HTP RGH-150 User manual

272 Duchaine Blvd. New Bedford, MA 02745 www.htproducts.com
LP-590 REV. 3.23.17
Crossover
Water Heater
INSTALLATION
START-UP
MAINTENANCE
PARTS
RGH-150 / 199 Models*
*“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.
NOTE TO CONSUMER: PLEASE KEEP ALL INSTRUCTIONS FOR FUTURE REFERENCE.
The surfaces of these products contacted by consumable water contain less than 0.25% lead by weight, as required by the Safe
Drinking Water Act, Section 1417.
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 WATER HEATER.
WHAT TO DO IF YOU SMELL GAS
Do not try to light any water heater.
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.
California Proposition 65 Warning: This product contains chemicals known to the State of California to cause cancer, birth defects, or
other reproductive harm.

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LP-590 REV. 3.23.17
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.
NOTICE
SAFETY INSTRUCTIONS
NOTICE is used to address practices not related to personal
injury.
SAFETY INSTRUCTIONS (or equivalent) signs indicate specific
safety related instructions or procedures.
NOTE: Contains additional information important to a procedure.

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LP-590 REV. 3.23.17
FOREWORD
This manual is intended to be used in conjunction with other literature provided with the water 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 Authority Having Jurisdiction, local code authorities, and utility
companies which pertain to this type of water heating equipment.
Authority Having Jurisdiction (AHJ) –The Authority Having Jurisdiction may be a federal, state, local government, or individual such
as a fire chief, fire marshal, chief of a fire prevention bureau, labor department or health department, building official or electrical
inspector, or others having statutory authority. In some circumstances, the property owner or his/her agent assumes the role, and at
government installations, the commanding officer or departmental official may be the AHJ.
NOTE: HTP, Inc. reserves the right to modify product technical specifications and components without prior notice.
FOR THE INSTALLER
This appliance must be installed by qualified and licensed personnel. The installer should be guided by the instructions furnished with
the water 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.
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 substantial property damage, severe personal injury, or death.

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LP-590 REV. 3.23.17
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 the water heater underwent tests specified
in ANSI Z21.10.3 –latest edition.
TABLE OF CONTENTS
PART 1 –ITEMS SHIPPED WITH THE WATER HEATER.........................................................................................................6
PART 2 –SAFETY REGULATIONS ...........................................................................................................................................7
A. OPERATION AND INSTALLATION WARNINGS.......................................................................................................................7
B. IMPROPER COMBUSTION .......................................................................................................................................................8
C. GAS............................................................................................................................................................................................8
D. WHEN SERVICING THE WATER HEATER ..............................................................................................................................8
E. WATER CHEMISTRY REQUIREMENTS...................................................................................................................................8
F. FREEZE PROTECTION.............................................................................................................................................................9
G. SCALDING.................................................................................................................................................................................9
H. HIGH ELEVATION INSTALLATIONS.......................................................................................................................................10
PART 3 –TECHNICAL SPECIFICATIONS...............................................................................................................................10
PART 4 –PREPARE WATER HEATER LOCATION................................................................................................................13
A. BEFORE LOCATING THE WATER HEATER..........................................................................................................................13
B. LEVELING................................................................................................................................................................................14
C. CLEARANCES FOR SERVICE ACCESS................................................................................................................................14
D. RESIDENTIAL GARAGE AND CLOSET INSTALLATIONS.....................................................................................................15
E. EXHAUST VENT AND INTAKE PIPE.......................................................................................................................................15
F. CARBON MONOXIDE DETECTORS.......................................................................................................................................15
G. PREVENT COMBUSTION AIR CONTAMINATION.................................................................................................................15
H. REMOVING A WATER HEATER FROM A COMMON VENT SYSTEM ..................................................................................16
I. UNCRATING THE WATER HEATER........................................................................................................................................17
J. WALL-MOUNTING THE WATER HEATER ..............................................................................................................................17
PART 5 –VENTING...................................................................................................................................................................18
A. INTAKE PIPE AND EXHAUST VENT GUIDELINES................................................................................................................18
B. APPROVED VENT MATERIALS..............................................................................................................................................20
C. ALLOWED COMBINED VENT LENGTHS...............................................................................................................................21
D. TIGHTENING WATER HEATER COLLAR TO EXHAUST VENT AND INTAKE PIPE.............................................................22
E. VENT TERMINATION ..............................................................................................................................................................23
1. Direct Vent, Two Pipe Roof and Sidewall Vent Terminations................................................................................................23

