Pentair ETi 400 User manual

ETi™400 HIGH EFFICIENCY HEATER
DO NOT store or use gasoline or other ammable vapors and liquids in the vicinity
of this or other appliances.
FOR
YOUR
SAFETY
Improper installation, adjustment, alteration, service
or maintenance can cause property damage,
personal injury or death. Installation and service must
be performed by a qualied installer, service agency
or the gas supplier.
Pentair Water Pool and Spa, Inc.
1620 Hawkins Ave., Sanford, NC 27330 •[phone] or [phone]
10951 W. Los Angeles Ave., Moorpark, CA 93021 •[phone] or [phone]
FOR YOUR SAFETY - READ BEFORE OPERATING
If you do not follow these instructions exactly, a re or explosion may result, causing property damage,
personal injury or loss of life. For additional free copies of this manual; call USA [phone]
OWNER:
Retain For
Future
Reference
Model Natural
120 / 240 VAC NATURAL GAS / LP GAS
INSTALLATION AND USER’S GUIDE
FORYOUR SAFETY - This product must be installed and serviced by authorized personnel, qualified
in pool/spa heater installation. Improper installation and/or operation can create carbon monoxide gas,
fire or explosion, and flue gases which can cause serious injury, property damage, or death.For indoor
installations, as an additional measure of safety, Pentair Water Pool and Spa, Inc.strongly recommends
installation of suitable Carbon Monoxide detectors in the vicinity of this appliance and in any adjacent
occupied spaces.Improper installation and/or operation will void the warranty.
WHAT TO DO IF YOU SMELL GAS
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any phone in your building.
• Immediately call your gas supplier from a neighbor’s phone.
Follow the gas supplier’s instructions.
• If you cannot reach your gas supplier, call the re department.
ETi™ 400 NA - ASME 461113

ETi 400 High Efficiency Pool and Spa Heater Installation and User’s Guide Rev. A 9/2016
2
P/N 475349 Revision A. 9/2016
Customer Service and Technical Support
If you have questions about ordering Pentair Water Pool and Spa, Inc. replacement parts, and
pool products, please call:
Phone: [phone]
Fax: [phone]
(8 AM to 7:30 PM EasternTime/PacificTime)
Web sites: www.pentairpool.com - www.staritepool.com
Customer Service and Technical Support

Rev. A 9/2016 ETi 400 High Efficiency Pool and Spa Heater Installation and User’s Guide
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Contents
Warning and Safety Information ............................................................................... 5
Important Notices ........................................................................................................................................... 5
Heater Application Information ....................................................................................................................... 5
Code Requirements........................................................................................................................................ 6
Consumer Information and Safety Information............................................................................................... 6-8
General Specifications.................................................................................................................................... 9
Heater Identication Information .............................................................................. 9
Section 1. Operation Instructions.............................................................................. 10
Operator Control Panel................................................................................................................................... 10-11
Basic System Operation ................................................................................................................................. 11
Heater DSI Electronic Ignition Lighting/Operation ...................................................................................... 11
Start-Up Operation .................................................................................................................................... 12
Putting the Heater into Service .................................................................................................................. 12
Heater Operating Instructions .................................................................................................................... 13
To Turn Off Gas to the Appliance.................................................................................................................... 13
Safety Controls (Air Flow Switches, Water Pressure Switches, Hight Limit Shut-Off Switches) .................... 14-15
(Stack Flue Sensor, Thermal Fuse, Float Switch)
Ignition Module Operation .......................................................................................................................... 15
Section 2. Installation................................................................................................. 16
Heater Description.......................................................................................................................................... 16
Putting the Heater into Service....................................................................................................................... 16
Sequence Of Operation.................................................................................................................................. 17
Specifications ................................................................................................................................................. 17-18
Plumbing Connections.................................................................................................................................... 19
Water Connections ......................................................................................................................................... 19
Valves ............................................................................................................................................................. 20
Manual By-Pass ............................................................................................................................................. 20
Below Pool Installation ................................................................................................................................... 20
Gas Connections ............................................................................................................................................ 21
Gas Pipe Sizing ............................................................................................................................................. 21
Gas Pressure Testing ..................................................................................................................................... 22
Sediment Traps .............................................................................................................................................. 22
Outdoor Installation (US and Canada) ........................................................................................................... 23-24
Outdoor Installation Venting Guidelines .................................................................................................... 23
Heater Clearances - Outdoor .................................................................................................................... 25
Indoor Venting — General Requirements (Category IV Vertical and Horizontal requirements)..................... 26
Heater Clearances — General Requirements (Indoor and Outdoor Installation for US and Canada) ........ 26
Direct Air Intake Cover.................................................................................................................................... 26
Combustion Air Supply ................................................................................................................................... 27
Air Supply Requirements Guide for the Heater .......................................................................................... 27
Direct Air Intake Exhaust Duct using 4-inch PVC Pipe (Indoor Installation) ............................................... 28-30
Direct Air Intake Kit Installation (Combustion Air Supply) ........................................................................... 30
Corrosive Vapors and Possible Causes ......................................................................................................... 30
Horizontal or Vertical Venting (Category IV) - Positive Pressure................................................................... 30
Vent Installation (Indoor Installation for U.S. or Outdoor Shelter for Canada)................................................ 31
Direct Vent Requirements............................................................................................................................... 32
Direct Vent - Horizontal Through- the-Wall (Termination) ............................................................................... 34
Contents

