMENDED COMBUSTION
AIR SUPPLY TO EQUIPMENT ROOM
Model
Number
*Outside Air from
2 Openings Directly from
Outdoors
*Outside Air from
1 Opening Directly
from Outdoors, in
2
Inside Air from
2 Ducts Delivered from
Outdoors
Inside Air from
2 Ducts Delivered from Interior
Space
Top
Opening, in
2
Bottom
Opening, in
2
Top
Opening, in
2
Bottom
Opening, in
2
Top
Opening, in
2
Bottom
Opening, in
2
500
125
(807 cm
2
)
125
(807 cm
2
)
167
(1077 cm
2
)
250
(1613 cm
2
)
250
(1613 cm
2
)
500
(3226 cm
2
)
500
(3226 cm
2
)
750
188
(1213 cm
2
)
188
(1213 cm
2
)
250
(1613 cm
2
)
375
(2420 cm
2
)
375
(2420 cm
2
)
750
(4839 cm
2
)
750
(4839 cm
2
)
1000
250
(1613 cm
2
)
250
(1613 cm
2
)
333
(2149 cm
2
)
500
(3226 cm
2
)
500
(3226 cm
2
)
1000
(6452 cm
2
)
1000
(6452 cm
2
)
1500
375
(2420 cm
2
)
375
(2420 cm
2
)
500
(3226 cm
2
)
750
(4839 cm
2
)
750
(4839 cm
2
)
1500
(9678 cm
2
)
1500
(9678 cm
2
)
2000
500
(3226 cm
2
)
500
(3226 cm
2
)
667
(4303 cm
2
)
1000
(6452 cm
2
)
1000
(6452 cm
2
)
2000
(12904 cm
2
)
2000
(12904 cm
2
)
*Outside air openings shall directly communicate with the outdoors. When combustion air is drawn from the outside through a
duct, the net free area of each of the two openings must have twice (2 times) the free area required for Outside Air/2 Openings. The
above requirements are for the water heater only; additional gas fired appliances in the equipment room will require an increase in
the net free area to supply adequate combustion air for all appliances.
Installation & Operation Manual
12
1 Determine unit location
The result is improper combustion and a non-warrantable,
premature appliance failure.
EXHAUST FANS: Any fan or equipment which exhausts air
from the equipment room may deplete the combustion air
supply and/or cause a downdraft in the venting system. Spillage
of flue products from the venting system into an occupied
living space can cause a very hazardous condition that must be
immediately corrected. If a fan is used to supply combustion
air to the equipment room, the installer must make sure that it
does not cause drafts which could lead to nuisance operational
problems with the appliance.
500 - 1000
1500 - 2000
Figure 1-6_Filter Access
Combustion air requirements are based on the latest edition
of the National Fuel Gas Code, ANSI Z223.1; in Canada refer
to the latest edition of CGA Standard CAN B149.1 or B149.2.
Check all local code requirements for combustion air.
All dimensions based on net free area in square inches. Metal
louvers or screens reduce the free area of a combustion air
opening a minimum of approximately 25%. Check with louver
manufacturers for exact net free area of louvers. Where two
openings are provided, one must be within 12" (30cm) of the
ceiling and one must be within 12" (30cm) of the floor of the
equipment room. Each opening must have net free area as
specified in the chart on page 11 (Table 1B). Single openings
shall commence within 12" (30cm) of the ceiling.
CAUTION
Under no circumstances should the
equipment room ever be under negative
pressure. Particular care should be taken
where exhaust fans, attic fans, clothes dryers,
compressors, air handling units, etc., may
take away air from the unit.
The combustion air supply must be
completely free of any flammable vapors
that may ignite or chemical fumes which
may be corrosive to the appliance. Common
corrosive chemical fumes which must be
avoided are fluorocarbons and other
halogenated compounds, most commonly
present as refrigerants or solvents, such as
Freon, trichlorethylene, perchlorethylene,
chlorine, etc. These chemicals, when burned,
form acids which quickly attack the heat
exchanger finned tubes, headers, flue
collectors, and the vent system.
