HTP Versa Hydro PHE130-55 Installation manual

120 Braley Rd. P.O. Box 429 East Freetown, MA 02717-0429 www.htproducts.com
Versa-Hydro
INSTALLATION
START-UP
MAINTENANCE
PARTS
Versa-Hydro Water Heater Models*
PHE130-55 / 199-55
PHE130-80 / 199-80
PHE130-119 / 199-119
*A suffix of “LP” denotes propane gas
“S” indicates solar models
“SNHX” indicates solar models without heat exchanger
NOTICE: HTP reserves the right to make product changes or updates without notice and will not be held
liable for typographical errors in literature.
This manual must be used by a qualified installer/service technician. Read all instructions in this manual
before installing. Perform steps in the given order. Failure to comply could result in substantial property
damage, severe personal injury, or death.

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IF THE INFORMATION IN THIS MANUAL IS NOT FOLLOWED EXACTLY, A FIRE OR EXPLOSION
MAY RESULT, CAUSING PROPERTY DAMAGE, PERSONAL INJURY, OR LOSS OF LIFE. DO NOT
STORE GASOLINE OR OTHER FLAMMABLE VAPORS AND LIQUIDS IN THE VICINITY OF THIS OR
ANY OTHER APPLIANCE.
WHAT TO DO IF YOU SMELL GAS
•Do not try to light any appliance.
•Do not touch any electrical switch.
•Do not use any phone in your building.
•Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s
instructions.
•If you cannot reach your gas supplier, call the fire department. Installation and service must be
provided by a qualified installer, service agency, or the gas supplier.

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The following defined 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 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.
FOREWORD
This manual is intended to be used in conjunction with other literature provided with the heater. This
includes all related control information. It is important that this manual, all other documents included with
this system, and additional publications including the National Fuel Gas Code, ANSI Z223.1-2002, be
reviewed in their entirety before beginning any work.
Installation should be made in accordance with the regulations of the local code authorities and utility
companies which pertain to this type of heating equipment.
NOTE TO CONSUMER: PLEASE KEEP ALL INSTRUCTIONS FOR FUTURE REFERENCE.

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FOR THE INSTALLER
This appliance must be installed by qualified and licensed personnel. The installer should be guided by
the instructions furnished with the boiler, and with local codes and utility company requirements. In the
absence of local codes, preference should be given to the National Fuel Gas Code, ANSI Z223.1-2002.
INSTALLATIONS MUST COMPLY WITH:
Local, state, provincial, and national codes, laws, regulations and ordinances.
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.
In Canada – CGA No. B149 (latest version), from Canadian Gas Association Laboratories, 55 Scarsdale
Road, Don Mills, Ontario, Canada M3B 2R3. Also, Canadian Electrical Code C 22.1, from Canadian
Standards Association, 5060 Spectrum Way, Suite 100, Mississauga, Ontario, Canada L4W 5N6.
Code for the installation of Heat Producing Appliances (latest version), from American Insurance
Association, 85 John Street, New York, NY 11038.
The latest version of the National Electrical Code
, NFPA No. 70.
NOTE: The gas manifold and controls met safe lighting and other performance criteria when undergoing
tests specified in ANSI Z21.10.3 – latest edition.
This manual must only be used by a qualified heating installer/service technician. Read all instructions in
this manual before installing. Perform steps in the order given. Failure to comply could result in severe
personal injury, death or substantial property damage.