ETi 400 High Efficiency Pool and Spa Heater Installation and User’s Guide Rev. A 9/2016
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Contents
Section 2. Installation (Continued) .............................................................................. 35
Garage or Utility Room Installation................................................................................................................. 35
Vent Installation - Indoor Installtion US and Canada)................................................................................. 35
Final Installation Check .................................................................................................................................. 35
Condensate Management (Maintenance, Condensate Neutralizer Cartridger Drain/Tubing Installation)...... 36
Electrical Connections .................................................................................................................................... 37
Bonding ..................................................................................................................................................... 37
120 VAC / 240 VAC Wiring ......................................................................................................................... 38
Remote Control Connections ......................................................................................................................... 39
Fireman’s Switch Connection ......................................................................................................................... 39
Heater Connection Wiring Diagram................................................................................................................ 40
Heater Ladder Wiring Diagram....................................................................................................................... 41
Section 3. Troubleshooting........................................................................................ 42
Initial Troubleshooting and Troubleshooting Chart ......................................................................................... 42
Heater Will Not Fire A .................................................................................................................................. 43
Heater Will Not Fire B.................................................................................................................................. 44
Diagnostics LEDs: PS, HLS, TF, IGN, AFS, AG1, AG2, FS ........................................................................ 45-49
Burner Troubleshooting .................................................................................................................................. 50
Heat Exchanger Troubleshooting ................................................................................................................... 50
Operator Control Panel Displays RNC Code.................................................................................................. 50
Section 4. Maintenance and Care Instruction .......................................................... 51
Care and Maintenance...................................................................................................................... 51
TitanTough Heat Exchanger Assemblies Annual Inspection ............................................................. 51
Burner Spark Electrode and Flame Sensor Rod Annual Inspection ................................................. 52
Pressure Relief Valve (50 psi)........................................................................................................... 52
After Start-Up .................................................................................................................................... 53
Spring and Autumn........................................................................................................................ 53
Winter Operation and Winterization .............................................................................................. 53
Return the Heater to Service............................................................................................................. 54
Maintaining Pool Temperature .......................................................................................................... 54
Energy Saving Tips ....................................................................................................................... 54
Chemical Balance ............................................................................................................................. 55-56
Section 5. Heater Replacement Parts........................................................................ 57-63
Heater Replacement Parts List ......................................................................................................... 57
General Replacement Parts.............................................................................................................. 58
Heater Heat Exchanger and Blower Assemblies Replacement Parts............................................... 59-60
Heater Manifold Assembly - Inlet and Outlet Assembly Replacemant Parts..................................... 61
Heater Condensate and Exhaust Assembly Replacement Parts...................................................... 62
Heater Operator Control Panel Assembly Replacement Parts ......................................................... 63
Contents

Rev. A 9/2016 ETi 400 High Efficiency Pool and Spa Heater Installation and User’s Guide
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Thanks you for choosing the Pentair ETi™ 400 High Efciency Pool and Spa Heater. With proper installation and service
of your new heating system, and correct chemical maintenance of the water will ensure years of heater operation. The
ETi 400 High Efciency heater is equipped with Pentair advanced heater technology which includes a multifunction
temperature controller to continuously monitor the heater for proper operation. ETi 400 High Efciency heaters are
designed with direct spark ignition (DSI) for on demand heat, which eliminates the need for a standing pilot.
SPECIALINSTRUCTIONS TO OWNER: Retain this manual for future reference. This instruction manual provides
operating instructions, installation and service information for the heater. READ AND REVIEW THIS MANUAL
COMPLETELY, it is very important that the owner/installer read and understand the section covering installation
instructions, and recognize the local and state codes before installing the ETi™ 400 High Efciency heater. Its use will
reduce service calls and chance of injury and will lengthen product life. History and experience has shown that most
heater damage is caused by improper installation practices.
IMPORTANT NOTICES
For the installer and operator of the ETi 400 High Efciency Heater: The manufacturer’s warranty may be void
if, for any reason, the heater is improperly installed and/or operated. Be sure to follow the instructions set forth in this
manual. If you need any more information, or if you have any questions regarding to this pool heater, please contact
Pentair Water Pool and Spa Customer Support at [phone].
HEATER APPLICATION INFORMATION
The ETi 400 Heater is sold with a limited factory warranty. Pentair Water Pool and Spa high standards of excellence
include a policy of continuous product improvement resulting in your advanced technology pool and spa heater. Pentair
reserves the right to make improvements which change the specications of the heater without incurring an obligation
to update the current heater equipment.
The ETi 400 Heater is designed for the heating of chlorine, bromine or salt system swimming pools and spas. The heater
should never be employed for use as space heating boilers or general purpose water heaters. The manufacturer’s warranty
may be void if, for any reason, the heater is improperly installed and/or operated. Be sure to follow the instructions set
forth in this manual.
Warning and Safety Instructions
Warning and Safety Instructions
IMPORTANT SAFETY INSTRUCTIONS
READ AND FOLLOW ALL INSTRUCTIONS
SAVETHESE INSTRUCTIONS
ETi™ 400 High Efficiency Pool and Spa Heater
CODE REQUIREMENTS
Installation must be in accordance with all local codes and/or the latest edition of the National
Fuel Gas Code, ANSI Z223.1 and the latest edition of the National Electrical Code, NFPA 70
(US).
Installation in Canada must be in accordance with the latest CAN/CGA-B149.1 or .2 and CSA
C22.1 Canadian Electric Code, part 1.
The heater, when installed, must be electrically grounded and bonded in accordance with local
codes, or, in absence of local codes, with the National Electrical Code, ANSI/NFPA70 (US) or
in Canada in accordance with the Canadian Electric Code, part 1 as applicable.
The ETi 400 Pool Heater meets the requirements of the ASME Boiler and Pressure Vessel Code.

