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Review Rheem Marathon Water Heater/
Non-metallic residential water heater 
Use 6 wraps teflon tape
? White for water lines
? Yellow for gas lines

Teflon tape at Amazon

Pipe wrench at Amazon
Channel locks

How to remove rusted element

Knipex channel locks
Irwin pliers
replace anode rod
Inspect anode each 2-5 years
Anode rod prevents tank from rusting
Anode rods at Amazon

Replace anode rod
How to maintain water heater

Impact wrench at Amazon

Replace anode rod
How to remove short water heater nipple
Water pressure gauge

Pressure gauge/ attach to water heater drain valve
Pressure over 80 psi can damage water heater and household plumbing
Water pressure gauge
Temperature-pressure gauge

Identify water heater valves
Troubleshoot water pressure
Automatic water heater shut off valve
Prevent flood
Automatic water shut off valve
Water detectors at Amazon
Automatic water heater leak shut off at Amazon
Leaking water heater/ steps
Pressure reducing valve
Pressure reducing valve
Pressure over 80 psi can damage water heater and household plumbing
Pressure reducing valve

Identify water heater valves
Troubleshoot water pressure
Sharkbite pressure gauge
Sharkbite pressure gauge

Sharkbite pressure gauge

Water heater valves

Water heater circulation system

Grundfos at Amazon

How to install recirculation system
COLD side Sharkbite flexible water heater connector
COLD side Sharkbite flexible water heater connector

Sharkbite water heater connection
Braided water heater line
Stainless steel flexible connection

How to install electric water heater
How to install gas water heater
Leaking water heater
HOT side Sharkbite flexible water heater connector
HOT side Sharkbite flexible water heater connector

Sharkbite water heater connection
Braided water heater line
Stainless steel flexible connection
Braided water heater line
Flexible water heater connection

How to install electric water heater
How to install gas water heater
Leaking water heater
marathon water heater Marathon 240 Volt water heater
30-40-50 gallon
Two-element / 240 volt electric

Marathon tanks
50 gallon
30 gallon

Titanium low-density Elements  It is NOT necessary to buy the exact replica model number/ Select correct wattage and length
Vacuum relief valve

Buy upper thermostat for 240 volt 2-element:
120-208-240V-277-480 volt/ 90-150/ ECO 170
Thermostat differential 17-27F
Rheem UV11698
Rheem SP11698
Camco 08163
Camco 07863 / 110-160
Lower thermostat
Rheem UV11695
Rheem SP11695
Therm-o-disc 08123 or Camco 8123
Camco 07723 / 110-160
Marathon under-counter water heater
Larger image
Marathon 120Volt under-counter water heater
15-20 gallon
Single element, 120-240 volt

20 gallon Marathon tank
15 gallon

2000 watt Element
Vacuum relief valve

Buy thermostat for 120 volt 1-element:
120-208-240V-277-480 volt/ 90-150/ ECO 170
Rheem UV11700
Rheem SP11700
Therm-o-disc 08013
Thermostat for 240 volt 1-element:
120-208-240V-277-480 volt/ 90-150/ ECO 170
Rheem UV11698
Rheem SP11699
Camco 8143

Marathon Point-of-use sell sheet with specs
How to install under-counter water heater
Water heater element burned out elementMarathon elements burn out frequently
Install 3800 watt element to prevent early failure of elements.
Use water softener when hard water is present. Turn tank temperature down. Flush and clean water heater each 6 months.
It is NOT necessary to buy the exact replica model number/ Select correct wattage and length
Buy Rheem marathon elements from my affiliate links

How to replace elements
Parts sheet

Some companies offer 'Lifetime Element Warranty' or '5-year element warranty.' Warranty means nothing if you cannot find foreign manufacturer. The company selling element is not the warranty carrier, and sellers generally do not underwrite warranty. Applies to all water heaters.
Rheem marathon element wrenchRheem marathon element wrench
1-7/8" water heater element wrench/ Use screwdriver for handle
Professional 1-7/8" sockets

