Pentair ETi 250 User manual

ETi 250® HIGH EFFICIENCY POOL 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 / PROPANE GAS
INSTALLATION AND USER’S GUIDE
FOR YOUR 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 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 250 NA - ASME 461112

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
2
P/N 476361 Revision A. 2/2022
Customer Service and Technical Support
Phone: [phone]
Fax: [phone]
(USA - 8 AM to 7:30 PM)
www.pentair.com
Customer Service and Technical Support

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
3
Thank you for choosing the Pentair ETi 250 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 250 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 250 High Efciency heaters are
designed with direct spark ignition (DSI) for on demand heat, which eliminates the need for a standing pilot.
SPECIAL INSTRUCTIONS 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 250 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 250 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 250 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 250 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
SAVE THESE INSTRUCTIONS
ETi®250 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 250 Pool Heater meets the requirements of the ASME Boiler and Pressure Vessel
Code.

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
4Warning and Safety Instructions
CONSUMER AND SAFETY INFORMATION
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.

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
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The ETi®250 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
EXPERIENCE ANY OF THE ABOVE SYMPTOMS, IMMEDIATELY TURN OFF THE POOL HEATER,
LEAVE THE VICINITY OF THE POOL OR SPA AND 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 — FOR YOUR 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
positive pressure of 1.4 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.
Do not attempt to adjust the gas flow by adjusting the regulator setting.

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
6Warning 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 or propane 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.
• If a propane gas conversion is necessary, this MUST be done by a qualified professional service
technician qualified in pool heater installation or by qualified gas supplier before the heater is operational.
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 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 27 - 29 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.
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.

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
7
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 which has a set
point of 1.4 in wc, and is different than other Pentair heaters. If it must be replaced, for safety reasons replace
it only with an identical gas control valve model. Ne sure the part number is the same.
• 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 certied 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® 250 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
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 : (250) : Input rating (Btu/hr)
X 1000
3) Fuel Type : NA = Natural gas
4) Construction : ASME = Commercial Model
ETI 250 NA ASME
ETi = High Eciency
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 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
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Contents
Warning and Safety Information ............................................................................... 3
Important Notices ........................................................................................................................................... 3
Heater Application Information ....................................................................................................................... 3
Code Requirements........................................................................................................................................ 4
Consumer Information and Safety Information............................................................................................... 4-6
General Specifications.................................................................................................................................... 7
Heater Identification Information (HIM)........................................................................................................... 7
Contents....................................................................................................................... 8
Operation Instructions................................................................................................ 10
Operator Control Panel................................................................................................................................... 10
Menu Navigation............................................................................................................................................. 10
Operating the Heater (Temperature Settings)................................................................................................. 10
Menu............................................................................................................................................................... 11
Basic Heater Operation.................................................................................................................................. 11
Heater DSI Electronic Ignition Lighting/Operation ...................................................................................... 12
Start-Up Operation / Before You Start ....................................................................................................... 13
Putting the Heater into Service / High Altitude Requirement .............................................................. 13
Heater Operating Instructions .................................................................................................................... 14
To Turn Off Gas to the Appliance ............................................................................................................... 14
Safety Controls (Air Flow Switch, Water Pressure Switch, High Limit Shut-Off Switch) .............................. 15-16
(Stack Flue Sensor (SFS), Thermal Fuse, Float Switch)
Ignition Module Operation / Flame Current Check Point / Diagnostic LEDs .................................................. 16
Installation ................................................................................................................... 17
Heater Description.......................................................................................................................................... 17
Putting the Heater into Service....................................................................................................................... 17
Sequence Of Operation.................................................................................................................................. 18
Specifications ................................................................................................................................................. 18-19
Plumbing Connections.................................................................................................................................... 20
Water Connections ......................................................................................................................................... 20
Multiple Heater Connections .......................................................................................................................... 21
Valves............................................................................................................................................................. 22
Manual By-Pass ............................................................................................................................................. 22
Automatic By-Pass ......................................................................................................................................... 22
Below Pool Installation ................................................................................................................................... 23
Gas Connections....................................................................................................................................................... 23
Gas Pipe Sizing / Gas Pipe Escutcheon ................................................................................................... 24
Gas Pressure Testing..................................................................................................................................... 25
Checking Gas Pressure Through Gas Control Valve ..................................................................................... 25
Sediment Traps .............................................................................................................................................. 26
Outdoor Installation (US and Canada) ........................................................................................................... 27-28
Outdoor Installation Venting Guidelines .................................................................................................... 29
Heater Clearances - Outdoor .................................................................................................................... 29
Indoor Venting — General Requirements (Category IV Vertical and Horizontal requirements) .................... 30
Heater Clearances — General Requirements (Indoor and Outdoor Installation for US and Canada) ........ 30
Direct Air Intake Cover ................................................................................................................................... 30
Combustion Air Supply ................................................................................................................................... 31
Air Supply Requirements Guide for the ETi 250 Heater............................................................................. 31
Direct Air Intake Exhaust Duct using 4-inch PVC Pipe (Indoor Installation)............................................... 32
Direct Air Intake Kit Installation (Combustion Air Supply)........................................................................... 33
Corrosive Vapors and Possible Causes ......................................................................................................... 34
Contents

