Pioneer PHR100-55 User manual

120 Braley Rd. P.O. Box 429 East Freetown, MA 02717-0429 www.htproducts.com
Pioneer
INSTALLATION
START-UP
MAINTENANCE
PARTS
Pioneer Water Heater Models*
PHR100-55 / 130-55 / 160-55 / 199-55
*A suffix of “LP” denotes propane gas
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.

2
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 heater, 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.
This product is for installation in closed loop systems ONLY! Use of this product in any manner other
than described in this manual may result in premature product failure, substantial property damage,
severe personal injury, or death. Damage or failure of this product (or the system in which it is installed)
due to unauthorized use IS NOT COVERED BY WARRANTY.
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. WATER QUALITY ................................................................................................................................8
F. WINTERIZING ......................................................................................................................................9
PART 2 – BEFORE YOU START ................................................................................................................9
A. WHAT’S IN THE BOX...........................................................................................................................9
B. HOW THE HEATER OPERATES ........................................................................................................9
C. OPTIONAL EQUIPMENT...................................................................................................................11
PART 3 – DIMENSIONS AND CLEARANCES..........................................................................................12
PART 4 – PREPARE HEATER LOCATION ..............................................................................................13
A. BEFORE LOCATING THE HEATER..................................................................................................13
B. LEVELING ..........................................................................................................................................14
C. CLEARANCES FOR SERVICE ACCESS..........................................................................................14
D. RESIDENTIAL GARAGE INSTALLATION.........................................................................................14
E. EXHAUST VENT AND INTAKE AIR VENT........................................................................................14
1. DIRECT VENT INSTALLATION OF EXHAUST AND INTAKE.......................................................15
2. INDOOR COMBUSTION AIR INSTALLATION IN CONFINED OR UNCONFINED SPACE.........15
F. PREVENT COMBUSTION AIR CONTAMINATION...........................................................................16
G. REMOVING A HEATER FROM A COMMON VENT SYSTEM.........................................................16
PART 5 – PREPARE THE HEATER..........................................................................................................17
PART 6 – HEATER PIPING .......................................................................................................................18
A. GENERAL PIPING INFORMATION...................................................................................................18
B. RELIEF VALVE...................................................................................................................................18
C. BACKFLOW PREVENTER ................................................................................................................19
D. SYSTEM WATER PIPING METHODS ..............................................................................................19
E. CIRCULATOR PUMPS.......................................................................................................................19
F. INDIRECT FIRED WATER HEATER SCALDING..............................................................................20
G. HYDRONIC PIPING - CIRCULATORS, ZONE VALVES AND MULTIPLE HEATERS.....................20
H. FILL AND PURGE HEATING SYSTEM.............................................................................................21
I. ZONING WITH ZONE VALVES...........................................................................................................22
J. ZONING WITH CIRCULATORS .........................................................................................................22

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K. MULTIPLE HEATERS........................................................................................................................22
L. PIPING DETAIL ..................................................................................................................................23
PART 7 – VENTING, COMBUSTION AIR AND CONDENSATE REMOVAL...........................................26
A. GENERAL...........................................................................................................................................26
B. APPROVED MATERIALS FOR EXHAUST AND INTAKE AIR VENTS.............................................26
C. EXHAUST AND INTAKE AIR VENT PIPE LOCATION .....................................................................27
1. DETERMINE EXHAUST VENT LOCATION...................................................................................27
2. DETERMINE AIR INTAKE VENT LOCATION................................................................................27
D. EXHAUST AND INTAKE AIR VENT SIZING.....................................................................................28
E. LONGER VENT RUNS.......................................................................................................................29
F. EXHAUST VENT AND INTAKE AIR PIPE INSTALLATION...............................................................30
G. VENTING DRAWINGS.......................................................................................................................31
1. DIRECT VENT INSTALLATION OF EXHAUST AND INTAKE.......................................................31
2. INDOOR COMBUSTION AIR INSTALLATION IN CONFINED OR UNCONFINED SPACE.........37
H. EXHAUST VENT AND INTAKE AIR PIPE INSTALLATION..............................................................39
I. REMOVING AN EXISTING WATER HEATER....................................................................................39
J. CONDENSATE REMOVAL SYSTEM.................................................................................................40
PART 8 – FIELD WIRING...........................................................................................................................41
A. INSTALLATION MUST COMPLY WITH: ...........................................................................................41
B. FIELD WIRING...................................................................................................................................41
C. LINE VOLTAGE WIRING FOR STANDARD HEATER......................................................................42
D. THERMOSTAT...................................................................................................................................42
E. OUTDOOR SENSOR (OPTIONAL) ...................................................................................................43
F. INDIRECT SENSOR (OPTIONAL).....................................................................................................43
G. 0-10 VOLT BUILDING CONTROL SIGNAL (OPTIONAL).................................................................43
H. UL353 LOW WATER CUT-OFF INTERFACE KIT (OPTIONAL........................................................44
I. WIRING OF CASCADE SYSTEM COMMUNICATION BUS...............................................................44
J. CASCADE MASTER PUMP AND SENSOR WIRING........................................................................45
K. CASCADE FOLLOWER PUMP AND SENSOR WIRING ..................................................................46
PART 9 – START-UP PREPARATION......................................................................................................46
A. CHECK/CONTROL WATER CHEMISTRY........................................................................................47
B. FREEZE PROTECTION (WHEN USED) ...........................................................................................47
C. FILL AND TEST WATER SYSTEM....................................................................................................48
D. PURGE AIR FROM WATER SYSTEM..............................................................................................48
E. CHECK THERMOSTAT CIRCUIT(S).................................................................................................48