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LP-590 REV. 3.23.17
2. Direct Vent, Optional Horizontal and Vertical Vent Kits.........................................................................................................24
3. Screen Installation.....................................................................................................................................................................24
4. Power Venting, Indoor Combustion Air Installation in Confined or Unconfined Space......................................................25
PART 6 –INSTALL THE CONDENSATE DRAIN.....................................................................................................................27
PART 7 –GAS PIPING..............................................................................................................................................................27
A. GAS PIPE SIZING TABLES .....................................................................................................................................................27
1. Gas Pipe Sizing..........................................................................................................................................................................27
2. Natural Gas Pipe Sizing ............................................................................................................................................................27
3. LP (Liquid Propane) Gas Pipe Sizing.......................................................................................................................................28
B. GAS CONNECTION REQUIREMENTS...................................................................................................................................28
C. ADDITIONAL PRECAUTION FOR EXCESS FLOW VALVE (EFV) .........................................................................................30
D. ADJUSTING GAS PRESSURE AT THE WATER HEATER.....................................................................................................30
E. SETTING AND VERIFYING THE COMBUSTION SETTING ...................................................................................................30
PART 8 –WATER PIPING ........................................................................................................................................................31
A. GENERAL PLUMBING CONNECTION GUIDELINES.............................................................................................................31
B. INSTALL A BACKFLOW PREVENTER....................................................................................................................................32
C. PIPING THE WATER HEATER................................................................................................................................................32
D. APPLICATIONS .......................................................................................................................................................................32
E. CIRCULATOR SIZING .............................................................................................................................................................41
F. PRESSURE RELIEF VALVE....................................................................................................................................................42
PART 9 –CONNECT ELECTRICAL POWER / INITIAL STARTUP .........................................................................................42
A. WIRING INFORMATION..........................................................................................................................................................43
B. DIP SWITCHES........................................................................................................................................................................43
PART 10 –OPERATING SYSTEM INSTRUCTIONS................................................................................................................49
A. CONTROL PANEL ...................................................................................................................................................................49
B. LCD DISPLAY DESCRIPTIONS ..............................................................................................................................................49
C. START-UP SEQUENCE ..........................................................................................................................................................49
D. CHANGING THE DHW SET-POINT ........................................................................................................................................50
E. CHANGING THE TIME.............................................................................................................................................................51
F. STATUS DISPLAY....................................................................................................................................................................51
G. INSTALLER MODE..................................................................................................................................................................52
H. USING RECIRCULATION MODES –STEP 1 .........................................................................................................................54
I. RECIRCULATION FUNCTIONS –USING RECIRCULATION MODES –STEP 2....................................................................55
1. Smart Auto-Learn Recirculation Function...............................................................................................................................56
2. Pro1, Pro2, Pro3, and PULS Recirculation Functions............................................................................................................56
J. ERROR MODE .........................................................................................................................................................................57
K. ERROR TREE ANALYSIS........................................................................................................................................................61
1. FLAME DETECTION...................................................................................................................................................................61
2. GAS DETECTION .......................................................................................................................................................................61
3. AIR PRESSURE SWITCH...........................................................................................................................................................62
4. Recirculation / Inlet / DHW / Operating Temperature / Exhaust SENSORS ..........................................................................62

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LP-590 REV. 3.23.17
PART 11 –FINAL INSTALLATION CHECKLIST .....................................................................................................................63
PART 12 –TROUBLESHOOTING ............................................................................................................................................65
PART 13 –MAINTENANCE PROCEDURES............................................................................................................................66
REPLACEMENT PARTS ................................................................................................................................................................69
Limited Warranty for RGH-150 / 199 Water Heaters....................................................................................................................74
MAINTENANCE REPORT ..............................................................................................................................................................76
MAINTENANCE NOTES.................................................................................................................................................................78
CUSTOMER INSTALLATION RECORD FORM.............................................................................................................................79
PART 1 –ITEMS SHIPPED WITH THE WATER HEATER
ITEM
DESCRIPTION
QUANTITY
Hybrid Water Heater
1
User and Installation Manuals
1 Each
Condensate Hose
(7855P-089)
1
Anchors and Wall Mounting
Bracket
(7850P-084)
4
Spare Parts Kit
(Gaskets and O-Rings)
(7850-280)
1
LP Conversion Kit –150 Model
(Part #7855P-698)
LP Conversion Kit –199 Model
(Part #7855P-452)
1
Vent Screens (3”)
(7850P-085)
2 Screens
OPTIONAL PARTS (Not Included)
150 PSI Pressure Relief Valve
(7850P-103)
1
¾” Tankless DHW Isolation
Valves
(7850P-090)
2

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LP-590 REV. 3.23.17
Vent Screens (2” Mesh)
(7850P-088)
2 Screens
Table 1 –Items Included with the Water Heater
PART 2 –SAFETY REGULATIONS
A. OPERATION AND INSTALLATION WARNINGS
To avoid serious injury or death, read, understand, and follow all the precautions listed here.
Vapors from flammable liquids will explode and can cause a fire, resulting in personal injury or death. The water heater has a burner
that can come on at any time and ignite vapors. DO NOT use or store flammable liquids around the water heater.
Improper venting can cause a build-up of carbon monoxide. Breathing carbon monoxide can result in brain damage or death. DO NOT
operate the water heater unless it is properly vented to the outside and has an adequate fresh air supply for safe operation. Inspect the
exterior exhaust gas outlet port and fresh air inlet port on a regular basis to ensure they are functioning properly.
A concentration of carbon monoxide as small as .04% (400 parts per million) in the air can be fatal. When making high fire or low fire
adjustments, CO levels must be monitored using a flue gas analyzer such that a CO level of no more than 150 ppm is exceeded at any
time during operation.
Adjusting the “low fire offset” or the “main flow restrictor” in small increments can result in a significant increase in CO concentration. To
avoid serious injury or death, DO NOT make any adjustments to the gas valve without monitoring the exhaust gases with a fully
functional and calibrated flue gas analyzer.
This water heater must be installed by a licensed plumber, licensed gas fitter, and/or professional service technician. Improper
installation and/or operation can cause a potentially hazardous situation, which, if not avoided, could result in serious injury or death,
and will void the warranty.
HTP, Inc. cannot anticipate every circumstance that might involve a potential hazard. Each installation has its own specialized
characteristics, requirements, and possible hazards. Therefore, all possible incidents are not included in these warnings. Proper and
safe installation, operation, and service are the responsibility of the professional service technician.
Proper care of the water heater is the user’s responsibility. Ensure the user carefully reads and understands the User’s Information
Manual before operating and maintaining the water heater.
Make sure the user knows the location of the gas shut-off valve and how to operate it. Immediately close the gas shut-off valve if the
water heater is subjected to fire, overheating, flood, physical damage, or any other damaging condition that might affect the operation of
the unit. Have the water heater checked by a qualified technician before resuming operation.
Do not power up the unit unless the gas and water supply valves are fully opened. Make sure the fresh air intake port and exhaust gas
port are open and functional.
No one but a professional service technician should attempt to install, service, or repair this water heater. There are no serviceable
parts which can be changed by the user / owner. User / Owner: Contact the original professional service technician if the water heater
needs repair or maintenance. If the original technician is unavailable, ask your gas supplier for a list of qualified service providers.
Keep the area around the water heater clean and free of all materials that can burn. DO NOT store or place gasoline, oils, spray paint,
or other flammable products near the water heater.
DO NOT use spray paint, hair spray, or any other flammable spray near the water heater or near the exterior fresh air intake port. DO
NOT place any items in or around the exterior exhaust gas outlet port and/or fresh air inlet port that could restrict or block the flow in or
out of the vent system.
DO NOT store or place newspapers, laundry, or other combustible items near the water heater or the exterior exhaust gas outlet and/or
fresh air inlet port.
The owner should inspect the system monthly for damage, water stains, signs of rust, corrosion, and exhaust vent and air intake
blockage. If inspection of the unit shows signs of damage, the water heater should be shut off until the problem is repaired by a
qualified technician.
After installation, all water heater safety devices should be tested.
This water heater is certified for indoor installations only. The water heater consists of gas ignition system components which must be
protected from water (dripping, spraying, etc.) during operation and service. Carefully consider installation location and the placement of
critical components (circulators, condensate neutralizers, etc.) before installing the water heater.
DO NOT allow children to operate this unit. DO NOT use this unit if it does not appear to be operating correctly. A qualified technician
should service and inspect the water heater annually.
The water heater temperature is factory set to 125oF (51.7oC). To avoid scalding, always check the temperature of the hot water before
bathing, showering, washing, etc. DO NOT adjust the water temperature while the water heater is being used by other persons.