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TABLE OF CONTENTS
PART 1 – GENERAL SAFETY INFORMATION..........................................................................................7
A. PRECAUTIONS ....................................................................................................................................7
B. IMPROPER COMBUSTION..................................................................................................................8
C. GAS.......................................................................................................................................................8
D. WHEN SERVICING THE HEATER ......................................................................................................8
E. HEATER WATER..................................................................................................................................8
PART 2 – HOW THE HEATER OPERATES................................................................................................8
PART 3 – PREPARE WATER HEATER LOCATION................................................................................10
A. BEFORE LOCATING THE HEATER..................................................................................................10
B. LEVELING...........................................................................................................................................10
C. CLEARANCES FOR SERVICE ACCESS..........................................................................................11
D. RESIDENTIAL GARAGE INSTALLATION.........................................................................................11
E. EXHAUST VENT AND INTAKE AIR VENT........................................................................................11
1. DIRECT VENT INSTALLATION OF EXHAUST AND INTAKE .......................................................12
2. INDOOR COMBUSTION AIR INSTALLATION IN CONFINED OR UNCONFINED SPACE..........12
F. PREVENT COMBUSTION AIR CONTAMINATION ...........................................................................13
G. REMOVING A HEATER FROM A COMMON VENT SYSTEM..........................................................13
H. WATER CHEMISTRY.........................................................................................................................14
PART 4: DOMESTIC WATER PIPING.......................................................................................................15
A. TEMPERATURE AND PRESSURE RELIEF VALVE FOR DHW.......................................................15
B. DOMESTIC HOT WATER EXPANSION TANK..................................................................................16
C. DOMESTIC WATER PIPING..............................................................................................................17
D. HEATER PIPING ................................................................................................................................17
E. MIXING VALVE INSTALLATION........................................................................................................17
F. AUXILIARY PIPING ............................................................................................................................20
PART 5: HYDRONIC PIPING.....................................................................................................................20
A. HYDRONIC HEATING MODULE PIPING..........................................................................................20
B. PRESSURE RELIEF VALVE FOR THE HYDRONIC SYSTEM.........................................................21
C. HYDRONIC EXPANSION TANK AND MAKE UP WATER................................................................21
D. HYDRONIC HEATING MODULE SYSTEM PIPING..........................................................................21
E. HYDRONIC HEATING MODULE OUTPUT........................................................................................22
F. HYDRONIC PIPING............................................................................................................................25
PART 6: FIELD WIRING ............................................................................................................................30
A. FIELD WIRING COMPLIANCE REQUIREMENTS ............................................................................30

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B. FIELD WIRING....................................................................................................................................30
C. LINE VOLTAGE WIRING....................................................................................................................30
D. LOW VOLTAGE WIRING ...................................................................................................................30
E. FIELD CONNECTION BOARD...........................................................................................................31
F. INTERNAL WIRING............................................................................................................................32
PART 7: GAS CONNECTION....................................................................................................................33
A. GAS SUPPLY .....................................................................................................................................33
B. GAS PIPING .......................................................................................................................................33
C. GAS TABLE........................................................................................................................................34
D. GAS VALVE........................................................................................................................................34
E. HOW TO VERIFY COMBUSTION......................................................................................................35
PART 8: VENTING, COMBUSTION AIR AND CONDENSATE REMOVAL.............................................35
A. GENERAL...........................................................................................................................................36
B. APPROVED MATERIALS FOR EXHAUST AND INTAKE AIR VENTS.............................................36
C. EXHAUST AND INTAKE AIR VENT PIPE LOCATION......................................................................36
1. DETERMINE EXHAUST VENT LOCATION....................................................................................36
2. DETERMINE AIR INTAKE VENT LOCATION ................................................................................37
D. EXHAUST AND INTAKE AIR VENT SIZING......................................................................................39
E. LONGER VENT RUNS.......................................................................................................................39
F. EXHAUST AND INTAKE AIR VENT INSTALLATION........................................................................40
G. VENTING DRAWINGS.......................................................................................................................41
1. DIRECT VENT INSTALLATION OF EXHAUST AND INTAKE .......................................................41
2. INDOOR COMBUSTION AIR INSTALLATION IN CONFINED OR UNCONFINED SPACE..........47
H. CONDENSATE REMOVAL SYSTEM ................................................................................................49
PART 9: CONTROL OVERVIEW...............................................................................................................50
A. NAVIGATION OF THE DISPLAY .......................................................................................................50
B. PROGRAMMING THE CONTROL.....................................................................................................50
C. APPLIANCE SETTING PROGRAM NAVIGATION MENU ................................................................51
D. PROGRAMMING THE SYSTEM SETTING.......................................................................................53
E. SYSTEM SETTING PROGRAM NAVIGATION..................................................................................53
F. CONTROL STATUS MENU................................................................................................................56
PART 10: START-UP PROCEDURE.........................................................................................................59
A. FILL AND PURGE DHW.....................................................................................................................60
B. FILL AND PURGE HYDRONIC HEATING LOOP..............................................................................60
C. PURGE AIR FROM HYDRONIC HEATING MODULE.......................................................................61

