Pentair MasterTemp 175 User manual

Rev.N 10/2018 MASTERTEMP Pool and Spa Heater Installation and User’s Guide
1
INSTALLATION AND USER’S GUIDE
®
MASTERTEMP POOL AND SPA HEATER
DO NOT store or use gasoline or other flammable vapors and liquids in the vicinity
of this or other appliances.
FORFOR
FORFOR
FOR
YOURYOUR
YOURYOUR
YOUR
SAFETYSAFETY
SAFETYSAFETY
SAFETY
Improper installation, adjustment, alteration, service or maintenance can cause
propertydamage, personal injury or death. Installation and service must be performed by
a qualified installer, service agency or the gas supplier.
WHAT TO DO IF YOU SMELL GASWHAT TO DO IF YOU SMELL GAS
WHAT TO DO IF YOU SMELL GASWHAT TO DO IF YOU SMELL GAS
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.
1620 Hawkins Ave., Sanford, NC 27330 •[phone] or [phone]
10951 W. Los Angeles Ave., Moorpark, CA 93021 •[phone] or [phone]
Models Natural Propane
175K BTU/HR 460792 460793
200K BTU/HR (ASME) 461000 461001
200K BTU/HR 460730 460731
200K BTU/HR (HD ASME) 461032 –
250K BTU/HR 460732 460733
250K BTU/HR (HD) 460806 –
250K BTU/HR
(ASME) 460771 460772
250K BTU/HR (HD ASME) 461020 –
300K BTU/HR 460734 460735
400K BTU/HR 460736 460737
400K BTU/HR (HD) 460805 –
400K BTU/HR (ASME) 460775 460776
400K BTU/HR (HD ASME) 461021 –
FOR YOUR SAFETYFOR YOUR SAFETY
FOR YOUR SAFETYFOR YOUR SAFETY
FOR YOUR SAFETY - This product must be installed and serviced by authorized personnel, qualified inpool/spa
heater installation. Improper installation and/or operation can create carbon monoxide gas 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 strongly recommends installation of suitable Carbon Monoxide detectorsCarbon Monoxide detectors
Carbon Monoxide detectorsCarbon Monoxide detectors
Carbon Monoxide detectors in the vicinity of this
appliance and in any adjacent occupied spaces. Improper installation and/or operation will void the warranty.
FOR YOUR SAFETY - READ BEFORE OPERATINGFOR YOUR SAFETY - READ BEFORE OPERATING
FOR YOUR SAFETY - READ BEFORE OPERATINGFOR YOUR SAFETY - READ BEFORE OPERATING
FOR YOUR SAFETY - READ BEFORE OPERATING
If you do not follow these instructions exactly, a fire or explosion may result, causing
property damage, personal injury or loss of life. For additional free copies of this manual;
call [phone].
Pentair Water Pool and Spa, Inc.
OWNER:OWNER:
OWNER:OWNER:
OWNER:
Retain ForRetain For
Retain ForRetain For
Retain For
FutureFuture
FutureFuture
Future
ReferenceReference
ReferenceReference
Reference
120/240 VAC NATURAL GAS/LP GAS120/240 VAC NATURAL GAS/LP GAS
120/240 VAC NATURAL GAS/LP GAS120/240 VAC NATURAL GAS/LP GAS
120/240 VAC NATURAL GAS/LP GAS

MASTERTEMPPoolandSpa HeaterInstallation andUser’sGuide Rev. N 10/2018
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Customer Service
8:00 AM to 8:00 PM
Phone: [phone]
Fax: [phone]
Visit www.pentair.com
Technical Support
Sanford, North Carolina (8:00 AM to 8:00 PM ET)
Phone: [phone]
Fax: [phone]
Moorpark, California (8:00 AM to 5:00 PM PT)
Phone: [phone]
Fax: [phone]
P/N 472592 Rev.N 10/2018