Buy socket:
1-7/8" socket with 3/4" drive
1-7/8 sockets at Amazon
24" breaker bar with 3/4" drive
Marathon water heater installation
Larger image
Use flexible copper to connect Marathon to water supply
Make plumbing attachment using 3/4" female nipples. Brass nipples recommended, not galvanized. Flexible copper connections are reliable. Use new flex lines, old flex lines can leak.
Braided steel lines have rubber hose inside that can shed black particles over time. Stainless flex lines can rust in softened water. Insulate pipes completely when finished.
Marathon installation starts page 4

Do not make solder joints at water heater, or within 12" of water heater. 
Direct heat from torch can damage Marathon tank. Can damage any heater or appliance.
Pre-assemble copper pipe and then thread pre-assembled copper pipe onto tank.
When using soldered joints instead of flexible connections, then plan for at least 12" space above heater.
Flexible water heater connections
3/4" brass nipples
How to solder pipe
Stick menIf you have electric water heater, Marathon is viable alternative

Advantages Marathon:
Lightweight by comparison. 30 gallon 70 lbs. 40 gallon 81 lbs, 50 gallon 91 lbs
1) Tank will not rust 2) Limited lifetime warranty on tank for single-family residential, non-commercial installation, 3) No anode rod means tank life not diminished by water softener. No anode eliminates need for anode inspection, and eliminates odors caused by harmless bacteria reacting with anode rod, 4) Polybutylene construction means tank will not rust out and cause leak. 6) Larger element openings make sediment removal easier, 7) Can be installed in moist environments such as boat or agricultural installation, with diminished warranty. 8) Marathon can replace any ordinary electric water heater without electric wiring change. 9) Wiring is enclosed inside conduit means easy rewire for off-peak operation or to meet other objectives. 9) Brass drain valve/ not plastic. 10) Large 85-100 gallon tanks are still available as storage units with 1 back up element.
Rheem Marathon
Disadvantages Marathon:
1) Marathon costs more. 2) Parts are expensive and non-generic: Marathon elements, vacuum valve and other parts are non-generic but can be ordered in advance to avoid repair delays 3) Marathon elements burn out more frequently and are susceptible to hard water. Use softener.
4) If home has hard water, Marathon elements should be changed to 3800 watts, which slows heating and recovery. 5) Other water conditions can affect Marathon elements. The real issue is cost of brand-specific elements. 6) Maximum 6-year parts warranty,

Similarities to other tank-type electric water heaters

1) Same efficiency as regular tank-type electric water heater... .90-.92, and can be maintained to preserve full efficiency,2) Can be repaired homeowner. Replacement parts available. Can be maintained to last forever. Electric water heaters are simple to install and repair. Homeowner repair and installation is generally easy. 3) Maintenance schedule is same as typical electric water heater, except no anode inspection needed. 4) Installation is same as typical electric water heater, except Marathon is easier to lift. 4) Marathon is non-simultaneous/ both elements are not ON at same time, Marathon can replace any ordinary electric water heater without electric wiring change 5) All electric water heaters can be re-wired to meet off-peak objectives. Rewiring inside tank will void warranty. 6) Adding timer to any electric water heater will not void product warranty. 7) Marathon tank warranty is reduced if water heater installed anywhere except residential home, but this is true for all brands residential water heaters gas and electric. If you relocate, and take Marathon with you, then warranty is voided. Leaving unit in old home, the new homeowner receives 15 years extended warranty / requires purchase receipt.
Marathon water heaters
How to troubleshoot and fix water heaters
Marathon water heater elements
Marathon thermostats
Off-peak wiring
Read about anodes
According to mfg, there are no toxic chemicals from using Marathon polybutylene water heaters, which is business-speak nonsense because at some level all chemicals are toxic. Page 1 of Marathon use and care manual has following warning: 'Calif Proposition 65: This product contains chemicals known to State of California to cause cancer, birth defects.'
Manufacturer's stated purpose for disclaimer is avoidance of lawsuit, which means you-the-consumer cannot claim harm since you were warned. On other hand, much information on this page is also from product manual, so Rheem is offering a level of transparency, albeit by force of the people.