ETi 400 High Efficiency Pool and Spa Heater Installation and User’s Guide Rev. A 9/2016
6Warning and Safety Instructions
CONSUMER INFORMATION AND SAFETY
WARNING
The U.S. Consumer Product Safety Commission warns that elevated water temperature can be hazardous.
See below for water temperature guidelines before setting temperature.
1. Spa or hot tub water temperatures should never exceed 104° F (40° C). A temperature of 100° F (38° C) is considered
safe for a healthy adult. Special caution is suggested for young children.
2. Drinking of alcoholic beverages before or during spa or hot tub use can cause drowsiness which could lead to
unconsciousness and subsequently result in drowning.
3. Pregnant women beware! Soaking in water above 102° F (39° C) can cause fetal damage during the rst three
months of pregnancy (resulting in the birth of a brain-damaged or deformed child). Pregnant women should stick
to the 100° F (38° C) maximum rule.
4. Before entering the spa or hot tub, the user should check the water temperature with an accurate thermometer. Spa
or hot tub thermostats may error in regulating water temperatures by as much as 4° F (2.2° C).
5. Persons with a medical history of heart disease, circulatory problems, diabetes or blood pressure problems should
obtain their physician’s advice before using spas or hot tubs.
6. Persons taking medication which induce drowsiness, such as tranquilizers, antihistamines or anticoagulants should
not use spas or hot tubs.
WARNING
Should overheating occur or the gas supply fail to shut off, turn off the manual gas control valve to the heater.
Do not use this heater if any part has been under water. Immediately call a qualified service technician to
inspect the heater and to replace any part of control system and gas control which has been under water.
1. Carbon monoxide is produced by burning fuel, including natural gas and propane.
2. Proper installation, operation and maintenance of fuel-burning appliances in the home is the most important
factor in reducing carbon monoxide poisoning.
3. Be sure that fuel burning appliances such as heaters are installed by professionals according to manufacturer’s
instructions and codes.
4. Always follow the manufacturer’s directions for safe operation.
5. Have the heating system (including vents) inspected and serviced annually by a trained service technician.
6. Examine vents regularly for improper connections, visible cracks, rust or stains.
7. Install battery-operated carbon monoxide alarms. The alarms should be certied to the requirements of the most
recent UL, IAS, CSA and IAPMO standard for carbon monoxide alarms. Test carbon monoxide alarms regularly
and replace dead batteries.
WARNING
The U.S. Consumer Product Safety Commission warns that carbon monoxide is an “invisible killer”. Carbon monoxide
is a colorless and odorless gas.

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The ETi™ 400 High Efficiency Pool and Spa Heater is designed and manufactured to provide many years of safe and reliable
service when installed, operated and maintained according to the information in this manual. Throughout this manual, safety
warnings and cautions are identified by the “ “ symbol. Be sure to read and comply with all of the warnings and cautions.
SAFETY INFORMATION
Warning and Safety Instructions
CARBON MONOXIDE GAS IS DEADLY
READ OWNERS MANUAL COMPLETELY BEFORE OPERATING
THIS PRODUCT MUST BE INSTALLED AND SERVICED BY A PROFESSIONAL SERVICE TECHNICIAN,
QUALIFIED IN POOL HEATER INSTALLATION. Some jurisdictions require that installers be licensed.
Check with your local building authority about contractor licensing requirements. Improper installation
and/or operation could create carbon monoxide gas and flue gases which could cause serious injury or
death. Improper installation and/or operation will void the warranty.
Exhaust from this pool heater contains toxic levels of carbon monoxide, a dangerous, poisonous gas you
cannot see or smell. Symptoms of carbon monoxide exposure or poisoning include dizziness, headache,
nausea, weakness, sleepiness, muscular twitching, vomiting and inability to think clearly. IF YOU
EXPERIENCEANY OFTHEABOVE SYMPTOMS, IMMEDIATELY TURN OFFTHE POOLHEATER, LEAVE
THE VICINITY OF THE POOL OR SPAAND GET INTO FRESH AIR IMMEDIATELY. THE POOL HEATER
MUST BE THOROUGHLY TESTED BY A GAS PROFESSIONAL BEFORE RESUMING OPERATION.
EXCESSIVE CARBON MONOXIDE EXPOSURE CAN CAUSE BRAIN DAMAGE OR DEATH.
DANGER —
WARNING — FORYOUR SAFETY
This product must be installed and serviced by a professional service technician, qualified in pool
heater installation. Some jurisdictions require that installers be licensed. Check with your local building
authority about contractor licensing requirements. Improper installation and/or operation could create
carbon monoxide gas and flue gases which could cause serious injury or death. Improper installation
and/or operation will void the warranty.
• NEVER use this pool heater indoors without specified ventilation system (and properly installed
vent pipe).
• NEVER use this pool heater in the home or in partly enclosed areas (such as garages), unless the
specified ventilation system is used. If used outdoors, install far from open windows, doors, vents
and other openings.
• Pentair strongly recommends that all vents, pipes and exhaust systems be initially and periodically
tested for proper operation. This testing can be accomplished by using a hand-held carbon
monoxide meter and/or by consulting with a gas professional.
• Pool heaters must be used in conjunction with carbon monoxide detectors installed near the pool
heater. The carbon monoxide detectors must be periodically inspected for proper operation so as
to insure continued safety. Broken or malfunctioning carbon monoxide detectors must be replaced
immediately.
WARNING — This heater is equipped with an unconventional gas control valve that is factory set at a
pressure of -.2 inches wc. Improper installation, adjustment, alteration, service or maintenance
can cause property damage, personal injury or loss of life. Installation or service must be performed
by a qualified installer, service agency or the gas supplier. If this control is replaced, it must be
replaced with an identical control.