Rev.N 10/2018 MASTERTEMP Pool and Spa Heater Installation and User’s Guide
3
Contents
Section 1. Heater Identification Information ....................................................................... 4
Section 2. Warning and Safety Information ......................................................................... 5
ImportantNotices................................................................................................................................................................................. 5
WarrantyInformation ............................................................................................................................................................................ 5
CodeRequirements .............................................................................................................................................................................. 6
ConsumerInformation andSafety Information ...................................................................................................................................... 6 - 9
GeneralSpecifications ......................................................................................................................................................................... 9
Section 3. Installation ............................................................................................................. 10
HeaterDescription................................................................................................................................................................................ 10
PuttingtheHeater into Service ............................................................................................................................................................ 10
Specifications ...................................................................................................................................................................................... 11
PlumbingConnections .......................................................................................................................................................................... 12
Valves .................................................................................................................................................................................................. 12
ManualBy-Pass .................................................................................................................................................................................. 12
WaterConnections ............................................................................................................................................................................... 13
BelowPool Level Installation ................................................................................................................................................................ 13
GasConnections ................................................................................................................................................................................. 14
SedimentTraps.................................................................................................................................................................................... 14
Gas Pipe Sizing ................................................................................................................................................................................... 15
Testing Gas Pressure / Gas Pressure Requirements .......................................................................................................................... 15-16
Outdoor Installation / Heater Clearances ............................................................................................................................................ 16
Outdoor Installation Venting Guidelines ............................................................................................................................................. 17
Indoor Venting — General Requirements (Category I and Category III requirements)...................................................................... 18
Heater Clearances — General Requirements (Indoor Installation US / Canada) .............................................................................. 18
Outside Vent Cover Removal .............................................................................................................................................................. 18
CombustionAir Supply / DirectAir Intake Duct with 3-inch PVC Pipe (Indoor Installation) .................................................................. 19-20
Corrosive Vapors and Possible Causes .............................................................................................................................................. 20
Vent Installation (Indoor Installation for US and Canada).................................................................................................................... 21
Vertical Venting - Negative Pressure .................................................................................................................................................. 21 - 23
Horizontal or Vertical Venting - Positive Pressure .............................................................................................................................. 24
Connecting Special Gas Venting ........................................................................................................................................................ 24 - 26
Garage or Utility Room Installation ..................................................................................................................................................... 27
Control Panel Indexing ....................................................................................................................................................................... 28
Final Installation Check....................................................................................................................................................................... 28
Electrical Connections ........................................................................................................................................................................ 29
Fireman’s Switch Connection / Remote Control Connections ............................................................................................................ 30
MasterTemp Heater Wiring Diagram................................................................................................................................................... 31
Electrical Schematic Ladder Diagram ................................................................................................................................................. 32
Section 4. Operation ............................................................................................................... 33
BasicSystem Operation ...................................................................................................................................................................... 33
HSI (Hot-Surface Ignition) Lighting / Operation ................................................................................................................................... 33
Operating ............................................................................................................................................................................................ 34
To Turn Off Gas toAppliance .............................................................................................................................................................. 34
SafetyControls .................................................................................................................................................................................... 35 - 37
Section 5. Troubleshooting .................................................................................................... 38
InitialTroubleshootingandTroubleshooting Chart ................................................................................................................................. 38
HeaterWill Not FireTroubleshooting .................................................................................................................................................... 39-42
LEDDiagnostics .................................................................................................................................................................................. 43- 44
Burner/ Heat ExchangerTroubleshooting ............................................................................................................................................ 45
Section 6. Maintenance..........................................................................................................46
CareandMaintenance.......................................................................................................................................................................... 46
Pressure ReliefValve ........................................................................................................................................................................... 46
After Start-Up ...................................................................................................................................................................................... 47
Spring,Fall andWinterOperation ......................................................................................................................................................... 47
MaintainingPoolTemperature ............................................................................................................................................................... 48
EnergySavingTips.............................................................................................................................................................................. 49
ChemicalBalance ................................................................................................................................................................................ 48 - 49
Replacement Parts.............................................................................................................................................................................. 50 - 54
Addendum: For Gas Pipe Escutcheon Installation.............................................................. 55

MASTERTEMPPoolandSpaHeater Installation and User’sGuide Rev. N 10/2018
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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 Identification Number (HIN).
a. Heater Identification Number (HIN)
The following example simplifies the identification system:
1) MT : MasterTemp
2) Model Size : (175, 200, 250, 300 or 400) : Input rating (Btu/hr) X 1000
3) FuelType : (LP = Propane gas or NA = Natural gas)
4) Construction :(STD = Standard Model)
(HD = Heavy Duty Model)
(ASME = ASME Certified Model)
(HD ASME = Heavy Duty ASME Model)
Section 1. Heater Identification Information
Section 1: Heater Identification Information
HEATER IDENTIFICATION INFORMATION — (HIN)
MT 250 NA ASME
MT = MASTERTEMP
FUEL TYPE =
CONSTRUCTION =
MODEL SIZE = BTU INPUT in 1000 of BTU / HR
H. I. N.
HEATER IDENTIFICATION NUMBER
ID DESIGNATOR FOR PENTAIR AQUATIC SYSTEMSMASTERTEMP HEATERS
STD = STANDARD MODEL
HD = HEAVY DUTY MODEL
ASME = ASME CERTIFIED MODEL
HD ASME = HEAVY DUTY ASME MODEL
NA = NATURAL GAS
LP = PROPANE GAS
Example:
1 2 34
®