Is Marathon polybutylene cause for alarm? My opinion:  Probably no more cause for alarm than everyday life.
Polybutylene is widely used for household water pipe and other products, for years. All household products pose risk, from bug-spray to pills to gasoline. The modern world is covered in chemical waste, air pollutants CO2, NO, CO, O3, CHO, CH4, smoke and particulates.
My friend who owns a Marathon heater remains full of strong-headed opinions, same as before he owned product. No change observed.
Keep in mind following things
1) You do not drink large amounts of hot water from the water heater tank. Cold water line does not take water from water heater. See image
2) All steel tanks have anode rod. Marathon does not have anode rod. There are health concerns over aluminum anode rods. Read
3) EPA permeation and leaching science 2002  Read pdf   Polybutylene is better than pvc, however all plastics absorb minerals.
Marathon energy cost
Rheem makes several grades of  Marathon
*This review covers 15-20-30-40-50 gallon residential lifetime tank rated 170F.
Other grades include: Heavy duty commercial 75-85-100 gallon.
50-85-105 gallon storage tank w/ 1 element for solar etc/ rated 170F.
105 gallon storage w/ 1 element rated for 180F
Light duty commercial 3-phase.
$400-500 per year to operate any residential electric water heater
Same for Marathon or ordinary steel-tank electric water heater
Numbers shown on chart are similar to all tank electric water heaters.*
No energy payback from Marathon
Marathon does not save money vrs ordinary box-store electric water heater
Figures are for comparison only, and assume average household of 4.
Lower cost by reducing consumption, and/or re-wiring water heater for off-peak. Same applies for Marathon or any electric water heater.
9 ways to save with water heater
Off-peak options
Cost chart for all types water heater
Ways to increase hot water
Water heater size chart Choose correct size water heater
First hour delivery chart generally applies to all water electric heaters.
First hour rating can be increased by raising thermostat temperature, installing low flow shower head, rewiring for simultaneous operation etc.

Homes with oversized bath or whirlpool bath: Install minimum 80 gallon electric, or 50 gallon gas
Home with 5-7 or more people/ install 2 water heaters.

Calculate first hour delivery
Two water heaters
How to wire for simultaneous operation
Ways to increase hot water
First hour delivery is amount of hot water a fully heated water heater can deliver in the first hour period.
It does not mean the hot water will last for one full hour. First hour shows on yellow energy label, but is approximation. Actual first hour depends on incoming water temperature, thermostat setting, standby loss, pipe length, and other variables.
Recovery Capacity
... is the maximum amount of water that can be heated by a water heater with a given temperature rise in one hour.
Recovery is typically measured in gallons per hour (GPH).
Generally, higher wattage input means faster recovery rate. So elements can be changed for higher wattage, or water heater can be wired for simultaneous operation. Recovery rates are also a component of First Hour Rating which is basis for water heater sizing. The issue of failed elements with Marathon means higher wattage is probably not best alternative.
Calculate First Hour Rating
How to calculate first hour
How to wire for simultaneous operation
Limited Lifetime Warranty
Tank: Lifetime
Parts: 6 year
Order extra elements.

Marathon Warranty/ Certificate of warranty comes with each product
Marathon warranty, and claim procedure
Rheem offers extended warranty for Marathon and for ordinary steel tanks
Limited LIFETIME on tank
6 YEARS parts
Privately owned, single family dwellings – the tank is warranted not to leak “for as long as you own your home”. If the home is sold, the warranty reverts to fifteen years from the date of the installation and the second owner received coverage for the time remaining. Parts are warranted for 6 years from the date of manufacture or 5 years from the effective date, whichever is greater.
Tank must be maintained as outlined in product manual

10 YEARS tank /1 YEAR parts
Apartments, condominiums, restrooms in office and commercial buildings, multifamily housing or any light duty commercial/industrial use – the tank is warranted for 10 years from the date of installation. Parts are warranted for 1 year from the date of manufacture.

Any application where water is used as process
5 YEARS tank/ 1 YEAR parts
Remove sediment from marathon

Larger 1-7/8" element gives larger opening for cleaning out sediment.
Use element wrench SP610070, or buy 1-7/8" socket at local auto parts.