Combustion air filter
This unit has a standard air filter located at the combustion air
inlet as shown above in FIG. 1-6. This air filter is provided to
help ensure clean air is used for the combustion process. Check
this filter every month and replace when it becomes dirty. The
filter size on Models 500 -1000 is 16" x 12" x 1" (40.6cm x 30.5cm
x 2.5cm) and for Models 1500 - 2000 it is 16" x 16" x 1" (40.6cm
x 40.6cm x 2.5cm). You can find these commercially available
filters at any home center or HVAC supply store. Follow the
steps below when replacing the combustion air filter:
1. Locate the combustion air filter box mounted on the rear of
the appliance.
2. Locate the flat thumb bolt at the top of the air filter box and
turn it a 1/4 turn counterclockwise to align it with the slot
in the air filter box.
3. Lift and remove the air filter box cover to gain access to the
air filter.
4. Slide the air filter out the top of the air filter box.
5. Inspect the air filter for dirt and debris, replace if necessary.
6. Replace the air filter and the air filter box cover. Turn the
thumb bolt clockwise a 1/4 turn to secure the air filter box
cover to the air filter box.
CAUTION
During construction the air filter should be
checked more frequently to ensure it does
not become clogged with combustion dirt
and debris.
NOTICE
Sustained operation of an appliance with
a clogged burner may result in nuisance
operational problems, bad combustion, and
non-warrantable component failures.
Installation & Operation Manual
2 Venting
BEFORE YOU BEGIN
Identify your appliance’s vent system:
This manual covers venting requirements for CAT II/IV models. Be sure to correctly identify the type of vent system your
appliance requires before proceeding.
Category II/IV Models: See page 15
VWH0500
VWH0750
VWH1000
VWH1500
VWH2000
A
D
B C
E F
CAT II requires vent
increaser kit.
Venting options:
DANGER
Failure to use correct venting materials can result in loss of life from flue gas spillage into working or
living space.
Venting Category Definitions: (Reference National Fuel Gas Code ANSI Z223.1)
CAT IV: Positive pressure condensing
An appliance that operates with a positive vent static pressure with a vent gas temperature that may cause excessive condensate
production in the vent.
CAT II: Negative pressure condensing
An appliance that operates with a non-positive vent static pressure with a vent gas temperature that may cause excessive
condensate production in the vent.
NOTICE
Category II venting is required when common
venting multiple units .
13
Installation & Operation Manual
14
2 Venting
Vent Materials:
Category II/IV Vent Material Suppliers:
Category II/IV flue pipe materials and vent adapters (see FIG. 2-1) can be obtained from the following manufacturers:
Heat-Fab Inc., Saf-T CI Vent with AL29-4C stainless steel
Protech Systems Inc., Fas N Seal Vent with AL29-4C stainless steel
Flex-L International Inc., StaR 34 Vent with AL29-4C stainless steel
Metal-Fab Inc., Corr/Guard Vent with AL29-4C stainless steel
Z-Flex, Z-Vent with AL29-4C stainless steel
Or other listed Category IV vent systems suitable for a condensing, positive pressure, gas fired appliance.
A Category IV flue MUST have all vent joints and seams sealed gastight and have provisions for a drain to properly collect and
dispose of condensate that may occur in the venting system.
*
Figure 2-1_Category IV Vent Adapter
Increaser
Connector
Figure 2-2_Category IV to II Conversion Kit
TABLE - 2A
FLUE ADAPTER SIZES
MODEL FLUE ADAPTER SIZE
VWH0500 4"
VWH0750 5"
VWH1000 6"
VWH1500 6"
VWH2000 8"
TABLE - 2B
CATEGORY IV TO CATEGORY II
CONVERSION KITS
MODEL FLUE SIZE KIT NUMBER
VWH0500 4" to 7" 9910116000
VWH0750 5" to 9" 9910116001
VWH1000 6" to 10" 9910116002
VWH1500 6" to 8" 9910116003
VWH2000 8" to 10" 9910116004
*Note: The manufacturer of the selected vent material can also provide a vent adapter to connect the vent material to the VF Series
vent connection.