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D. HEATER PUMP CONTROL TO ASSIST IN PURGING AIR FROM SYSTEM LOOPS.....................61
E. PROGRAMMING THE TOTAL SYSTEM CONTROL.........................................................................61
PART 11: SHUTDOWN AND MAINTENANCE .........................................................................................64
A. SHUTDOWN PROCEDURE...............................................................................................................64
B. VACATION PROCEDURE..................................................................................................................65
C. MAINTENANCE..................................................................................................................................65
D. FAILURE TO OPERATE.....................................................................................................................65
PART 12: TROUBLESHOOTING ..............................................................................................................65
A. APPLIANCE ERROR CODE ..............................................................................................................65
B. APPLIANCE ERROR..........................................................................................................................66
C. APPLIANCE FAULT ...........................................................................................................................66
D. APPLIANCE CONTROL FAULT CODES...........................................................................................66
PART 13: MAINTENANCE.........................................................................................................................80
MAINTENANCE NOTES ............................................................................................................................83
HTP CUSTOMER INSTALLATION RECORD FORM ........................................................................84
PART 1 – GENERAL SAFETY INFORMATION
A. PRECAUTIONS
This appliance is for indoor installations only. Clearance to combustible materials: 0” top, bottom, sides
and back. Unit must have room for service: 24” front and 12” sides are minimum recommended service
clearances. (A combustible door or removable panel is acceptable front clearance.) This appliance has
been approved for closet installation. Do not install this appliance directly on carpeting. For installation on
combustible flooring. Use only Category IV vent systems.
INSTALLER – Read all instructions in this manual before installing. Perform steps in the order given.
USER – This manual is for use only by a qualified heating installer/service technician. Refer to user’s
information manual for your reference. Have this heater serviced/inspected by a qualified service
technician annually.
FAILURE TO ADHERE TO THE GUIDELINES ON THIS PAGE CAN RESULT IN SUBSTANTIAL
PROPERTY DAMAGE, SEVERE PERSONAL INJURY, OR DEATH.

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NOTE: If the heater is exposed to the following, do not operate until all corrective steps have been made
by a qualified serviceman:
1. FIRE
2. DAMAGE
3. WATER
Any claims for damage or shortage in shipment must be filed immediately against the transportation
company by the consignee.
DO NOT USE THIS APPLIANCE IF ANY PART HAS BEEN UNDERWATER. Immediately call a qualified
service technician. Replace any part of the control unit that has been under water.
B. IMPROPER COMBUSTION
NOTE: Do not obstruct the flow of combustion and ventilating air. Adequate air must be provided for safe
operation.
C. GAS
Should overheating or gas supply fail to shut off, do not turn off or disconnect electrical supply to
circulator. Instead, shut off the gas supply at a location external to the appliance.
D. WHEN SERVICING THE HEATER
•To avoid electric shock, disconnect electrical supply before performing maintenance.
•To avoid severe burns, allow heater to cool.
E. HEATER WATER
•Do not use petroleum-based cleaning or sealing compounds in a heater system. Gaskets and
seals in the system may be damaged. This can result in substantial property damage.
•Do not use “homemade cures” or “heater patent medicines”. Substantial property damage,
damage to heater, and/or serious personal injury may result.
PART 2 – HOW THE HEATER OPERATES
The Versa Hydro with Total System Control is truly revolutionary, providing high efficiency central
heating and domestic hot water from one appliance. Total System Control manages system needs,
assuring maximum comfort and efficient operation. Some features of the heater are:
Stainless Steel Water Storage Tank
The storage tank is constructed of 316L stainless steel to provide maximum corrosion resistance. Water
blown foam insulation and a plastic jacket provide superior insulation, allowing no more than a ½ degree
heat loss per hour.
High Efficiency Heat Exchanger
The highly efficient 90/10 copper nickel heat exchanger provides direct energy transfer from the
combustion gases into domestic water. Hot gases travel from the primary circuit to heat the combustion
walls, which then transfer heat directly into the water. The secondary circuit then transfers the last bit of