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LP-590 REV. 3.23.17
NOTICE
If the water heater is exposed to the following, do not operate until all corrective steps have been made by a qualified service
technician:
1. FIRE
2. DAMAGE
3. WATER
DO NOT alter or modify the water heater or water heater controls. This can be dangerous and WILL VOID the warranty.
This water heater is equipped with a three prong plug. It should only be plugged directly into a properly grounded three prong
receptacle. DO NOT remove the ground plug from the plug.
Any claims for damage or shortage in shipment must be filed immediately against the transportation company by the consignee.
This water heater provides a overheat shutdown limit. In the event the water heater water exceeds the set point of the control limit, the
cutoff will trip and the water heater will shut down. Certain local codes require additional temperature limits. In addition, certain types of
systems may operate at temperatures below the minimum set point of the limit provided with the water heater. Contact HTP, Inc. for
additional overheat controls.
NOTE: When inquiring about service or troubleshooting, reference the model and serial numbers from the water heater rating label.
DO NOT USE THIS APPLIANCE IF ANY PART HAS BEEN SUBMERGED IN WATER. Immediately call a qualified service technician.
The appliance MUST BE replaced if it has been submerged. Attempting to operate an appliance that has been submerged could create
numerous harmful conditions, such as a potential gas leakage causing a fire and/or explosion, or the release of mold, bacteria, or other
harmful particulates into the air. Operating a previously submerged appliance could result in property damage, severe personal injury,
or death.
NOTE: Appliance damage due to flood or submersion is considered an Act of God, and IS NOT covered under product warranty.
Be sure to disconnect electrical power before opening water heater cabinet or performing service. Label all wires while performing
service to ensure proper re-wiring of the water heater. Wiring errors can cause improper or dangerous operation. Failure to do so could
result in an electrical shock, improper water heater operation, property damage, serious personal injury, or death.
B. IMPROPER COMBUSTION
Do not obstruct the flow of combustion and ventilating air. Adequate air must be provided for safe operation. Failure to keep the
exhaust vent and intake pipe clear of ice, snow, or other debris could result in property damage, serious personal injury, or death.
C. GAS
Should overheating or gas supply fail to shut off, do not turn off or disconnect electrical supply to the circulator. Instead, shut off the gas
supply at a location external to the appliance.
D. WHEN SERVICING THE WATER HEATER
To avoid electric shock, disconnect electrical supply before performing maintenance.
To avoid severe burns, allow water heater to cool.
Do not use petroleum-based cleaning or sealing compounds in a water heater system. Gaskets and seals in the system may
be damaged, possibly resulting in substantial property damage.
Do not use “homemade cures” or “patent medicines”. Substantial property damage, damage to water heater, and/or serious
personal injury may result.
Always verify proper operation after servicing the water heater.
E. WATER CHEMISTRY REQUIREMENTS
Chemical imbalance of the water supply may affect efficiency and cause severe damage to the appliance and associated equipment.
Water quality must be professionally analyzed to determine whether it is necessary to treat the water. Various solutions are available to
adjust water quality. Adverse water quality will affect the reliability of the system. In addition, operating temperatures above 135oF will
accelerate the build-up of lime scale and possibly shorten appliance service life. Failure of an appliance due to lime scale build-up, low
pH, or other chemical imbalance IS NOT covered by the warranty.
The water must be potable, free of corrosive chemicals, sand, dirt, and other contaminates. It is up to the installer to ensure the water
does not contain corrosive chemicals or elements that can damage the heat exchanger. Potable water is defined as drinkable water
supplied from utility or well water in compliance with EPA secondary maximum contaminant levels (40 CFR Part 143.3) as shown in the
table below. If the water contains contaminants higher than outlined by the EPA, water treatment is recommended and additional, more
frequent maintenance may be required.

