HTP EP-220 VWH User manual

Elite Premier
Volume Water Heaters
Installation
Start-Up
Maintenance
Parts
Warranty
EP-220 / 299 / 301 / 399 VWH Models*
* “N” Denotes Natural Gas Operation
“LP” Denotes Propane Gas Operation
“VWH” Denotes Hot Water Supply Boiler
This manual must only be used by a qualied installer / service technician. Read all instructions in this manual before installing.
Perform steps in the given order. Failure to do so could result in substantial property damage, severe personal injury, or death.
HTP reserves the right to make product changes or updates without notice and will not be held liable for typographical errors
in literature.
NOTE TO CONSUMER: PLEASE KEEP ALL INSTRUCTIONS FOR FUTURE REFERENCE.
272 Duchaine Blvd. New Bedford, MA 02745 www.htproducts.com
LP-551 Rev. 000 Rel. 021 Date 4.2.21
The surfaces of these products contacted by potable (consumable) water contain less than 0.25% lead by weight as required
by the Safe Drinking Water Act, Section 1417.
Improper installation, adjustment, alteration, service, or maintenance could void product warranty and cause property
damage, severe personal injury, or death.
Heat Exchanger Bears the ASME “H” Stamp
California Proposition 65 Warning: This product contains chemicals known to the State of California to cause cancer, birth
defects, or other reproductive harm.

LP-551 Rev. 000 Rel. 021 Date 4.2.21
2
WARNING: If the information in these instructions is not followed exactly, a re or explosion may result causing property damage, personal
injury or death.
• Do not store or use gasoline or other ammable 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 re department.
• Installation and service must be provided by a qualied installer, service agency or the gas supplier.
Improper installation, adjustment, alteration, service, or maintenance can cause injury, property damage, or death. Refer to this
manual. Installation and service must be performed by a qualied installer, service agency, or gas supplier.

LP-551 Rev. 000 Rel. 021 Date 4.2.21
3
The following dened terms are used throughout this manual to
bring attention to the presence of hazards of various risk levels or
to important product information.
DANGER indicates an imminently hazardous situation which, if
not avoided, will result in serious personal injury or death.
WARNING indicates a potentially hazardous situation which, if not
avoided, could result in personal injury or death.
CAUTION indicates a potentially hazardous situation which, if not
avoided, may result in moderate or minor personal injury.
CAUTION used without the safety alert symbol indicates a
potentially hazardous situation which, if not avoided, may result
in property damage.
NOTICE is used to address practices not related to personal injury.
Foreword
This manual is intended to be used in conjunction with other
literature provided with the VWH. This includes all related control
information. It is important that this manual, all other documents
included in this system, and additional publications including the
National Fuel Gas Code - ANSI Z223.1 (latest versions), be reviewed in
their entirety before beginning any work.
For the Installer
This VWH must be installed by qualied and licensed personnel. The
installer should be guided by the instructions furnished with the VWH,
and by local codes and utility company requirements. In the absence
of local codes, preference should be given to the National Fuel Gas
Code - ANSI Z223.1 in the United States and the Natural Gas and Propane
Installation Code - B149.1 in Canada (latest versions).
Installations Must Comply With:
Local, state, provincial, and national codes, laws, regulations, and
ordinances.
In the United States - The latest version of the National Fuel Gas Code,
ANSI Z223.1, from American Gas Association Laboratories, 8501 East
Pleasant Valley Road, Cleveland, OH 44131.
The latest version of the National Electrical Code, NFPA No. 70.
In Canada - The latest versions of the Natural Gas and Propane
Installation Code, CSA B149.1, and the Canadian Electrical Code, C22.1,
from CSA Group, 178 Rexdale Blvd, Toronto, Ontario, Canada M9W 1R3.
NOTE: The gas manifold and controls met safe lighting and other
performance criteria when undergoing tests specied in ANSI Z21.13
- latest edition.
Installation should be made in accordance with the regulations of
the Authority Having Jurisdiction, local code authorities, and utility
companies which pertain to this type of water heating equipment.
Authority Having Jurisdiction (AHJ) – The AHJ may be a federal, state,
local government, or individual such as a re chief, re marshal, chief
of a re prevention bureau, labor department or health department,
building ocial or electrical inspector, or others having statutory
authority. In some circumstances, the property owner or his/her agent
assumes the role, and at government installations, the commanding
ocer or departmental ocial may be the AHJ.
NOTE: HTP reserves the right to modify product technical specications
and components without prior notice.

LP-551 Rev. 000 Rel. 021 Date 4.2.21
4
Part 5 - Venting 25
A. General 25
B. Approved Materials for Exhaust Vent and Intake Pipe 26
C. Additional Requirements for Installation in Canada 26
D. Exhaust Vent and Intake Pipe Location 27
E. Exhaust Vent and Intake Pipe Sizing 28
F. Longer Vent Runs 28
G. Exhaust Vent and Intake Pipe Installation 28
H. Applications 29
1. Direct Vent Installation of Exhaust and Intake 29
2. Venting Through an Existing System 33
3. Power Venting, Indoor Combustion Air in Conned or Unconned
Space 34
Part 6 -Condensate Removal 35
Part 7 - Wiring 36
A. Installation Must Comply With 36
B. Field Wiring Terminations 36
C. Field Wiring 36
D. Line Voltage Wiring for Standard VWH 36
E. Alarm Connections 36
F. Low Voltage Connections for Standard VWH 36
G. Tank Sensor or Mechanical Control 36
H. System / Pipe Sensor 37
I. Optional 0-10 Volt Building Control Signal 37
J. Optional UL353 Low Water Cut-O Interface Kit 37
K. Wiring of Cascade System Communication Bus 37
L. Cascade Master Pump and Sensor Wiring 38
M. Cascade Follower Pump and Sensor Wiring 38
N. Variable Speed Pumping 38
Part 8 - Gas Connections 41
A. Gas Piping 41
B. Gas Table 42
C. Additional Precaution for Excess Flow Valve (EFV) 42
D. Check Inlet Gas Pressure 42
E. VWH Gas Valve 43
Part 9 - Start-Up Preparation 44
A. Check / Control Water Chemistry 44
B. Check for Gas Leaks 44
C. Condensate Removal 44
D. Filling and Testing the VWH System 44
E. Final Checks Before Starting VWH 44
F. Setting Up a Single VWH 45
G. Setting Up a Cascaded System 45
H. Lockout Condition 45
I. Cascade System Programming 45
Part 10 - Start-Up Procedure 47
A. Control Overview 47
B. Navigation of the Display 47
C. Operating Instructions 47
D. Programming VWH Settings 47
E. Programming the System Setting 48
F. System Setting Program Navigation 48
G. Resetting the Maintenance Schedule 50
Part 11 - Start-Up Procedures for the Installer 51
A. VWH Control Status Menu 51
B. Cascade Menu 53
C. VWH Test Mode 54
Part 12 - Troubleshooting 54
A. VWH Error and Fault Codes 54
B. VWH Error 54
C. VWH Fault 54
D. User Interface Display 55
Part 13 - Maintenance 60
A. Procedures 60
B. Combustion Chamber Coil Cleaning Instructions 60
C. Cleaning Water Side of Heat Exchanger 61
D. Maintaining the Condensate System 61
Table of Contents
Part 1 - General Safety Information 5
A. Operation and Installation Warnings 5
B. Improper Combustion 6
C. Gas 6
D. When Servicing the Water Heating System 6
E. Water Chemistry Requirements* 6
F. Freeze Protection 6
G. Water Temperature Adjustment 7
H. High Elevation Installations 7
Part 2 - Before You Start 8
A. What’s in the Box 9
B. How the VWH Operates 9
C. Optional Equipment 10
Part 3 - Prepare the VWH 10
A. Locating the VWH 10
B. Flooring 11
C. Leveling 11
D. Clearances for Service Access 12
E. Residential Garage and Closet Installations 12
F. Exhaust Vent and Intake Pipe 12
1. Direct Vent of Exhaust and Intake 12
2. Power Venting, Indoor Combustion Air in Conned or Unconned Space
13
G. Carbon Monoxide Detectors 13
H. Prevent Combustion Air Contamination 13
I. Removing a VWH from a Common Vent System 13
K. Technical Specications 15
Part 4 - Piping 18
A. General Plumbing Information 18
B. Backow Preventer 18
C. Potable Expansion Tank 18
D. Circulators 18
E. Flow Switch Installation 19
F. Relief Valve 19
G. Scalding 20
H. High Velocity Circulator Pump 20
I. Check / Control Water Chemistry 22
J. Plumbing 22
K. Applications 23
The CSD-1 ASME Code, Section CW-400 requires that hot water
heating and supply boilers have a) a UL 353 temperature control
device, b) at least one (1) temperature-actuated control to shut
o the fuel supply when system water reaches a preset operating
temperature, c) a high temperature limit control that prevents
the water temperature from exceeding the maximum allowable
temperature by causing a safety shutdown and lockout, and d) its
own sensing element and operating switch.
The temperature control system integrated into the 926 control
provided with this heating appliance complies with the requirements
of CSD-1 Section CW-400 as a temperature operation control. The
control monitors the temperature dierence between the inlet
and the outlet sensor, which is aected by boiler water ow. If this
temperature dierence exceeds 55°F (typically because of low water
ow or very low heat load), the control will reduce the maximum fan
speed. If the temperature dierence exceeds 60°F, the control will
eectively sense there is little or no water ow or heat load and shut
the boiler down. The controller will restart automatically once the
temperature dierence has dropped below 55°F and the minimum
o time (anti-cycle time) has expired. In addition, if the control senses
that the outlet water temperature has reached 210°F, the boiler is put
into a hard lockout and requires manual reset to restart.