Installation & Operation Manual
2 Venting (continued)
15
Condensing Vent Options: CAT II & IV
(CAT II vent options A, B, & C requires an adapter kit - see page 14)
A
CAT II
requires an
adapter kit.
See page 14.
Vertical vent with combustion air from
equipment room - see page 16.
CAT II/
IV
D
Sidewall termination with combustion air from
equipment room - see page 17.
CAT IV
B
CAT II
requires an
adapter kit.
See page 14.
Vertical Direct Vent installation with rooftop
combustion air inlet - see page 16.
CAT II/IV
E
Horizontal Direct Vent installation with sidewall
combustion air inlet - see page 18.
CAT IV
C
CAT II
requires an
adapter kit.
See page 14.
Vertical Vent/Air installation with sidewall
combustion air inlet - see page 17.
CAT II/
IV
F
Horizontal Vent/Air installation with vertical
combustion air inlet - see page 18.
CAT IV
Installation & Operation Manual
16
2 Venting
A
CAT II
requires an
adapter kit.
See page 14.
CAT II/IV
Vertical vent with combustion air from equipment room - see page 15.
The flue outlet terminates on the rooftop.
The termination point for the flue products must follow the vertical vent termination clearance requirements
on pages 24 and 25. These units can be identified by the Category IV as noted on the unit’s rating plate.
The flue from this Category IV appliance must have all vent joints and seams sealed gastight. A Category IV
vent system has specific vent material and installation requirements.
The flue products in the vent system may be cooled below their dew point and form condensate in the flue.
The materials used for a Category IV vent must be resistant to any corrosive damage from flue gas condensate.
The flue from a Category IV vent system must have a condensate drain with provisions to properly collect and
dispose of any condensate that may occur in the venting system.
Follow all requirements in the General Venting and Category IV General Venting sections for proper installation
and for venting flue products to the outdoors with a vertical termination (see pages 19 and 20).
Condensing vent options: CAT II & IV
(CAT II vent options A, B, & C requires an adapter kit - see page 14)
TABLE - 2C
VENT TERMINATION SIZES
MODEL
CAT II
VENT SIZE
CAT IV
VENT SIZE
MODEL
CAT II
VENT SIZE
CAT IV
VENT SIZE
VWH0500 7" 4" VWH1500 8" 6"
VWH0750 9" 5" VWH2000 10" 8"
VWH1000 10" 6" -- -- --
B
CAT II requires
an adapter kit.
See page 14.
CAT II/IV
Vertical direct vent installation with rooftop combustion air inlet - see
page 15.
The Vertical Direct Vent system is installed with a Category IV flue and a separate combustion air pipe to the
outdoors. The flue outlet and combustion air intake must both terminate on the rooftop.
The termination point for the flue products must follow the vertical vent termination clearance requirements
on pages 24 and 25. These units can be identified by the Category IV as noted on the unit’s rating plate.
The optional Direct Vent system requires the installation of specific venting materials that are purchased locally.
Follow all requirements in the General Venting and Category IV General Venting sections for proper installation
and for venting flue products to the outdoors with a vertical termination (see pages 19 and 20).
The Vertical Direct Vent system requires the installation of an additional pipe to supply combustion air from
outdoors directly to the appliance. Follow all requirements under the Combustion Air Inlet section on pages
22 and 23.
TABLE - 2D
AIR & VENT TERMINATION SIZES
MODEL
CAT II CAT IV
MODEL
CAT II CAT IV
AIR
SIZE
VENT
SIZE
AIR
SIZE
VENT
SIZE
AIR
SIZE
VENT
SIZE
AIR
SIZE
VENT
SIZE
VWH0500 5" 7" 5" 4" VWH1500 6" 8" 6" 6"
VWH0750 5" 9" 5" 5" VWH2000 8" 10" 8" 8"
VWH1000 6" 10" 6" 6" -- -- -- -- --
Installation & Operation Manual
2 Venting (continued)
17
Condensing vent options: CAT II & IV
(CAT II vent options A, B, & C requires an adapter kit - see page 14)
C
CAT II
requires an
adapter kit.