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LP-590 REV. 3.23.17
If you suspect that your water is contaminated in any way, discontinue use of the appliance and contact an authorized technician or
licensed professional.
Contaminant
Maximum Allowable Level
Contaminant
Maximum Allowable Level
Total Hardness
(Residential Use - Below 140oF water
temperature)
200 mg/l
(12 grains/gallon)
Manganese
0.05 mg/l or PPM
Total Hardness
(Commercial Use - 140oF and above
water temperature)
120 mg/l
(7 grains/gallon)
pH
6.5-8.5
Aluminum
0.05 to 0.2 mg/l or PPM
Sulfate
205 mg/l or PPM
Chloride
100 mg/l or PPM
Total Dissolved Solids (TDS)
500 mg/l or PPM
Copper
1 mg/l or PPM
Zinc
5 mg/l or PPM
Iron
0.3 mg/l or PPM
Dissolved Carbon Dioxide
(CO2)
15 mg/l or PPM
Table 2 –Water Quality Specifications
F. FREEZE PROTECTION
Consider water heater piping and installation when determining water heater location.
NOTE: Damages resulting from incorrect installation or from use of products not approved by HTP, Inc. ARE NOT covered by warranty.
The water heater control is equipped with freeze protection that activates based on internal water temperature. See the table below for
details on freeze protection operation.
NOTE: Freeze protection will not be active if the water heater loses power.
System Freeze Protection
(Activates Based on Internal Water
Temperature)
Freeze Protection Operation
Stage 1 –If control detects water temperature of 46oF (8oC) and below, it turns the internal and external pumps
On for 600s and Off for 30s. This cycle repeats until the control detects return water temperature of 50oF (10oC)
and above.
Stage 2 –If control detects water temperature of 41oF (5oC) and below, it turns the burner on to meet a target
temperature of 104oF (40oC). The burner and internal and external pumps will run continuously during this stage
until the control detects return water temperature of 104oF (40oC) and above.
Stage 3 - If control detects water temperature of 34oF (1oC) and below, Er: 85 will appear on the display.
Table 3 –Freeze Protection Detail
G. 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 4 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.
Table 4 –Time and Temperature Relationship in Scalds
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

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LP-590 REV. 3.23.17
H. HIGH ELEVATION INSTALLATIONS
Natural gas at high elevation might contain less heating value than typical 1,000 BTU/cu ft and therefore can cause improper air / gas
mix leading to improper combustion. For natural gas installations above 3,000 ft, call your gas provider to determine the heating value
of the supplied natural gas.
PART 3 –TECHNICAL SPECIFICATIONS
MODEL
150
199
Installation
Indoor, Wall Hung, Fully Condensing
Minimum / Maximum Input (Btu/Hr)
15,000 / 150,000
19,900 / 199,000
Hot Water
Capacity
35oF Rise
8.2 GPM
11 GPM
45oF Rise
6.4 GPM
8.5 GPM
77oF Rise
3.7 GPM
5 GPM
Flue System
Sealed Combustion Direct Vent, Power Vent
Vent Run
2” (50 feet), 3” (100 feet), Schedule 40 PVC, CPVC, PP
Weight (lbs)
90
100
Orifice Size
NG
7.2 mm (0.284”)
8.3 mm (0.327”)
LP
5.5 mm (0.217”)
6.2 mm (0.240”)
Gas Supply
Pressure
NG
3.5” to 14” WC
LP
3.5” to 14” WC
Manifold
Pressure
Min (3”)
NG/LP: 0.006
NG: 0.003” / LP: 0.004” WC
Max (3”)
NG/LP: -0.13
NG: -0.19” / LP: -0.20” WC
Power Supply
Main Supply
120V 60 Hz, 6A
Maximum Power
Consumption
72W (With Pump 100W)
General Operating Conditions
Temperature
Ambient Temperature Range: 33 –104oF (0.6 –40oC)
Operating Relative Humidity: Up to 90% at 104oF (40oC)
Shipping and Storage Temperature Range: -4 –176oF (-20 –80oC)
Input Ratings
Power Supply and Communication (CN4): 14V DC
Product Approvals and Requirements
EMC: 89/336/EEC
LVD: 73/23/EEC
Ignition System
Direct Electronic Ignition / Automatic Flame Sensing
Burner System
Single Orifice Premixed Fuel Modulation / Ceramic Fiber Burner
Gas Valve System
Air Ratio Valve
Minimum Flow Rate
0.5 GPM (zero activation with internal recirculation mode active)
Internal Pipe Material
Copper
Dimensions
W 17.5” – H 30” – D 15.5”
W 19.7” – H 32” – D 16.3”
Heat Exchanger Water Capacity (DHW)
2.3 Gallons
3.5 Gallons
Control Panel / Main Controller
P-950H / NGTH-10C
Water Pressure
Min 12 –Max 150 PSI
DHW Setpoint Temperature Range
100oF –140oF (35oC –60oC)
Connection
Sizes
Cold Water Inlet / Hot
Water Outlet /
Recirculation Inlet
¾” NPT
Gas Inlet
¾” NPT
Materials
Cabinet
Cold Rolled Carbon Steel
Heat Exchanger
316L Stainless Steel
Safety Devices
Optical Flame Sensor, Burner Plate High Limit (392oF), Water Temperature High Limit
Sensor (203oF), Gas and Water Leak Detection Devices, Freeze Protection (Three
Stage Operation - Activates at 46oF –See Freeze Protection in Installer Menu for
Details), Exhaust Temperature High Limit Sensor (190oF), Blocked Flue and Intake
Sensor, Condensate Switch, Built-In Low Water Cut-Off Probe
Table 5 –Technical Specifications