Rev.N 10/2018 MASTERTEMP Pool and Spa Heater Installation and User’s Guide
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Congratulations on your purchase of the MasterTemp Pool and Spa Heater. Proper installation and service of your new
heating system and correct chemical maintenance of the water will ensure years of enjoyment. The MasterTemp heater
is a compact, lightweight, efficient, induced-draft, gas fired high performance pool and spa heater that can be directly
connected to schedule 40 PVC pipe. The MasterTemp heater also comes equipped with the Pentair multifunction
temperature controller which shows, at a glance, the proper functioning of the heater. All MasterTemp heaters are
designed with a direct ignition device, HSI (hot-surface ignition), which eliminates the need for a standing pilot. The
MasterTemp heater requires an external power source (120/240 VAC 60 Hz) to operate.
SPECIAL INSTRUCTIONS TO OWNER: Retain this manual for future reference. This instruction manual provides
operating instructions, installation and service information for the MasterTemp high performance heater. The information
in this manual applies to all MasterTemp heater models. READ AND REVIEW THIS MANUAL COMPLETELY,
itis very important that theowner/installer read and understand the section coveringinstallation instructions, and recognize
the local and state codes before installing the MasterTemp heater. Its use will reduce service calls and chance of injury
andwill lengthenproduct life.History andexperience hasshown thatmost heaterdamage iscaused byimproper installation
practices.
IMPORTANT NOTICES
For the installer and operator of the MasterTemp 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 at [phone].
WARRANTY INFORMATION
The MasterTemp pool and spa heater is sold with a limited factory warranty. Specific details are described on the
warranty registration card which is included with the product.Return the warranty registration card after filling in
the serial number from the rating plate inside the heater.
Pentair Water Pool and Spa high standards of excellence include a policy of continuous product improvement resulting
in your state-of-the-art heater. We reserve the right to make improvements which change the specifications of the heater
without incurring an obligation to update the current heater equipment.
These heaters are designed for the heating of chlorine, bromine or salt system swimming pools and spas or
in non-stationary installations, and 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.
CAUTION
OPERATING THIS HEATER CONTINUOUSLY AT WATER TEMPERATURE BELOW 68° F. WILL CAUSE HARMFUL
CONDENSATION AND WILL DAMAGE THE HEATER AND VOID THE WARRANTY. Do not use the heater to protect
pools or spas from freezing if the final maintenance temperature desired is below 68° F., as this will cause condensation
related problems.
Section 2: Warning and Safety Instructions
Section 2. Warning and Safety Instructions
IMPORTANT SAFETY INSTRUCTIONS
READ AND FOLLOW ALL INSTRUCTIONS
SAVE THESE INSTRUCTIONS
MASTERTEMP®
Pool and Spa Heater

MASTERTEMPPoolandSpaHeater Installation and User’sGuide Rev. N 10/2018
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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 firstthree 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 err 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.
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.
Section 2. Warning and Safety Instructions
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.

Rev.N 10/2018 MASTERTEMP Pool and Spa Heater Installation and User’s Guide
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SAFETY INFORMATION
Section 2. Warning and Safety Instructions
The MasterTemp®pool heaters are 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 the manual, safety warnings and
cautions are identified by the “ “ symbol. Be sure to read and comply with all of the warnings and cautions.
WARNING — This heater is equipped with an unconventional gas control valve that is factory set with a
manifold 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.
Do not attempt to adjust the gas flow by adjusting the regulator setting.
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.
Improperinstallationand/oroperationcouldcreatecarbon monoxidegasandfluegaseswhichcould 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,LEAVETHEVICINITYOFTHEPOOLORSPAANDGETINTOFRESHAIRIMMEDIATELY.
THE POOL HEATER MUST BE THOROUGHLY TESTED BY A GAS PROFESSIONAL BEFORE
RESUMING OPERATION.
EXCESSIVE CARBON MONOXIDE EXPOSURE CAN CAUSE BRAIN DAMAGE OR DEATH.
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.
Poolheaters must beused in conjunctionwith carbon monoxide detectors installed near thepool 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.
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
couldcreatecarbon monoxidegasand fluegaseswhich couldcause serious injuryor death.Improper
installation and/or operation will void the warranty.

MASTERTEMPPoolandSpaHeater Installation and User’sGuide Rev. N 10/2018
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Section 2. Warning and Safety Instructions
SAFETY INFORMATION,(cont’d.)
WARNING — Risk of fire or explosion from incorrect fuel use or faulty fuel conversion. 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 LP (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 fuel conversion is necessary, refer this work to a qualified service technician or gas supplier
before putting the heater into operation.
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 drafthood 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 outdoor installation.
A vent conversion kit (See Page 24 for Part Numbers for Conversion Kits) is available for installations
indoors (US and Canada). Use the specified venting, and only the specified venting, when heater is
installedinanenclosure orindoors.
CAUTION — Labelall wires prior todisconnection when servicing controls.Wiring errors can causeimproper
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.