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
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Contents
Installation (Continued) ................................................................................................ 35
Horizontal Or Vertical Venting (Category IV) - Positive Pressure.................................................................... 35
Direct Vent Requirements............................................................................................................................... 36
Direct Vent Indoor Installation (US and Canada) Horizontal Through-the-Wall (Termination).................. 37
Garage or Utility Room Installation (Vent Installation - Indoor Installation US and Canada).................... 39
Final Installation Check....................................................................................................................... 39
Condensate Management (Maintenance, Condensate Neutralizer Cartridge Drain/Tubing Installation)....... 40
Electrical Connections .................................................................................................................................... 42
Bonding ..................................................................................................................................................... 42
120 VAC / 240 VAC Wiring......................................................................................................................... 42
Remote Control Connections ......................................................................................................................... 43
Fireman’s Switch Connection ......................................................................................................................... 43
Connecting the Heater to the IntelliCenter Control System Load Center via RS-485 .................................... 45
Connecting the RS-485 Cable from the Heater to the Load Center............................................................... 46
Heater Connection Wiring Diagram................................................................................................................ 48
Heater Ladder Wiring Diagram....................................................................................................................... 49
Troubleshooting.......................................................................................................... 50
Initial Troubleshooting and Error / Fault Codes .............................................................................................. 50
Initial Troubleshooting Chart........................................................................................................................... 51
Heater Will Not Fire A.................................................................................................................................. 52
Heater Will Not Fire B.................................................................................................................................. 53
Diagnostics LEDs: PS, HLS, TF, IGN, AFS, AG1, FS ................................................................................ 54-55
Diagnostics Alarms: PS, AFS, AGS, HLS .................................................................................................. 56
Alarms: SFS ............................................................................................................................................... 57
ALarms: CFS, TF, E01 or 126 .................................................................................................................... 58
Burner Troubleshooting .................................................................................................................................. 59
Heat Exchanger Troubleshooting ................................................................................................................... 59
Operator Control Panel Displays RNC Code.................................................................................................. 59
Maintenance and Care Instruction ............................................................................ 60
Care and Maintenance...................................................................................................................... 60
TitanTough Heat Exchanger Assemblies Annual Inspection ............................................................ 60
Burner Spark Electrode and Flame Sensor Rod Annual Inspection ................................................. 61
Pressure Relief Valve (50 psi)........................................................................................................... 61
After Start-Up................................................................................................................................... 62
Spring and Autumn ....................................................................................................................... 62
Winter Operation and Winterization .............................................................................................. 62
Removal of Condensate Cartridge in Freezing Temperatures.......................................................... 63
Return the Heater to Service............................................................................................................. 63
Maintaining Pool Temperature.......................................................................................................... 63
Energy Saving Tips....................................................................................................................... 63
Chemical Balance ............................................................................................................................. 64-65
Heater Replacement Parts.......................................................................................... 66-73
Heater Replacement Parts List ......................................................................................................... 66
General Replacement Parts.............................................................................................................. 67
Heater Blower Assembly Replacement Parts ................................................................................... 68
Heat Exchanger Assembly Replacement Parts ................................................................................ 70/71
Heater Manifold Assembly - Inlet and Outlet Assembly Replacement Parts .................................... 72
Heater Condensate and Exhaust Assembly Replacement Parts...................................................... 73
Heater Operator Control Panel Assembly Replacement Parts ......................................................... 74
Contents