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F. FINAL CHECKS BEFORE STARTING HEATER...............................................................................49
PART 10 – START-UP PROCEDURE.......................................................................................................49
A. OPERATING INSTRUCTIONS ..........................................................................................................49
B. CASCADE SYSTEM...........................................................................................................................50
C. ADJUSTING THE SET POINT...........................................................................................................50
D. STATUS MENU..................................................................................................................................51
E. TEST MODE.......................................................................................................................................52
F. PURGE AIR FROM WATER SYSTEM...............................................................................................53
PART 11 – PROGRAMMING THE HEATER.............................................................................................53
A. PROGRAM ACCESS .........................................................................................................................53
B. PROGRAM SYSTEM SETTINGS ......................................................................................................53
PART 12 – TROUBLESHOOTING.............................................................................................................56
A. HEATER ERROR CODE....................................................................................................................56
B. HEATER ERROR ...............................................................................................................................56
C. HEATER FAULT.................................................................................................................................56
PART 13: MAINTENANCE.........................................................................................................................61
MAINTENANCE NOTES ............................................................................................................................64
HTP CUSTOMER INSTALLATION RECORD FORM........................................................................65
PART 1 – GENERAL SAFETY INFORMATION
A. PRECAUTIONS
This appliance is for indoor installations only. Clearance to combustible materials: 0” top, bottom, sides
and back. Front must have room for service, 24” recommended. (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. Category IV vent systems only.
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.
Be sure to disconnect electrical power before opening heater cabinet. Failure to do so could result in an
electrical shock that could result in serious injury or death.
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. WATER QUALITY
•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.
•Continual fresh make-up water will reduce heater life. Mineral buildup reduces heat transfer,
overheats the heat exchanger, and causes failure. Addition of oxygen by make-up water can
cause internal corrosion in system components. Leaks in the heater or piping must be repaired at
once.
•If you have an old system with cast iron radiators, thoroughly flush the system (without heater
connected) to remove sediment. Sediment can reduce the efficiency of the heater and, in extreme
cases, cause damage to the internal heat exchanger.
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 injury or death.

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F. WINTERIZING
NOTE: Consider piping and installation when determining heater location. Do not place the heater in an
area where it will be prone to freezing.
To winterize the heater, drain the entire system. Pump two gallons of non-toxic, NSF food grade, FDA
rated GRAS (Generally Recognized As Safe) propylene glycol into the tank. Consult the glycol
manufacturer for specific instructions on concentration percentage as well as freeze and burst protection
methods. Check the concentration of antifreeze to assure protection is adequate to protect the bottom of
the heater from freezing.
PART 2 – BEFORE YOU START
A. WHAT’S IN THE BOX
Also included with the heater:
•Pressure and Temperature Gauge
•30 psi Temperature and Pressure Relief Valve
•Intake PVC Tee with Screens
•Exhaust PVC Coupling with Screens
•Installation Manual
•Warranty
•Outdoor Sensor (Part # 7250P-319)
B. HOW THE HEATER OPERATES
Condensing Technology maximizes efficiency by measuring the needs of your heating system through
the use of sensors and a control unit. The heater uses data gathered by these sensors to intelligently
deliver highly efficient hydronic heating.
Heat Exchanger
The highly efficient combustion heat exchanger flows exhaust gas through the primary section into the
secondary heat exchanger section, where the coldest water on the bottom of the tank extracts the last
residual amount of energy.
Modulating Combustion System
Modulation during central heating operation is based on the supply temperature. The set point used for
the control depends upon the programmed central heating curve. The slope of the heating curve can be
changed by the heater installer. The control monitors the system, regulating burner output during
operation to match system demand, effectively increasing efficiency and providing substantial fuel
savings.
Gas Valve
The gas valve senses suction from the blower, allowing gas to flow only if combustion air is flowing.
Swirl Plate System
The Swirl Plate on the gas valve controls air and gas flow into the burner, assuring better mixing for
improved combustion.
Combination Top High Temperature Sensor
This sensor monitors supply temperature. The control module adjusts heater firing rate, correcting supply
temperature.

