20 Most Recent Rheem MR105245 Marathon Electric Water Heater 105 Gal Questions & Answers

Question posted under marathon electric water heater.
Marathon is 240Volt dual element non-simultaneous water heater.
Non-simultaneous means that upper part of tank has to reach temperature before power is sent to lower thermostat and element. So if upper element is bad, then water heater has no hot water.
http://waterheatertimer.org/Replace-anode-rod.html#audibleBW

1) You need to by-pass upper element without by-passing upper thermostat.
2) You should never by-pass upper thermostat because it has ECO-reset protection.
http://waterheatertimer.org/How-water-heater-thermostats-work.html

3) Open following link for image of wiring:
http://waterheatertimer.org/images/Marathon-wiring-700.jpg
4) Take photo of your wiring in case color code is different on your specific model

5) Look at upper thermostat.
Remove yellow wire from terminal 2 on upper thermostat, and cap off temporarily.
Remove red wire from terminal 4 on upper thermostat, and move it to terminal 2 on upper thermostat.
6) For more effective operation, look at lower thermostat.
Remove black wire from lower thermostat terminal 1 and move wire to terminal 2 on lower thermostat.

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http://waterheatertimer.org/How-to-install-electric-water-heater.html http://waterheatertimer.org/How-to-wire-Tankless-electric-water-heater.html Gene If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

You have marathon water heater?Thermostat is probably bad. Has gone out of calibration. Replace both upper and lower thermostats for $25 from local hardware store, takes about 20 minutes, turn off power, take photo of wires before starting. These thermostats can be adjusted all the way down to 90 degrees, and then dial up a bit to reach 110.Copy following link for instructions how to replace thermostat yourself.http://waterheatertimer.org/How-to-replace-thermostat-on-electric-water-heater.htmlIf problem continues, then replace both elements.Elements are special order made specifically for marathon.Requires 1-7/8" socket to remove elements.Upper 3800 watt, order part SP610130 Lower 3800 watt, order part SP210197http://hometips.me/Mar/Rheem-Marathon-parts-2.pdfhttp://waterheatertimer.org/How-to-replace-water-heater-element.htmlMore information about Marathon:http://waterheatertimer.org/Review-Rheem-Marathon-water-heater.htmlGeneh If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Marathon elements are specific to that water heater and can be ordered online, but generally are not at the local hardware.
Good to keep a couple spares around.
Marathon is 240Volt water heater.
Thermostats turn off one leg of the 240Volt circuit, so elements and themostats will always test for 120volts.
You removed wires off elements and tested each for continuity and tests showed elements to be good.
Test top two screws of upper thermostat and make sure you are getting 240V to the water heater.

If water heater has some hot water, then that says water heater is getting 240V, upper element is good, and remaining suspects are bad thermostats, bad lower element, or sediment build-up, or combination.

Open following link for troubleshoot run-down:
http://waterheatertimer.org/How-to-troubleshoot-electric-water-heater.html

Water well.
If you have sediment build-up that reaches lower element, then water does not circulate around the element and water heater no longer heats very fast or accurately. If sediment is the problem, sooner or later the lower element will burn out.
Doesn't hurt to flush out the tank now and then, and vacuum out the sediment if that is problem.
http://waterheatertimer.org/Clean-sediment-out-of-water-heater.html

Check 240 circuit breaker.
Open top cover on water heater and push in ECO red reset button.
If reset button will not reset, then replace thermostat.
If reset is not tripped out, then either upper thermostat is bad, upper element is bad, or water heater might be getting 120V instead of 240V.
If you have some hot water, then best suspect is lower element.
http://waterheatertimer.org/How-to-troubleshoot-electric-water-heater.html

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You have 240Volt Marathon water heater.
These heaters have element burn-out problems.
http://www.thetankatwaterheaterrescue.com/forums/forum3/

Yes sediment can cause decreased amount of hot water when water cannot circulate around lower element, and sediment can cause lower element to burn out.
http://waterheatertimer.org/Clean-sediment-out-of-water-heater.html

Following list is overview of tank troubleshoot:

If you have some hot water, then that says several things:
-Upper element is working.
-Electricity from circuit breaker to upper thermostat is good.
-ECO reset button is not tripped.
-You do not have overheating event.
-Access doors and insulation are in place and thermostat not exposed to cool temperature that causes overheating.