ETi 400 High Efficiency Pool and Spa Heater Installation and User’s Guide Rev. A 9/2016
8Warning and Safety Instructions
SAFETY INFORMATION (continued)
WARNING — Risk of fire or explosion from incorrect fuel use. Do not try to run a heater set up for natural gas on propane
gas or vice versa. Only qualified service technicians should attempt to convert heater from one fuel to the other.
Do not attempt to alter the rated input or type of gas by changing the orifice. If it is necessary to convert to a
different type of gas, consult your Pentair dealer. Serious malfunction of the burner can occur which may result
in loss of life. Any additions, changes, or conversions required in order for the appliance to satisfactorily meet
the application needs must be made by a Pentair dealer or other qualified agency using factory specified and
approved parts. The heater is available for use with natural gas only. It is not designed to operate with any other
fuels. Refer to the nameplate for the type of gas the heater is equipped to use.
• Use heater only with the fuel for which it is designed.
WARNING — Risk of fire or explosion from flammable vapors. Do not store gasoline, cleaning fluids, varnishes, paints,
or other volatile flammable liquids near heater or in the same room with heater.
WARNING — Risk of explosion if unit is installed near propane gas storage. Propane (LP) gas is heavier than air. Consult
local codes and fire protection authorities about specific installation requirements and restrictions. Locate the
heater away from propane gas storage and filling equipment as specified by the Standard for the Storage and
Handling of Liquefied Petroleum Gases, CAN/CSA B149.2 (latest edition) or ANSI/NFPA 58 (latest edition).
WARNING — Risk of fire, carbon monoxide poisoning, or asphyxiation if exhaust venting system leaks. Only qualified
service technicians should attempt to service the heater, as leakage of exhaust products or flammable gas may
result from incorrect servicing.
WARNING — Risk of asphyxiation if exhaust is not correctly vented. Follow venting instructions exactly when installing
heater. Do not use a draft hood with this heater, as the exhaust is under pressure from the burner blower and
a draft hood will allow exhaust fumes to blow into the room housing the heater. The heater is supplied with an
integral venting system for indoor installation. Canada: In Canada, this pool heater can only be installed
outdoors or in an enclosure that is not normally occupied and has no openings directly into occupied areas.
See Page 24 - 27 for enclosure venting requirements.
CAUTION — Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and
dangerous operation. Wiring errors can also destroy the control board.
• Connect heater to 120 or 240 Volt, 60 Hz., Single Phase power only.
• Verify proper operation after servicing.
• Do not allow children to play on or around heater or associated equipment.
• Never allow children to use the pool or spa without adult supervision.
• Read and follow other safety information contained in this manual prior to operating this pool heater.
DANGER
CARBON MONOXIDE GAS IS DEADLY – Exhaust from this pool heater contains toxic levels of carbon monoxide, a dangerous,
poisonous gas you cannot see or smell.

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GENERAL SPECIFICATIONS
NOTICE
• Combustion air contaminated by corrosive chemical fumes can damage the heater and will void the warranty.
• The Combination Gas Control Valve on this heater differs from most appliance gas controls. If it must be
replaced, for safety reasons replace it only with an identical gas control.
• The heater’s access side panels must be in place to provide proper ventilation and to avoid water intrusion. Do
not operate the heater for more than ve (5) minutes with the side panels removed.
• This heater is design tested by CSA International as complying with the Standard for Gas Fired Pool Heaters,
ANSI Z21.56/CSA 4.7, and is intended for use in heating fresh water swimming pools or spas.
• The ETi™ 400 Heater is designed for the heating of chlorine, bromine or salt system swimming pools and
spas. It should NOT be used as a space heating boiler, or general purpose water heater.
• The heater should be located in an area where leakage of the heater or connections will not result in damage to
the area adjacent to the heater or to the structure. When such locations cannot be avoided, it is recommended
that a suitable drain pan, adequately drained, be installed under the heater. The pan must not restrict air ow.
• The heater may not be installed within 5 ft. (1.5M ) of the inside surface of a pool or spa unless it is separated
by a solid fence, wall or other permanent barrier.
• In the United States, installation must be in accordance with local codes and the most recent edition of the
National Fuel Gas Code, ANSI Z223.1/NFPA-54. The Code can be obtained from: National Fire Protection
Association 1 Batterymarch Park Quincy, MA 02169 www.nfpa.org
• In Canada, install the heater in accordance with local codes and the most recent edition of the Natural Gas and
Propane Installation Code, CAN/CSA B149.1.
Warning and Safety Instructions
Heater Identification Information (HIN)
To identify the heater, see rating plate on the inner front panel of the heater. There are two designators for each heater,
one is the Model Number and the other is the Heater Identication Number (HIN).
Heater Identification Number (HIN)
The following example simplifies the identification system:
1) ETi
2) Model Size : (400) : Input rating (Btu/hr)
X 1000
3) Fuel Type : NA = Natural gas
4) Construction : ASME = Commercial Model
ETI 400 NA ASME
ETi = High Efficiency
FUEL TYPE =
CONSTRUCTION =
MODEL SIZE = BTU INPUT in 1000 of BTU / HR
H. I. N.
HEATER IDENTIFICATION NUMBER
ID DESIGNATOR FOR PENTAIR WATER POOL AND SPA, ETi HEATER
NA = NATURAL GAS
Example:
1 2 3 4
ASME = COMMERCIAL MODEL

