HTP EFTC-140W Installation manual

272 Duchaine Blvd. New Bedford, MA 02745 www.htproducts.com
LP-520 REV. 5.1.17
Elite Fire Tube Combi
Wall Mount
INSTALLATION / START-UP
MAINTENANCE / PARTS
WARRANTY
Models
EFTC-140W / 199W
Heat Exchanger Bears the ASME “H” Stamp
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.
WARNING: If the information in these instructions is not followed exactly, a fire or explosion may result causing property damage,
personal injury or death.
•Do not store or use 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.
Improper installation, adjustment, alteration, service, or maintenance can cause injury, property damage, or death. Refer to
this manual. Installation and service must be performed by a qualified installer, service agency, or 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-520 REV. 5.1.17

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LP-520 REV. 5.1.17
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
NOTICE is used to address practices not related to personal injury.
SAFETY INSTRUCTIONS
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-520 REV. 5.1.17
FOREWORD
This manual is intended to be used in conjunction with other literature provided with the appliance. 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 appliance, and with local codes and utility company requirements. In the absence of local codes, preference should be given to the
National Fuel Gas Code, ANSI Z223.1-2002.
INSTALLATIONS MUST COMPLY WITH:
Local, state, provincial, and national codes, laws, regulations and ordinances.
The latest version of the National Fuel Gas Code, ANSI Z223.1, from American Gas Association Laboratories, 8501 East Pleasant
Valley Road, Cleveland, OH 44131.
In Canada –CGA No. B149 (latest version), from Canadian Gas Association Laboratories, 55 Scarsdale Road, Don Mills, Ontario,
Canada M3B 2R3. Also, Canadian Electrical Code C 22.1, from Canadian Standards Association, 5060 Spectrum Way, Suite 100,
Mississauga, Ontario, Canada L4W 5N6.
Code for the installation of Heat Producing Appliances (latest version), from American Insurance Association, 85 John Street, New
York, NY 11038.
The latest version of the National Electrical Code, NFPA No. 70.
NOTE: The gas manifold and controls met safe lighting and other performance criteria when the appliance underwent tests specified in
ANSI Z21.13 –latest edition.
The hydronic supply and return connections of these products are 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.
TABLE OF CONTENTS
PART 1 –ITEMS SHIPPED WITH THE APPLIANCE.................................................................................................................7
PART 2 –SAFETY REGULATIONS ...........................................................................................................................................8
A. OPERATION AND INSTALLATION WARNINGS.......................................................................................................................8
B. IMPROPER COMBUSTION.......................................................................................................................................................9
C. GAS............................................................................................................................................................................................9
D. WHEN SERVICING THE APPLIANCE.......................................................................................................................................9
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-520 REV. 5.1.17
E. WATER CHEMISTRY...............................................................................................................................................................10
F. FREEZE PROTECTION...........................................................................................................................................................10
G. SCALDING...............................................................................................................................................................................10
H. HIGH ELEVATION INSTALLATIONS.......................................................................................................................................11
PART 3 –TECHNICAL SPECIFICATIONS...............................................................................................................................11
PART 4 –PREPARE APPLIANCE LOCATION........................................................................................................................14
A. UNCRATING THE APPLIANCE...............................................................................................................................................14
B. BEFORE LOCATING THE APPLIANCE ..................................................................................................................................15
C. LEVELING................................................................................................................................................................................16
D. CLEARANCES FOR SERVICE ACCESS................................................................................................................................16
E. RESIDENTIAL GARAGE AND CLOSET INSTALLATIONS .....................................................................................................17
F. EXHAUST VENT AND INTAKE PIPE.......................................................................................................................................17
G. CARBON MONOXIDE DETECTORS ......................................................................................................................................17
H. PREVENT COMBUSTION AIR CONTAMINATION .................................................................................................................18
I. REMOVING AN APPLIANCE FROM A COMMON VENT SYSTEM..........................................................................................18
J. WALL-MOUNTING THE APPLIANCE.......................................................................................................................................19
K. FLOW RESTRICTOR...............................................................................................................................................................19
PART 5 –VENTING...................................................................................................................................................................21
A. INTAKE PIPE AND EXHAUST VENT GUIDELINES................................................................................................................21
B. APPROVED VENT MATERIALS..............................................................................................................................................25
C. ALLOWED COMBINED VENT LENGTHS...............................................................................................................................25
D. TIGHTENING APPLIANCE COLLAR TO EXHAUST VENT AND INTAKE PIPE.....................................................................26
E. VENT TERMINATION ..............................................................................................................................................................27
1. Direct Vent, Two Pipe Roof and Sidewall Vent Terminations................................................................................................ 27
2. Direct Vent, Optional Horizontal and Vertical Vent Kits.........................................................................................................28
3. Screen Installation.....................................................................................................................................................................28
4. Power Venting, Indoor Combustion Air Installation in Confined or Unconfined Space......................................................29
PART 6 –INSTALL THE CONDENSATE DRAIN.....................................................................................................................31
PART 7 –GAS PIPING..............................................................................................................................................................32
A. GAS PIPE SIZING TABLES.....................................................................................................................................................32
1. Gas Pipe Sizing..........................................................................................................................................................................32
2. Natural Gas Pipe Sizing ............................................................................................................................................................32
3. LP (Liquid Propane) Gas Pipe Sizing.......................................................................................................................................33
B. GAS CONNECTION REQUIREMENTS...................................................................................................................................33
PART 8 –WATER PIPING ........................................................................................................................................................35
A. GENERAL PLUMBING CONNECTION GUIDELINES.............................................................................................................35
B. DHW PIPING............................................................................................................................................................................37
C. CENTRAL HEATING PIPING SYSTEM WATER PIPING METHODS.....................................................................................37
D. CH AND DHW PRESSURE RELIEF VALVES.........................................................................................................................42
PART 9 –CONNECT ELECTRICAL POWER / INITIAL STARTUP .........................................................................................42
A. GENERAL OPERATING CONDITIONS...................................................................................................................................43