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
10
OPERATOR CONTROL PANEL
Operation Instructions
Operation Instructions
Control Panel Description
LCD Display: The control panel LCD displays two
lines of text. During normal heater operation the current
pool or spa water temperature is shown on line 1 of
the display. The heater set point for the pool or spa is
shown on line 2 of the display. The display will turn off
after two (2) minutes of inactivity on the keypad. When
the display is off due to inactivity, pressing any button
will turn it back on.
POOL/SPA: Toggles between POOL and SPA mode:
Displays the selected pool or spa body of water
actual temperature and set point.
HEATER OFF: Press this button to put the heater into
IDLE/OFF mode. The LCD will display HEATER OFF.
UP Arrow Button: Increase heater temperature set point. Scroll through menu items and
change settings.
DOWN Arrow Button: Decrease heater temperature set point. Scroll through menu
items and change settings.
SELECT: Select current menu item or save menu item settings.
MENU/BACK: Enter menu items. Press Down to scroll through menu item. Press Menu/Back to return to main
screen.
HEATING (LED): Solid Red LED on indicates the heater currently heating. LED Off: Heater is not active. Note:
During the heater ignition process, this LED blinks. Note: See page 12 for Heating (LED) and Errors description.
Menu Navigation
1. Press MENU/BACK to display POOL MAX. Use the DOWN or UP button to scroll through each of the highlighted
menu items.
2. Press SELECT to access the highlighted item. Press UP/DOWN to change or view the highlighted item.
3. Press SELECT to save, exit the setting and return to the menu items. Note: To exit the menu without saving and
return to the main screen, press MENU/BACK two times.
Operating the Heater (Temperature Settings)
The heater temperature default settings are factory set at 70° F (21° C) for the pool mode and 95° F (35° C) for the
spa mode. Using the up and down arrows, you can set the thermostats to a minimum pool temperature of 65° F.
(18.3° C), or a maximum temperature of 104° F (40° C).
Heating the Pool or Spa (Press the HEATER OFF button to turn OFF the heater).
• Press POOL/SPA to select either Pool or Spa. The display shows the current set point and water temperature.
Press Up/Down to increase or decrease water set point temperature. If the current water temperature is below
the Set point water temperature, the heater will begin heating.
Temperature
Controls
Up/Down
LCD Temperature
Display
Menu/Back
Select
Buttons
Toggle
switch
displays
Heater/Off
Heater ON
Red LED
Indicator
Pool/Spa
Toggle Button
Figure 1. Heater Control Panel

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
11
Menu
POOL MAX (65°F-104°F): The maximum heater operating temperature for the pool.
SPA MAX (65°F-104°F): The maximum heater operating temperature for the spa.
UNITS: Select F (Fahrenheit) or C (Celsius) to display change the display of the heat settings. Select US or Metric units.
HISTORY: Use Up/Down button to scroll through the last ve heater errors.
CYCLES: Number of heater on/off cycles.
RUNTIME: Total number of hours the heater has spent heating the water.
RNC ALERT: RNC Alert enabled or disabled:
RNC Alert Enabled: Enables The 1000 hour timer for replacing the condensate neutralizer cartridge.
After 1000 hours of heating, the main display will show REPLACE. To replace the neutralizer cartridge
and reset the timer see page 59.
RNC Alert Disabled: Disables the Replace Neutralizer Cartridge (RNC) alert in the event you do not utilize a
neutralizer cartridge.
RNC TIME: If RNC Alert Enabled, Displays the amount of time remaining on the 1000 hour timer for replacing the condensate
neutralizer cartridge.
RNC RESET: If RNC Alert Enabled, Resets the 1000 hour RNC timer. After performing maintenance and
replacing the Neutralizer Cartridge, this menu resets the 1000 hour timer.
SFS TEMP: Displays the current Stack Flue Sensor temperature.
FLAME: Displays the current ame sensor status (Normal or Low).
BACKLITE: Time-Out Enabled/Disabled:
Time-Out Enabled: The LCD backlight will turn off after two minutes of no control panel key pad activity. After three
minutes of no key pad activity the LCD will turn off. When the LCD and/or the Backlight are off, any button press will
turn the LCD and backlight back on. After that, the control panel buttons are in normal operating mode.
Time-Out Disabled: The LCD and backlight will stay on continuously and will not timeout.
HTR ADDR: Set the heater address (1-16) for automation control. Up to 16 heaters can be connected to an automation
control system via RS-485.
BP-VALVE (By-pass Valve): Enabled/Disabled, For more information, see page 22.
By-pass Valve Description
The purpose of the automatic BPVALVE (bypass valve) feature is to by-pass the ow of water from the heater inlet to the
heater outlet when the heater is not ring. There is a minimal amount of water ow through the heater when the heater
is not ring, and a maximum water ow through the heater when the heater is ring. For more information about Manual
By-Pass and Automatic By-Pass valves, see page 22.
By-Pass Enabled
When the BYPASS VALVE feature is enabled and there is a call for heat, the by-pass valve closes to allow
water to ow through the heater. It takes 30 seconds for the bypass valve to rotate to the closed position. This allows
the valve to complete rotation so there is sufcient water ow and pressure to prevent the water pressure switch from
trigging an error. When the call for heat ends, the water ow continues through the heat exchanger for a cool down
period of one minute. After the cool down period, the by-pass valve will rotate so that water no longer ows through
the heater.
By-Pass Disabled
When the BYPASS VALVE feature is disabled, there is no automatic switching of the by-pass valve when the heater
starts a heating cycle. The valve stays in the position and water always ows through the heater.
LANGUAGE: English, Spanish or French
Operation Instructions