The SP610070 is ordinary cheap element wrench, while auto parts socket will grab elements better
Marathon SP610070 element socket / Amazon
Marathon dip tube reduces sediment/ does not prevent sediment
Marathon dip tube can help stir sediments off bottom of tank, but this does not prevent sediment from forming.
Most heaters offer same dip tube feature. Read about dip tubes

Element advisory: Marathon elements burn out more frequently in some cases. Homes with hard water should install 3800 watt element to reduce sediment, and to reduce problem with elements burning out frequently.  Rheem Marathon parts list

Removal of sediment is easier with Marathon water heater, because element opening is slightly larger.
Full efficiency is restored to all tank-type electric water heaters when sediment removed. Unlike gas water heater, any remaining sediment inside electric heater will not affect efficiency since the element sits several inches above tank bottom.
Remove Marathon elements using 1-7/8" socket

All gas and electric water heaters that are exposed to hard water will form sediment deposits. Calcium-based sediments are not harmful, but must be removed periodically. Flush tank every 6 months to prevent problems.  Read about sediment and flushing
Marathon water heater Marathon tank has 2-1/2" foam insulation
By contrast, most electric water heaters manufactured after April 2015 have thicker insulation to meet the DOE (department of energy standard).
Both Marathon and ordinary steel tank electric water heaters have same EF energy factor and same expected annual cost of operation.

Water heater blanket does not void warranty
Water heater insulation blanket can be installed on any tank-type electric water heater, including Marathon, but not hybrid electric water heaters, or tankless electric.
Insulation blanket can cover entire tank and pipes, but cannot cover or obstruct TP valve.
TP valve overflow tube installation code
Warranty void or diminished if water temperature exceeds 180F
 Read hot water scald advisory manual page 15
When temperature is set higher, the first hour delivery increases, but EF factor decreases and tank generally costs more to operate.
Temperatures above 140 will distill more chemicals out of water. Temperature for killing bacteria is 140 Read advisories and cautions for hot water
Any temperature above 120F can scald quickly and is generally dangerous for household. Typical bath-shower-hot tu is 104F

Commercial Light Duty Marathon 208-240-277-480 Volt 1-phase or 3-phase is made for high temperatures. Available in 75-86-105 gallon, simultaneous and non-simultaneous models.
Buy high temperature upper thermostat:
Minimum temperature 110 Maximum 170 High Limit trips at 190/ 208-240-277-480 Volt
Thermostat differential 17-27F
Marathon water heater thermostatRheem SP8293 / 170
Camco 08304 / 180
Buy lower:
Rheem SP8295 / 170
Camco 08314 / 180

How to replace thermostats
How to install meter on electric water heater
Change water temperature using timer
Control water temperature using Z-wave
Marathon Storage tank
High heat from solar
Marathon is often used for solar applications, and saves buying special-order high-heat-rated steel tank
Solar water heater installation can produce hot water up to 180 degrees.
Ordinary tanks may warn against use as solar collectors because high heat and temperature will damage tank.
Rheem Marathon product literature does not mention solar.
Unknown if solar application will void product warranty.
Warranty void or diminished if water temperature exceeds 180F
Marathon does not have anode rod because tank is non-metallic
Anode rods are installed in steel tanks to prevent rusting, and is not needed for Marathon

Marathon advantage: Homes that must replace anode rod frequently because of odor problems will benefit from Marathon water heater.
Marathon does not eliminate all water heater odors, nor eliminate other water problems such as hard water, etc. If odor is present at all hot water faucets, and not at cold, then problem is inside water heater. But other causes can also cause tank odors such as dirt inside the line or inside the tank.

Typical anode problems are solved by installing Marathon:
1) Anode rod prevents rusting.  If steel-tank anode is not inspected and replaced each 2-4 years, then steel tank will rust, eventually leading to tank failure. Marathon tank will not rust and solves this problem.

2) Harmless bacteria is in all water. Some bacteria, typically found in well water, can react with anode rod inside steel tank. This reaction results in odor, requiring anode rod replacement, and/or periodic cleaning of tank with hydrogen peroxide. Marathon solves this problem.