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energy to the bottom of the tank, where the hot gases are converted to water vapor, giving the heater a
combustion efficiency of 98% and thermal efficiency of up to 96%.
Modulating Combustion System
The modulating combustion system is designed to regulate firing rate based on heat demand. Total
System Control monitors tank operation, system parameters, and controls the firing rate of the burner,
providing only the energy required to satisfy both the domestic hot water and central heating needs.
Total System Control
Total System Control automatically manages the needs of both the central heating and domestic hot
water systems through the use of sensors. These sensors monitor inputs (such as outdoor temperature,
tank temperature, and heating module outlet temperature) providing data that allows accurate control of
the entire system. You may choose to use the control’s factory default settings or reprogram the system
parameters to provide design flexibility.
Hydronic Heating Module
The hydronic heating module connects to the storage tank through two dip tubes. The first dip tube draws
heated water from the top of the storage tank and circulates it through a brazed plate heat exchanger that
transfers the water’s stored energy to the hydronic side of the plate. Once the energy is transferred, the
water returns through the second dip tube to a lower section of the storage tank to continue circulating. A
stainless steel circulator pump modulates output, varying flow through the brazed plate heat exchanger to
meet domestic hot water and central heating demand. An outlet sensor provides feedback to the control
to assure accurate temperature control.
Venting System
This appliance vents in plastic pipe. Use only the approved venting material outlined in the venting
section (Part 8) of this manual. Vent size can vary from 2” to 3” depending on the appliance input rate.
The venting system requires an intake and exhaust vent. Special attention should be taken when
selecting vent location. Vents can run horizontally or vertically, depending on system design. Support the
vents as shown in the Venting Details Part 8.
Burner
The burner is constructed of high grade stainless steel and uses pre-mixed air and gas to provide a wide
range of firing rates.
Condensate Drain Connection
This is a condensing high efficiency appliance, and therefore has a condensate removal system.
Condensate is nothing more than water vapor derived from combustion products. Heater condensate is
similar to that of an automobile when it is initially started.
It is very important that the condensate line slopes away from the heater, down to a suitable drain. If the
condensate outlet is lower than the drain, you must use a condensate removal pump (kit p/n 554200,
available from HTP).
A condensate filter, if required by local authorities, will neutralize the condensate, and can be made up of
lime crystals, marble or phosphate chips. This filter can be purchased from HTP (p/n 7450P-212) and
installed in the field.
It is also very important that the condensate line not be exposed to freezing temperatures or any other
type of blockage. Plastic pipe must be the only material used for condensate line. Steel, brass, copper, or
other materials will be subject to corrosion or deterioration.
In a long, horizontal condensate line, a second vent may be necessary to prevent vacuum lock. Also, an
increase in pipe size and support of the condensation line may be necessary to allow condensate to drain
properly.

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Spark Ignition
The burner flame is ignited by applying high voltage to the system spark electrode. This causes a spark
from electrode to ground.
Outdoor Sensor
The outdoor sensor monitors outdoor temperature and adjusts the set point to provide greater efficiency.
Water temperature over 125oF can instantly cause severe burns, or death, from scalds. Children,
disabled, and elderly are at the highest risk of being scalded. See instruction manual before
setting temperature at water heater. Feel water before bathing or showering! Temperature limiting
valves are available.
PART 3 – PREPARE WATER HEATER LOCATION
Before considering location, many factors need to be addressed. Piping, Venting, and Condensation
Removal are just a few of the issues that need attention prior to the installation of the heater. Please read
the entire manual, as it could save time and money.
A. BEFORE LOCATING THE HEATER
Check for nearby connections to:
•System water piping
•Venting connections
•Gas supply piping
•Electrical power
•Condensate drain
Check area around heater. Remove any combustible materials, gasoline, and other flammable liquids.
Failure to keep heater area clear and free of combustible materials, liquids, and vapors can result in
substantial property damage, severe personal injury, or death.
The heater gas control system components must be protected from dripping or spraying water during
operation and service.
If replacing an existing heater, check for and correct any existing system problems, such as:
•System leaks
•Heater is located in a condition that could cause the system to freeze and leak.
•Incorrectly-sized expansion tank
•Clean and flush existing system when reinstalling a heater.
B. LEVELING
In order for the condensate to properly flow out of the collection system, the area where you locate the
heater must be level. Location must also fully support the weight of the filled water heater.