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
12
VIEW FAULT CODES: The current error/fault will be displayed on the control panel LCD. If you'd like to review
the last ve errors, you can press the Menu button, then use the Down arrow button to scroll to the History menu
where the last ve (5) heater errors are displayed.
VIEW STACK FLUE GAS TEMPERATURE: Press and hold the POOL/SPA button for more than ve (5) seconds to
view the current Stack Flue Gas temperature.
BASIC HEATER 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 and 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.
Operation Instructions
HEATING (LED) Indicator:
● This Red LED is on and stays on when the heater’s burner chamber is ring and
should be on whenever the burner is on.
● When this Red LED blinks, it indicates the heater is calling for heat but the burner
chamber is not ring. If this LED is on but the burner fails to re, an error is
OPERATOR CONTROL PANEL
A ashing RNC message is displayed on the second line of the main screen when the heater has been heating for 1000
hours or more. It is recommened to replace the CNC and reset the counter. After the cartridge is replaced, go to the
RNC RESET menu screen to reset the cartridge counter. At any time, to view the amount of time remaining on the 1000
hour timer, go to the RNC TIME menu. Alternately you can turn the heater off and then press and hold the Heater Off
button for 5 seconds to reset the timer. Note: If the counter is reset back to 1000 and the cartridge is not replaced,
the heater still can be used for normal operations. However, Pentair recommends regular maintenance and
replacement.
RNC MESSAGE: CONDENSATE NEUTRALIZER CARTRIDGE (CNC)

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
13
BASIC SYSTEM OPERATION (CONTINUED)
START-UP AND OPERATION
START-UP AND SHUTDOWN INSTRUCTIONS ARE ON THE LABEL ATTACHED TO THE INSIDE COVER OF THE APPLI-
ANCE 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. BEFORE OPERATING, 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.
Operation Instructions
PUTTING THE HEATER INTO SERVICE
If the heater’s Water Pressure Switch (PS) is below or above the water level by 1 ft (30 cm), after the heater installation
the Water Pressure Switch setting should be adjusted. See WATER PRESSURE SWITCH, in SAFETY CONTROLS
on page 15.
Note: Before putting the heater into service for the first time, follow the instructions under BEFORE
START-UP, as described above. Check for proper operation of the heater by following the steps under HEATER
OPERATING INSTRUCTIONS on page 14. Damage to equipment caused by improper installation or repair will
void the warranty.
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.
HIGH ALTITUDE REQUIREMENT:HIGH ALTITUDE REQUIREMENT:
The ETi 250 pool heater requires altitude compensation The ETi 250 pool heater requires altitude compensation
for places above 4,500 Ft. Therefore, the heater needs for places above 4,500 Ft. Therefore, the heater needs
a reduction of gas ow (derating) to obtain a complete a reduction of gas ow (derating) to obtain a complete
combustion and avoid ignition issues. The ETi 250 pool combustion and avoid ignition issues. The ETi 250 pool
heater can be installed without derating the heater up to heater can be installed without derating the heater up to
4500 Ft. 4500 Ft. For locations at elevation above 4500 ft andFor locations at elevation above 4500 ft and
up to 10,000 ft,up to 10,000 ft, the heater can be installed for Natural the heater can be installed for Natural
gas ONLY in the USA and Canada. Please contact gas ONLY in the USA and Canada. Please contact
Pentair Customer Support Pentair Customer Support [phone](800) 831-7133 to order the to order the
High Altitude kit (P/N 462057).High Altitude kit (P/N 462057).