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Bottom Water Temperature Sensor
This sensor monitors return water temperature. The control module reduces or increases heater input
accordingly.
Temperature and Pressure Gauge
Allows the user to monitor system temperature and pressure.
Control
The integrated control system monitors return and supply water temperature. The control system
regulates the unit’s BTU output by controlling fan speed, allowing the unit to deliver only the amount of
heated energy required.
Burner
Constructed with metal fiber and stainless steel, the burner uses pre-mixed air and gas, providing a wide
range of firing rates.
Electrical Field Connections with Terminal Strips
The cabinet allows easy access to the line voltage and low voltage terminal strips, which are clearly
marked to facilitate wiring to the heater.
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. The 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 554200,
available from HTP).
A condensate filter, if required by local authorities, can be made up of lime crystals, marble or phosphate
chips, and will neutralize the condensate. This can be purchased from HTP (7450P-212) and installed in
the field.
It is also very important that the condensate line is not 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.
A second vent may be necessary to prevent a condensate line vacuum lock in a long, horizontal line.
Also, an increase in pipe size may be necessary to drain properly. Support of the condensation line may
be needed to avoid blockage of flow.
Spark Ignition
The burner flame ignites by applying high voltage to the system spark electrode. This causes a spark
from electrode to ground.
Outdoor Sensor
The outdoor sensor allows the installer to make the heater even more efficient by basing temperature
delivered to the central heating circuits on outdoor temperature. (See Optional Equipment, Section C).
(Optional) Indirect Tank Sensor – Indirect Priority
To control the temperature of low temperature heating circuits when using an indirect fired water heater, a
thermostatic mixing valve is required. Failure to install a thermostatic mixing valve could result in property
damage.

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The indirect sensor allows the installer to operate the heater with two temperatures: one for central
heating and the other for the SuperStor Indirect Water Heater. This allows the user to increase water
temperature supplied to the indirect to get faster recovery by prioritizing flow at a higher rate than may be
needed for central heating. NOTE: This application requires two separate circulators. (See Optional
Equipment, Section C).
C. OPTIONAL EQUIPMENT
Below is a list of optional equipment available from HTP:
•System Sensor (Part # 7250P-324)
•Indirect Tank Sensor (Part # 7250P-325)
•3” Stainless Steel Outside Termination Vent Kit (V1000)
•4” Stainless Steel Outside Termination Vent Kit (V2000)
•2” PVC Concentric Vent Kit (Part # KGAVT0501CVT)
•3" PVC Concentric Vent Kit (Part # KGAVT0601CVT)
•U.L. 353 Compliant Low Water Cut-Off Interface Kit with Manual Reset (Part # 7450P-225)
•Alarm System (Part # 7350P-602) (to monitor any failure)
•PC Connection Kit (Part # 7250P-320)
•Condensate Neutralizer (Part # 7450P-212)
•Vision 2 Temperature Mixing Control (Part # 7250P-322)
These additional options may be purchased through your HTP distributor.

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PART 3 – DIMENSIONS AND CLEARANCES
Figure 1 – LP-325-L

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CLEARANCE
ACCESS
PART 4 – PREPARE HEATER LOCATION
Before considering location, there are many factors to be addressed. These factors are covered in detail
in this installation manual. Please read the entire manual, as it could save time and money. Piping,
Venting, and Condensation Removal are just a few of the issues that need attention prior to the
installation of the heater.
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 water during operation and
service.
Figure 2 – LP-325-M