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C. CLEARANCES FOR SERVICE ACCESS
Figure 1 - If you do not provide the minimum clearances shown above, it might not be possible to service the
heater without removing it from the space.
A water heater pan must be installed to protect the surrounding area from damage caused by leaking
water.
The space must be provided with combustion/ventilation air openings correctly sized for all other
appliances located in the same space as the heater. Failure to comply with the above warnings could
result in substantial property damage, severe personal injury, or death.
D. RESIDENTIAL GARAGE INSTALLATION
PRECAUTIONS
If the heater is located in a residential garage, per ANSI Z223.1:
•Mount the bottom of the heater a minimum of 18” above the floor of the garage, to ensure the
burner and ignition devices are well off the floor.
•When raising the heater, be certain to fully support its entire filled weight.
•Locate or protect the heater so it cannot be damaged by a moving vehicle.
E. EXHAUST VENT AND INTAKE AIR VENT
The heater is rated ANSI Z21.10.3 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 Venting, Part 8 in this manual)
are the lone venting options approved for this water heater. Failure to vent the water heater in
accordance with the provided venting instructions will void the warranty.
Failure to vent the water heater properly will result in serious personal injury or death.
Vents must be properly supported. Heater intake and exhaust connections are not designed to carry
heavy weight. Vent support brackets must be within 1’ of the heater and the balance at 4’ intervals.
Heater must be readily accessible for visual inspection for the first 3’ from the heater.

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1. DIRECT VENT INSTALLATION OF EXHAUST AND INTAKE
If installing a direct vent option, combustion air must be drawn from the outdoors directly into the
appliance intake, and exhaust must terminate outside. There are three basic direct vent options detailed
in this manual: 1. Side Wall Venting, 2. Roof Venting, and 3. Unbalanced Venting.
Be sure to locate the heater such that the air intake and exhaust vent piping can be routed through the
building and properly terminated. Different vent terminals can be used to simplify and eliminate multiple
penetrations in the building structure (see Optional Equipment in Venting Section). The air intake and
exhaust vent piping lengths, routing and termination methods must all comply with the methods and limits
given in the Venting section, Part 8 of this manual.
When installing a combustion air intake from outdoors, care must be taken to utilize uncontaminated
combustion air. NOTE: To prevent combustion air contamination, see Table 1.
2. INDOOR COMBUSTION AIR INSTALLATION IN CONFINED OR UNCONFINED SPACE
This heater 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 1.
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 sufficient combustion air based on the appliance input. Never obstruct
the supply of combustion air to the appliance. If the appliance is installed in areas where indoor air is
contaminated (see Table 1) it is imperative that the appliance be installed as direct vent so that all
combustion air is taken directly from the outdoors into the appliance intake connection.
Unconfined space is space with volume greater than 50 cubic feet per 1,000 Btu/hour (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
Figure 25, p. 48 for details.
Confined space is space with volume less than 50 cubic feet per 1,000 Btu/hour (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 confined 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 floor. 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 confined space is within a building of tight construction, air for combustion must be obtained from
the outdoors as outlined in the Venting section, Part 8 of this manual.
When drawing combustion air from the outside into the mechanical room, care must be taken to provide
adequate freeze protection.
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.

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Failure to provide an adequate supply of fresh combustion air can cause poisonous flue gases to enter
living space, which could result in severe personal injury or death. NOTE: To prevent combustion air
contamination, see Table 1.
F. PREVENT COMBUSTION AIR CONTAMINATION
Install intake air piping for the heater as described in the Venting section. Do not terminate exhaust in
locations that can allow contamination of intake air.
You must pipe outside air to the heater air intake. Ensure that the intake air will not contain any of the
contaminants below. Contaminated air will damage the heater, resulting in possible substantial property
damage, severe personal injury, or death. For example, do not pipe intake air vent near a swimming pool.
Also, avoid areas subject to exhaust fumes from laundry facilities. These areas always contain
contaminants.
PRODUCTS TO AVOID
AREAS LIKELY TO HAVE CONTAMINANTS
Spray cans containing fluorocarbons
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 refinishing 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 1 – Contaminant Table
G. REMOVING A HEATER FROM A COMMON VENT SYSTEM
Do not install the heater into a common vent with any other appliance. This will cause flue gas spillage or
appliance malfunction, resulting in possible substantial property damage, severe personal injury, or death.
Failure to follow all instructions can result in flue gas spillage and carbon monoxide emissions, causing
severe personal injury or death.
When removing an existing heater, follow the steps below.
NOTE: DAMAGE TO THE HEATER CAUSED BY EXPOSURE TO CORROSIVE VAPORS IS NOT
COVERED BY WARRANTY. (Refer to the limited warranty for complete terms and conditions).