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LP-520 REV. 5.1.17
B. WIRING INFORMATION..........................................................................................................................................................43
C. DIP SWITCHES .......................................................................................................................................................................43
PART 10 –OPERATING SYSTEM INSTRUCTIONS................................................................................................................49
A. CONTROL PANEL ...................................................................................................................................................................49
B. LCD DISPLAY DESCRIPTIONS ..............................................................................................................................................50
C. START-UP SEQUENCE ..........................................................................................................................................................50
D. CHANGING THE DHW SET-POINT ........................................................................................................................................51
E. CHANGING THE TEMPERATURE INDICATOR .....................................................................................................................51
F. CHANGING THE CH SET-POINT............................................................................................................................................51
G. STORAGE MODE....................................................................................................................................................................52
H. STATUS DISPLAY MODE .......................................................................................................................................................52
I. INSTALLER MODE....................................................................................................................................................................53
J. ERROR MODE .........................................................................................................................................................................55
K. ERROR TREE ANALYSIS........................................................................................................................................................58
1. FLAME DETECTION...................................................................................................................................................................58
2. GAS DETECTION .......................................................................................................................................................................58
3. APS / BURNER OVERHEAT LIMIT / CONDENSATE BLOCK SWITCH...................................................................................59
4. DHW / OP / CH OVERHEAT / EXHAUST OVERHEAT SENSORS............................................................................................59
L. OUTDOOR TEMPERATURE MODE (OPTIONAL)...................................................................................................................59
M. 0-10 VOLT INPUT....................................................................................................................................................................60
PART 11 –START-UP PREPARATION....................................................................................................................................61
A. CHECK / CONTROL WATER CHEMISTRY.............................................................................................................................61
B. GLYCOL ANTIFREEZE SOLUTIONS......................................................................................................................................61
C. CHECK FOR GAS LEAKS.......................................................................................................................................................62
D. FILL AND TEST WATER SYSTEM..........................................................................................................................................62
E. PURGE AIR FROM CH AND INTERNAL STORAGE TANK....................................................................................................63
F. PURGE AIR FROM DHW SYSTEM .........................................................................................................................................63
G. CHECK THERMOSTAT CIRCUIT(S).......................................................................................................................................64
H. CONDENSATE REMOVAL......................................................................................................................................................64
I. FINAL CHECKS BEFORE STARTING APPLIANCE.................................................................................................................64
J. ADJUSTING GAS PRESSURE AT THE APPLIANCE..............................................................................................................64
K. SETTING AND VERIFYING THE COMBUSTION SETTING ...................................................................................................65
PART 12 –INSTALLATION AND START-UP CHECKLIST......................................................................................................67
PART 13 –TROUBLESHOOTING ............................................................................................................................................69
PART 14 –ANNUAL MAINTENANCE PROCEDURES............................................................................................................70
REPLACEMENT PARTS ................................................................................................................................................................75
Limited Warranty for EFTC Appliances .......................................................................................................................................84
START-UP REPORT.......................................................................................................................................................................86
MAINTENANCE REPORT ..............................................................................................................................................................87
MAINTENANCE NOTES.................................................................................................................................................................88
CUSTOMER INSTALLATION RECORD FORM.............................................................................................................................89