See page 14.
CAT II/IV
Vent/Air Vertical installation with sidewall combustion air inlet - see page
15.
The Vent/Air Vertical with a Sidewall Combustion Air Vent system terminates the flue at the rooftop and air inlet
at the sidewall. The flue outlet and combustion air intake terminate in different pressure zones.
The optional Vent/Air vent system requires the installation of specific venting materials that are purchased locally.
The termination point for the flue products must follow the vertical vent termination clearance requirements on
pages 24 and 25. These units can be identified by the Category IV as noted on the unit’s rating plate.
Follow all requirements in the General Venting and Category IV General Venting sections for proper installation and
for venting flue products to the outdoors with a vertical termination (see pages 19 and 20).
The Vent/Air Vertical system requires the installation of an additional pipe to supply combustion air from outdoors
directly to the appliance. Follow all requirements under the Combustion Air Inlet section on pages 22 and 23.
Sidewall combustion air inlet: The air inlet cap for the sidewall air inlet must be purchased from the appliance
manufacturer.
The part numbers for the required sidewall air inlet cap kit are listed by model. Each kit includes the special
combustion air inlet cap for installation on an exterior sidewall. The sidewall air inlet cap supplied in the kit is sized
to provide combustion air for a single appliance only.
TABLE - 2E
AIR INLET CAP TERMINATIONS
MODEL
CAT II CAT IV
CAT IV
KIT
NUMBER
MODEL
CAT II CAT IV
CAT
IV KIT
NUMBER
AIR
SIZE
VENT
SIZE
AIR
SIZE
VENT
SIZE
AIR
SIZE
VENT
SIZE
AIR
SIZE
VENT
SIZE
VWH0500 5" 7" 5" 4" 9910117000 VWH1500 6" 8" 6" 6" 9910117002
VWH0750 5" 9" 5" 5" 9910117000 VWH2000 8" 10" 8" 8" 9910117004
VWH1000 6" 10" 6" 6" 9910117002 -- -- -- -- -- --
Air Inlet Cap
D
CAT IV
Sidewall termination with combustion air from equipment room - see page
15.
The connection from the appliance flue outlet to the sidewall vent cap MUST be made with listed Category IV
vent materials and accessories. The installer must supply suitable vent pipe material. The sidewall vent cap must
be purchased from the appliance manufacturer.
The sidewall vent cap kit includes the wall penetration assembly and the discharge screen assembly. All required
Category IV vent pipe and fittings must be purchased locally.
The termination point for the flue products must follow the sidewall vent termination clearance requirements on
pages 25 and 26. These units can be identified by the Category IV as noted on the unit’s rating plate.
Follow all requirements in the General Venting and Category IV General Venting sections for proper installation
and for venting flue products to the outdoors with a sidewall termination (see pages 19 and 20).
TABLE - 2F
FLUE VENT TERMINATION SIZES
MODEL
CAT IV
VENT SIZE
CAT IV
KIT
MODEL
CAT IV
VENT SIZE
CAT IV
KIT
VWH0500 4" 9910118000 VWH1500 6" 9910118002
VWH0750 5" 9910118001 VWH2000 8" 9910118004
VWH1000 6" 9910118002 -- -- --
Vent Cap
18
2 Venting
E
CAT IV
Condensing vent options: CAT IV
Horizontal direct vent installation with sidewall combustion air inlet - see
page 15.
The horizontal direct vent system is installed with a Category IV flue and a separate combustion air pipe to the outdoors.
The flue outlet and combustion air intake must both terminate on the same sidewall.