ETi 400 High Efficiency Pool and Spa Heater Installation and User’s Guide Rev. A 9/2016
10
The heater operator controls are as follows:
POOL ON Press this button to control the heater operation by the pool temperature setting.
SPA ON Press this button to control the heater operation by the spa temperature setting.
HEATER OFF Press this button to switch off the heater.
▲TEMP Press this button to raise the temperature setting.
▼TEMP Press this button to lower the temperature setting.
To toggle the display between degrees Centigrade (°C) and degrees Fahrenheit (°F):
1. Press the HEATER OFF button to switch the heater OFF.
2. Press ▲TEMP or ▼TEMP for 5 seconds. The display will ash once and change modes (°C to °F or vice versa).
3. Press the HEATER OFF button to switch the heater ON.
When either the ▲TEMP or ▼TEMP buttons are depressed, the digital display will indicate the temperature setting.
After ve seconds, the display will return to the actual pool/spa temperature.
In addition to the digital temperature display, there are ve indicator lights:
The POOL ON light indicates the pool water temperature is controlling the heater operation.
The SPA ON light indicates the spa water temperature is controlling the heater operation.
The HEATING light comes on and stays on when the heater’s burner chamber is ring. This light should be on whenever
the burner is on. This light blinks when the heater is calling for heat but not ring. If this light is on but the burner fails
to come on, one of the “service” lights should come on, indicating a fault in the system.
The SERVICE SYSTEM light indicates that there is insufcient water ow to the heater. If the pump is operating, this
usually indicates that the lter and/or skimmers should be cleaned (some lters may require back-washing). If the light
remains on after the lter/skimmers have been serviced, the system should be checked by a qualied service technician.
The SERVICE HEATER light indicates a fault in the heater or its controls. If this light comes on, shut down the heater
(SeeTOTURNOFFGASTOTHEAPPLIANCEonpage13), and have a qualied service technician check the system.
Temperature
Up and Down Digital Temperature Display
System Operation
Indicator Lights Dual Temperature Controls Heater "OFF" Switch
OPERATOR CONTROL PANEL
Section 1: Operation Instructions
The ETi™ 400 Heater is shipped factory set at 70° F (35°
C) for pool mode and 95° F (21° C) for spa mode. Using
the up and down arrows, you can set the thermostats to a
minimum temperature of 65° F (18.3° C), or a maximum
of 104° F (40° C). If you desire to heat only one body of
water, the thermostat is capable of an off mode.
TEMPERATURE SETTING
Section 1: Operation Instructions

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OPERATOR CONTROL PANEL
VIEW FAULT CODES: Press the POOL ON button and the ▲TEMP button to view the last fault code.
Press the ▲TEMP button to scroll up to view the previous 4th. fault codes. The next message displayed after the
5th. fault code is END.
VIEW STACK FLUE GASTEMPERATURE: Press and hold the POOL ON (or SPA ON) button for more than 5
seconds to view the current Stack Flue Gas temperature. Each heat exchange has one temperature sensor (SF1 and
SF2), the SF1 temperature is displayed on the heater’s LCD with a dot on the upper left corner of the LCD. Scroll
up or down to display the SF2 current temperature and the dot will not be displayed on the LCD.
BASIC SYSTEM OPERATION
Start the pump. Be sure the pump is running and primed to close the water pressure switch and
supply power to heater. Be sure the pool and/or spa is properly filled with water. Follow the Lighting/
Operating instructions below.
FOR YOUR SAFETY: READ BEFORE LIGHTING
HEATER DSI ELECTRONIC IGNITION LIGHTING/OPERATION
If you do not follow these instructions exactly, a fire or explosion may result
causing property damage, personal injury or loss of life.
Do not attempt to light the heater if you suspect a gas leak. Lighting the heater
can result in a fire or explosion which can cause personal injury, death, and
property damage.
WARNING
WARNING
Risk of explosion or fire causing burns or death if safety interlocks are disabled. DO NOT attempt to operate heater when
SERVICE HEATER light is on or if blower or burner will not start. Instead, follow instructions under “To Switch Off Gas to the
Appliance,” and call a qualified service technician to repair unit.
Section 1: Operation Instructions

ETi 400 High Efficiency Pool and Spa Heater Installation and User’s Guide Rev. A 9/2016
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BASIC SYSTEM OPERATION (CONTINUED)
START-UP AND OPERATION
START-UP AND SHUTDOWN INSTRUCTIONS ARE ON THE LABELATTACHED TO THE INSIDE COVER OF THE APPLIANCE
WATER CONNECTION PANEL.
BEFORE START-UP
A. This appliance does not have a pilot. It is equipped
with an ignition device which automatically lights the
burners. DO NOT try to light the burners by hand.
B. BEFOREOPERATING,smell all around the appliance
area for gas. Be sure to smell next to the oor because
some gas is heavier than air and will settle on the oor.
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.
C. Use only your hand to turn the gas control on or off.
Never use tools. If you cannot change the ON/OFF
setting by hand, don’t try to repair it, call a qualied
service technician. Forced or attempted repair may result
in a re or explosion.
D. Do not use this heater if any part has been under water.
Immediately call a qualied service technician to inspect
the heater and to replace any part of the control system
and any gas control which has been under water.
E. Do not operate the pool heater unless the pool or spa is
properly lled with water.
F. Before operating the appliance for the rst time or
after it has been off for an extended time, perform the
following checklist:
1. Remove debris or other articles from inside the heater
and the area around the heater and its exhaust vent.
Make sure the ventilation openings are clear of debris
or obstruction. For installations in an enclosed space,
make sure openings for combustion and ventilation
air are unobstructed.
2. Keep heater area clear and free from combustibles,
ammable liquids and chemicals.
3. Check that all water connections are tight.
4. Water must be owing through the heater during
operation. Make sure that pool/spa is lled with water
and have pump operating. Check that water ow is
unobstructed from the appliance. When operating
for the rst time or after an extended shut-down, run
lter pump for several minutes to clear all air from
the system.
Section 1: Operation Instructions
PUTTINGTHE HEATER INTO SERVICE
If the heater’s Water Pressure Switches (PS) are below or above the water level by 3 ft (61 cm), after the heater
installation the Water Pressure Switch setting should be adjusted. See WATER PRESSURE SWITCH, in SAFETY
CONTROLS on page 14.
Note: Before putting the heater into service for the rst time, follow the instructions under BEFORE START-UP
on page 12. Check for proper operation of the heater by following the steps under OPERATING INSTRUCTIONS
on page 13. Damage to equipment caused by improper installation or repair will void the warranty.