Rev.N 10/2018 MASTERTEMP Pool and Spa Heater Installation and User’s Guide
9
GENERAL SPECIFICATIONS
NOTICE:
• Combustion air contaminated by corrosive chemical fumes can damage the heater and will void the warranty.
• TheCombinationGasControlValveonthisheaterdiffersfrommostappliancegascontrols.Ifitmustbereplaced,
for safety reasons replace it only with an identical gas control.
• The access door panels must be in place to provide proper ventilation. Do not operate the heater for more than
five (5) minutes with the access door panels removed.
• This heater is design certified 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.
• Theheaterisdesignedfortheheatingofchlorine,bromineorsaltsystemswimmingpoolsandspas.Itshould
NOT beused as a space heating boiler, or general purpose water heater.
• The heater is design certified by CSA International for installation on combustible flooring. Specified minimum
clearances must be maintained to combustible surfaces (see “Heater Clearances”, page 18).
• The heater should be located in an area where leakage of the heater or connections will not result in damage
totheareaadjacenttotheheater ortothestructure.Whensuchlocationscannotbeavoided,itisrecommended
that a suitable drain pan, adequately drained, be installed under the heater. The pan must not restrict air flow.
• Theheatermay notbeinstalledwithin5 ft.(1.5M)ofthe insidesurfaceofapool orspaunlessitis separated
by a solid fence, wall or other permanent barrier.
CONSUMER INFORMATION AND SAFETY
WARNING
The U.S. Consumer Product Safety Commission warns that carbon monoxide is an "invisible killer". Carbon monoxide
is a colorless and odorless gas.
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
factorin reducing carbonmonoxidepoisoning.
3. Besurethatfuelburningappliancessuchasheatersareinstalledbyprofessionalsaccordingtomanufacturer'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 certified 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.
Section 2. Warning and Safety Instructions

MASTERTEMPPoolandSpaHeater Installation and User’sGuide Rev. N 10/2018
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Section 3. Installation Instructions
Section 3: Installation Instructions
Gas
Air
Mixer
Blower
Inlet
(Cold
Water)
Exhaust
Heating Coils
Outlet
(Mixed
Water) Burner
Figure 1.
HEATER DESCRIPTION
Figure1 is adiagram of theheater showinghowit operates.Precisely
matched orifice plates 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 flame holder. A sealed heat exchanger surrounds the
flame holder, discharging exhaust gases out the flue.
Two inchPVC water pipingconnects directlyto the manifold/header
on the heat exchanger using 2" PVC slip unions provided with the
heater. The outer manifold remains cool; no heat sinks are required.
A thermal regulator and an internal bypass regulate the water flow
through the heat exchanger to maintain the correct outlet
temperature. The heater operator control panel board assembly is
located on top of the heater.
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 operating
control, the burner controller supplies power to the combustion
air blower through a series of safety interlocks. The interlocks consist of:
• the pressure switch (PS), which senses that the pump is running,
• the high limit switch (HLS), which opens if the heat exchanger outlet temperature goes above 135° F (57° C), and
• the air flow switch (AFS), which senses the pressure drop across the air metering orifice,
• the automatic gas shut-off (AGS) switch, which opens if the heat exchanger outlet temperature goes above 140° F
(60° C).
• the stack flue sensor (SFS), which shuts down the heater if the flue gas temperature reaches 480° F (249° C).
The air flow switch (AFS) senses the pressure drop across the air metering orifice.As soon as there is sufficient air flow,
theAFS closes, closing the circuit to the hot surface igniter (HSI), which ignites the fuel mixture. On a call for heat, the
blower and HSI are energized. In about 20 seconds, the gas valve opens and ignition occurs. The HSI then switches to a
sensing mode and monitors the flame.
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.
PUTTINGTHE HEATER INTO SERVICE
If the heater is installed below the level of the pool, or more than two feet above pool level, the pressure switch setting
should be adjusted. See WATER PRESSURE SWITCH, in the SAFETY CONTROLS Section.
Before putting the heater into service for the first time, follow the instructions under “BEFORE START-UP” (page 33) in
the front of this manual. Check for proper operation of the heater by following the steps under “OPERATION
INSTRUCTIONS.”
Damage to equipment caused by improper installation or repair will void the warranty.

Rev.N 10/2018 MASTERTEMP Pool and Spa Heater Installation and User’s Guide
11
Section 3. Installation Instructions
These installation instructions are designed for use by qualified 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 2 for Outdoor and Indoor
Installations.
SPECIFICATIONS
DIMENSIONS IN INCHES
Figure 2.
21.0"
(53.3 cm)
32.61"
(82.8 cm)
23.02"
(58.5 cm)
28.15"
(71.5 cm)
16"
(40.6 cm)
TOPFRONT
EXHAUST SIDE PLUMBING SIDE
10.13"
(25.7 cm)
5.6"
(14.2 cm)
ELECTRICAL
CONDUIT PORT
28.2"
(71.6 cm)
22.7"
(57.7 cm)
16.0"
(40.6 cm)