The connection from the appliance flue outlet to the sidewall vent cap MUST be made with listed Category IV vent
materials and accessories. The installer must supply suitable vent pipe material. The horizontal direct vent must be
purchased from the appliance manufacturer.
The termination point for the flue products must follow the sidewall vent termination clearance requirements on pages
25 and 26. These units can be identified by the Category IV as noted on the unit’s rating plate.
The horizontal direct vent kit includes the wall penetration assembly and the discharge screen assembly for the flue and
a combustion air inlet cap. All required vent pipe and fittings must be purchased locally.
Follow all requirements in the General Venting and Category IV General Venting sections for proper installation and for
venting flue products to the outdoors with a sidewall termination (see pages 19 and 20).
The horizontal direct vent system requires the installation of an additional pipe to supply combustion air from outdoors
directly to the appliance. Follow all requirements under the Combustion Air Inlet section on pages 22 and 23.
TABLE - 2G
SIDEWALL AIR AND VENT TERMINATION SIZES
MODEL
CAT IV
CAT IV
KIT
MODEL
CAT IV
CAT IV
KIT
AIR
SIZE
VENT
SIZE
AIR
SIZE
VENT
SIZE
VWH0500 5" 4" 9910119000 VWH1500 6" 6" 9910119002
VWH0750 5" 5" 9910119001 VWH2000 8" 8" 9910119006
VWH1000 6" 6" 9910119002 -- -- -- --
Vent Cap
Air Inlet Cap
F
CAT IV
Horizontal vent/air installation with vertical or sidewall combustion air -
page 15.
The Horizontal Vent/Air vent system terminates the flue at the sidewall and air inlet at either the rooftop or a sidewall
opposite the vent termination. The flue outlet and combustion air intake terminate in different pressure zones.
The connection from the appliance flue outlet to the sidewall vent cap MUST be made with listed Category IV vent
materials and accessories. The installer must supply suitable vent pipe material. The Horizontal Vent/Air vent cap must
be purchased from the appliance manufacturer.
The termination point for the flue products must follow the sidewall vent termination clearance requirements on pages
25 and 26. These units can be identified by the Category IV as noted on the unit’s rating plate.
The Horizontal Vent/Air vent system with a vertical air inlet requires a sidewall vent kit. The Horizontal Vent/Air vent
system with a sidewall air inlet requires a horizontal direct vent kit. All required vent pipe and fittings must be purchased
locally.
Follow all requirements in the General Venting and Category IV General Venting sections for proper installation and for
venting flue products to the outdoors with a sidewall termination (see pages 19 and 20).
The Horizontal Vent/Air vent system requires the installation of an additional pipe to supply combustion air from
outdoors directly to the appliance. Follow all requirements under the Combustion Air Inlet section on pages 21 and 22.
TABLE - 2H
SIDEWALL VENT TERMINATION SIZES
MODEL
CAT IV
CAT IV
KIT
MODEL
CAT IV
CAT IV
KIT
AIR
SIZE
VENT
SIZE
AIR
SIZE
VENT
SIZE
VWH0500
5"
4" 9910118000 VWH1500 6" 6" 9910118002
VWH0750
5"
5" 9910118001 VWH2000 8" 8" 9910118004
VWH1000
6"
6" 9910118002 -- -- -- --
Vent Cap
Installation & Operation Manual
Installation & Operation Manual
2 Venting (continued)
19
Common Venting CAT II:
Flues of multiple VF Series water heaters may be combined by incorporating a vent increaser to change the Category IV appliance
to a Category II vent system which can be common vented using an engineered vent system. The increaser kit must be provided
by the manufacturer and the combined engineered vent system must be designed to ensure that flue products will be properly
exhausted from the building at all times. Failure to use the correct vent increaser or a properly sized vent system may result in
a hazardous condition where flue gases spill into an occupied living space. Consult a vent designer to determine the diameter of
the common vent pipe required for combined vent installation. It is recommended that all vent joints and seams are sealed gastight.