LP-551 Rev. 000 Rel. 021 Date 4.2.21
5
Part 1 - General Safety Information
ThisVWH is approved for indoor installations only and is not intended
for use as a pool heater. Clearance to combustible materials: 0”
top, bottom, sides, and back. Left side has all VWH mechanical
connections. VWH must have room for service: 24” front is minimum
recommended service clearance. (A combustible door or removable
panel is acceptable front clearance.) This VWH has been approved
for closet installation and installation on combustible ooring. Do
not install directly on carpeting. Install the VWH in a location where
temperature and pressure relief valve discharge or a leak will not
result in damage to the surrounding area. If such a location is not
available install an auxiliary catch pan.
This appliance is rated Category IV (pressurized vent, likely to form
condensate in the vent) and requires a special vent system designed
for pressurized venting. Use only Category IV vent systems.
Installer - Read all instructions in this manual before installing.
Perform steps in the given order.
User - This manual is for use only by a qualied heating installer /
service technician. Have this VWH serviced / inspected annually by
a qualied service technician.
FAILURE TO ADHERE TO THE GUIDELINES ON THIS PAGE
CAN RESULT IN SUBSTANTIAL PROPERTY DAMAGE, SEVERE
PERSONAL INJURY, OR DEATH.
NOTE: Obey all local codes. Obtain all applicable permits before
installing the VWH.
NOTE: Install all system components and piping in such a manner
that does not reduce the performance of any re rated assembly.
A. Operation and Installation Warnings
To avoid serious injury or death, read, understand, and follow all of
the precautions listed here.
DANGER
!
Vapors from ammable liquids will explode and cause a re,
resulting in personal injury or death. The VWH has a burner that
can come on at any time and ignite vapors. DO NOT use or store
ammable liquids around the VWH.
Improper venting can cause a build-up of carbon monoxide.
Breathing carbon monoxide can result in brain damage or death.
DO NOT operate the VWH unless it is properly vented to the
outside and has an adequate fresh air supply for safe operation.
Inspect the exterior exhaust gas outlet port and fresh air inlet port
on a regular basis to ensure they are functioning properly.
A concentration of carbon monoxide as small as .04% (400 parts
per million) in the air can be fatal. When making high re or low
re adjustments, CO levels must be monitored using a calibrated
combustion analyzer such that a CO level of no more than 150
ppm is exceeded at any time during operation.
Adjusting the “low re oset” or the “main ow restrictor” in small
increments can result in a signicant increase in CO concentration.
To avoid serious injury or death, DO NOT make any adjustments
to the gas valve without monitoring the exhaust gases with a fully
functional and calibrated combustion analyzer.
Failure to follow these instructions will result in property damage,
severe personal injury, or death.
NOTE: If the VWH is exposed to re or water (or is any way damaged),
do not operate. Immediately call a qualied service technician.
Failure to follow this information could result in property damage,
severe personal injury, or death.
WARNING
!
The manufacturer cannot anticipate every circumstance that might
involve a potential hazard. Each installation has its own specialized
characteristics, requirements, and possible hazards. Therefore, all
possible incidents are not included in these warnings. Proper and
safe installation, operation, and service are the responsibility of the
qualied service technician.
Proper care of the VWH is the user’s responsibility. Ensure the user
carefully reads and understands the User’s Information Manual
before operating the VWH.
Make sure the user knows the location of the gas shut-o valve and
how to operate it. Immediately close the gas shut-o valve if the
appliance is subjected to re, overheating, ood, physical damage, or
any other damaging condition that might aect the operation of the
unit. Have the appliance checked by a qualied service technician
before resuming operation.
Do not power up the unit unless the gas and water supply valves are
fully opened. Make sure the fresh air intake port and exhaust gas port
are open and functional.
No one but a qualied service technician should attempt to install,
service, or repair this VWH. There are no serviceable parts which can
be changed by the user / owner.
User / Owner: Contact the original qualied service technician if
the VWH needs repair / maintenance. If the original technician
is unavailable, ask your gas supplier for a list of qualied service
providers.
DO NOT store or place newspapers, laundry, or other combustible
items near the appliance or the exterior exhaust gas outlet and/or
fresh air inlet port.
The owner should inspect the system monthly for damage, water
stains, signs of rust, corrosion, and exhaust vent and air intake
blockage. If inspection of the unit shows signs of damage, the
VWH should be shut o until the problem is repaired by a qualied
technician.
After installation, all appliance safety devices should be tested.
Carefully consider installation location and the placement of critical
components (circulators, condensate neutralizers, etc.) before
installing the VWH.
DO NOT allow children to operate this VWH. DO NOT use this VWH
if it does not appear to be operating correctly. A qualied service
technician should service and inspect the VWH annually.
This VWH must be installed by a licensed plumber, licensed gas tter,
and/or professional service technician. Improper installation and/
or operation can cause a potentially hazardous situation, which, if
not avoided, could result in serious injury or death, and will void the
warranty.
DO NOT USE THIS VWH IF ANY PART HAS BEEN SUBMERGED
IN WATER. Immediately call a qualied service technician. The
VWH MUST BE replaced if it has been submerged. Attempting to
operate a VWH that has been submerged could create numerous
harmful conditions, such as a potential gas leakage causing a re
and/or explosion, or the release of mold, bacteria, or other harmful
particulates into the air. Operating a previously submerged VWH
could result in property damage, severe personal injury, or death.
NOTE: VWH damage due to ood or submersion is considered an Act
of God, and IS NOT covered under product warranty.
Part 14 - Installation Checklist 63
Part 15 - Maintenance Report 63
Part 16 - Replacement Parts 65
Limited Warranty 69
Maintenance Notes 71
Customer Installation Record Form 72