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LP-520 REV. 5.1.17
PART 1 –ITEMS SHIPPED WITH THE APPLIANCE
ITEM
DESCRIPTION
QUANTITY
Elite Fire Tube Combi
Appliance
140W / 199W
1
Installation and User’s
Information Manuals, H2
Document
1 Each
Condensate Hose
(7855P-089)
1
CH Pressure Relief Valve
With ¾” X 1” Bushing
(CH Line ¾” 30 psi)
(7855P-077)
1 Each.
Vent Screens (3”)
(7855P-085)
2 Screens
Outdoor Sensor with
Screws and Anchors
(7855P-084)
1
Combi Venting Kit
3” CPVC
(S7855-002)
6” Length
½” X ¾” Bell Coupling
for Gas Line
140W Model Only
(7855P-086)
1
Spare Parts Kit
(Gaskets and O-Rings)
(7855P-258)
1
Propane (LP) Conversion Kit
(140W Model - 7855P-099)
(199W Model –7855P-452)
1
Anchors and Wall Mounting
Bracket
(7850P-084)
1
Blue Flow Restrictor
(Limits Flow to 4.5 GPM)
140W Model Only
(7855P-260)
1

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LP-520 REV. 5.1.17
OPTIONAL PARTS (Not Included)
ITEM
DESCRIPTION
PART NUMBER
Threaded ¾” DHW Tankless
Isolation Valves
(With Pressure Relief Valve)
(7850P-090)
2
Vent Screens (2” Mesh)
(7850P-088)
2 Screens
Table 1 –Items Included with the Appliance
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 appliance has a burner that
can come on at any time and ignite vapors. DO NOT use or store flammable liquids around the appliance.
Improper venting can cause a build-up of carbon monoxide. Breathing carbon monoxide can result in brain damage or death. DO NOT
operate the appliance 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 400 ppm is exceeded at any
time during operation.
Adjusting the “low fire offset” on the gas valve in even 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.
Failure to follow these statements will result in property damage, severe personal injury, or death.
This appliance 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 appliance is the user’s responsibility. Ensure the user carefully reads and understands the User’s Information Manual
before operating and maintaining the appliance.
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
appliance is subjected to fire, overheating, flood, physical damage, or any other damaging condition that might affect the operation of
the unit. Have the appliance 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 appliance. There are no serviceable parts
which can be changed by the user / owner. User / Owner: Contact the original professional service technician if the appliance 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 appliance clean and free of all materials that can burn. DO NOT store or place gasoline, oils, spray paint, or
other flammable products near the appliance.
DO NOT use spray paint, hair spray, or any other flammable spray near the appliance 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 appliance or the exterior exhaust gas outlet and/or
fresh air inlet port.
The owner should inspect the system monthly for damage, water stains, signs of rust, corrosion, and exhaust vent and air intake
blockage. If inspection of the unit shows signs of damage, the appliance should be shut off until the problem is repaired by a qualified
technician.