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Section 1: Operation Instructions
HEATER OPERATING INSTRUCTIONS
1. STOP! Read the safety information on (page 12).
2. Set both pool and spa thermostats to the lowest settings.
3. Turn off all electric power to the appliance.
4. This appliance does not have a pilot. It is equipped with an ignition
device which automatically lights the burner. Do not try to light the
burner by hand.
5. Remove the access door panels by unfastening the latch located on each
door, then lift up and out from the bottom of the panel
to remove.
6. Toggle-Style Valve: Pull toggle toward you to turn gas off ,
see Figure 1.
7. Wait ve (5) minutes to clear out any gas. If you then smell gas,
STOP! Follow B in the BEFORE START-UP instructions on page 12.
If you don’t smell gas, go to the next step.
8. Push the toggle switch away from you to switch the gas on.
9. Replace the Door Access Panels. All panels must be in place when operating the heater.
10. Set 3-way valves on inlet and outlet to pool or spa, as appropriate.
11. Turn on all electric power to the appliance.
12. Press either the POOL ON or SPA ON button switch on the operating control.
13. Set the thermostat to desired setting. NOTICE: Setpoint must be above actual water temperature or burner
will not re. See OPERATOR CONTROL PANEL on page 11.
14. The blower should come on immediately, and after about 15 seconds, the burner should re. When operating for
the rst time, the burner may not re on the rst try because of air in the gas line. If it does not re at rst, push the
OFF switch, wait ve minutes, and again push the POOL or
SPA ON switch. The burner should re after about 15 seconds. You
may have to repeat this until all of the air has cleared the gas line.
15. The burner should re until the pool/spa temperature reaches the desired
temperature set on the thermostat. The blower will continue to run for about 45 seconds after the burner shuts
off. If any of the safety interlocks should open during burner operation, the burner shuts off immediately, but the
blower continues to run for about 45 seconds. Should overheating occur or the gas supply fail to shut off, turn off
the manual gas control valve to the appliance.
16. If the appliance will not operate, follow the instructions TO TURN OFF GAS TO THEAPPLIANCE below,
and call your service technician or gas supplier.
17. If the electrical power is shut off to the heater while it is running, once power is restored, the heater will power up
with the previous programed settings.
TOTURN OFF GASTO APPLIANCE
1. Press the OFF button on operating control.
2. Switch off all electric power to the unit.
3. Remove the access door panels.
4. Toggle-Style Valve: Pull toggle toward you to turn gas off, see Figure 1 on page 13.
5. Replace the Access Door Panels.
Figure 1.
Gas control is shown
OFF. Push toggle switch
away from you to switch ON.

ETi 400 High Efficiency Pool and Spa Heater Installation and User’s Guide Rev. A 9/2016
14
SAFETY CONTROLS
AIR FLOW SWITCH (AFS)
There are two air ow switches, (see Figure 2), designed as a safety device to ensure
the two combustion air blowers (fans) are operating and are monitoring the differential
(negative) pressure within the blower housing. These air pressure switches are factory
set. The switches (see page 61 #29) are connected upstream of the ignition module.
The ignition module does not operate unless the air ow switches and all safety
switches are closed.
WATER PRESSURE SWITCHES
WARNING
Hazardous pressure. Do not bypass the Water Pressure Switches or render
it inoperable.
The heater has two Water Pressure switches, see Figure 3.
If the water ow is restricted, the water pressure switches
may prevent the burner from ring and cause the Service
System LED indicator to go on. Note: If the light remains
on after the lter has been serviced, have a qualied
service technician check the system.
For deck-level heater installations, the Water Pressure
switches are factory set at 3.00 psi (20.6 kPa). Note:
See Below Pool Level Installation, on page 20. If the
pressure switches are 1 ft (0.3M) below or above the pool
water level, reset the switches so that it is open when the
pump is off and closed when the pump is running. Turn
the star-wheel on the switch clockwise ( ) to raise
setting (heater below the pool level) and counterclockwise
( ) to lower the setting (heater above the pool
level), see Figure 4. Test each switch after resetting.
NOTICE: When the heater is mounted more than
3 ft (0.9 m) above or 3 ft (0.9 m) below the deck level,
a pressure switch is no longer adequate.A Flow
Switch must be installed instead.
CAUTION! Heater operation with an incorrect water
pressure switch setting, may cause the heater to
operate without sufficient water flow, and may cause
severe heater damage.
HIGH LIMIT SWITCH AND
AUTOMATIC GAS SHUT-OFF
SWITCHES (AG1 AND AG2)
A High Limit Switch (HLS), is a safety device that
opens the electrical circuit and shuts off the heater based
on a water temperature set point within the HLS. The
heater contains two AGS switches and one HLS
switch. The AGS switches are located in the outlet
plumbing assembly, and the HLS switch is located on
the main Inlet/Outlet Header (see page 16).
Section 1: Operation Instructions
Figure 4.
A reference scale is on
the back of pressure switch
Turn star wheel clockwise to raise
pressure set point if water pressure switch is
more than 1 ft (30 cm) below water level
Turn star wheel counterclockwise to lower
pressure set point if pressure switch is more
than 1 ft (30 cm) above water level
Water Pressure
Switch
Star Wheel
Figure 2. Air Flow Switch
Water Pressure
Switch
Star Wheel
Figure 3: Water Pressure Switch

Rev. A 9/2016 ETi 400 High Efficiency Pool and Spa Heater Installation and User’s Guide
15
IGNITION MODULE OPERATION
The Ignition Module, (Figure 5), is microprocessor based and operates on 24VAC supplied by the transformer. The
control works in conjunction with a fan control board (Figure 6), and utilizes a microprocessor to continually safely
monitor, analyze, and control the proper operation of the gas ame holder. The module with the presence of the ame
sensor, using ame rectication, allows the heater to operate.
Figure 5. Ignition Control Module
Flame Current
Check Point Diagnostic LED
1 Flash - Air Flow Fault
2 Flashes - Flame No Call for Heat
3 Flashes - Ignition Lockout
PS2
TH
START
NC IN
FAN1
L1
FAN2
GND
R 24 VAC
UNUSED
PS1
SAFETY CONTROLS (continued)
STACK FLUE SENSORS (SF1, SF2)
The heater is equipped with two Stack Flue sensors; one for each heat exchanger. These sensors monitor the stack ue
temperature and if needed will shut down the heater if the stack ue temperature exceeds 170° F (77° C).
THERMAL FUSE
A Thermal Fuse (TF) is a safety protection device that opens the electrical circuit if the temperature reaches 187° F
(86° C). The fuse cannot be reset, it must be replaced. See page 17 for more information.
FLOAT SWITCH
The Float Switch (FS) is a sensing application that shuts down the heater once the condensate level exceeds the
permitted level in the condensate container. See page 17 for more information.
Section 1: Operation Instructions
Figure 6. Fan Control Circuit
Heater left side panel removed