This vent system has specific vent material and installation requirements. The negative draft in a conventional vent installation
must be within the range of 0.02 to 0.08 inches w.c. to ensure proper operation. Make all draft readings while the unit is in stable
operation (approximately 2 to 5 minutes).
CAT II & IV General venting information - Vent options: All Categories
Vent installation for connection to gas vents or chimneys must be in accordance with “Venting of Equipment”, of the latest edition
of the National Fuel Gas Code, ANSI Z223.1, in Canada, the latest edition of CAN/CGA Standard B149 Installation Code for Gas
Burning Appliances and Equipment or applicable provisions of the local building codes.
All venting applications where combustion air is drawn from the equipment room must have adequate combustion and ventilation
air supplied to the equipment room in accordance with the latest edition of CAN/CGA Standard B149 Installation Code for Gas
Burning Appliances and Equipment or applicable provisions of the local building codes.
The distance of the vent terminal from adjacent buildings, windows that open and building openings MUST comply with the
minimum clearances stated in this manual and the latest edition of the National Fuel Gas Code, ANSI Z223.1, in Canada, the latest
edition of CAN/CGA Standard B149 Installation Code for Gas Burning Appliances and Equipment.
The vent connection is made directly to the flue outlet opening on the rear of the unit. The connection from the appliance vent to
the stack must be made as direct as possible with no reduction in diameter.
NOTICE
Examine the venting system at least once a year. Check all joints and vent pipe connections for tightness. Also
check for corrosion or deterioration. Immediately correct any problems observed in the venting system.
CAT IV Specific venting information: Vent Options A, B, C, D, E, & F
A Category IV venting system operates with a positive pressure in the vent. This positive pressure is generated by the internal
combustion air blower which operates the combustion process and also exhausts the flue products from the building. The Category
IV flue from this appliance cannot be combined with the vent from any other appliance. The Category IV flue from this appliance
must be a dedicated stack, there is one exception however. The Category IV flues from multiple VF Series appliances may only
be combined when using an engineered vent system incorporating an induced draft fan to ensure that flue products will be
properly exhausted from the building at all times. Failure to use a properly sized induced draft fan on a combined Category
IV vent installation may result in a hazardous condition where flue gases spill into an occupied living space. Consult the
induced draft fan manufacturer to size the induced draft fan and to determine the diameter of the common vent pipe required
for a combined vent installation. The flue from this Category IV appliance must have all vent joints and seams sealed gastight. A
Category IV vent system has specific vent material and installation requirements.
The flue products in the vent system may be cooled below their dew point and form condensate in the flue. The flue materials
used for a Category IV vent must be resistant to any corrosive damage from flue gas condensate. The flue from a Category IV vent
system must have a condensate drain with provisions to properly collect and dispose of any condensate that may occur in the
venting system.
The connection from the appliance vent to the stack or vent termination outside the building must be made with listed Category IV
vent material and must be as direct as possible. The Category IV vent and accessories such as firestop spacers, thimbles, caps, etc.,
must be installed in accordance with the vent manufacturer’s instructions. 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 vent materials specified must be listed by a nationally recognized test agency for use as a Category IV vent material.
The venting system must be planned so as to avoid possible contact with concealed plumbing or electrical wiring inside walls, floors,
or ceilings. Locate the appliance as close as possible to a chimney or gas vent.
Horizontal portions of the venting system shall be supported to prevent sagging. Horizontal runs should slope upwards not less
than a 1/4 inch per foot from the drain tee installed in the flue to the vertical portion of the flue or to the vent terminal on sidewall
venting installations. This ensures proper removal of any condensate that may form in the flue. Follow the installation instructions
from the vent material manufacturer.
Installation & Operation Manual
2 Venting
20
CAT IV Specific venting information (continued): Vent options A, B, C, D, E, & F
Do not use an existing chimney as a raceway if another appliance or fireplace is vented through the chimney. The weight of the
venting system must not rest on the unit. Adequate support of the venting system must be provided in compliance with local codes
and other applicable codes. All connections should be secured and sealed per the vent manufacturer’s specifications.