LP-551 Rev. 000 Rel. 021 Date 4.2.21
6
B. Improper Combustion
Do not obstruct the ow of combustion and ventilating air. Adequate
air is necessary for safe operation. Failure to keep the exhaust vent
and combustion air intake clear of ice, snow, or other debris could
result in property damage, serious personal injury, or death.
C. Gas
Should overheating or gas supply fail to shut o, turn o the manual
gas control valve to the VWH.
The appliance is certied for indoor installations only. The appliance
consists of gas ignition system components which must be
protected from water (dripping, spraying, etc.) during operation and
service. Carefully consider installation location and the placement of
critical components (circulators, condensate neutralizers, etc.) before
installing the appliance.
This VWH has been designed to heat potable water ONLY. Using this
VWH to heat non-potable uid WILL VOID product warranty, and
could result in property damage, personal injury, or death.
NOTICE
This appliance provides an overheat shutdown limit. In the event
the appliance water temperature exceeds the setpoint of the control
limit, the cuto will trip and the appliance will shut down. Certain
local codes require additional temperature limits. In addition, certain
types of systems may operate at temperatures below the minimum
setpoint of the limit provided with the appliance. Contact the
manufacturer for additional overheat controls.
CAUTION
High heat sources (sources generating heat 100oF / 37oC or greater,
such as stove pipes, space heaters, etc.) may damage plastic
components of the VWH as well as plastic vent pipe materials. Such
damages ARE NOT covered by warranty. It is recommended to keep
a minimum clearance of 8” from high heat sources. Observe heat
source manufacturer instructions, as well as local, state, provincial,
and national codes, laws, regulations and ordinances when installing
this VWH and related components near high heat sources.
DO NOT alter or modify the appliance or appliance controls. Altering
any HTP VWH with parts not manufactured by HTP WILL INSTANTLY
VOID the VWH warranty and could result in property damage,
personal injury, or death.
D. When Servicing the Water Heating System
Be sure to disconnect electrical power before opening VWH cabinet
or performing service. Label all wires while performing service
to ensure proper re-wiring of the VWH. Wiring errors can cause
improper or dangerous operation. Failure to do so could result in
an electrical shock, improper VWH operation, property damage,
serious personal injury, or death.
• To avoid electric shock, disconnect electrical supply before
performing maintenance.
• To avoid severe burns, allow VWH and associated equipment
to cool before servicing.
• Do not use petroleum-based cleaning or sealing compounds
in a water heating system. Gaskets and seals in the system may
be damaged. This can result in substantial property damage.
• Do not use “homemade cures” or “patent medicines”.
Damage to the VWH, substantial property damage, and/or
serious personal injury may result.
• Always verify proper operation after servicing the VWH.
NOTE: When inquiring about service or troubleshooting, reference
the model and serial numbers from the VWH rating label.
E. Water Chemistry Requirements*
Chemical imbalance of the water supply may aect eciency and
cause severe damage to the appliance and associated equipment.
Water quality must be professionally analyzed to determine
whether it is necessary to treat the water. Various solutions are
available to adjust water quality. Adverse water quality will aect
the reliability of the system. In addition, operating temperatures
above 135oF will accelerate the build-up of lime scale and possibly
shorten appliance service life. Failure of an appliance due to
lime scale build-up, low pH, or other chemical imbalance IS NOT
covered by the warranty.
The water must be potable, free of corrosive chemicals, sand,
dirt, and other contaminates. It is up to the installer to ensure the
water does not contain corrosive chemicals or elements that can
damage the heat exchanger. Potable water is dened as drinkable
water supplied from utility or well water in compliance with EPA
secondary maximum contaminant levels (40 CFR Part 143.3) as
shown in the table below. If the water contains contaminants higher
than outlined by the EPA, water treatment is recommended and
additional, more frequent maintenance may be required.
If you suspect that your water is contaminated in any way,
discontinue use of the appliance and contact an authorized
technician or licensed professional.
Contaminant
Maximum
Allowable
Level
Contaminant
Maximum
Allowable
Level
Total Hardness
(Commercial
Use - 140oF and
above water
temperature)
120 mg/l
(7 grains/gallon)
pH 6.5-8.5
Sulfate 205 mg/l
Total
Dissolved
Solids (TDS)
500 mg/l
Aluminum 0.05 to 0.2 mg/l Zinc 5 mg/l
Chloride 100 mg/l
Copper 1 mg/l Dissolved
Carbon
Dioxide (CO2)
15 mg/l or
PPM
Iron 0.3 mg/l
Manganese 0.05 mg/l
Table 1 - Water Quality Specications
*NOTE: It is recommended to clean heat exchanger at least once
a year to prevent lime scale buildup. Follow the maintenance
procedure in the Maintenance Section of this manual to clean the
heat exchanger.
F. Freeze Protection
NOTE: Consider piping and installation when determining heater
location.
Failure of the VWH due to freeze related damage IS NOT covered
by product warranty.

LP-551 Rev. 000 Rel. 021 Date 4.2.21
7
NEVER use any toxic chemical, including automotive, standard
glycol antifreeze, or ethylene glycol made for hydronic (non-
potable) systems. These chemicals can attack gaskets and seals in
water systems, are poisonous if consumed, and can cause personal
injury or death.
NOTE: HTP DOES NOT WARRANT THE APPLIANCE AGAINST FREEZE-
RELATED DAMAGE.
G. Water Temperature Adjustment
This VWH can deliver scalding water. Be careful whenever using
hot water to avoid scalding injury. Certain appliances such as
dishwashers and automatic clothes washers may require increased
water temperatures. By setting the thermostat on this heater
to obtain the increased water temperature required by these
appliances you may create the potential for scald injury.
To protect against injury, install a mixing valve in the water system.
This valve will reduce point of use discharge temperatures by mixing
cold and hot water in branch supply lines. Such valves are available
from your local plumbing supplier.
Table 2 details the relationship of water temperature and time with
regard to scald injury and may be used as a guide in determining
the safest water temperature for your applications.
Households with small children, disabled, or elderly persons may
require a 120oF or lower temperature setting to prevent severe
personal injury or death due to scalding.
Approximate Time / Temperature Relationships in Scalds
120oF More than 5 minutes
125oF 1 1/2 to 2 minutes
130oF About 30 seconds
135oF About 10 seconds
140oF Less than 5 seconds
145oF Less than 3 seconds
150oF About 1 1/2 seconds
155oF About 1 second
Table 2 - Approximate Time / Temperature Relationships in Scalds
Households with small children, disabled, or elderly persons may
require a 120oF or lower temperature setting to prevent severe
personal injury or death due to scalding.
An ASSE 1017 or ASSE 1070 temperature limiting or mixing valve
is recommended in installations servicing disabled or elderly
persons, or children. Mixing valves do not eliminate the risk of
scalding.
To avoid scalding:
• Set the VWH set point temperature as low as possible.
• Feel water before bathing or showering.
• If thermostatic valves are required, use devices specically
designed for such purpose. Install these devices in
accordance with instructions provided by the manufacturer.
Failure to install a temperature limiting or mixing valve and
follow these instructions could result in property damage, severe
personal injury, or death due to scalds.
H. High Elevation Installations
WARNING
!
Combustion - At elevations above 2000 ft, the combustion of the
VWH must be checked with a calibrated combustion analyzer to
ensure safe and reliable operation. It is the Installer’s responsibility
to check and adjust the combustion in accordance with this
manual. Failure to follow these instructions may result in property
damage, serious personal injury, or death.
Elevations 2001 ft
(610 m)
3000 ft
(914 m)
4000 ft
(1219 m)
4500 ft
(1372 m)
5000 ft
(1524 m)
In Canada1,
de-rate by: 10% 10% 10% 10% may vary
In USA2,
de-rate by: - 12% 16% 18% 20%
NOTES:
1Canada: Elevations between 2000 - 4500 ft (610 - 1372 m), de-rate by 10%.
Consult local authorities for de-rating for elevations above 4500 ft (1372 m).
2USA: If elevation is above 2000 ft (610 m), de-rate capacity by 4% for every
1000 ft (305 m).
Table 3 - De-Rate % for High Elevations
This VWH is designed to operate at its maximum listed capacity in
installations located at 0 - 2000 ft above Sea Level. Since the density
of air decreases as elevation increases, maximum specied capacity
should be de-rated for elevations above 2000 ft (610 m) in accordance
with the table below.