ETi 400 High Efficiency Pool and Spa Heater Installation and User’s Guide Rev. A 9/2016
16
HEATER DESCRIPTION
The ETi™ 400 Heater has precisely matched orice plates to meter the air and gas into the mixer. The blower draws the air
and gas through the mixer and forces it into the burner’s ame holder. A sealed TitanTough™ Heat Exchanger surrounds
the ame holder, discharging exhaust gases out the ue (See Figure 7 & 8). Use a 2 in tting to connect to the 2 in PVC
slip unions provided with the heater. The outer manifold remains cool; no heat sinks are required. The heater operator
control panel is located on the side of the heater.
Section 2: Installation Instructions
Section 2: Installation Instructions
Pentair strongly recommends that all vents, pipes and exhaust systems be initially and periodically tested for proper
operation.This testing can be accomplished by using a hand-held carbon monoxide meter and/or by consult-
ing with a gas professional. Pool and spa heaters must be used in conjunction with carbon monoxide detectors
installed near the pool heater.The carbon monoxide detectors must be periodically inspected for proper operation so
as to insure continued safety. Broken or malfunctioning carbon monoxide detectors must be replaced immediately.
Figure 7. ETI™ 400 Heater (Left Side View) Figure 8. ETI™ 400 Heater (RIght Side View)
Electrical
and
Bonding
lug
2-in Inlet
Plumbing
Assembly
Upper Blower
Assembly
Lower Blower
Assembly
Upper Heat
Exchanger
Lower Heat
Exchanger
Vent Cap
CPVC Flue
Outlet
Exhaust
Assembly
Inlet Plumbing
Assembly Tridicator (Water pressure and
Temperature gauges)
High
Limit
Switch
(HLS)
Auto gas
shut-off
switch
(AGS)
Condensate Neutralizer Cartridge
(Optional, P/N 475612 sold separately).
The cartridge may be mounted onto the heater
base for heater outdoor installation.
THIS HEATER MUST BE INSTALLED AND SERVICED BY A PROFESSIONAL SERVICETECHNICIAN,
QUALIFIED IN POOL HEATER INSTALLATION.
Tubing for
Condensate
Neutralizer
Cartridge
Heater Base (Top View)
To drainTo drain
2-in Outlet
Plumbing
Assembly

Rev. A 9/2016 ETi 400 High Efficiency Pool and Spa Heater Installation and User’s Guide
17
SEQUENCE OF OPERATION
An electronic temperature sensing thermistor in the manifold adapter inlet controls the heater operation. When the inlet
water temperature drops below the temperature set on the operator control panel, the control board supplies power to
the combustion air blowers through a series of safety interlocks. The heater interlocks consist of:
• the two water pressure switches (PS), which senses that the pump is running,
• the tridicator gauges (2) which monitors the water temperature in degree Fahrenheit and pressure in psi.
• the high limit switch (HLS), which opens if the heat exchanger outlet temperature goes above 135° F (57° C), and
• the two air ow switches (AFS), sense the pressure drop across the air metering orices.
• the two thermal fuses (TF) open if the ue gas temperature reaches 187° F (86° C).
• the automatic gas shut-off (AG1, AG2) switches, which open if the heat exchanger outlet temperature goes above
150° F (66° C).
• the oat switch (FS) which opens if the condensate overows at the oat switch due to blockage in the condensate
drain hose or neutralizer cartridge.
• the stack ue sensors (SF1, SF1), which shut down the heater if the ue gas temperature reaches 170° F (77° C).
The air ow switches (AFS) sense the pressure differential between both of the air metering orices. As soon as there is
sufcient air ow, the AFS closes, completing the circuit to the Fan Conrol board. The gas ignition control then opens
the gas valve and the fuel mixture is ignited by the Direct Spark Ignition (DSI). On a call for heat, the blowers are
energized for 15 seconds, the gas valve opens simultaneously as the direct spark igniters are energized, then ignition
occurs. The heater is equipped with a digital operating control that enables the user to pre-set the desired pool and spa
water temperatures. The control enables the user to select between pool and spa heating, and features a digital display
Section 2: Installation Instructions
The installation instructions contained in this manual are designed for use by qualied personnel only, trained especially
for installation of this type of heating equipment and related components. Some states require installation and repair by
licensed personnel. If this applies in your state, be sure your contractor bears the appropriate license. See Figure 9, 10
& 11 for Outdoor and Indoor installations, dimensions and orientation of the heater.
SPECIFICATIONS
Figure 9.
Dimensions in Millimeters / Inches
Heater Top View
762
30.0
863.6
34.0
1012.8
39.9
548.1
21.6
664.9
26.2

ETi 400 High Efficiency Pool and Spa Heater Installation and User’s Guide Rev. A 9/2016
18
421.2
16.6
537.3
21.2
243.5
9.6
670.3
26.4 22.2
Ă .88
ELECTRICAL
145.6
5.7
Heater Plumbing Side
2 in WATER INLET
CONNECTIONS
1087.5
42.8
108
4.3
38.1
Ă 1.5
GAS
226.6
8.9
4-IN CPVC FLUE
EXHAUST
SOCKET
1160.5
45.7
CONTROL CONTROL TOUCH
PAD/ DISPLAY
4-IN CPVC FLUE EXHAUST SOCKET
BONDING LUG
Heater Rear View
Heater Front View
4-IN PVC AIR INLET CONNECTION
(INDOOR OPTIONAL KIT)
4-IN PVC VENT CAP
Section 2: Installation Instructions
Figure 10.
Figure 11.
SPECIFICATIONS (CONTINUED)