MASTERTEMPPoolandSpaHeater Installation and User’sGuide Rev. N 10/2018
12
PLUMBINGCONNECTIONS
The MasterTemp heater has the unique capability of direct
schedule 40 PVC plumbing connections. A set of bulkhead
fittings is included with the MasterTemp heater to insure
conformity with Pentair’s recommended PVC plumbing
procedure. Other plumbing connections can be used. See
Figure 3 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 insure that all air is purged from the heater.
WATER CONNECTIONS
The heater requires proper water flow and pressure for its
operation. See Figure 5 for the recommended installation.
The filter pump discharges to the filter, the filter discharges
to the heater, and the heater discharges directly to the pool
or spa.
A manual bypass valve should be installed across the heater
when the pump flow exceeds 120 GPM (454 LPM). See
“WATER FLOW RATE” on page 13- Table 1 for setting of
the manual by-pass valve.
Make sure that the outlet plumbing from the heater contains
noshut-offvalves orotherflow restrictions thatcould prevent
flowthrough theheater (except forpool installationsas noted
below, or winterizing valves where needed). To switch flow
between the pool and spa, use a diverter valve. Do not use
any valve that can shut off the flow.
Install the chemical feeder downstream of the heater. Install
achemical resistant one-way check valve between theheater
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 filter is not reversed
when installing heater.
Connect the heater directly to 2" PVC pipe, using the integral unions provided. 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 flow 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 5.
PUMP
FILTER
POOL
HEATER MANUAL
BY-PASS
TO
POOL
GATE
VALVE
FROM
POOL
Section 3. Installation Instructions
Figure 3.

Rev.N 10/2018 MASTERTEMP Pool and Spa Heater Installation and User’s Guide
13
BELOW POOL LEVEL INSTALLATION
If the heater is below water level, the pressure switch must be adjusted. This adjustment must be done by a qualified
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 heater is to be installed more than 1’ above or below, the water pressure switch must be adjusted by a qualified
service technician. See page 35, Figure 29.
FLOW SWITCH
If the heater is installed more than 5’ above the pool or more than 4’ 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.
Section 3. Installation Instructions
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
Where the water flow rate exceeds the maximum 120 GPM, a manual
bypassshould be installed and adjusted. Afterinstalling the valve, adjust
thevalve to bring the flowrate within the acceptable range. Then remove
the valve handle or lock it in place to avoid tampering. See Figure 4.
Table 1.
See page 46 for Pressure ReliefValve Installations.
ledoM)MPL()MPG(.niM*)MPL()MPG(.xaM
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002)67(02)454(021
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003)411(03)454(021
004)251(04)454(021
wolfdednemmocermumixamehtdeecxetonoD* .gnipipgnitcennocehtrofetar
Cool water
Warm water out
Outlet to pool
Inlet to heater
1. Set Manual By-Pass Valve.
2. Remove Handle.
Figure 4.
* Pumps 2 HP or larger can produce water pressure
flow in excess of 120 GPM. For these pumps, a
BY-PASS VALVE is recommended.

MASTERTEMPPoolandSpaHeater Installation and User’sGuide Rev. N 10/2018
14
GASCONNECTIONS
GAS LINE INSTALLATIONS
Before installing the gas line, be sure to check which gas the heater has been designed to burn. This is important because
different types of gas require different gas pipe sizes. The rating plate on the heater will indicate which gas the heater is
designed to burn. TheTable 2, shown on page 15, show which size pipe is required for the distance from the gas meter to
the heater. The table is for natural gas at a specific gravity of .65 and propane at a specific gravity of 1.55.
When sizing gas lines, calculate three (3) additional feet of straight pipe for every elbow used. When installing the gas line,
avoid getting dirt, grease or other foreign material in the pipe as this may cause damage to the gas valve, which may result
in heater failure.
The gas meter should be checked to make sure that it will supply enough gas to the heater and any other appliances
that may be used on the same meter. The gas line from the meter will usually be of a larger size than the gas valve
supplied with the heater. Therefore a reduction of the connecting gas pipe will be necessary. Make this reduction
as close to the heater as possible.
The heater requires a gas supply of not less than 4" (10.2 cm) wc and not more than 14" (35.6 cm) wc. Gas supply
pressures outside of this range may result in improper burner operation. A minimum flowing or dynamic inlet pressure
(while the heater is running) of 4" (10.2cm) wc is required to maintain input rating with no more than a 2” pressure drop
between static and dynamic. The gas supply must be installed in accordance with the National Fuel Gas Code,
ANSIZ223.1, or standard CSA B149.1, Natural Gas and Propane Installation Codes, as applicable and all applicable
local codes. Install a manual shut-off valve and a sediment trap and union located outside the heater panels, see Figure 6.
Do not use a restrictive gas cock. The following minimum gas pipe sizes are recommended for natural gas supply piping,
see Table 2 on page 15. For low pressure LP gas, pipe size may be reduced by 1/4", with a minimum pipe size of 1/2".
Check for compliance with local codes.
The heater and any other gas appliances must be disconnected from the gas supply piping system during any pressure
testing on that system, (greater than ½ PSI). The heater and its gas connection must be leak tested before placing the
heater in operation. Do not use flame to test the gas line. Use soapy water or another nonflammable method.
NOTE
A manual main shut-off valve must be installed externally to the heater.
WARNING
DO NOT INSTALL THE GAS LINE UNION INSIDE THE HEATER CABINET. THIS WILL VOID YOUR WARRANTY.
SEDIMENTTRAPS
Install a sediment trap and union located outside the
heater panels in accordance with National code
requirements. Do not use a restrictive gas cock. The
sediment trap shall be either a tee fitting with a capped
nipple in the bottom outlet which can be removed for
cleaning, as illustrated in Figure 6, or an other device
recognized as an effective sediment trap. All gas piping
should be tested after installation in accordance with
local codes. Figure 6.
Section 3. Installation Instructions
Manual
Shut-off
Valve
Sediment
Trap
Union
At least 9"
At least 3"
1" Dia. or larger
(See "Recommended
Pipe Sizes" Chart)
18–24" of 3/4"
Gas line from
Valve
Bell
Reducer
NOTE: SEE PAGE 55 TO INSTALL THE GAS PIPE ESCUTCHEON.
THIS ENSURES THE HEATER IS RODENT RESISTANT.