LP-551 Rev. 000 Rel. 021 Date 4.2.21
8
Part 2 - Before You Start
These VWH units must be connected to a storage tank. You must not have a direct connection of the potable water system into the heat
exchanger. This could cause ow issues, short cycling, and an increase of mineral build-up in the unit. This system is designed to have
incoming potable water ow through the storage tank rst, then through the heat exchanger. Failure to connect the VWH to a storage
tank of the minimum size requirements (80 gallons for these VWH models) will result in property damage and/or premature VWH failure.
Damages resulting from incorrect installation or from use of products not approved by HTP ARE NOT covered by warranty.
∆T
(Delta T)
(oF)
220VWH 299VWH / 301VWH 399VWH
Gallons
Per Hour
First
Hour
Rating
80
Gallon
Tank
First
Hour
Rating
119
Gallon
Tank
First
Hour
Rating
175
Gallon
Tank
Gallons
Per
Hour
First
Hour
Rating
80
Gallon
Tank
First
Hour
Rating
119
Gallon
Tank
First
Hour
Rating
175
Gallon
Tank
Gallons
Per Hour
First
Hour
Rating
80
Gallon
Tank
First
Hour
Rating
119
Gallon
Tank
First
Hour
Rating
175
Gallon
Tank
Contact HTP for Avail-
able Storage Tanks
Contact HTP for Available
Storage Tanks
Contact HTP for Available
Storage Tanks
40o635 397 414 438 866 529 546 570 1152 693 709 733
50o508 406 427 457 693 538 559 589 922 701 722 752
60o424 415 440 476 578 547 572 608 768 710 735 771
70o363 423 452 494 495 555 584 626 658 718 748 790
80o318 432 465 513 433 564 597 645 576 727 760 808
90o282 440 478 532 385 572 610 664 512 736 773 827
100o254 449 491 551 347 581 623 683 461 744 786 846
110o231 457 503 569 315 589 635 701 419 753 799 865
120o212 466 516 588 289 598 648 720 384 761 811 883
130o196 475 529 607 267 607 661 739 355 770 824 902
140o182 483 542 626 248 615 674 758 329 778 837 921
Table 4 - VWH Ratings with Storage Tanks - NOTE: Gallons Per Hour Does Not Take a Storage Tank into Account
Min Tank Size (Gal.) = Required Flow (GPM) X 10
Mixing Factor (Mf) = VWH Outlet Temp - Inlet Temp
70
First Hour Rating = Total VWH Output X VWH Eciency + .75 X Total Storage X Mf
[ (VWH Outlet Temp - Inlet Temp) X 8.31 ]
Example:
2 220VWHs - Total Output = 440,000 BTU @ 96% Eciency
VWH Outlet Temp = 140oF - Inlet Temp = 40oF
2 Storage Tanks (80 Gallons Each) =Total Storage = 160 Gallons
Mixing Factor (Mf) = 140 - 40 = 1.43
70
First Hour Rating = 440,000 X .96 + .75 X 160 X 1.43
[ (140 - 40) X 8.31 ]
First Hour Rating = 422,400 + 120 X 1.43
[ 831 ]
First Hour Rating = [ 508 + 120 ] X 1.43
First Hour Rating = 628 X 1.43
First Hour Rating = 898 Gallons

LP-551 Rev. 000 Rel. 021 Date 4.2.21
9
Spark Ignition
The burner is ignited by applying high voltage through the system
spark electrode. The spark from the electrode ignites mixed gas o
of the burner.
Dual Supply Water Temperature Sensor / High Limit Water ECO
This dual sensor monitors the VWH outlet water temperature
(System Supply). The control adjusts VWH ring rate so the supply
temperature will match the VWH set point. The dual sensor meets
all requirements to function as a safety, eliminating the mechanical
ECO and increasing safety and reliability.
Return Water Temperature Sensor
This sensor monitors VWH return water temperature (System
Return).
Flue Sensor
Monitors ue temperature and adjusts ring rate.
Temperature and Pressure Gauge
Allows the user to monitor system temperature and pressure.
Electrical eld connections with terminal strips
The electrical cover allows easy access to the clearly marked line
voltage and low voltage terminal strips to facilitate wiring the VWH.
Condensate Collection System
This VWH is a high eciency appliance and will produce condensate.
The condensate collection system has a oat which monitors
condensate level and prevents condensate from backing up into
the combustion system. Inside the collection system is a built in trap
which seals the combustion system from the connected drain. This
condensate should be neutralized to avoid damage to the drainage
system or piping.
Flow Protection
The supplied ow switch is designed to protect the VWH during low
ow conditions. The VWH control also monitors ow through the
heat exchanger by monitoring the return and supply sensors and
will shut down the burner before overheating occurs.
0-10 Volt Input
Allows the installer to connect a BMS (Building Management
System) to control the VWH.
0-10 Volt Output A (Congured through Control System)
0-10 Volt Output A is congured through the VWH’s control system.
0-10 Volt Output A is related to one of the following VWH values:
VWH power, cascade power, fan speed, alarm status, or temperature
setting based on outdoor reset curve.
UL 353 Internal Low Water Cuto (LWCO)
The supplied internal Low Water Cuto meets UL 353 requirements
to function as a safety, locking out the VWH when water level is
inadequate for safe operation. To test LWCO function, press and hold
v and RESET simultaneously for ve (5) seconds. Press RESET to clear
the error code.
Boost Timer Function
This function temporarily overrides the outdoor reset curve in order
to satisfy a thermostat setpoint in a short amount of time, especially
during a relatively warm day.
Flue Temperature Modulation
As an additional safety feature, if the ue temperature exceeds
200oF, the control will modulate the VWH down based on the
vent temperature, rather than the supply temperature. If the ue
temperature exceeds 210oF the control will lock out the VWH.
System Sensor (Optional)
This sensor is designed to be used in a cascade system. The
system pipe sensor measures the temperature of return water and
communicates with the control system to modulate the ring rate of
the connected VWHs.
NOTE: When using a system sensor, pipe insulation must be
wrapped around it to improve temperature measurement accuracy
and increase overall system eciency.
External Low Water Cuto (Optional)
Connection points are provided on the Field Connection Board to
install an external LWCO if required by local codes.
B. How the VWH Operates
Condensing technology intelligently delivers large amounts of hot
water while maximizing eciency. Outlined below are the features of
the system and how they operate:
Stainless Steel Heat Exchanger
The highly ecient stainless steel heat exchanger is designed to
extract all available heat from the storage tank cold water return
before it is exhausted.
Modulating Combustion System
The combustion system modulates the output of the burner during
operation to match system demand and achieve the control set point
while in operation. The set point can change by internal or external
signals to enhance the overall performance of the system.
Control
The integrated control system monitors the system and regulates fan
speed to control VWH output. This allows the VWH to deliver only the
amount of heat energy required and nothing more.
The control can regulate the output of multiple VWHs through its
cascade system function. The cascade system is capable of connecting
up to eight VWHs together in such a way that they function as one
VWH system. This allows for greater turn down ratios and provides
systematic control of the multiple VWHs in an installation to minimize
downtime and maximize eciency.
The cascade system works by establishing one VWH as the master and
the other connected VWHs as followers. The master VWH requires a
sensor to provide feedback on set point temperature in order to adjust
heating input from the connected VWHs. Each cascaded VWH will have
its own pump to provide maximum ow and control heat exchanger
ow rate.
Text Display and Operational LED Light Indicators
The display allows the user to change system parameters and monitor
system outputs.
Gas Valve
Senses suction from the blower, allowing gas to ow only if powered
and combustion air is owing.
All Metal Integrated Venturi
Controls air and gas ow into the burner.
Burner
The high grade stainless steel burner uses premixed air and gas to
provide a wide range of ring rates.
Components (and Part #) included with the VWH:
• Temperature and Pressure Gauge (7250P-499)
• Pressure Relief Valve (7450P-254)
• Intake PVC Tee with Screens
• Exhaust PVC Coupling with Screens
• Outlet Combination Fitting (220 Model - 7450P-235, 299/301
Models - 7450P-236, 399 Model - 7450P-237)
• Flow Switch and Paddles (7250P-517)
• Installation Manual and Warranty
• CSD-1 Form
• H-3 Data Sheet
A. What’s in the Box
UNCRATING THE VWH - Any claims for damage or shortage in
shipment must be led immediately against the transportation
company by the consignee.
Remove the VWH and accessories from the packaging. Take care to
place the VWH and accessories in a safe location prior to installation to
prevent damage to the mechanical connections.
The VWH is also equipped with leveling feet that can be used to level
the VWH properly on an uneven location surface. If surface ooring is
rough, take care when moving the VWH into position, as catching the
leveling feet could damage the VWH.