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LP-520 REV. 5.1.17
After installation, all appliance safety devices should be tested.
This appliance is certified for indoor installations only. The appliance consists of gas ignition system components which must be
protected from water (dripping, spraying, etc.) during operation and service. Carefully consider installation location and the placement of
critical components (circulators, condensate neutralizers, etc.) before installing the appliance.
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 appliance annually.
The appliance DHW temperature is factory set to 125oF (51oC). To avoid scalding, always check the temperature of the hot water
before bathing, showering, washing, etc. DO NOT adjust the water temperature while the appliance is being used by other persons.
If the appliance 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
This appliance 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.
DO NOT alter or modify the appliance or appliance controls. This can be dangerous and WILL VOID the warranty.
Failure to follow these statements could result in property damage, severe personal injury, or death.
NOTICE
Any claims for damage or shortage in shipment must be filed immediately against the transportation company by the consignee.
This appliance provides a overheat shutdown limit. In the event the appliance water exceeds the set point of the control limit, the cutoff
will trip and the appliance will shut down. Certain local codes require additional temperature limits. In addition, certain types of systems
may operate at temperatures below the minimum set point of the limit provided with the appliance. Contact a qualified service
technician for additional overheat controls.
NOTE: When inquiring about service or troubleshooting, reference the model and serial numbers from the appliance 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 appliance cabinet or performing service. Label all wires while performing service
to ensure proper re-wiring of the appliance. Wiring errors can cause improper or dangerous operation. Failure to do so could result in
an electrical shock, improper appliance operation, property damage, serious personal injury, or death.
Due to the low water content of the appliance, improper sizing of the appliance with regard to heating system load will result in
excessive cycling and accelerated component failure. HTP DOES NOT warrant failures caused by improperly sized appliance
applications. DO NOT oversize the appliance to the system. Modular appliance installations greatly reduce the likelihood of appliance
oversizing.
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 APPLIANCE
•To avoid electric shock, disconnect electrical supply before performing maintenance.
•To avoid severe burns, allow appliance to cool.
•Do not use petroleum-based cleaning or sealing compounds in an appliance 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 appliance, and/or serious
personal injury may result.