Rev.N 10/2018 MASTERTEMP Pool and Spa Heater Installation and User’s Guide
15
GAS PIPE SIZING
Table 2.
Section 3. Installation
SNOITCENNOCENILSAGROFGNIZISEPIP
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tooFcibuCrep.U.T.B0001tasaGlarutaN tooFcibuCrep.U.T.B0052tasaGenaporP
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TANORPTANORPTANORPTANORPTANORPTANORPTANORP
571-’02’03’08’521’052’054’006 ------
002-’02’03’08’521’052’054’006 ------
052-’01’02’05’07’051’052’005’006 -----
003--’01’03’05’001’002’053’004’006----
004--- ’01’02’06’001’051’002’054’004 ---
STAGE TWO “LOW PRESSURE” GAS PIPE SIZING
Before operating the heater, the heater and its gas connections must be leak tested. Do NOT use an open flame to test
for leaks. Test all gas connections for leaks with soapy water or another non-flammable method (see page 14).
The heater and its individual shut-off valve must be disconnected from the gas supply piping system during any pressure
testing of that system at test pressures in excess of 1/2 psig (3.5 kPa).
The heater must be isolated from the gas supply system by closing its individual manual shut-off valve during any pressure
testing of the gas supply at test pressures equal to or less than 1/2 psig (3.5 kPa).
CHECKING THE GAS PRESSURE THROUGH THE COMBINATION GAS CONTROL VALVE
WARNING
Risk of fire and explosion. Improper installation, incorrect adjustment, alteration, service, or maintenance of the Combination
Gas Control Valve can lead to fire or explosion, causing loss of life, personal injury, and/or property damage. If it is necessary
to adjust the gas valve, this must be done by only by a qualified service agency. These instructions are for the use of
qualified service technicians only!
This appliance is equipped
with an unconventional gas
control valve that is factory
set with a manifold
pressure of –.2" (–0.5cm)
wc. Installation or service
must be performed by a
qualifiedinstaller,service
agency, or the gas supplier.
If this control valve is
replaced, it must be
replaced with an identical
control.
The combination gas
valve incorporates dual shut-off valves and a negative-pressure regulator. For proper operation, the regulated pressure
at the outlet manifold of the valve must be –0.2" (–0.5cm) wc below the reference pressure at the blower mixer inlet,
and the gas valve ‘VENT’ tap must be connected to the end cap air orifice as shown in Figure 7.
Do not attempt to adjust the gas input by adjusting the regulator setting. The correct gas regulator setting is
required to maintain proper combustion and must NOT be altered.
TESTING GAS PRESSURE
To Air Flow
Switch
To Gas
Valve Vent
Vent
Pressure Tap
To High Side
of Differential
Pressure Gauge
To Low Side of
Differential Pressure Gauge
Pressure Tap
Inlet
Figure 7.
To Air Flow
Switch
To Gas
Valve Vent
Connection
forService
Connection
for Test