LP-551 Rev. 000 Rel. 021 Date 4.2.21
10
Part 3 - Prepare the VWH
Optional equipment available from HTP (and Part #):
• Wall Mount Bracket (7450P-211)
• System Sensor (7250P-324)
• Indirect Tank Sensor (7250P-325)
• 3” Stainless Steel Vent Termination Kit (V1000)
• 4” Stainless Steel Vent Termination Kit (V2000)
• 6” Stainless Steel Vent Termination Kit (V3000)
• 2” PVC Concentric Vent Kit (KGAVT0501CVT)
• 3” PVC Concentric Vent Kit (KGAVT0601CVT)
• 3” Polypro Vent Kit (8400P-001)
• 3” Polypro Pipe
(33’ length # 8400P-002, 49.5’ length # 8400P-003)
• Low Water Cut-O Kit (7450P-904)
• Manual Reset High Limit (7450P-910)
• Alarm System (to monitor any failure) (7350P-602)
• 928 PC Connection Kit with Software (7450P-330)
• Condensate Neutralizer (220/299/301 Models - 7450P-212, 399
Model - 7350P-611)
• Eighty Gallon Glass-Lined Storage Tank (GL-80)
• Eighty Gallon Stainless Steel Storage Tank (SSU-80CB)
VWH Circulator Kits
• 220 Model - Part # 7450P-248
• 299 / 301 Models - Part # 7450P-249
• 399 Model - Part # 7450P-250
NOTE: When using an optional system sensor, pipe insulation must be
wrapped around it to improve temperature measurement accuracy
and increase overall system eciency.
COLD WEATHER HANDLING - If the VWH has been stored in a very
cold location (BELOW 0oF) before installation, handle with care until
the components come to room temperature. Failure to do so could
result in damage to the VWH.
Carefully consider installation when determining VWH location.
Please read the entire manual before attempting installation. Failure
to properly take factors such as VWH venting, piping, condensate
removal, and wiring into account before installation could result in
wasted time, money, and possible property damage and personal
injury.
ThisVWH is certied for indoor use only. DO NOT INSTALL OUTDOORS.
Outdoor installations ARE NOT covered by warranty. Failure to install
the VWH indoors could result in property damage, severe personal
injury, or death.
A. Locating the VWH
Incorrect ambient conditions can lead to damage to the heating
system and put safe operation at risk. Ensure that the installation
location adheres to the information included in this manual. Failure
to do so could result in property damage, serious personal injury,
or death. Failure of VWH or components due to incorrect operating
conditions IS NOT covered by product warranty.
This VWH must be installed upright in the vertical position as
described in this manual. DO NOT attempt to install thisVWH in any
other orientation. Doing so will result in improper VWH operation
and property damage, and could result in serious personal injury
or death.
1. Installation Area (Mechanical Room) Operating Conditions
• Ensure ambient temperatures are higher than 33oF / 0.6oC
and lower than 104oF / 40oC
• Prevent the air from becoming contaminated by the
products, places, and conditions listed in this manual
• Avoid continuously high levels of humidity
• Never close existing ventilation openings
• Ensure a minimum 1” clearance around hot water and
exhaust vent pipes
• NOTE: To prevent condensing in the fan, it is recommended
to avoid prolonged exposure to temperatures below 45oF
2. Check for nearby connections to:
• System water piping
• Venting connections
• Gas supply piping
• Electrical power
• Condensate drain
3. Check area around VWH. Remove any combustible materials,
gasoline, and other ammable liquids.
Failure to keep the VWH area clear and free of combustible
materials, liquids, and vapors can result in substantial property
damage, severe personal injury, or death.
C. Optional Equipment
Condensate Flue Check System
The check system prevents heat exchanger exhaust from backing up
into the cabinet.
Pump Service Mode
Allows manual operation of pumps to commission system and check
pump operation.
This VWH is heavy. Take precautions when moving the VWH into
its installation location to avoid tipping, bumping, or dropping it.
Failure to take such precautions may result in property damage,
severe personal injury, or death.
This VWH has a condensate disposal system that may freeze if
exposed to sustained temperatures below 32oF. Precautions
should be taken to protect the condensate trap and drain lines
from sustained freezing conditions. Failure to take precautions
could result in property damage, severe personal injury, or death.
Do not connect the VWH to any heating systems or components
that have been previously used for non-potable applications.
Do not introduce toxic chemicals, such as antifreeze or VWH
treatments, into the VWH or any piping meant for potable water
purposes.
Ensure that all piping and components connected to the VWH are
suitable for potable water applications.
Do not use this VWH for space heating applications.
Circulators suitable for DHW applications must be used.
Failure to follow these instructions could result in serious personal
injury or death.

LP-551 Rev. 000 Rel. 021 Date 4.2.21
11
4. Gas control system components must be protected from dripping
water during operation and service.
5. If the VWH is to replace an existing VWH, check for and correct any
existing system problems, such as:
• System leaks
• Location that could cause the system and VWH to freeze and
leak
• Incorrectly sized expansion tank
6. Clean and ush system when reinstalling a VWH.
NOTE: When installing in a zero clearance location, it may not be
possible to read or view some product labeling. It is recommended
to make note of the heater model and serial number.
NOTE: A combustible door or removable panel is acceptable front
clearance.
The service life of the VWH’s exposed metallic surfaces, such as
the casing, as well as internal surfaces, such as the heat exchanger,
are directly inuenced by proximity to damp and salty marine
environments. In such areas higher concentration levels of
chlorides from sea spray coupled with relative humidity can lead
to degradation of VWH components. In these environments,
heaters must not be installed using direct vent systems which
draw outdoor air for combustion. Such heaters must be installed
using room air for combustion. Indoor air will have a much lower
relative humidity, and hence potential corrosion will be minimized.
Failure of the VWH or components due to incorrect operating
conditions IS NOT covered by product warranty.
All VWHs eventually leak. Locate the VWH where any leakage from
the relief valve, related piping, tank, or connections will not result
in damage to surrounding areas or lower oors of the building.
Any VWH should be installed in such a manner that if it should
leak the resulting ow of water will not cause damage to the area
in which it is installed. National Plumbing codes require a drain
pan for any VWH installation. This drain pan should be sized with
a maximum depth of 2”, and a minimum diameter 2” greater than
the diameter of the VWH. The drain pan should empty into an
open drain line. This drain line should be 3/4” ID minimum, piped
to an open drain. Leakage damages ARE NOT covered by warranty.
Failure to install a drain pan is the sole responsibility of the owner
and/or installer. Reference UPC 2000 (Uniform Plumbing Code)
Section 510 - Protection from Damage or IPC 200 (International
Plumbing code) Section 504 - Safety Devices. Leakage damages
ARE NOT covered by warranty.
In addition, water leak detection devices and automatic water
shuto valves are readily available at plumbing supply houses. IT
IS HIGHLY RECOMMENDED BY THE MANUFACTURER TO INSTALL
WATER LEAK DETECTION DEVICES AND AUTOMATIC SHUTOFF
VALVES IN ANY VWH INSTALLATION WHERE A LEAKAGE OF WATER
COULD RESULT IN PROPERTY DAMAGES.
Always take future maintenance into consideration when locating
the VWH. If the VWH is located in an installation location with
limited clearances, it may be necessary to remove the VWH
from the space to perform maintenance. Failure to consider
maintenance when determining installation location could result
in property damage.
Do not mount the VWH to a hollow wall. Mount to the studs only.
Use extreme care not to drop the VWH or cause bodily injury while
lifting or mounting the VWH onto the optional wall mount bracket.
Gas conversion should be performed BEFORE the VWH is installed.
Carefully follow the gas conversion instructions when performing
the conversion.
Failure to follow these instructions could result in property damage,
severe personal injury, or death.
C. Leveling
In order for the condensate to properly ow out of the collection
system, the area where you locate the VWH must be level. Location
must also fully support the weight of the lled VWH.
CORRECT INCORRECT
Figure 1 - Correct and Incorrect Leveling
Ensure that the oor and structure of the installation location are
sucient to support the full installed weight of the VWH, including
water content of the heat exchanger and related piping. Failure
to ensure the oor and structure of the installation location are
structurally sound before installation of the VWH can result in
structural failure, substantial property damage, severe personal
injury, or death.
This VWH is approved for installation on combustible ooring,
but must never be installed on carpeting. Installing this VWH on
carpeting could result in re, property damage, severe personal
injury, or death.
B. Flooring