3) Other rare anode problems can occur if steel-tank water heater has not been used for several weeks. Certain bacteria react with anode rod to produce hydrogen gas, which is flammable and explosive, and can ignite when faucet is first turned on and then light switch turned ON. Marathon solves this rare tank problem, but does NOT prevent natural gas from entering water well due to local hydrocarbon drilling and fracking.
Anode rods
Marathon water heater connections Marathon water heater connections
Read page 7-13 manual
Read warranty exclusions page 22

Electric connection: Read manual Page 10. Typical electrical connection is made with flexible conduit.
Use 10 gauge wire and 30 amp breaker for elements larger than 3800 watts.
Read label on side of tank to check element wattage. Wattage also printed on end of each element.
Marathon requires 10 gauge wire and 30 amp breaker

See wire sizes
See basic water heater circuit

Water connections: Cold and Hot must be connected to correct side, or water heater will not work as expected. If unsure which pipe: Before disconnecting old heater, run hot water for a few moments and feel which pipe is hot. Note also that incoming cold water pipe usually has shut off valve.

Vacuum relief valve: Do not connect anything to relief valve, except cold water connects at top. "Certain conditions produce vacuum or negative pressure condition inside tank. Negative pressure can cause tank to fail. To prevent problems, make sure water heater is full of water before turning on power. Run each hot faucet to remove air, then briefly open TP valve on water heater to make sure last of air is gone.
Vacuum relief valve

TP valve: All water heaters today have temperature-pressure relief valve to prevent high-temperature causing tank failure.
How to install TP valve overflow tube:
Applies to all water heaters
Use overflow pipe off old heater. Connections do not have to be water-tight, but joints must be secure so pressurized scalding hot water is released downward away from people. Overflow tube must be same diameter as valve discharge connection. Do not downsize pipe into smaller pipe. Overflow tube can have maximum 4 elbows and 30 feet length. End of overflow tube cannot be threaded. Tube cannot be lower than top edge of drip pan. Tube must terminate 6" above open drain. TP valve can draw water back into water heater if overflow tube is under water. Do not cap off TP valve or obstruct overflow tube.  Overflow tube cannot have shut off valve installed, or any obstructive valve. TP valve is first line of safety for water heater. TP valve releases water when pressure or temperature is too high, and prevents possible water heater explosion  
How to test and replace TP valve
Water heater element
Marathon tank must be full of water before power is turned ON
All electric water heaters must be full of water before power is turned ON.
Otherwise elements burn out instantly.
Fill tank until bathtub tap runs full with no air gaps, then open Marathon TP valve for a moment to bleed last of air from tank. Then turn power ON. Marathon will heat 20 gallons per hour, so expect tank to be fully heated in 2-3 hours depending on tank size.
Remove Marathon elements using 1-7/8" socket
Read manual for advisories
Page 14 manual
Required maintenance Maintain Marathon water heater
Warranty void or diminished if tank improperly maintained.
For example if water pressure exceeds 80-100 psi limit, or water temperature exceeds 180 degrees, or if TP valve not opened and tested each year.
Page 16 manual
Manual says to flush water heater each month, typical metal-tank water heaters say once per six months.
Troubleshoot Marathon water heater
Page 17 manual

Replacement parts and element installation for Marathon
Page 18 manual
marathon water heater Marathon can resist water
Installation in damp or wet location reduces warranty, but tank will not rust.
If water heater is flooded, the electrical parts can be replaced and water heater put back into service as soon as surfaces, covers and conduit channels are dry.

'Car-bumper tough polyethylene exterior' can be cleaned with soap and water and/or graffiti remover
'Seamlessly blow-molded polybutylene tank surrounded by a filament wound fiberglass outer tank' is resistant to moist locations.

Steel tank heaters: recommend  replacement after flood
Read about Flooded water heater
Marathon wiring
Larger image
Marathon is ordinary Non-Simultaneous water heater
Non-simultaneous means both elements are not ON at same time.
Upper element is ON, or lower element is ON, or both elements are OFF
This is typical for residential 240Volt water heaters
How electric water heaters work
How to troubleshoot electric water heaters