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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
deficiencies that could cause an unsafe
condition.
3. If practical, close all building doors, windows
and doors between the space in which the
appliance 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 fireplace 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
flame of a match or candle or smoke from a cigarette.
6. After it has been determined that each appliance remaining connected to common venting system
properly vents when tested as outlined, return doors, windows, exhaust fans, fireplace dampers and any
other gas burning appliance 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 in the
National Fuel Gas Code, ANSI Z 223.1.
H. WATER CHEMISTRY
Chemical imbalance of your water can cause severe damage to your water heater and associated
equipment, and may also affect efficiency. You may have to have your water quality professionally
analyzed to determine whether you need to install a water softener. It is important that the water
chemistry on both the domestic hot water and central heating sides are checked before installing the
heater, as water quality will affect the reliability of the system.
Outlined below are those water quality parameters which need to be met in order for the system to
operate efficiently for many years. Failure of a heat exchanger due to lime scale build-up on the
heating surface, low pH or other imbalance IS NOT covered by the warranty.
Water Hardness
Water hardness is mainly due to the presence of calcium and magnesium salts dissolved in the water.
The concentration of these salts is expressed in mg/L, ppm or grains per gallon, as a measure of relative
hardness of water. Grains per gallon is the common reference measurement used in the U.S. water
Figure 2

15
heater industry. Hardness expressed as mg/L or ppm may be divided by 17.1 to convert to grains per
gallon. Water may be classified as very soft, slightly hard, moderately hard, or hard based on its hardness
number. The minerals in the water precipitate out when the water is heated and cause accelerated lime
and scale accumulation on a heat transfer surface.
If the hardness of the water exceeds the maximum level of 7 grains per gallon, water should be softened
to a hardness level no lower than 5 grains per gallon. Water softened as low as 0 to 1 grain per gallon
may be under-saturated with respect to calcium carbonate, resulting in water that is aggressive and
corrosive.
pH of Water
pH is a measure of relative acidity, neutrality or alkalinity. Dissolved minerals and gases affect water pH.
The pH scale ranges from 0 to 14. Water with a pH of 7.0 is considered neutral. Water with a pH lower
than 7 is considered acidic. Water pH higher than 7 is considered alkaline. A neutral pH (around 7) is
desirable for most potable water applications. Corrosion damage and heater failures resulting from
water pH levels of lower than 6 or higher than 8 ARE NOT covered by the warranty.The ideal pH
range for water used in a storage tank or a water heater system is 7.2 to 7.8.
Total Dissolved Solids
Total Dissolved Solids (TDS) is a measurement of all minerals and solids dissolved in a water sample.
The concentration of total dissolved solids is usually expressed in parts per million (ppm).
Water with a high TDS concentration will greatly accelerate lime and scale formation in the hot water
system. Most high TDS concentrations precipitate out of the water when heated. This can generate a
scale accumulation on the heat transfer surface that will greatly reduce the service life of a water heater.
This scale accumulation can also impede the ability of the heat exchanger to transfer heat into the water.
A heat exchanger damaged or blocked by lime/scale accumulation must be replaced.
The manufacturer of the water heater has no control of water quality, especially TDS levels in your
system. Total dissolved solids in excess of 2,000 ppm will accelerate lime and scale formation in the heat
exchanger. Heat exchanger failure due to total dissolved solids in excess of 2,000 ppm is a non-
warrantable condition. Failure of a water heater due to lime scale build up on the heating surface IS
NOT covered by the warranty.
Hardness: 7 grains
Chloride levels: 100
pH levels: 6-8
TDS: 2000
PART 4: DOMESTIC WATER PIPING
A. TEMPERATURE AND PRESSURE RELIEF VALVE FOR DHW
Install a temperature and pressure relief valve into the marked port (upper right). We recommend a
WATTS 40XL5 valve or equivalent for 130,000 BTU models or above input. The valve must meet the
ANSI Z21.22B requirements for relief valves for hot water heaters as per a nationally recognized lab that
maintains a periodic inspection of production of such listed safety device. The pressure rating of the valve
must not exceed the listed working pressure of this appliance, and must be rated to the proper BTU/hr
capacity of the water heater.