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LP-520 REV. 5.1.17
•Always verify proper operation after servicing the appliance.
E. WATER CHEMISTRY
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.
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 Chemistry Specifications
F. FREEZE PROTECTION
Consider appliance piping and installation when determining appliance location.
NOTE: Damages resulting from incorrect installation or from use of products not approved by
HTP, Inc. ARE NOT covered by warranty.
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 3 –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-520 REV. 5.1.17
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.
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
140W
199W
Installation
Indoor, Wall Mount, Fully Condensing
Minimum /
Maximum Input
(Btu/Hr)
Central Heating
(CH)
28,000 / 140,000
19,900 / 140,000*
Domestic Hot
Water (DHW)
19,900 / 199,000*
AFUE
95%
Hot Water
Capacity
35oF Rise
7.1 Gal
9.9 GPM
45oF Rise
5.5 Gal
7.7 GPM
77oF Rise
3.2 Gal
4.8 GPM
Flue System
Sealed Combustion Direct Vent, Power Vent
Combined Vent Length
2” (50 feet), 3” (100 feet)
Shipping Weight (lbs est.)
110
120
Orifice Size
NG
0.255” (6.5 mm)
0.327” (8.3mm)
LP
0.19” (4.85 mm)
0.244” (6.2mm)
Gas Supply
Pressure
NG
3.5” to 14” WC
LP
Manifold
Pressure
Min (2” / 3” Vent)
NG/LP: 0” WC
NG/LP: -0.015” WC
Max (2” / 3” Vent)
NG/LP: -0.22” WC
NG/LP: -0.134’WC / -0.173”WC
Power Supply
Main Supply
120V 60 Hz / 6A
Maximum Power
Consumption
160W
Ignition System
Direct Electronic Ignition / Automatic Flame Sensing
Burner System
Single Orifice Premixed Fuel Modulation Ceramic Fiber Infrared
Gas Valve System
Combination Modulating (Current Proportional)
Internal Pipe Material
Copper
Dimensions
W 17.25” – H 34” – D 15.5”
W 19.7” – H 37” – 16.8”
Minimum Flow Rate
0.5 GPM
Internal Storage Tank Water Capacity
(DHW)
1 Gallon
1.5 Gallons
Heat Exchanger Capacity
4 Gallons
3.5 Gallons
Total Water Capacity
5 Gallons
Main Controller / Control Panel
NGTX-900C / P-920C_CB-HTP
CH Pressure
Min 12 PSI - Max 30 PSI
DHW Pressure
Max 150 PSI
Connection
Sizes
DHW Inlet / Hot
Water Outlet
¾” NPT
CH Supply / Return
1” NPT
Gas Inlet
½” NPT (1/2” X ¾” Bell Coupling
Provided to Upsize Gas Line)
¾” NPT
Materials
Cabinet
Cold Rolled Carbon Steel
Heat Exchanger
Primary Heat Exchanger: Stainless Steel
Storage Tank: Stainless Steel
Safety Devices
Optical Flame Sensor, Burner Plate High Limit (392oF), Water Temperature High Limit
Sensor (200oF), Freeze Protection (Three Stage Operation - Activates at 46oF –See
Freeze Protection in Installer Menu for Details), Exhaust Temperature High Limit Sensor
(190oF), Blocked Flue Switch, Condensate Switch, Built-In Low Water Cut-Off Probe
Table 4 –Technical Specifications –NOTE: 199W Models Offer a Maximum BTU/Hr Input of 140,000 as Shipped. Maximum
BTU/Hr can be increased up to 199,000 BTU/Hr with a Larger External Pump Installed in the Primary Loop

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LP-520 REV. 5.1.17
Figure 1 –140W Specifications and Dimensions
DESCRIPTION
DIAMETER (ALL NPTM)
A
Automatic Air Vent
-
B
Intake Pipe Connection
3”
C
Exhaust Vent Connection
3”
D
Relief Valve Adapter
¾” NPT
E
CH Supply Adapter
1” NPT
F
CH Return Adapter
1” NPT
G
DHW Outlet Adapter
¾” NPT
H
DHW Inlet Adapter
¾” NPT
I
Gas Connection Adapter
½” NPT (1/2” X ¾” Bell Coupling Provided to Upsize Gas Line)
J
Condensate Adapter
-
Table 5 –140W Adapter Specifications

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LP-520 REV. 5.1.17
Figure 2 - 199W Specifications and Dimensions
DESCRIPTION
DIAMETER (ALL NPTM)
A
Automatic Air Vent
-
B
Intake Pipe Connection
3”
C
Exhaust Vent Connection
3”
D
Relief Valve Adapter
¾” NPT
E
CH Supply Adapter
1” NPT
F
CH Return Adapter
1” NPT
G
DHW Outlet Adapter
¾” NPT
H
DHW Inlet Adapter
¾” NPT
I
Gas Connection Adapter
¾” NPT
J
Condensate Adapter
½” NPT
Table 6 - 199W Adapter Specifications