That leaves following suspects:
1) Check if TP valve is stuck open, or pipe cracked, or faucet leaking and running hot water down a drain.

2) Upper or lower thermostat is bad.

3) Lower element is bad -and- maybe tank has built-up sediment
http://waterheatertimer.org/How-to-test-water-heater-element.html
http://waterheatertimer.org/Clean-sediment-out-of-water-heater.html

4) Loose wire. Open covers and inspect. Tighten screws very tight against copper wire.

5) Bad wire between upper and lower sections of tank.

6) Do complete 30 minute troubleshoot before replacing any parts.
http://waterheatertimer.org/How-to-troubleshoot-electric-problems-with-water-heater.html

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You posted under Marathon electric heater.
If you have tankless or tank-type gas heater, information below does not apply.

Absence of hot water say upper element is not working.
1) This can be caused by tripped reset button located on upper thermostat. Open upper cover and push in reset button. Put ear against tank to hear bubbly fizzing sound. Put insulation and cover back over thermostat. Continue reading information below because reset button trips when thermostats are bad or element is shorted.
2) Upper thermostat is bad. Replace upper thermostat. I usually replace both upper and lower thermostats.
http://waterheatertimer.org/How-to-replace-thermostat-on-electric-water-heater.html
3) Electricity going to water heater from breaker box is interrupted.
http://waterheatertimer.org/Test-electricity-to-water-heater.html
4) Upper element is bad. Test element. Replace element if needed.
http://waterheatertimer.org/How-to-test-water-heater-element.html
http://waterheatertimer.org/How-to-replace-water-heater-element.html

5) Add a comment for more free help.

6) Also take advantage of fixya phone service.
For a price, expert speaks with you over phone while you work on heater or any do-it-yourself project.
Fixya is always less expensive than a service call.

You may be able to clean out the old valve - or you may want to just replace it. Either way, you'll need to remove the valve to clean it. There is a possibility you can remove the upper nut on the valve and unscrew the valve assembly to clean.Loosen the upper nut under the handle and unscrew the stem as you loosen the nut you will need to turn off the power and the water supply to the water heater. Have a large plastic cup of water handy to flush out the valve body after you've removed the stem and GENTLY scrape out the deposits stuck to the seat. This deposit is what is keeping the valve from sealing up. The bottom of the stem has a small washer secured with a screw and that washer may also be bad. If the valve body is plastic, there is little chance you can successfully clean it without damaging it and replacement would be the best option. Examine the valve body before you start - if it is plastic then you should get a replacement before you remove the old one. When you remove the old one, you will need to clean out the thread area so the new valve will install and seat correctly. Using Teflon tape to seal the threads would be recommendable to keep it from leaking when you are done. The threaded stem of the valve ( the part that goes into the heater) may be 1/2 or 3/4 inch. Measure the existing for replacement. When you go to remove the old valve, be very careful if it is plastic as it may break off - very bad news, as this normally results in needing to replace the water heater. Bets of luck to you in this job - and thanks for using Fixya!!! p.s. Please rate my solution if it has been helpful - Thank you!!

Hi, W/D here.
You'll need an electrical test meter to find what ails ya. The reset button was a good idea, and it may help. If not:
1. Disconnect the power to the water heater (Trip the breaker to "Off").
2. Check the electrodes where they screw into the tank. There are two terminals. Test for continuity. If either electrode tests open, replace it.
3. With power on the heater, test for power through each thermostat to the electrode and back. Replace any defective thermostats.
Hope that this helps you, --W/D--

I got a new Rheem heater and it's complete garbage. No water pressure.

recently installed?

Brian sounds like it's Leaking From Anode rod.... Check here.... https://lildutchuncle.com/rheem-water-heater-leaking/

The three most common reasons for this happening to you are 1) a defective gas valve, 2) a rusty thermopile, and/or 3) the automatic shut-off not working as it should. So, the most common reason for many people having this problem stems from having a gas valve that is not working as it should. When your gas control valve is faulty, it will mean that your burner is not going to be igniting as it should-or at all. Something that worked for me one time was to turn the Temp all the way down then all the way to Max a couple of times..gradually. Why it worked I don't know. Got a couple more years out of it though. Good luck! Best to you.

there is pressure adjustment, just temp. water pressure in + water pressure out

I don't know for sure but look at page 117.... http://snowcrest.net/thriftysupply/pdf/RTG-Service-Manual-REV-2.pdf