LP-551 Rev. 000 Rel. 021 Date 4.2.21
12
D. Clearances for Service Access
Figure 2 - Recommended Service Clearances
Precautions
If the VWH is located in a residential garage, per ANSI Z223.1:
• Install the VWH burner and ignition devices a minimum of
18”above the oor of the garage. This will ensure the burner
and ignition devices are well o the oor.
• When raising the VWH ensure the entire bottom and fully
lled weight of the VWH are fully supported.
• Locate or protect the VWH so it cannot be damaged by a
moving vehicle.
E. Residential Garage and Closet Installations
Check with your local Authority Having Jurisdiction for
requirements when installing theVWH in a garage or closet. Please
read the entire manual before attempting installation. Failure to
properly take factors such as venting, piping, condensate removal,
and wiring into account before installation could result in wasted
time, money, and possible property damage and personal injury.
The space must be provided with correctly sized combustion/
ventilation air openings for all other appliances located in the
space with the VWH. For power venting installations using room
air for combustion, refer to the venting section, this manual, for
descriptions of conned and unconned spaces. Do not install the
VWH in an attic. Failure to comply with these warnings could result
in substantial property damage, severe personal injury, or death.
F. Exhaust Vent and Intake Pipe
The VWH is rated ANSI Z21.13 Category IV (pressurized vent, likely
to form condensate in the vent) and requires a special vent system
designed for pressurized venting.
NOTE: The venting options described here (and further detailed
in the Venting section, this manual) are the lone venting options
approved for this VWH. Failure to vent the VWH in accordance
with the provided venting instructions will void the warranty.
Failure to vent the VWH properly will result in serious personal
injury or death.
Do not attempt to vent this VWH by any means other than those
described in this manual. Doing so will void the warranty and may
result in severe personal injury or death.
The exhaust discharged by this VWH may be very hot. Avoid
touching or other direct contact with the exhaust gases of the vent
termination assembly. Doing so could result in severe personal
injury or death.
Vents must be properly supported. VWH exhaust and intake
connections are not designed to carry heavy weight. Vent support
brackets must be within 1’ of the VWH and the balance at 4’
intervals. VWH must be readily accessible for visual inspection for
rst 3’from the VWH. Failure to properly support vents could result
in property damage, severe personal injury, or death.
1. Direct Vent of Exhaust and Intake
If installing a direct vent option, combustion air must be drawn
from the outdoors directly into the VWH intake and exhaust must
terminate outdoors. There are three basic direct vent options
detailed in this manual: 1. Side Wall Venting, 2. Roof Venting, and 3.
Unbalanced Venting.
NOTE: If you do not provide the minimum clearances shown in Figure
2 it might not be possible to service the VWH without removing it from
the space.
NOTE: A combustible door or removable panel is acceptable front
clearance.
Minimum Clearances from Combustible Materials
• Hot water pipes - at least 1”from combustible materials
• Exhaust vent pipe - at least 1”from combustible materials
NOTE: For closet installations, a combustible door or removable
panel is acceptable front clearance. A 3” minimum clearance must be
provided from the appliance front cover to the removable panel or
combustible door.
Appliance Area Ventilation Air Openings - Closet Installations
If the appliance is installed in a closet or alcove the appliance area/
room must be ventilated.
EXCEPTION: If the appliance area/room has a volume of 150 ft3or gre-
ater, ventilation of the appliance area/room is not required.
Each ventilation air opening must meet the minimum requirements
of 1 in2per 1000 BTU/hr., but not less than 100 in2. The lower ventila-
tion opening must be located within 6 in. of the oor, while the upper
opening must be located 6 in. from the top of the space.
WARNING
!
If the appliance area has a volume less than 150 ft3, it is considered a
Closet or Alcove. In the US/Canada, PVC vent pipe and ttings SHALL
NOT BE USED within the closet or alcove. Only approved CPVC,
Polypropylene, or Stainless Steel vent pipe and ttings may be used.
See Table 5 for a list of approved materials. Under all circumstances
proper ventilation must be provided.
The space must be provided with correctly sized combustion/
ventilation air openings for all other appliances located in the space
with the appliance. For power venting installations using room air for
combustion, refer to the appliance venting section, this manual, for
descriptions of conned and unconned spaces. Do not install the
appliance in an attic. The appliance cover must be securely fastened
to prevent the appliance from drawing air from the appliance room.
This is particularly important if the appliance is in a room with other
appliances. Failure to comply with the above warnings could result in
substantial property damage, severe personal injury, or death.
Alcove Installations
Alcove installations have the same minimum dimensions as closet
installations, except the installation must be completely open to the
room at a distance no greater than 18 in. (457 mm) from the front of
the appliance and the room must be at least three (3) times the size of
the alcove. Provided these conditions are met, the appliance requires
no extra ventilation air openings to the space. If these conditions are
not met, follow the requirements for Closet Installations.

LP-551 Rev. 000 Rel. 021 Date 4.2.21
13
This VWH requires fresh, uncontaminated air for safe operation and
must be installed in a mechanical room where there is adequate
combustion and ventilating air. NOTE: To prevent combustion air
contamination, see Table 5.
Combustion air from the indoor space can be used if the space has
adequate area or when air is provided through a duct or louver to
supply sucient combustion air based on the VWH input. Never
obstruct the supply of combustion air to the VWH. If the VWH is
installed in areas where indoor air is contaminated (see Table 5)
it is imperative that the VWH be installed as direct vent so that all
combustion air is taken directly from the outdoors into the VWH
intake connection.
Unconned space is space with volume greater than 50 cubic feet
per 1,000 BTU/hr (4.8 cubic meters per kW) of the total input rating of
all fuel-burning appliances installed in that space. Rooms connected
directly to this space through openings not furnished with doors are
considered part of the space. See Venting Section for details.
Conned space is space with volume less than 50 cubic feet per
1,000 BTU/hr (4.8 cubic meters per kW) of the total input rating of all
fuel-burning appliances installed in that space. Rooms connected
directly to this space through openings not furnished with doors are
considered part of the space.
When drawing combustion air from inside a conventionally
constructed building to a conned space, such space should be
provided with two permanent openings: one located 6” (15 cm)
below the space ceiling, the other 6” (15cm) above the space oor.
Each opening should have a free area of one square inch per 1,000
BTU/hr (22cm2/kW) of the total input of all appliances in the space,
but not less than 100 square inches (645cm2).
If the conned space is within a building of tight construction, air for
combustion must be obtained from the outdoors as outlined in the
Venting section of this manual.
2. Power Venting, Indoor Combustion Air in Conned or
Unconned Space
When drawing combustion air from the outside into the
mechanical room, care must be taken to provide adequate freeze
protection.
Failure to provide an adequate supply of fresh combustion air can
cause poisonous ue gases to enter the living space, resulting
in severe personal injury or death. To prevent combustion air
contamination, see Table 5.
In the Commonwealth of Massachusetts and As Required by
State and Local Codes:
Installation of Carbon Monoxide Detectors: At the time of installation
or replacement of the vented gas fueled appliance, the installing
plumber or gas tter shall observe that a hard wired carbon
monoxide detector with an alarm and battery back-up is installed
on the oor level where the gas appliance is installed, unless the
appliance is located in a detached, uninhabitable structure separate
from the dwelling, building, or structure used in whole or in part for
residential purposes.
G. Carbon Monoxide Detectors
Be sure to locate the VWH such that the exhaust vent and intake
piping can be routed through the building and properly terminated.
Dierent vent terminals can be used to simplify and eliminate
multiple penetrations in the building structure (see Optional
Equipment in Venting Section). The exhaust vent and intake piping
lengths, routing, and termination methods must all comply with the
methods and limits given in the Venting Section, this manual.
When installing a combustion air intake from outdoors, care must
be taken to utilize uncontaminated combustion air. To prevent
combustion air contamination, see Table 5.
In addition, the installing plumber or gas tter shall observe that a hard
wired carbon monoxide detector with an alarm and battery back-up is
installed on each additional level of the dwelling, building, or structure
served by the vented gas appliance. It shall be the responsibility of the
property owner to secure the service of qualied licensed professionals
for the installation of hard wired carbon monoxide detectors.
a. In the event that the vented gas fueled appliance is installed in a
crawl space or attic, the hard wired carbon monoxide detector with
alarm and battery back-up shall be installed on the next adjacent
oor level.
b. In the event that these requirements cannot be met at the time
of completion of installation, the owner shall have a period of thirty
(30) days to comply with the above requirements; provided, however,
that during said thirty (30) day period, a battery operated carbon
monoxide detector with an alarm shall be installed.
H. Prevent Combustion Air Contamination
Install intake air piping for the VWH as described in the Venting
Section, this manual. Do not terminate exhaust in locations that can
allow contamination of intake air.
Ensure that the intake air will not contain any of the contaminants in
Table 5. Contaminated air will damage the VWH, resulting in possible
substantial property damage, severe personal injury, or death. For
example, do not pipe intake air near a swimming pool or laundry
facilities. These areas always contain contaminants.
I. Removing a VWH from a Common Vent System
Failure to follow all instructions can result in ue gas spillage and
carbon monoxide emissions, causing severe personal injury or death.
Do not install the VWH into a common vent with any other appliance.
This will cause ue gas spillage or appliance malfunction, resulting
in possible substantial property damage, severe personal injury, or
death.
When removing an existing VWH, follow the steps below.
1. Seal any unused openings in the common venting system.
2. Visually inspect the venting system for proper size and horizontal
pitch to determine if there is blockage, leakage, corrosion, or other
deciencies that could cause an unsafe condition.
3. If practical, close all building doors, windows, and doors between the
space in which the VWH remains connected to the common venting
system and other spaces in the building. Turn on clothes dryers and
any appliances not connected to the common venting system. Turn
on any exhaust fans, such as range hoods and bathroom exhausts,
at maximum speed. Do not operate a summer exhaust fan. Close all
replace dampers.
4. Place in operation the appliance being inspected. Follow the
lighting instructions. Adjust the thermostat so the appliance will
operate continuously.
5. Test for spillage at the draft hood relief opening after 5 minutes of
main burner operation. Use the ame of a match or candle or smoke
from a cigarette.
Do not attempt to vent this appliance by any means other than those
described in this manual. Doing so will void the warranty and may
result in severe personal injury or death.
Approved Carbon Monoxide Detectors: Each carbon monoxide
detector as required in accordance with the above provisions shall
comply with NFPA 70 and be ANSI/UL 2034 listed and IAS certied.