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
14
HEATER OPERATING INSTRUCTIONS
1. STOP! Read the Consumer and Safety information on
(page 4, 5, and 6).
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 2.
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 13.
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 10.
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 THE APPLIANCE 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.
TO TURN OFF GAS TO 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 2.
5. Replace the Access Door Panels.
Operation Instructions
Gas control is shown OFF.
Push toggle switch away
from you to switch ON.
Figure 2.

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
15
SAFETY CONTROLS
AIR FLOW SWITCH (AFS)
There is one Air Flow Switch (AFS) with a control set point of 0.5”WC. This set point
is not the same as other Pentair pool heaters, (see Figure 3). The AFS is designed
as a safety device to ensure the combustion air blower is operating and is monitoring
the differential (negative) pressure within the blower housing. These air pressure
switches is factory set. The switch (see page 68) is connected upstream of the
ignition module. The ignition module does not operate unless the air ow switch and
the safety switch is closed.
WATER PRESSURE SWITCH (PS)
WARNING Hazardous pressure. Do not bypass the Water Pressure Switch or render it inoperable.
The heater has one Water Pressure switch, see Figure 4.
If the water ow is restricted, the water pressure switch
may prevent the burner from ring and cause a Service
System message on the LCD control panel. 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
switch is factory set at 3.00 psi (20.6 kPa). Note: See
Below Pool Level Installation, on page 23. If the
pressure switch is 1 ft (0.3M) below or above the pool
water level, reset the switch 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 5. Test each switch after resetting.
NOTICE: When the heater is mounted more than
1 ft (30 m) above or 1 ft (30 cm) 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 sufcient water ow, and may cause
severe heater damage.
HIGH LIMIT SWITCH AND
AUTOMATIC GAS SHUT-OFF SWITCH
(AGS)
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 one AGS switch and one HLS switch. The
AGS switch is located in the outlet plumbing assembly,
and the HLS switch is located on the main Inlet/Outlet
Header (see page 9).
Figure 5.
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 3. Air Flow Switch
Water Pressure
Switch Star Wheel
Figure 3: Water Pressure Switch
Operation Instructions
Figure 4. Water Pressure Switch

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
16
Figure 6. Ignition Control Module (ICM)
SAFETY CONTROLS (continued)
STACK FLUE SENSOR (SFS)
The heater is equipped with one Stack Flue Sensor (SFS), in the heat exchanger. The SFS monitors the stack ue
temperature and if needed will shut down the heater if the stack ue temperature exceeds 170° F (77° C). For more
information see page 57, Error Fault Code (ERR SFS).
THERMAL FUSE
A Thermal Fuse (TF) is a safety protection device that opens the electrical circuit if the ue gas temperature exceeded
the limit. There are two thermal fuses connected in series. One fuse controls the temperature of the heat exchanger
coils and the other controls the temperature of the ue gas leaving the heat exchanger. For more information see
page 58, Error Fault Code (ERR TF).
FLOAT SWITCH
The oat switch (CFS) is reed type oat switch. The oat activates the reed switch once the condensate level in the
exhaust exceeds the permitted level, the heater will shut down. For more information see page 58, Error Fault Code
(ERR CFS).
IGNITION CONTROL MODULE OPERATION
The Ignition Control Module, (Figure 6), is microprocessor based and operates on 24 VAC supplied by the transformer.
The control module utilizes a microprocessor to continually safely monitor, analyse, 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 7. Heater left side panel
Operation Instructions
ETi 250 ICM
IND
FENWALL
TH
VAL
NC
F2
L1
B.
Diagnostic errors are displayed on
the control panel LCD: PS, HLS, SFS,
AFS, AGS, IGN, or NONE.
See Troubleshooting (page 52-57)
Flame Current
Check Point
Figure 37.
Displayed Message Description
CONTROL FAULT Displays Message on Automation System
AIR FLOW FAULT Displays Message on Automation System
FLAME NO CALL FOR HEAT Displays Message on Automation System
IGNITION LOCKOUT Displays Message on Automation System
WEAK FLAME Displays Message on Automation System
and viewed on Heater menu
GOOD FLAME Displays Message on Automation System
and viewed on Heater menu
Diagnostic Indicator