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LP-520 REV. 5.1.17
Figure 3 –Model Components
NUMBER
COMPONENT DESCRIPTION
NUMBER
COMPONENT DESCRIPTION
1
Air Vent
16
Condensate Adapter
2
Air Intake Adapter
17
Condensate Trap
3
Air / Gas Mixing Pipe
18
Condensate Air Pressure Switch
4
Gas Valve
19
Mixing Valve
5
Internal Storage Tank
20
Terminal Block
6
Main PCB
21
Control Panel
7
Manual ON/OFF Power Switch
22
Heat Exchanger
8
Internal Recirculation Pump (DHW) / CH Internal Primary Pump
23
Ignition Transformer
9
CH Supply Adapter
24
Flame Detecting Sensor
10
CH Return Adapter
25
BLDC Fan
11
CH Return Filter
26
Air Pressure Switch
12
CH Pressure Gauge
27
Exhaust Vent Pipe
13
DHW Outlet Adapter
28
Exhaust Vent Adapter
14
Gas Inlet Adapter
29
Relief Valve Adapter
15
DHW Inlet Adapter With Filter and Flow Restrictor
Table 7 –Component List
PART 4 –PREPARE APPLIANCE LOCATION
A. UNCRATING THE APPLIANCE
UNCRATING APPLIANCE –Any claims for damage or shortage in shipment must be filed immediately against the transportation
company by the consignee.
Cold weather handling –If appliance 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 appliance to be lifted into its installation location.

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LP-520 REV. 5.1.17
Carefully consider installation when determining appliance location. Please read the entire manual before attempting installation.
Failure to properly take factors such as appliance venting, piping, condensate removal, and wiring into account before installation could
result in wasted time, money, and possible property damage and personal injury.
B. BEFORE LOCATING THE APPLIANCE
Incorrect ambient conditions can lead to damage to the heating system and put safe operation at risk. Ensure that the appliance
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 appliance 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 appliance’s exposed metallic surfaces, such as the casing, 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 appliance components.
In these environments, appliances must not be installed using direct vent systems which draw outdoor air for combustion. Such
appliances 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 appliance is certified for indoor installations only. Do not install the appliance outdoors. Failure to install this appliance indoors
could result in substantial property damage, severe personal injury, or death.
This appliance must be installed as described in this manual: upright, with the vent adapters in the vertical position. DO NOT attempt to
install this appliance in any other orientation. Doing so will result in improper appliance 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 appliance 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 appliance should be located near a floor drain, or installed in 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 appliance. Remove any combustible materials, gasoline, and other flammable liquids.
Failure to keep appliance 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 appliance is to replace an existing appliance, check for and correct any existing system problems, such as:
•System leaks

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LP-520 REV. 5.1.17
•Location that could cause the system and appliance to freeze and leak.
•Incorrectly-sized expansion tank
Do not connect the appliance to any heating systems or components that have been previously used for non-potable applications.
Do not introduce toxic chemicals, such as antifreeze or appliance treatments, into the appliance or any piping meant for potable water
purposes.
Ensure that all piping and components connected to the appliance are suitable for potable water applications.
Do not use this appliance only for space heating applications.
Circulators suitable for DHW applications must be used.
Failure to follow these instructions could result in property damage, personal injury, or death.
6. Clean and flush system when reinstalling an appliance.
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 appliance model and serial number.
C. LEVELING
D. CLEARANCES FOR SERVICE ACCESS
See Figure 4 and Table 7 for recommended service clearances. If these minimum clearances are not provided, it may not be possible
to service the appliance without removing it from the space.
Space must be provided with combustion/ventilation air openings
correctly sized for all other appliances located in the same space as
the appliance. The appliance cover must be securely fastened to
prevent it from drawing air from the appliance room. This is particularly
important if the appliance is in a room with other appliances. Failure to
comply with the above 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: 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.
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 appliance. If the appliance is located in an installation location with
limited clearances, it may be necessary to remove the appliance 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 appliance must be installed level. Failure to ensure the
appliance is installed level will result in improper appliance operation.
Figure 4 –Minimum Service Clearances