LP-551 Rev. 000 Rel. 021 Date 4.2.21
14
Figure 3 - CO Warning Label
Products to Avoid Areas Likely to Have
Contaminants
Spray cans containing
uorocarbons
Dry cleaning / laundry areas
and establishments
Permanent wave solutions Swimming pools
Chlorinated waxes / cleaners Metal fabrication plants
Chlorine-based swimming pool
chemicals Beauty shops
Calcium chloride used for thawing Refrigeration repair shops
Sodium chloride used for water
softening Photo processing plants
Refrigerant leaks Auto body shops
Paint or varnish removers Plastic manufacturing plants
Hydrochloric or Muriatic acid Furniture renishing areas
and establishments
Cements and glues New building construction
Antistatic fabric softeners used in
clothes dryers Remodeling areas
Chlorine-type bleaches, laundry
detergents, and cleaning solvents Garages and workshops
Adhesives used to fasten building
products
Table 5 - Products and Areas Likely to Have Contaminants
NOTE: DAMAGE TO THE VWH CAUSED BY EXPOSURE TO
CORROSIVE VAPORS IS NOT COVERED BY WARRANTY. (Refer to
the limited warranty for complete terms and conditions.)
6. After it has been determined that each appliance remaining
connected to the common venting system properly vents when
tested as outlined, return doors, windows, exhaust fans, replace
dampers, and any other gas burning appliances to their previous
condition of use.
7. Any improper operation of the common venting system should
be corrected to conform to the National Fuel Gas Code, ANSI Z223.1.
When resizing any portion of the common venting system, the
system should approach the minimum size as determined using the
appropriate tables in Appendix G of ANSI Z223.1.

LP-551 Rev. 000 Rel. 021 Date 4.2.21
15
K. Technical Specications
Model 220 299 301 399
Installation Indoor, Floor Standing or Wall Mount (with Optional Kit), Fully Condensing
Minimum / Maximum Input (Btu/Hr) 22,000 / 220,000 30,000 / 299,000 30,000 / 301,000 40,000 / 399,000
Heating Capacity (MBH) 204 277 289 385
Flue System Category IV, Sealed Combustion Direct Vent, Power Vent
Minimum Combined Vent Run 16 feet
Maximum Combined Vent Run 3” (200 feet), 4” (275 feet) 4” (200 feet), 6”(275 feet)
Approved Exhaust Vent Materials PVC, CPVC, PP, Stainless Steel
Shipping Weight (lbs) 164 211 256
Gas Supply
Pressure
NG 3.5” to 14” WC
LP
Manifold
Pressure Min / Max NG/LP: -0.01”WC
Power Supply 120V 60 Hz, 6.3A
General Operating Conditions Ambient Temperature Range: 33 – 104oF (0.6 – 40oC)
Product Approvals and Requirements: ANSI Z21.13 / CSA 4.9
Ignition System Direct Electronic Spark Ignition / Flame Rectication
Burner System Premixed Fuel Modulation / Stainless Steel Metal Fiber Burner
Gas Valve System Air Ratio Valve
Dimensions
(in Inches)
W14.5
H24.5 36.5 36
D26.5 24.75 31.75
VWH Water Content (Gallons) 2.6 3.1 3.7
Minimum Flow Rate @ 30oF ∆T (GPM) 14.6 20 26
DHW Setpoint Temperature Range 95 – 180oF
Water Pressure
(PSI)
Heat Exchanger
MAWP 160
Pressure Relief
Valve 125
Control Panel / Main Controller LCD Display with LED Indicators / 928 SIT Control
Connection
Sizes
Supply / Return 1” NPTF 1 1/4” NPTF 1 1/2” NPTF
Gas Inlet 1” NPTF
Materials Cabinet Powder Coated Galvaneal Steel
Heat Exchanger 316L Stainless Steel Water Tube
Safety Devices
Flame Rectier Probe, Dual Water Supply Temperature Sensor (210oF), Water Pressure High
Limit Switch, Freeze Protection, Condensate Pressure Switch, Condensate Trap with Float, Dual
Flue Sensor (210oF), Blocked Vent Pressure Switch, Optional External Low Water Cut-O
Table 6 - Technical Specications

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Figure 4 - VWH Dimensions - NOTE: All Dimensions Are Approximate - VWH in Model Number Denotes Volume Water Heater Model

LP-551 Rev. 000 Rel. 021 Date 4.2.21
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Figure 5 - VWH Dimensions - NOTE: All Dimensions Are Approximate - VWH in Model Number Denotes Volume Water Heater Model