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LP-590 REV. 3.23.17
Figure 1 –150 Model Specifications and Dimensions
Figure 2 –199 Model Specifications and Dimensions
DESCRIPTION
DIAMETER
A
Air Intake Adapter
3”
B
Exhaust Outlet Adapter
3”
C
Gas Inlet Adapter
¾”
D
Condensate Adapter
½”
E
DHW Outlet Adapter
¾”
F
DHW Inlet Adapter
¾”
G
Recirculation Return Adapter
¾”
Table 6 –Adapter Specifications

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LP-590 REV. 3.23.17
Figure 3 –Components
NUMBER
COMPONENT DESCRIPTION
NUMBER
COMPONENT DESCRIPTION
1
Air Intake Adapter
20
Cold Water Thermistor
2
Flue Air Pressure Sensor
21
Recirculation Return Adapter
3
Air Inlet Orifice
22
Recirculation Pump
4
Air Inlet Pipe
23
Flow Control Valve
5
Gas Outlet Pipe
24
Water Mixing Valve
6
Burner High Limit Switch
25
Terminal Strip
7
Gas Valve
26
Recirculation Return Water Sensor
8
Hot Water High Limit Switch
27
Control Panel
9
Heat Exchanger Water Thermistor
28
Heat Exchanger
10
Gas Inlet Pipe
29
Flame Detection Sensor
11
Hot Water Outlet Pipe
30
Water Level Detection Sensor
12
Manual Power Switch
31
Main Control Board
13
Condensate Air Pressure Switch
32
Igniter Rod
14
Condensate Trap
33
Burner Case
15
Gas Pipe Adapter
34
Igniter Transformer
16
Condensate Adapter
35
BLDC Fan
17
Hot Water Adapter
36
Exhaust Thermistor
18
Hot Water Thermistor
37
Exhaust Duct
19
Cold Water Inlet Adapter
38
Exhaust Vent Adapter
Table 7 –Component List

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LP-590 REV. 3.23.17
PART 4 –PREPARE WATER HEATER LOCATION
Carefully consider installation when determining water heater location. Please read the entire manual before attempting installation.
Failure to properly take factors such as water heater venting, piping, condensate removal, and wiring into account before installation
could result in wasted time, money, and possible property damage and personal injury.
A. BEFORE LOCATING THE WATER HEATER
Incorrect ambient conditions can lead to damage to the heating system and put safe operation at risk. Ensure that the water heater
installation location adheres to the information included in this manual. Failure to do so could result in property damage, serious
personal injury, or death.
Failure of water heater or components due to incorrect operating conditions IS NOT covered by product warranty.
1. Installation Area (Mechanical Room) Operating Conditions
Ensure ambient temperatures are higher than 32oF/0oC and lower than 104oF/40oC.
Prevent the air from becoming contaminated by the products, places, and conditions listed in this manual.
Avoid continuously high levels of humidity
Never close existing ventilation openings
The service life of the water heater’s exposed metallic surfaces, such as the cabinet, as well as internal surfaces, such as the heat
exchanger, are directly influenced by proximity to damp and salty marine environments. In such areas, higher concentration levels of
chlorides from sea spray coupled with relative humidity can lead to degradation of the heat exchanger and other water heater
components. In these environments, water heaters must not be installed using direct vent systems which draw outdoor air for
combustion. Such water heaters must be installed using room air for combustion. Indoor air will have a much lower relative humidity
and, hence, potential corrosion will be minimized.
This water heater is certified for indoor installations only. Do not install the water heater outdoors. Failure to install this water heater
indoors could result in substantial property damage, severe personal injury, or death.
This water heater must be installed as described in this manual: upright, with the vent adapters in the vertical position. DO NOT attempt
to install this water heater in any other orientation. Doing so will result in improper water heater operation and property damage, and
could result in serious personal injury or death.
2. Check for nearby connections to:
System water piping
Venting connections
Gas supply piping
Electrical power
Condensate drain
Locate the water heater where any leakage from the relief valve, related piping, tank, or connections will not result in damage to
surrounding areas or lower floors of the building. The water heater should be located near a floor drain, or installed in proximity to an
adequately drained drain pan. HTP WILL NOT be held liable for leakage damages.
To conserve water and energy, insulate all water piping, especially the hot and recirculation water lines.
3. Check area around water heater. Remove any combustible materials, gasoline, and other flammable liquids.
Failure to keep water heater area clear and free of combustible materials, liquids, and vapors can result in substantial property damage,
severe personal injury, or death.
4. Gas control system components must be protected from dripping water during operation and service.
5. If the water heater is to replace an existing water heater, check for and correct any existing system problems, such as:
System leaks