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LP-520 REV. 5.1.17
E. RESIDENTIAL GARAGE AND CLOSET INSTALLATIONS
Check with your local Authority Having Jurisdiction for requirements when installing appliance 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 appliance 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 appliance 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 appliance 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 appliance. 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 appliance in an attic. Failure to comply with these warnings could result in
substantial property damage, severe personal injury, or death.
F. EXHAUST VENT AND INTAKE PIPE
Vents must be properly supported. The appliance exhaust and intake connections are not designed to carry heavy weight. Vent support
brackets must be within 1’ of the appliance and the balance at 4’ intervals. Venting must be readily accessible for visual inspection for
the first 3’ from the appliance.
NOTE: To prevent combustion air contamination, see Table 9 in this section when considering exhaust vent and intake pipe
termination.
The appliance is rated ANSI Z21.13 Category IV (pressurized vent, likely to form condensate in the vent), and requires a special vent
system designed for pressurized venting.
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 appliance 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.
G. 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.

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LP-520 REV. 5.1.17
H. PREVENT COMBUSTION AIR CONTAMINATION
Install intake piping for the appliance 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 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
appliance, 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 APPLIANCE CAUSED BY EXPOSURE TO CORROSIVE VAPORS IS NOT COVERED BY WARRANTY.
(Refer to the limited warranty for complete terms and conditions).
I. REMOVING AN APPLIANCE FROM A COMMON VENT SYSTEM
Do not install the appliance 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 appliance, 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.
Figure 5 - CO Warning Label

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LP-520 REV. 5.1.17
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.
J. WALL-MOUNTING THE APPLIANCE
The appliance must be installed on a wall that can bear its weight (more than 110 lbs. when fully plumbed and full of water). Installing
the appliance on a wall which cannot support its weight could result in property damage, personal injury, or death.
The appliance may be installed on any suitable internal wall (suitable sound-proofing may be required when installing onto a stud
partition wall).
This appliance is too heavy for one person to lift. It is highly recommended to install the appliance with two people. Use caution as to
not drop the appliance, which could damage the appliance and cause property damage and/or severe personal injury. Verify that the
appliance is properly and securely mounted before leaving unsupervised. Failure to comply with the above and properly mount the
appliance 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 appliance could result in substantial property damage, severe personal injury, or death.
POSITIONING THE APPLIANCE ON THE WALL
1. Attach the wall bracket on the location where you want to install the appliance. 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 6A.
5. Align the heater bracket grooves on the back of the appliance with the tongues on the wall bracket and hang the appliance on
the bracket. See Figure 6B.
Figure 6 –Wall Mounting the Appliance
K. FLOW RESTRICTOR
A flow restrictor is installed on this appliance at the DHW inlet adapter to avoid excessive flow at the faucets. See Flow Charts, this
manual, for more information.
If it is necessary to further increase flow to the system, replace the factory installed white flow restrictor with the blue included with the
appliance by following the instructions below.
If the appliance is already fully installed, turn the gas, power, and water off to the appliance and drain all water from the appliance
BEFORE proceeding. Failure to comply could result in substantial property damage, severe personal injury, or death.

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LP-520 REV. 5.1.17
1. Locate the DHW inlet adapter on the bottom of the appliance.
2. Pull the two pins to release the DHW inlet filter. See Figure 7-A. The flow restrictor is attached to the top of the filter assembly.
3. Remove the installed white flow restrictor and replace it with the blue flow restrictor included with the appliance. See Figure 7-B.
4. Reinstall the DHW inlet filter.
5. Reinstall the two pins.
Figure 7 –A –Removing the DHW Inlet Filter, B –Removing the Flow Restrictor
Figure 8 –Water Pressure vs. Flow Through the Restrictors –140W Models