Rev. A 9/2016 ETi 400 High Efficiency Pool and Spa Heater Installation and User’s Guide
19
PLUMBING CONNECTIONS
The heater has the unique capability of direct schedule 40 PVC plumbing connections. A set of bulkhead ttings is
included with the heater to ensure conformity with Pentair’s recommended PVC plumbing procedure. Other plumbing
connections can be used. See Figure 12 for plumbing connections.
CAUTION
Before operating the heater on a new installation, turn on
the circulation pump and bleed all the air from the filter
using the air relief valve on top of the filter. Water should
flow freely through the heater. Do not operate the heater
unless water in the pool/spa is at the proper level. If a
manual by-pass is installed, temporarily close it to ensure
that all air is purged from the heater.
WATER CONNECTIONS
The heater requires proper water ow and pressure
for its operation. See Figure 13 for the recommended
installation. The lter pump discharges to the lter,
the lter discharges to the heater, and the heater
discharges directly to the pool or spa.
A manual bypass valve should be installed before
the heater when the pump ow exceeds 120 GPM
(454 LPM ). See WATER FLOW RATE Table 1
on page 20 for setting of the manual by-pass valve.
Make sure that the outlet plumbing from the heater
contains no shut-off valves or other ow restrictions
that could prevent ow through the heater (except
for pool installations as noted below, or winterizing
valves where needed). To switch ow between the
pool and spa, use a diverter valve. Do not use any
valve that can shut off the ow.
Install the chemical feeder downstream of the
heater. Install a chemical resistant one-way check
valve between the heater and the chemical feeder
to prevent back-siphoning through the heater
when the pump is off.
NOTICE: If the heater is plumbed in backwards, it will cycle continuously. Make sure piping from lter is not reversed
when installing heater.
Connect the heater directly to 2 in PVC pipe, using the provided unions. Heat sinks are not required. The low thermal mass
of the heater will prevent overheating of the piping connected to the pump even if the heater shuts down unexpectedly.
Occasionally a two-speed pump will not develop enough pressure on the low speed to operate the heater. In this case, run
the pump at high speed only to operate the heater. If this does not solve the problem, do not try to run the heater. Instead,
correct the installation.
Do not operate the heater while an automatic pool cleaner is also operating. If the circulation pump suction is plugged
(for example by leaves), there may not be adequate ow to the heater. Do not rely on the pressure switch in this case.
Pool
Main
Drain Spa
From Pool 3-Way
Valve
3-Way
Valve
3-Way
Valve
Chlorinator
Heater
Pump
Check Valve
Filter
Figure 13.
PUMP
FILTER
HEATER
MANUAL
BY-PASS
TO
POOL GATE
VALVE
FROM
POOL
FROM
FILTER
INLET
OUTLET
Figure 12.
Section 2: Installation Instructions

ETi 400 High Efficiency Pool and Spa Heater Installation and User’s Guide Rev. A 9/2016
20
VALVES
When any equipment is located below the surface of the pool or spa, valves should be placed in the circulation piping
system to isolate the equipment from the pool or spa. Check valves are recommended to prevent back-siphoning. Back-
siphoning is most likely to occur when the pump stops, creating a pressure-suction differential. Do NOT sanitize the
pool by putting chlorine tablets or sticks into the skimmer(s). When the pump is off, this will cause a high concentration
of chlorine to enter the heater, which could cause corrosion damage to the heat exchanger.
CAUTION
Exercise care when installing chemical feeders so as to not allow back siphoning of chemical into the heater, filters
or pump. When chemical feeders are installed in the circulation of the piping system, make sure the feeder outlet line
is down stream of the heater, and is equipped with a positive seal noncorrosive Check Valve, (P/N R172288), between
the feeder and heater.
MANUAL BY-PASS
Figure 14.
(*) Compare Tby observing the Temperature Pressure gauges
located inside the heater (see page 16), and the water inlet
temperature displayed on the Control Board LCD.
WARM WATER OUTLET
COLD WATER INLET
COLD
WATER
FROM POOL
WARM WATER TO POOL
1. Set Manual By-Pass Valve.
2. Remove Handle.
Section 2: Installation Instructions
ETi™
400
GPM (min. / max) Max. T (°F) / Min T (°F)
40 / 120 35 / 25*
Where the water ow rate exceeds the maximum 120 GPM,
a manual bypass should be installed. After installing the
valve, adjust the valve to bring the ow rate within the
acceptable range. Then remove the valve handle or lock
it in place to avoid tampering. See Figure 14.
Table 1: Heater Water Pressure.
BELOW POOL INSTALLATION
If the heater is below water level, the pressure switch must be adjusted.
This adjustment must be done by a qualied service technician. See following CAUTION before installation.
CAUTION
BELOW OR ABOVE POOL INSTALLATION
The water pressure switch is set in the factory at 3.00 PSI (± 0.75 PSI). This setting is for a heater installed at pool level.
If the water pressure switch is more than 1 ft (30 cm) below or above the pool level, the water pressure switch must be
adjusted by a qualified service technician. Figure 4 on page 14.
FLOW SWITCH
If the water pressure switch is installed more than 3 ft (0.9 m) above the pool or more than 3 ft (0.9 m) below the pool
level, you will be beyond the limits of the pressure switch and a flow switch must be installed. Locate and install the
flow switch externally on the outlet piping from the heater, as close as possible to the heater. Connect the flow switch
wires in place of the water pressure switch wires.