MASTERTEMPPoolandSpaHeater Installation and User’sGuide Rev. N 10/2018
16
OUTDOOR INSTALLATION LOCATED OUTDOORS, USING THE
BUILT-IN STACKLESS VENTING SYSTEM.
WARNING
Risk of explosion if a unit burning propane gas is installed in a pit or other low spot. Propaneis heavier thanair. Donot install
the heater using propane in pits or other locations where gas might collect. Consult your local building code officials to determine
installation requirements and specific installation restrictions of the heater relative to propane storage tanks and filling equipment.
Installation must meet the requirements for the Standard for the Storage and Handling of Liquid Petroleum Gases,ANSI/NFPA58
(latestedition) in the U.S., or CAN/CSA B149.2(latest edition) in Canada.Consult local codes and fire protectionauthorities about
specificinstallationrestrictions.
Locate the heater on a level surface in an open area that is protected from drainage or run-off. Install the heater in an area
where leaves or other debris will not collect on or around the heater.
To avoid damage to the electronic components in the heater, take care to prevent prolonged exposure to driving sources
of water (such as lawn sprinklers, heavy roof runoff, hoses, etc.). Avoid operation in persistent, extreme, moist or salty
environments. In extreme weather, shut down the heater and disconnect the power to it until the weather has moderated.
In areas subject to hurricanes or very high winds, purchase the Bolt Down Bracket Kit, P/N 460738.
HEATER CLEARANCES – OUTDOOR
IMPORTANT!
• In an outdoor installation it is important to ensure water is diverted from overhanging
eveswith a propergutter/drainage system.The heater must beset ona levelfoundation
for proper drainage.
• This unit shall not be operated outdoors at temperatures below -20o F.
If the heater is located under a roof overhang, there must be at least three (3) feet (1m) of
clearance between the bottom of the overhang and the top of the heater exhaust vent, see Figure
8. If the heater is under a roof overhang, the space around the heater must be open on three sides.
DO NOT, under any circumstances, install the heater underANYdeck.
Lead
Anchor
For Heater mounting
bolts and clamps,
purchase separately
Bolt Down Bracket Kit,
Part No. 460738.
Section 3. Installation Instructions
Table 3.
CAUTION
The use of Flexible Connectors (FLEX) is NOT recommended unless they are properly sized according to the supplier
recommendations for the heater rating.
GAS PRESSURE REQUIREMENTS
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Rev.N 10/2018 MASTERTEMP Pool and Spa Heater Installation and User’s Guide
17
Section 3. Installation Instructions
3 ft. (1 M) or more
Figure 8.
For minimum exhaust vent clearances for allbuilding openings, includingbut not limitedto ventedeaves, doors, windows,
gravity air inlet, see Figure 9, show below.
In Canada, the heater must be installed with the top of the vent at least 10 feet (3m) below, or to either side of, any opening
intoabuilding.
Orient the heater for convenient access to the water connections and the gas and electrical connections.
Note: Check local building codes for installing the heater from any property line set back requirements (see the
installation diagram below).
If installing the heater next to or near an air
conditioning unit or a heat pump, allow a
minimum of 36 in. (91.4 cm) between the air
conditioning unit and the heater.
CAUTION
VENTING GUIDELINES
OUTDOOR INSTALLATION
Check local building codes
for setback requirements.
Force
Air Inlet
Property Line
4'
4'
4'
3'
SIDE VIEW
Building
From building wall
Exhaust Grill
(Vent)
6 in
From window or door
Must be at least 3 ft. above any forced
air inlet located within a 10 ft. radius.
Vent Termination:
Must be located 6 in. away from the building
wall and the following distances away from any building
wall openings, included but not limited to vented eaves,
doors, windows, gravity air inlet:
4 ft. below,
4 ft. horizontally
Figure 9.

MASTERTEMPPoolandSpaHeater Installation and User’sGuide Rev. N 10/2018
18
INDOORVENTING — General Requirements
The heater may be installed as a Category I or Category III appliance.
Vented Appliance (Category I) – Vertical only
An appliance that operates with a nonpositive vent static pressure and with a vent gas temperature that avoids excessive
condensate production in the vent, see pages 20-23.
Vented Appliance (Category III) – Vertical or Horizontal
An appliance that operates with a positive vent static pressure and with a vent gas temperature that avoids excessive
condensate production in the vent, see pages 24-26.
If you are considering connecting this heater to a pre-existing vent system, make sure that the vent system meets the
appropriate venting requirements as given in this manual on pages 18-28. If not, replace the vent system. DO NOT use
a draft hood with this heater.
The MasterTemp heaters are capable of a 270-degree discharge rotation and operate with a positive vent static pressure
and with a vent gas temperature less than 400° F (204° C). The total length of the horizontal run must not exceed the length
that is listed in Table 11 on page 21-22.
6 in.*
6 in.*
6 in.
6 in.
(*) For service access, it is advisable to allow for
sufficient clearance on at least one door panel.
Figure 10.
Section 3. Installation Instructions
HEATER CLEARANCES — General Requirements
INDOOR INSTALLATION (US / CANADA)
The following clearances must be maintained from combustible surfaces:
TOP ..............................6 in. (15 cm)
EXHAUST SIDE ...........6 in. (15 cm)
HEADER SIDE .............6 in. (15 cm)
DOOR PANELS* ..........6 in. (15 cm)
Note (*) For service access it is advisable to allow for sufficient clearance
on at least one door panel. The heater is design certified by CSA
International for installation on combustible flooring. For installation on
carpeting, the heater must be mounted on a metal or wood panel that
extends at least three (3) inches beyond the base of the heater. If the
heater is installed in a closet or alcove, the entire floor shall be covered by
the panel. On an outdoor shelter installation, the exhaust discharges into a
vent pipe. Orient the heater so that the vent pipe does not interfere with
adjustment of the operating controls. The control panel located on the top
panel can be rotated to any of the three sides of the heater for easy access.
However, the control panel must not be located on the side where the vent
islocated.
OUTSIDEVENT COVER REMOVAL
The heater is supplied from the factory with a built-in stackless outside vent for outdoor installation. Remove the outside
vent cover for outdoor shelter installation.