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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 floor
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 shutoff valve may be installed between the relief valve and heater or in the discharge line. Do
not plug or place any obstruction in the discharge line.
•Test the operation of the relief valve after filling 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 heater “off” 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.
Do not, under any circumstances, thread a cap or plug into the relief valve! Explosion, serious injury or
death may result. Relief valve piping must be directed to the floor or an open drain, but not connected.
There must be a 6" space between the outlet of relief valve piping and drain or floor. Do not hook up to
drain system directly without an air space. The relief valve must be checked periodically for proper
operation.
B. DOMESTIC HOT WATER EXPANSION TANK
A potable hot water expansion tank is required to offset the expansion as the water is heated. In most city
plumbing systems, the water meter has a no return or back flow device built into the system to prevent
water flowing back into city mains. Some local codes require back flow 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 water heater.
The expansion tank must be suitable for hot potable water.
Never use dielectric unions or galvanized steel fittings on any domestic water or auxiliary
connections. Use only copper or brass fittings. Thread sealant must be used on all connections.

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C. DOMESTIC WATER PIPING
Domestic water connections must be installed in accordance with all local and national plumbing codes or
any applicable prevailing standards. The appliance is supplied with a rated mixing valve certified to ASSE
1017. You must completely follow the instructions included with the mixing valve for proper installation.
This mixing valve must be installed on the domestic outlet to assure that hot water temperature does not
vary more than +/– 5°F, as the unit adjusts its stored water automatic set point to meet the requirements
of the hydronic heating module. The valve MUST NOT be allowed to freeze. If the mixing valve is
installed in a potentially freezing situation, suitable insulation must be fitted to prevent damage. DO NOT
use excess thread sealant (in liquid, tape or other form) as this may cause the mixing valve to fail. Toxic
chemicals shall not be introduced into the mixing valve system.
Recommend to the user that the mixing valve be checked annually to ensure its continued
function.
D. HEATER PIPING
The domestic inlet and outlet ports on the heater are 1” NPT connections. We recommend the installation
of shut-off valves and unions on both the inlet and outlet ports to isolate the appliance for future service.
It is important that the connections on the inlet and outlet are brass or copper. Never use dielectric unions
or galvanized steel fittings. Teflon thread sealant must be used to seal all tank connections. An approved
ASSE 1017 mixing valve is provided with every appliance and must be installed on the outlet to protect
the user from scalding temperatures. This valve reduces the point of discharge temperature by mixing the
hot and cold water from the discharge outlet or mixed outlet port. This device alone will not protect the
user from scalding temperature. To install and set up the mixing valve, follow the pre-installation steps in
this manual and also follow the enclosed instructions included with the mixing valve.
E. MIXING VALVE INSTALLATION
The mixing valve provided with this appliance must be installed on the hot water outlet connection to
reduce the risk of scalding. This mixing valve only reduces the risk of scalding injury.
1. All installations must be carried out by licensed
professionals.
2. The installer must ensure compatibility of all
installations. Example: Temperature of hot water
– marked “H”, cold water inlet – marked “C”, and
mixed outlet – marked with directional arrow.
3. The mixing valve may be installed in any
position.
APPROXIMATE TIME / TEMPERATURE
RELATIONSHIPS IN SCALDS
120oF
More than 5 minutes
125oF
1 ½ to 2 minutes
130oF
About 30 seconds
135oF
About 10 seconds
140oF
Less than 5 seconds
145oF
Less than 3 seconds
150oF
About 1 ½ seconds
155oF
About 1 second
Table 2

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4. Local codes shall take priority over any inconsistency in these instructions.
5. During startup, you must ensure that the valve is set to the desired temperature (the mixing valve
preset is 120oF). If the valve temperature needs to be adjusted, please refer to the mixing valve
instructions and/or the following settings.
Hotter water increases the risk of scald injury. Scalding may occur within 5 seconds at a setting of
140oF (60oC). Water temperature over 125oF can instantly cause severe burns, or death, from
scalds. Children, disabled, and elderly are at the highest risk of being scalded. See instruction
manual before setting temperature at water heater. Feel water before bathing or showering!
This water heater can deliver scalding temperature water at any faucet in the system. Be careful
whenever using hot water to avoid scalding injury. By setting the thermostat on this water heater to obtain
increased water temperature, you may create a higher potential for scald injury. To protect against injury,
you should install an ASSE approved thermostatic mixing valve (a device to limit the temperature of water
to protect against scaled injury by mixing hot and cold water supply) in the system. This valve will reduce
point of discharge temperature in branch supply lines. This water heater was shipped with an ASSE
approved thermostatic mixing valve. Install this valve according to the directions in the mixing device
container. DO NOT OPERATE THIS WATER HEATER WITHOUT AN ASSE APPROVED
THERMOSTATIC MIXING DEVICE. If this water heater was shipped without an ASSE approved
thermostatic mixing valve, contact the manufacturer.
Mixing Valve Specification
Max. Hot Water Inlet Temperature 210oF
Min. Cold Water Inlet Temperature 39oF
Inlet Pressure 200 PSI
Outlet Water Temperature Range 85oF – 150oF
Min. Temperature Differential 20oF
(Between Hot Supply and Outlet)
Performance –
CV – ½” 3.3
Max Flow – 1” 24 gpm
The mixing valve maintains a constant outlet temperature of +/– 5˚ F given limited variation of water inlet
temperature and pressure.
NOTE:At low flow operation, the outlet temperature may vary slightly more.
Differential pressure at the valve inlet should be within a 5 to 1 ratio under normal flow conditions.
Inline fittings, pipe work, layout and sizing must be taken into consideration. In installations where the
valve is supplied with unbalanced hot cold pressures greater than a 5 to 1 ratio, please call HTP
Technical Support Department.