Vent connectors serving appliances vented by natural draft shall not be connected to any portion of the Category IV positive
pressure vent system used by this appliance. Connection of a negative draft flue into the positive pressure stack from this appliance
may cause flue products to be discharged into an occupied living space causing serious health injury.
When a Category IV vent system is disconnected for any reason, the flue must be reassembled and resealed according to the vent
manufacturer’s instructions.
The flue may terminate either vertically at the rooftop or horizontally on a sidewall. Refer to the specific vent termination sections
for information about recommended vent termination location and clearances.
Length of flue pipe
The installed length of the Category IV flue from the appliance to the point of termination, outside of the building, must not exceed
a maximum of 50 equivalent feet (15.2m) in length. Subtract 5 feet (1.5m) of equivalent length for each 90° elbow installed in the
vent. Subtract 2 1/2 feet (0.7m) of equivalent length for each 45° elbow installed in the vent.
CAT II/IV Drain Tee Requirements: Vent options A, B, C, D, E, & F
Drain tee installation
A drain tee must be installed in the Category II & IV vent pipe to collect and dispose of any condensate that may occur in the vent
system. The drain tee should be installed at the point where the flue turns vertical for a rooftop termination or as one of the first
fittings in a horizontal flue connector that will terminate on a sidewall. Ensure that horizontal portions of the vent are properly
sloped to allow condensate to be evacuated at the drain tee. Plastic drain tubing, sized per the vent manufacturer’s instructions,
shall be provided as a drain line from the tee. The drain tubing must have a trap provided by a 10” (25.4cm) diameter circular
trap loop in the drain tubing. Prime the trap loop by pouring a small quantity of water into the drain hose before assembly to the
vent. Secure the trap loop in position with nylon wire ties. Use caution not to collapse or restrict the condensate neutralization
system or a suitable drain for disposal of condensate that may occur in the Category IV vent system. Ensure that the drain from the
condensate tee is not exposed to freezing temperatures. See Section 7, Startup - Freeze Protection for more information.
Figure 2-3_Drain Tee Installation
Installation & Operation Manual
21
2 Venting (continued)
Vertical Air Inlet: Vent options B & F
Vertical combustion air inlet
The air inlet cap for the vertical rooftop 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 first 90° elbow is installed on the rooftop at the highest
vertical point of the air inlet pipe and turned horizontal, the second 90° elbow is installed on the horizontal outlet of the first elbow
and turned down.
A 90° elbow and a 90° street elbow may be used to make this assembly. If a straight piece of pipe is used between the two elbows,
it should not exceed 6 inches (152mm) in length. The termination elbow on the air inlet must be located a minimum of 12 inches
(0.30m) above the roof or above normal levels of snow accumulation.
Location of a vertical air inlet cap
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 heater. This can result in incomplete combustion and potentially hazardous levels of carbon monoxide in the flue
products. This will cause operational problems with the heater and possible spillage of flue products that can cause personal injury,
death, or property damage.
The point of termination for the combustion air inlet cap MUST be at least 3 feet (0.91m) below the point of flue gas termination
(vent cap) if it is located within a 10 foot (3.05m) radius of the flue outlet. Use care to ensure that the 90° elbow assembly is properly
installed on the air inlet pipe.
The combustion air inlet cap must not be installed closer than 10 feet (3.05m) from an inside corner of an L-shaped structure.
The termination point of the combustion air inlet cap must be installed at least one foot (0.30m) above the rooftop and above
normal snow levels.
The combustion air cap assembly used MUST adequately protect the combustion air inlet from wind and weather.
Combustion air supplied from outdoors must be free of contaminants (see Combustion and Ventilation Air, page 10). To prevent
recirculation of flue products into the combustion air inlet, follow all instructions in this section.
The combustion air inlet caps for multiple appliance installations must maintain the minimum 3 foot (0.91m) clearance below the
closest vertical flue outlet if within 10 feet (3.05m).
Figure 2-4_Vertical Air Inlet Clearances
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