Water heaters can be rewired
How to wire thermostats
Advantage of electric water heater vrs gas water heater (Applies to non-hybrid electric water heaters)
Electric prices are stable. Electric heater avoids price fluctuations of NG and LP gas.
Electric water heaters can be installed anywhere inside a home as long as area does not flood. (Page 5 manual) No air supply required, while gas water heaters require fresh air for combustion. Can be installed in closet, or below grade, or in attic.
Electric needs no air supply. New gas water heaters can have FVIR problems and cannot be exposed to flammable vapors, or dust, or stored household chemicals.
Maintaining electric water heater is easier than gas. Gas water heaters require yearly service cleaning the air intake, burner and combustion parts
Electric heater are 'not as dangerous.' No danger of CO poisoning, or gas leak. No need for CO detector or gas detector.
Electric water heaters need no vent pipe, and do not draw air into house that will cause heat-air systems to run more.
Electric heaters are easier to install. Unlike gas water heaters, electric water heaters can be installed in direct contact with carpet, and personal belongings without creating fire hazard, assuming no obstruction over TP valve and wiring is up to code and inside approved conduit..
Electric heaters can be controlled by a timer and home automation. See timers
Disadvantage of Electric water heater vrs gas water heater
Burning coal to produce electricity produces more greenhouse gas than burning NG or LP gas. However power plant gasses are released at one central location instead of venting out at each home. Offsetting the lower carbon from burning natural gas, is that HVAC unit runs more because gas water heaters draw air into house from outdoors.
Yearly operating cost for electric water heater is usually higher than gas.
Gas heats water faster than electric, so gas water heaters have higher recovery and first-hour delivery.
Difference between gas and electric water heater EF energy factors
Electric water heaters have higher EF energy factor rating than gas water heaters. Higher EF is better.
Gas water heaters have lower EF, or worse EF than electric water heaters. But gas water heaters cost less per year to operate, despite gas water heaters having worse EF.
This is generally because burning gas releases more BTUs into water than electric. Gas heats water faster than electric.
Electric water heaters have higher EF rating because the element is immersed in water, and no heat is wasted up a vent pipe like gas water heater.
Gas water heaters can increase EF rating by recycling more heat from combustion by-product. This means less waste up the vent pipe. Read Effex water heater review
2008 Sell Sheet with model numbers
2012-Current Sell Sheet with model numbers
Rheem Marathon parts list
Rheem marathon parts list 2011/ pdf
Marathon storage tank parts
Marathon troubleshoot walk-thru/ pdf
Rheem parts warranty claim form
Marathon at Rheem
Marathon selection at Rheem
Marathon use and care guide
Marathon warranty, and claim procedure
Available 30-40-50 gallon.
Efficiency .90-.92 EUF/ same efficiency as ordinary steel tank heater.

Storage tank available for solar, geothermal
and indirect heating 50-85-105 gallon with back up elements
Pressure relief valve
2000 watt element
SP610130 3800 watt upper element
4500 watt upper or lower element

Rheem titanium Marathon element
Support the economy:
Buy water heaters from my associate links:

50 gallon Gas water heaters at Amazon
40 gallon gas water heaters at Amazon
50 gallon Electric water heaters at Amazon
40 gallon electric water heaters at Amazon
Hybrid / heat pump/ water heaters at Amazon

How to install gas water heater
How to install electric water heater
Troubleshoot gas water heater
Troubleshoot electric water heater
Point of use water heaters
Troubleshoot Gas valves with manuals
Icon gas valve

How to replace water heater element Waste King disposal
How to wire tankless electric

How to install tankless recirculation

Install point of use water heater
Titan tankless

Contactors/ relays
Install and troubleshoot garbage disposal Waste King disposal
Programmable timers

Woods timers
surge protection
Anode rods anode rods
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Tankless recirculation
Point of use water heater
Type 1 and type 2 surge protection surge protection
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Industrial supplies

Tools and home improvement

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Hayward pool
Pentair pool

Southwire electric

Black and Decker

Irwin Hand tools
Klein hand tools
Fluke electrical testing
Dremel hobby tools

Campbell Hausfeld air powered
Tekton automotive

Powerbuilt automotive
Saws and saw blades
box timers Resource:
Compare box timers
DPDT timers
Control water heater w/ Z-wave
Intermatic control centers Resource:
Intermatic control centers: and parts
Digital control centers and parts
Tork control centers and parts
All control centers and parts
programmable timer Resource:
Programmable timers
Countdown timers
Off delay timers
On delay timers
Timer modules
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Low voltage power packs Recirculation systems
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