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LP-590 REV. 3.23.17
Location that could cause the system and water heater to freeze and leak.
Incorrectly-sized expansion tank
Do not connect the water heater to any heating systems or components that have been previously used for non-potable applications.
Do not introduce toxic chemicals, such as antifreeze or water heater treatments, into the water heater or any piping meant for potable
water purposes.
Ensure that all piping and components connected to the water heater are suitable for potable water applications.
Do not use this water heater for space heating applications.
Circulators suitable for DHW applications must be used.
6. Clean and flush system when reinstalling a water heater.
NOTE: When installing in a zero clearance location, it may not be possible to read or view some product labeling. It is recommended to
make note of the water heater model and serial number.
B. LEVELING
C. CLEARANCES FOR SERVICE ACCESS
See Figure 3 and Table 7 for recommended service clearances. If these minimum clearances are not provided, it may not be possible
to service the water heater without removing it from the space.
Space must be provided with combustion/ventilation air openings correctly sized
for all other water heaters located in the same space as the water heater. The
water heater cover must be securely fastened to prevent it from drawing air from
the water heater room. This is particularly important if the water heater is in a
room with other water heaters. Failure to comply with the above could result in
substantial property damage, severe personal injury, or death.
MINIMUM CLEARANCES
Installation Clearances from Non-
Combustibles / Combustibles
Recommended Service and Proper
Operation Clearances
Top
18 in. (45.7 cm)
Back
0 in. (0 cm)
Bottom
12 in. (30.45 cm)
Front
24 in. (60.9 cm)
Right Side
3 in. (7.6 cm)
Left Side
Table 8 –Minimum Installation and Service Clearances - NOTE: For closet
installations, a combustible door or removable panel is acceptable front clearance.
A 3” minimum clearance must be provided from the appliance front cover to the
removable panel or combustible door.
NOTE: A combustible door or removable panel is acceptable front clearance.
MINIMUM CLEARANCES FROM COMBUSTIBLE MATERIALS
Hot water pipes –at least 1” from combustible materials.
Exhaust vent pipe –at least 1” from combustible materials.
Always take future maintenance into consideration when locating the water heater. If the water heater is located in an installation
location with limited clearances, it may be necessary to remove the water heater from the space to perform maintenance. Failure to
consider maintenance when determining installation location could result in property damage.
In order for the condensate to properly flow out of the collection system, the water heater must be installed level.
Figure 4 –Minimum Service Clearances

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LP-590 REV. 3.23.17
D. RESIDENTIAL GARAGE AND CLOSET INSTALLATIONS
Check with your local Authority Having Jurisdiction for requirements when installing water heater in a garage or closet. Please read the
entire manual before attempting installation. Failure to properly take factors such as venting, piping, condensate removal, and wiring
into account before installation could result in wasted time, money, and possible property damage and personal injury.
PRECAUTIONS
If the water heater is located in a residential garage, it should be installed per the latest edition of the National Fuel Gas Code, ANSI
Z223.1, and CGA-B149 Installation Code in Canada.
Mount the bottom of the water 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 water heater so it cannot be damaged by a moving vehicle.
The space must be provided with correctly sized combustion/ventilation air openings for all other appliances located in the space with
the water heater. For power venting installations using room air for combustion, refer to the venting section, this manual, for
descriptions of confined and unconfined spaces. Do not install the water heater in an attic. Failure to comply with these warnings could
result in substantial property damage, severe personal injury, or death.
E. EXHAUST VENT AND INTAKE PIPE
Vents must be properly supported. The water heater exhaust and intake connections are not designed to carry heavy weight. Vent
support brackets must be within 1’ of the water heater and the balance at 4’ intervals. Venting must be readily accessible for visual
inspection for the first 3’ from the water heater.
NOTE: To prevent combustion air contamination, see Table 9 in this section when considering exhaust vent and intake pipe
termination.
Exhaust vent and intake pipe may be vented vertically through the roof or out a side wall. Venting methods are detailed in the Venting
Section. Do not attempt installation using any other means. Be sure to locate the water heater so exhaust vent and intake piping can be
routed through the building and properly terminated. Exhaust vent and intake piping lengths, routing, and termination method must
comply with methods and limits given in the venting section.
F. CARBON MONOXIDE DETECTORS
In the Commonwealth of Massachusetts and As Required by State and Local Codes
Installation of Carbon Monoxide Detectors: At the time of installation or replacement of the vented gas fueled appliance, the installing
plumber or gas fitter shall observe that a hard wired carbon monoxide detector with an alarm and battery back-up is installed on the
floor level where the gas appliance is installed, unless the appliance is located in a detached, uninhabitable structure separate from the
dwelling, building, or structure used in whole or in part for residential purposes.
In addition, the installing plumber or gas fitter shall observe that a hard wired carbon monoxide detector with an alarm and battery back-
up is installed on each additional level of the dwelling, building, or structure served by the vented gas appliance. It shall be the
responsibility of the property owner to secure the service of qualified licensed professionals for the installation of hard wired carbon
monoxide detectors.
a. In the event that the vented gas fueled appliance is installed in a crawl space or attic, the hard wired carbon monoxide detector
with alarm and battery back-up shall be installed on the next adjacent floor level.
b. In the event that these requirements cannot be met at the time of completion of installation, the owner shall have a period of
thirty (30) days to comply with the above requirements; provided, however, that during said thirty (30) day period, a battery
operated carbon monoxide detector with an alarm shall be installed.
Failure to comply with these requirements could result in product damage, severe personal injury, or death.
Approved Carbon Monoxide Detectors: Each carbon monoxide detector as required in accordance with the above provisions shall
comply with NFPA 70 and be ANSI/UL 2034 listed and IAS certified.
G. PREVENT COMBUSTION AIR CONTAMINATION
Install intake piping for the water heater as described in the Venting section. Do not terminate exhaust in locations that can allow
contamination of intake air.