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
17
HEATER DESCRIPTION
The ETi® 250 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 8 and 9). Use a 2-in (5.08 cm) tting to connect to the
2-in (5.08 cm) 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. For ETi 250 Heater replacement parts, see page 66.
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 8. ETi 250 Heater (Left Side View) Figure 9. ETi 250 Heater (Right Side View)
Electrical
and Bonding lug
Blower
Heat
Exchanger
Vent Cap
CPVC Flue
Outlet
Exhaust
Assembly
Tridicator (Water
pressure and
Temperature gauge)
High-Limit
Switch (HLS)

Auto gas
shut-off switch
(AGS)
Condensate Neutralizer
Cartridge
(Optional, P/N 476375
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 SERVICE TECHNICIAN,
QUALIFIED IN POOL HEATER INSTALLATION.
Tubing for
Condensate
Neutralizer
Cartridge
Heater Base (Top View)
To drain
To drain
2-in Outlet
Plumbing
Installation
2-in Inlet
Plumbing















11
12
13
6
14
11
12
13
14 Ignition Control
Module (ICM)

GAS
CONTROL
VALV E
Condensate Neutralizer
Cartridge

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
18
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 blower through a series of safety interlocks. The heater interlocks consist of:
• Water pressure switch (PS) - senses that the pump is running,
• Tridicator Gauge - which monitors the water temperature in degrees Fahrenheit and pressure in psi.
• High limit switch (HLS) - which opens if the heat exchanger outlet temperature goes above 135° F (57° C).
• Air ow switch (AFS) - which senses the pressure drop across the air metering orices.
• Thermal fuse (TF) - which opens if the ue gas temperature reaches 187° F (86° C).
• Automatic gas shut-off switch (AGS) - which opens if the heat exchanger outlet temperature goes above
150° F (66° C).
• Float switch (CFS) - which opens if the condensate overows at the oat switch due to blockage in the condensate
drain hose or neutralizer cartridge.
• Stack ue sensor (SFS) - which shuts down the heater if the ue gas temperature reaches 170° F (77° C).
The air ow switch (AFS) senses the pressure differential of the air metering orice. As soon as there is sufcient air
ow, the AFS closes. 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 blower is energized, the gas valve opens simultaneously as the direct spark igniter
energizes, 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 that indicates the water temperature.
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 10,
11 and 12 for Outdoor and Indoor installations, dimensions and orientation of the heater.
SPECIFICATIONS
Figure 10. Heater Top View.
Dimensions in Inches (Millimeters)
(788.95)
31.00
(635)
25.0
268.35
10.6
436.29
17.2
182.47
7.2
512.58
20.2
(635)
25.0
Installation

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
19
Figure 11.
Figure 12.
SPECIFICATIONS (CONTINUED)
99.06
3.9
29.25
1.2
4-IN CPVC FLUE EXHAUST SOCKET
CONTROL CONTROL TOUCH
PAD/ DISPLAY
4-IN PVC AIR INLET CONNECTION
(INDOOR OPTIONAL KIT)
2 in WATER INLET
CONNECTIONS
4-IN PVC VENT CAP
GAS
141
5.6
257
10.1
289
11.4
808
31.8
881
34.7
GAS
401.79
15.8
39.41
1.6
BONDING LUG
ELECTRICAL
GAS
Heater Plumbing Side
Heater Rear View
Heater Front View
Installation

ETi 250 High Efficiency Pool and Spa Heater Installation and User’s Guide
20
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 which is the recommended PVC plumbing procedure by Pentair. Other
plumbing connections can be used. See Figure 13 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 14 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 22 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.
Note: For Multiple Heater installation, see page
21.
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 14.
PUMP
HEATER
MANUAL
BY-PASS
TO
POOL GATE
VALVE
FROM
POOL
INLET
OUTLET
CHLORINATOR
ACTUATOR
VALVE
IN
OUT
Figure 13.
Installation