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Part 4 - Piping
Failure to follow the instructions in this section WILL VOID the
warranty and may result in property damage, severe personal injury,
or death.
A. General Plumbing Information
The building piping system must meet or exceed the the piping
requirements in this manual.
NOTE: The addition of a high temperature limiting device is important
if the VWH is to be connected to a domestic hot water system.
The domestic water connections must be installed in accordance to all
local and national plumbing codes, or any applicable standard which
prevails.
• Pipe material must be suitable to meet local codes and industry
standards.
• The pipe must be cleaned and without blemish before any
connections are made.
• All water piping should be insulated.
Connect the cold water supply to both the storage bottom port and
the supply side of the VWH (shown in Applications, this manual). It is
important that you install a ow check on the supply line of the VWH
BEFORE connecting the feed line to the storage tank. This allows the
cold feed to ow through the storage tank rst. It is recommended that
you install shut o valves on the cold feed line for future ease of service.
B. Backow Preventer
Use a backow preventer specically designed forVWH installations.
This valve should be installed on the cold water ll supply line per
local codes.
A potable hot water expansion tank is required to oset heated
water expansion. In most city plumbing systems, the water meter
has a no return or back ow device built into the system to prevent
back owing of water into city mains. Some local codes require
back ow preventers on all incoming water supplies. The hot water
expansion tank must be listed for potable water use. The expansion
tank should be located on the cold inlet piping close to the VWH.
Expansion Tank and Make-Up Water
1. Ensure that the expansion tank is sized to correctly handle VWH
and system water volume and temperature.
Plumbing of this product should only be done by a qualied, licensed
plumber in accordance with all local plumbing codes. The VWH is
designed to be connected to a storage tank to supply domestic hot
water. HTP oers 60/80/119/175 gallon size storage tanks in either
stainless steel or glass-lined construction. These storage tanks will be
directly connected to the VWH supply and return connection. Expansion tanks must be sized according to total system volume.
This includes all length of pipe, all xtures, VWHs, etc. Failure to
properly size for system expansion could result in wasted time,
money, possible property damage, serious injury, or death.
DO NOT pipe this VWH with black iron, galvanized steel, steel, or lead
pipe. Doing so will result in premature product failure and property
damage, and WILL VOID the warranty.
Do not apply a torch within 12” of the VWH. If sweat connections are
used, sweat tubing to the adapter before tting adapter to the water
connections on the heater. Damages due to improper installation
practices ARE NOT covered by warranty.
Dielectric unions or galvanized steel ttings must not be used in a
system with this VWH. Doing so WILL VOID the warranty. Use only
copper, brass, or stainless steel ttings. Teon thread sealant must be
used on all connections.
Use two wrenches when tightening water piping at heater. Use one
wrench to prevent the heater return or supply line from turning.
Failure to prevent piping connections from turning could cause
damage to heater components.
The heater control module uses temperature sensors to provide
both high limit protection and modulating temperature control.
The control module also provides low water protection by sensing
the water level in the tank. Some codes / jurisdictions may require
additional external controls.
Pump motors should not be supported by any type of stand due
to possible misalignment of pump and motor. Failure to follow this
instruction may result in property damage or personal injury.
If there is a back ow preventer or any type of no return valve in the
system, then you must install an additional tee for a suitable potable
hot water expansion tank. Connect the storage tank return line to
the return connection located on the VWH (shown in Applications,
this manual). Then connect the storage tank hot water outlet to the
hot water plumbing lines.
C. Potable Expansion Tank
Undersized expansion tanks cause system water to be lost from
the relief valve, causing make-up water to be added. Eventual
VWH failure can result due to excessive make-up water addition.
SUCH FAILURE IS NOT COVERED BY WARRANTY.
The expansion tank must be suitable for hot potable water
systems.
2. The expansion tank must be located as shown in Applications,
this manual, or following recognized design methods. See
expansion tank manufacturer’s instructions for details.
Expansion Tank Sizing*
Model Heat Exchanger Volume (Gallons)
220 2.6
299 / 301 3.1
399 3.7
Table 7 - *Add Required Storage Tank Gallon Size to Heat Exchanger
Volume - 60, 80, 119, and 175 Gallon Tanks Available
DO NOT install automatic air vents on closed type expansion tank
systems. Air must remain in the system and return to the tank to
provide an air cushion. An automatic air vent would cause air to
leave the system, resulting in improper operation of the expansion
tank.
D. Circulators
Every VWH system requires special attention to circulator size to
overcome pressure drop through the VWH and its related piping.
All circulators installed on the VWH system must be designed for
potable water installations. VWH pressure drop is detailed in this
manual.

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Water temperature above 140oF requires the circulator to run
continuously. Water hardness must be between 5 and 7 grains.
Hardness above 7 grains will damage the heat exchanger and
shorten the service life of the VWH.
DO NOT use the VWH circulator in any location other than the
ones shown in this manual. The VWH circulator location is selected
to ensure adequate ow through the VWH. Failure to comply with
this caution could result in unreliable performance and nuisance
shutdowns from insucient ow.
E. Flow Switch Installation
1. Choosing the correct ow paddle.
The VWH comes with a ow switch and four ow paddles. Use the
table below to determine which paddle to use with the VWH.
Model Paddle Size
220 H1
299 / 301 H2
399 H3
N/A H4
Table 8 - Flow Paddle Sizing
2. Use a Phillips Head screwdriver to attach ow paddle as shown
below.
3. Thread outlet combination tting onto supply outlet of VWH
using pipe dope.
4. Thread ow switch into outlet combination tting using pipe
dope, making certain the FLOW arrow points in the correct
direction.
5. Thread relief valve into outlet combination tting using pipe dope.
6. Thread temperature and pressure gauge into outlet combination
tting using pipe dope.
7. Connect red wire from ow switch to VWH wire harness.
8. When installation is complete, power up the VWH and program
set point. *Please note that these illustrations are meant only
to demonstrate installation. The installer is responsible for all
equipment and detailing required by local codes.
F. Relief Valve
To avoid water damage or scalding due to relief valve operation:
• Discharge line must be connected to relief valve outlet and
run to a safe place of disposal. Terminate the discharge line
in a manner that will prevent possibility of severe burns or
property damage should the relief valve discharge.
• Discharge line must be as short as possible and the same
size as the valve discharge connection throughout its entire
length.
• Discharge line must pitch downward from the valve and
terminate at least 6” above the oor drain, making discharge
clearly visible.
• The discharge line shall terminate plain, not threaded, with
a material serviceable for temperatures of 375oF or greater.
• Do not pipe discharge to any location where freezing could
occur.
• No valve may be installed between the relief valve and VWH
or in the discharge line. Do not plug or place any obstruction
in the discharge line.
• Test the operation of the relief valve after lling and
pressurizing the system by lifting the lever. Make sure the
valve discharges freely. If the valve fails to operate correctly,
immediately replace with a new properly rated relief valve.
• Test T&P valve at least once annually to ensure the waterway
is clear. If valve does not operate, turn the VWH “o”and call a
plumber immediately.
• Take care whenever operating relief valve to avoid scalding
injury or property damage.
FAILURE TO COMPLY WITH THE ABOVE GUIDELINES COULD RESULT
IN FAILURE OF RELIEF VALVE OPERATION, RESULTING IN POSSIBILITY
OF SUBSTANTIAL PROPERTY DAMAGE, SEVERE PERSONAL INJURY,
OR DEATH.
Connect discharge piping to a safe disposal location following the
guidelines below.

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H. High Velocity Circulator Pump
Minimum VWH Flow Rates
Model Minimum Flow (GPM)
220 14.6
299 / 301 20
399 26
Table 10 - Minimum Flow Rates
Every VWH system requires special attention to pump size in order
to overcome pressure drop through the VWH and its related piping.
All circulators installed on the VWH system must be designed for a
potable water system.
In addition, the heat exchanger has a minimum total water volume
that must be taken into account when sizing the circulator. Minimum
ow rates are listed in the table below.
RE-INSPECTION OF T&P RELIEF VALVES: T&P valves should be
inspected AT LEAST ONCE EVERY THREE YEARS, and replaced if
necessary, by a licensed plumbing contractor or qualied service
technician to ensure that the product has not been aected by
corrosive water conditions and to ensure that the valve and discharge
line have not been altered or tampered with illegally. Certain naturally
occuring conditions may corrode the valve and its components over
time, rendering the valve inoperative. Such conditions can only be
detected if the valve and its components are physically removed
and inspected. Do not attempt to conduct an inspection on your
own. Contact your plumbing contractor for a re-inspection to assure
continued safety.
Do not thread a cap or plug into the relief valve or relief valve line
under any circumstances! Explosion and property damage, serious
injury, or death may result.
FAILURE TO RE-INSPECT THE T&P VALVE AS DIRECTED COULD
RESULT IN UNSAFE TEMPERATURE AND/OR PRESSURE BUILD-UP
WHICH CAN RESULT IN PROPERTY DAMAGE, SERIOUS PERSONAL
INJURY, OR DEATH.
G. Scalding
This VWH can deliver
scalding water at any
faucet in the system. Be
careful whenever using
hot water to avoid scalding
injury. Certain appliances
such as dishwashers and
automatic clothes washers
may require increased
water temperatures. By
setting the thermostat
on this VWH to obtain
the increased water
temperature required by
these appliances you may
create the potential for
scald injury.
To protect against injury,
install a mixing valve in the
water system. This valve
will reduce point of use
discharge temperatures by
mixing cold and hot water
in branch supply lines. Such
valves are available from
your local plumbing supplier.
Table 9 details the relationship of water temperature and time with
regard to scald injury and may be used as a guide in determining the
safest water temperature for your applications.
The risk of scalding increases when raising tank temperature. Use a
water tempering or mixing valve when raising tank temperature to
lessen the chance of scalds. Consult codes for conformance. Failure
to install a temperature limiting or mixing valve and follow these
instructions could result in property damage, severe personal injury,
or death due to scalds.
Approximate Time / Temperature Relationships in Scalds
120oF More than 5 minutes
125oF 1 1/2 to 2 minutes
130oF About 30 seconds
135oF About 10 seconds
140oF Less than 5 seconds
145oF Less than 3 seconds
150oF About 1 1/2 seconds
155oF About 1 second
Table 9 - Approximate Time / Temperature Relationships in Scalds