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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 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 heater when filled with water (650
lbs).
C. CLEARANCES FOR SERVICE ACCESS
See Part 3 for recommended service clearances. If you do not provide the minimum clearances shown, it
may not be possible to service the heater without removing it from the space.
The space must be provided with combustion/ventilation air openings correctly sized for all other
appliances located in the same space as the heater. The heater cover must be securely fastened to
prevent the heater from drawing air form the heater room. This is particularly important if the heater 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.
D. RESIDENTIAL GARAGE INSTALLATION
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.
•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 16 on page 38 for installation diagram.
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.
Ensure that the intake air will not contain any of the contaminants listed in Table 1. 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.
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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When removing an existing heater, 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
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.
PART 5 – PREPARE THE HEATER
UNCRATING HEATER – Any claims for damage or shortage in shipment must be filed immediately
against the transportation company by the consignee.
COLD WEATHER HANDLING
– If the heater has been stored in a very cold location (BELOW 0
o
F)
before installation, handle with care until the plastic components come to room temperature.
Remove all sides of the shipping crate to allow the heater to be lifted into its installation location.
Figure 4 - CO Warning Label
Figure 3

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PART 6 – HEATER PIPING
Plumbing of this heater should only be done by a qualified, licensed plumber in accordance with all local
plumbing codes. The heater may be connected to an indirect storage tank to supply domestic hot water.
HTP offers 30/45/60/80/119 gallon size indirect storage tanks in Stainless Steel or 50/80/119 in Glass
Lined construction. These indirect storage tanks will be directly connected to the supply and return
connection.
A. GENERAL PIPING INFORMATION
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 heater. Some codes/jurisdictions may require additional external controls.
B. RELIEF VALVE
Install supplied pressure and temperature relief valve. Connect discharge piping to a safe disposal
location, following the guidelines below. Replacement is available. See parts list.
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, replace with a new
properly rated relief valve.
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.
Never use dielectric unions for galvanized steel fittings when connecting to a stainless steel storage tank
or heater.

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C. BACKFLOW PREVENTER
Use a backflow preventer specifically designed for hydronic heater installations. This valve should be
installed on the cold water fill supply line per local codes (see Piping Details).
D. SYSTEM WATER PIPING METHODS
EXPANSION TANK AND MAKE-UP WATER
1. Ensure that the expansion tank is sized to correctly handle heater and system water volume and
temperature. The heater volume is 55 gallons.
Undersized expansion tanks cause system water to be lost from the relief valve, causing make-up water
to be added. Eventual heater failure can result due to excessive make-up water addition. SUCH
FAILURE IS NOT COVERED BY WARRANTY.
2. The expansion tank must be located as shown in the Heater Piping Details, or following recognized
design methods. See expansion tank manufacturer’s instructions for details.
3. Connect the expansion tank on the suction side of the circulator. Always install the system fill
connection at the same point as the expansion tank connection to the system.
4. Most chilled water systems are piped using a closed type expansion tank.
E. CIRCULATOR PUMPS
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.
SIZING SPACE HEAT SYSTEM PIPING
1. See piping details in this manual. Special attention must be paid when connecting an indirect storage
tank, as temperature delivered to low temperature circuits may be higher than desired. The use of
thermostatic mixing valves is required to protect these circuits.
To control the temperature of low temperature heating circuits when using an indirect fired water heater, a
thermostatic mixing valve is required. Failure to install a thermostatic mixing valve when using an indirect
fired water heater could result in serious personal injury or death due to scalds.
2. Size the piping and components in the space heating system using recognized design methods.

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F. INDIRECT FIRED WATER HEATER SCALDING
This heater 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 temperature. 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, you should install a mixing
valve in the water system. This valve will reduce
point of discharge temperature 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.
G. HYDRONIC PIPING - CIRCULATORS, ZONE VALVES AND MULTIPLE HEATERS
This heater is designed to function in a closed loop 15 PSI System. A factory installed low water cut off
will ensure that you have adequate water in the system. We have also included a T&P gauge which
allows the user to monitor system pressure and outlet temperature from the heater.
Install the heater so the gas ignition system components are protected from water (dripping, spraying,
etc.) allowing clearance for basic service of circulator replacement, valves and other parts. Observe
minimum 1” clearance around all hot water pipes not protected by non-combustible materials.
On a heater installed above radiation level, some states and local codes require a low water cut off device
at the time of installation. If the heater supplies hot water to heating coils in air handler units, flow control
valves or other devices must be installed to prevent gravity circulation of heater water in the coils during
the cooling cycle. Chilled water medium must be piped in parallel with the heater.
Basic steps are listed below which will guide you through the installation of the heater.
1. Connect the system return marked “Return”.
2. Connect the system supply marked “Supply”.
3. Install purge and balance valve or shut off valve and drain on system return to purge air out of each
zone.
4. Install a back flow preventer on the cold feed make-up water line.
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