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LP-590 REV. 3.23.17
Ensure that the intake air will not contain any of the contaminants below. For example, do not pipe intake near a swimming pool. Avoid
areas subject to exhaust fumes from laundry facilities. These areas always contain contaminants. Contaminated air will damage the
water heater, resulting in possible substantial property damage, severe personal injury, or death.
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 9
NOTE: DAMAGE TO THE WATER HEATER CAUSED BY EXPOSURE TO CORROSIVE VAPORS IS NOT COVERED BY
WARRANTY. (Refer to the limited warranty for complete terms and conditions).
H. REMOVING A WATER HEATER FROM A COMMON VENT SYSTEM
Do not install the water 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 water heater, the following steps must be followed.
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 all doors between 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 so the installation conforms to the National Fuel Gas
Code, ANSI Z223.1. When resizing any portion of the common venting system, the common venting system should be resized to
approach the minimum size as determined using the appropriate tables in Appendix G in the National Fuel Gas Code, ANSI Z 223.1.
Figure 5 - CO Warning Label

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LP-590 REV. 3.23.17
I. UNCRATING THE WATER HEATER
UNCRATING WATER HEATER –Any claims for damage or shortage in shipment must be filed immediately against the transportation
company by the consignee.
Cold weather handling –If water heater has been stored in a very cold location (below 0oF) before installation, handle with care until the
plastic components come to room temperature.
Remove all sides of the shipping crate to allow the water heater to be lifted into its installation location.
J. WALL-MOUNTING THE WATER HEATER
The water heater must be installed on a wall that can bear its weight (more than 100 lbs. when fully plumbed and full of water).
Installing the water heater on a wall which cannot support its weight could result in property damage, personal injury, or death.
The water heater may be installed on any suitable internal wall (suitable sound-proofing may be required when installing onto a stud
partition wall).
This water heater is too heavy for one person to lift. It is highly recommended to install the water heater with two people. Use caution as
to not drop the water heater, which could damage the water heater and cause property damage and/or severe personal injury. Verify
that the water heater is properly and securely mounted before leaving unsupervised. Failure to comply with the above and properly
mount the water heater could result in substantial property damage, severe personal injury, or death.
This wall mounting system is not seismic rated and should not be applied as such. Failure to comply with the above and properly mount
the water heater could result in substantial property damage, severe personal injury, or death.
POSITIONING THE WATER HEATER ON THE WALL
1. Attach the wall bracket on the location where you want to install the water heater. Ensure it is level and on stud (16” centers)
before proceeding.
2. Mark the four drill holes with a pencil or marker. Remove the wall bracket.
3. Drill four (4) holes using a 5/32 drill bit at the marked hole locations.
4. Mount the wall bracket to the wall with the four (4) included anchor bolts. Ensure the mounted bracket is level. See Figure 5A.
5. Align the heater bracket grooves on the back of the water heater with the tongues on the wall bracket and hang the water
heater on the bracket. See Figure 5B.
Figure 6 –Wall Mounting the Water Heater

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LP-590 REV. 3.23.17
PART 5 –VENTING
Vent this water heater in accordance with these instructions. Failure to do so will result in property damage, severe personal injury, or
death.
DO NOT mix vent systems or materials unless specifically told to do so in this manual.
DO NOT thermally insulate the exhaust vent or intake pipes.
DO NOT use an electric damper, vent damper, or draft hood with this water heater.
DO NOT locate the exhaust vent or intake pipe terminations where exposed to prevailing winds.
Moisture will be produced by the exhaust vent. Take precautions when determining exhaust vent termination. Moisture may fall from the
vent termination to the ground and turn to ice in freezing conditions. Moisture or ice can produce a hazardous condition.
Exhaust condensate is acidic, and could deteriorate the surface below the exhaust vent termination. Ensure this surface is in good
repair (sealed, painted, etc.) to prevent deterioration.
Failure to follow these instructions could result in property damage, severe personal injury, or death.
A. INTAKE PIPE AND EXHAUST VENT GUIDELINES
1. Vent system must be installed in accordance with local codes, or, in absence of
local codes, the National Fuel Gas Code, ANSI Z223.1 / NFPA 54 and/or CSA
B149.1, Natural Gas and Propane Installation Code.
2. For installation in Canada, installer supplied plastic vent piping must comply
with CAN/CGA B149.1 and be certified to the Standard for Type BH Gas Venting
Systems, ULC-S636. Components of this listed system must not be interchanged
with other vent systems or unlisted pipes or fittings. All plastic components and
specified primers and glues must be from a single system manufacturer and must
not be intermixed with another system manufacturer’s products. Clean and dry all
applicable surfaces before applying cement.
3. This water heater is designed to be installed in a power vent (using indoor air for
combustion and vented to the outdoors) type, or as a direct vent (sealed
combustion) type. In power vent installations, indoor air is used for combustion and
exhaust gases are vented directly to the outdoors through a sealed exhaust vent
piped through the wall or roof. In direct vent installations, combustion air must be
supplied directly from the outdoors to the burner, and the flue (exhaust) gases
should be vented directly to the outdoors through the wall or roof.
4. This water heater uses 2” or 3” diameter pipe for exhaust vent and intake pipe. It is important to ensure an airtight seal from the water
heater collar to the vent terminations. It is EXTREMELY IMPORTANT that the maximum allowed combined venting lengths are not
exceeded. See Table 10 for a list of Approved Vent Materials and Table 11 for Approved Vent Lengths.
5. Do not install venting system components on the exterior of the building except as specifically required by these instructions.
Vent terminals must be at least 1 foot from any door, window, or gravity inlet into the building.
Maintain the correct clearance and orientation between the exhaust vent and intake pipe terminals.
The exhaust vent and air intake terminals must be at the same height and their center lines must be spaced apart 1 foot
minimum.
The bottom of the exhaust vent and intake pipe terminals must be at least 1 foot above the normal snow accumulation level. In
no case should these terminals be installed less than 1 foot above normal snow accumulation level.
Do not install the exhaust vent terminals directly above windows or doors.
Intake pipe terminal must not terminate in areas that might contain combustion air contaminates, such as near swimming
pools.
For sidewall venting, the minimum horizontal distance between adjacent exhaust vent terminations is 1 foot. It is
recommended this distance be greater than 1 foot to better avoid frost damage to building surfaces.
For roof venting, minimum horizontal distance between any adjacent exhaust vent termination is 1 foot.
If the exhaust vent is to be terminated in a walled off area (such as a roof with a parapet wall), ensure the exhaust vent
terminates a minimum of 10' from nearest wall and extends level with or above the top of the wall. This will ensure flue gas
does not get trapped and possibly recirculated into the intake air pipe, which could contaminate the combustion air.
All joints of positive pressure vent systems must be sealed completely to prevent leakage of flue products into living space.