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The mixing valve is certified to ASSE 1017. It is not to be used to provide anti-scald service resulting from
system pressure fluctuations, and should not be used where more sophisticated compensating
temperature controls are required.
Installation of the Mixing Valve
1. Flush all pipe work thoroughly (with water only) before installing the mixing valve.
2. The mixing valve comes complete with union type connections for ease of installation and service.
3. The mixing valve must be removed from the pipe work prior to soldering the end connections. It is
recommended to use a spacer piece while soldering.
Do not solder unions while attached to the valve body. Solder connections prior to connecting
unions to the valve body to avoid damaging the valve and its function.
Setting the Mixing Valve Outlet Temperature
1. Remove the green knob by inserting a small screw driver in the notch and gently prying up as shown in
Fig. 3-1.
2. Set the mixing valve after the tank has heated to its set point. To set the valve, disconnect the outdoor
sensor from the control so the domestic hot water will reach its set point temperature (default setting is
160°F). Once domestic hot water has reached its set point, turn both the hot and cold water supplies on.
Open an outlet, preferably a sink or basin faucet rather than a shower. To calibrate, let water run for 2
minutes and measure the outlet temperature with a thermometer. Using the groove on the top of the
cover provided to fit over adjustment nut, adjust the knob counter clockwise to increase temperature and
clockwise to decrease temperature, as shown in Fig. 3-2.
Figure 3 – 1 and 2
3. Once the desired outlet temperature has been achieved, refit the green top so that it snaps onto the
body of the mixing valve.
4. Re-connect the outdoor sensor.
MIXING VALVE MAINTENANCE AND SERVICE
•It is recommended to check the mixing valve annually to ensure proper system capabilities. More
frequent checks are recommended in adverse water conditions.

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•When checking the mixed water supply temperature, use the same faucet used in the initial
installation temperature adjustment.
•There may be some variation in the water temperature from the mixing valve due to seasonal
temperature variations in the cold water supply.
If the water supply is of poor quality, the internal components may jam, requiring an additional
filter or strainer to be fitted to the system. Contact a plumbing professional for appropriate
materials and installation.
F. AUXILIARY PIPING
Auxiliary connections are provided to connect to an air handler, plate exchanger or other additional
devices. Auxiliary ports can also be used for recirculation line connections. These connections must be
installed in accordance with all local and national codes or any applicable prevailing standards. Auxiliary
connections are 1” on all models. Never use dielectric unions or galvanized steel fittings. Use only copper
or brass fittings. Teflon sealant must be used on all connections. The top port has a dip tube that draws
hot water from the dome of the unit and the bottom port dip tube returns the water to bottom of the unit.
Never connect auxiliary connections to any system that uses glycol or other solutions formulated for
hydronic systems. These auxiliary connections are to be used only in a potable water system. Failure to
follow this warning could result in death or serious injury.
PART 5: HYDRONIC PIPING
A. HYDRONIC HEATING MODULE PIPING
The hydronic heating module comes
pre-plumbed and connected directly
to the storage tank. The heated
water inside the tank will be
circulated through one side of the
brazed plate heat exchanger while
the heating system water flows
through the other side. The heating
system piping is connected to the
return and supply pipes located on
the top of the hydronic heating
module (see Figure 4). Piping of the
module to the system is not complex
and does not require any of the
primary or secondary piping normally
used on high efficiency low mass
boilers.
Figure 4