Rev.N 10/2018 MASTERTEMP Pool and Spa Heater Installation and User’s Guide
19
Section 3. Installation Instructions
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COMBUSTION AIR SUPPLY
For indoor installation, the heater location must provide sufficient air supply for proper combustion and ventilation of the
surrounding area.
The minimum requirements for the air supply specify that the room in which a heater is installed should be provided with
two permanent air supply openings; one within 12 inches (30 cm) of the ceiling, the other within 12 inches (30 cm) of the
floor for combustion air, in accordance with the latest edition of ANSI Z223.1, or the National Fuel Gas code, the CSA
B149.1, Natural Gas and Propane Installation Codes, as applicable, and any local codes that may apply. These openings
shall directly, or through duct, connect to outdoor air.
Note: For indoor installations where combustion air might be insufficient, see “Direct Air Intake Duct
with 3-inch PVC Pipe (Indoor Installation)” below.
Table 4.
Air Supply Requirements Guide
forMasterTempHeaters
Direct Air Intake Duct with 3-inch PVC Pipe (Indoor Installation)
For indoor heater installations where combustion air supply might be insufficient, the MasterTemp®Heater is certified for
a direct air intake duct using 3-inch PVC pipe. If outside air is drawn through 3” PVC duct directly into the heater, PVC
pipe can be installed in accordance with the following requirements:
The air intake opening MUST be installed at least 1 ft. above the roof line or normal snow levels for free air flow. The
Category I or III exhaust vent termination cap must have at least 3 ft. minimum vertical clearance from air intake duct.
(See diagram on page 20).

MASTERTEMPPoolandSpaHeater Installation and User’sGuide Rev. N 10/2018
20
Corrosive Vapors and Possible Causes
Section 3. Installation Instructions
Table 6.
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gnimmiwsdetanirolhC sapsdnasloop ,sdicA.slacimehcgninaelcapsrolooP .dicacitairumrocirolhcordyhsahcus
dnanoitcurtsnocweN saeragniledomer
noitcurtsnoc,stnemecdnaseulG tniapdna,sehsinrav,stniap,sevisehda dnasexaW.sreppirtshsinravdna muidosromuiclacgniniatnocsrenaelc .edirolhc
srolrapytuaeB ,sehcaelb,snoitulosevawtnenamreP snobracorolhcgniniatnocsnaclosorea .snobracoroulfro
rostnalpnoitaregirfeR gnihsiniflairtsudnisuoirav stnalpgnissecorpdna
,stnemecdnaseulg,sdica,stnaregirfeR .sevisehdanoitcurtsnoc
yrdnualdnagninaelcyrD saera
spaosyrdnualro,stnegreted,sehcaelB srenaelcdnasexaW.enirolhcgniniatnoc muidosromuiclac,enirolhcgniniatnoc .edirolhc
NOTE
Each 90-degree elbow reduces the maximum horizontal PVC air intake duct run by 12 feet and each 45-
degree elbow in the PVC air intake duct run reduces the maximum run by 6 feet.See theTable 5 above for
the maximum lengths using 90-degree elbows.
CAUTION
Chemicals should not be stored near the
heater installation. Combustion air can
be contaminated by corrosive chemical
fumes which can void the warranty.
WARNING!
DO NOT USE PVC PIPE FOR FLUE
EXHAUST VENT. FLUE EXHAUST
VENT TEMPERATURES CAN BE IN
EXCESS OF 400° F. FLUE EXHAUST
VENT MUST BE CATEGORY I or
CATEGORY III METAL VENT.
Note (*): Combustion Air Intake Duct Connection Kit (Part Number 461031) for all MasterTemp heater models can be
purchased separately. See page 52 for parts list.
Combustion 3 in. PVC Pipe
Inlet Air Intake Duct Requirements*
Combustion Air Intake 3 in. Pipe
(Vertical or Horizontal)
No. of 90° Elbows Maximum Length in Feet (M)
0 70 ft. (21.3 M)
1 58 ft. (17.7 M)
2 46 ft. (14.0 M)
3 34 ft. (10.4 M)
4 22 ft. ( 6.7 M)
Table 5.