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LP-590 REV. 3.23.17
Remove all burrs and debris from joints and fittings.
When using PVC or CPVC pipe, all joints must be properly cleaned, primed, and cemented. Use only cement and primer
approved for use with the pipe material. Cement must conform to ASTM D2564 for PVC and ASTM F493 for CPVC pipe.
NOTE: DO NOT CEMENT POLYPROPYLENE PIPE.
Ensure the vent is located where it will not be exposed to prevailing winds.
In all roof venting applications, exhaust discharge must point away from the pitch of the roof.
To prevent water leakage, install adequate roof flashing where the pipe enters the roof.
Do not locate vent over public walkways, driveways, or parking lots. Condensate could drip and freeze, resulting in a slip
hazard or damage to vehicles and machinery.
Due to potential moisture build-up, sidewall venting may not be the preferred venting option. To save time and cost, carefully
consider venting installation and location.
Horizontal lengths of exhaust vent must slope back towards the water heater not less than ¼" per foot to allow condensate to
drain from the vent pipe.
The exhaust vent must terminate where vapors cannot make accidental contact with people or pets, or damage shrubs or
plants.
In vacant chimney applications, install and seal a rain cap over existing chimney openings.
All piping must be fully supported. Use pipe hangers at a minimum of 4 foot intervals to prevent sagging of the pipe where
condensate may form.
Do not use the water heater to support any piping.
DO NOT vent near soffit vents, crawl space vents, or other areas where condensate or vapor could create a nuisance or
hazard or cause property damage.
DO NOT vent where condensate vapor could cause damage or could be detrimental to the operation of regulators, relief valve,
or other equipment.
DO NOT vent the water heater in a chimney flue serving a separate appliance designed to burn solid fuel. The water heater
may only be vented in vacant chimneys.
Maximum Snow Level Determination: These installation instructions reference snow levels in establishing a minimum height
for the installation of exhaust vent or air intake terminations. Snow levels shall be determined as follows:
a. The installation location may, by ordinance, designate how snow levels are calculated in that location; or
b. In the absence of specific ordinances, snow levels shall be calculated from the average monthly maximum depth of snow
accumulation as indicated by the National Weather Service’s 10 year statistics for the installation location/geographical
area.
In the Commonwealth of Massachusetts and as Required by State and Local Codes:
The vented gas fueled appliance shall not be installed so its combustion, ventilation, or dilution air is obtained from a bedroom
or bathroom.
Signage: Whenever any through-the-wall (horizontal or sidewall) vent is installed less than seven feet above the finished
grade, a metal or plastic identification plate shall be permanently mounted to the exterior of the building at a minimum height of
eight feet above grade directly in line with the exhaust vent terminal. The sign shall read, in print no less than 0.5 inches in
size, “GAS VENT DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS”.
Marking of Exhaust Vent and Intake Pipe: Piping used for ventilation, make-up, or combustion air intake shall be labeled as
follows:
a. Throughout the entire developed length:
i. Labels must be placed every ten feet for exposed/visible piping; or
ii. Labels must be placed every three feet for concealed piping.
b. At all changes of direction;
c. c. On each side of a penetration through a partition, wall or ceiling; and
d. d. The labels shall be black lettering that:
i. Indicates that the piping is used for ventilation, make-up, or combustion air intake, and
ii. The letters shall be sized equal to a minimum of the pipe diameter. However, for piping with a diameter exceeding
two inches, said lettering does not need to be larger than two inches.

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LP-590 REV. 3.23.17
Figure 7 –Vent Termination Detail
DESCRIPTION
US
CANADA
A
Clearance above grade, veranda, porch, deck, or balcony
1 foot
1 foot
B
Clearance to window or door that may be opened
1 foot
3 feet
C
Clearance to permanently closed window
*
*
D
Vertical clearance to ventilated soffit located above the
terminal within a horizontal distance of 2 feet from the center
line of the terminal
*
*
E
Clearance to unventilated soffit
*
*
F
Clearance to outside corner
*
*
G
Clearance to inside corner
*
*
H
Clearance to each side of center line extended above meter
/ regulator assembly
*
3 feet with a height 15 feet
above meter / regulator
assembly
I
Clearance to service regulator vent outlet
*
3 feet
J
Clearance to non-mechanical air supply inlet to building or
the combustion air inlet to any other appliance
1 foot
3 feet
K
Clearance to a mechanical air supply inlet
3 feet above if within 10 feet
horizontally
6 feet
L
Clearance above paved sidewalk or driveway located
*
7 feet
M
Clearance under veranda, porch, deck, or balcony
*
1 foot
Table 10 –Vent Termination Clearances - *NOTE: For clearances not specified in ANSI Z223.1/NFPA 54 or CAN/CSA-B 149.1,
please use clearances in accordance with local installation codes and the requirements of the gas supplier.
B. APPROVED VENT MATERIALS
NOTICE
Consult Table 10 or the most recent edition of ANSI Z223.1/NFPA 54 or CAN/CGA B149.1 as well as all applicable local codes and
regulations when selecting vent pipe materials.