Rheem Marathon 85 Gallon Electric - element questions

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Scooterbugg

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I searched forums for this but found no answers:

I have a Rheem Marathon MR85245 85 gallon water heater. 240 volt feed on 30 amp breaker with10 gauge wire. Under “Element Watts“ on the manufacturer’s placard, it reads “4500” for upper, lower, maximum, but it has OEM Rheem 3800 watt elements (stamped 240V 3800W) which is what I’d expect if there was a 12 gauge feed. Heater was made in 2004, we bought place in 2016. Based on previous owner’s feedback, I’m doubtful that they were replaced, pretty sure they were there from original installation. Why would there be 3800’s if feed wiring supports 4500s AND placard says 4500? I understand downgrading to 3800W if feed wiring is limited. Also, is it beneficial to replace both with 4500s? There is a Comverge DCU-S2000 box in series with the power feed that is supposed to allow the electric company to cut power to the heater under heavy load days if that is a factor? I’m not even sure that the power cut box or whatever it is even works. Thanks for the feedback.
 
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GReynolds929

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4500 watt/240 volt elements are 3800 watts at 208 volts. You probably have 4500 watt elements in there now. The placard sometimes has this info on also. Some elements will display both ratings on the element also.
 

Scooterbugg

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4500 watt/240 volt elements are 3800 watts at 208 volts. You probably have 4500 watt elements in there now. The placard sometimes has this info on also. Some elements will display both ratings on the element also.
Thanks for pointing that out. I guess I should have made it clear in my post, (I just edited it) both elements have “240V” and “3800W” stamped on them and when I look them up by their part number (210510 upper, 213470 lower), that is the spec I get.
 
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Fitter30

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Watts divided by volts = amps
3800w 15.8 amps
4500w 18.75 amps
Clamp on amp meter $25 can tell what element you have
If stamped 240vac 3800w that's what it is.
Only one element runs at a time.
Wh controls top element runs first then when thermostat satisfied powers lower element satisfied power go back to top element.
Don't need rheem elements can pull them and go to a box store match them.
 

christopherdbrown

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I searched forums for this but found no answers:

I have a Rheem Marathon MR85245 85 gallon water heater. 240 volt feed on 30 amp breaker with10 gauge wire. Under “Element Watts“ on the manufacturer’s placard, it reads “4500” for upper, lower, maximum, but it has OEM Rheem 3800 watt elements (stamped 240V 3800W) which is what I’d expect if there was a 12 gauge feed. Heater was made in 2004, we bought place in 2016. Based on previous owner’s feedback, I’m doubtful that they were replaced, pretty sure they were there from original installation. Why would there be 3800’s if feed wiring supports 4500s AND placard says 4500? I understand downgrading to 3800W if feed wiring is limited. Also, is it beneficial to replace both with 4500s? There is a Comverge DCU-S2000 box in series with the power feed that is supposed to allow the electric company to cut power to the heater under heavy load days if that is a factor? I’m not even sure that the power cut box or whatever it is even works. Thanks for the feedback.

One of my friend francias was also in the same boat but i advise him to find out the best certified local electrician in the town and let the professional handle it all and he contact electricien sherbrooke, and they did a great job in less time, francias save time and get stress free solution by calling a certified professional for this issue, but before moving on i would like to get your suggestions.
Thanks again
Your water heater likely has 3800W elements due to regional voltage (208V) or energy-saving considerations, even though the placard lists 4500W. If your 10-gauge wire and 30-amp breaker support 4500W elements, you can replace the 3800W ones for faster heating, but note that only one element runs at a time. To confirm the power cut-off box is working, use a clamp meter. ensure any replacement elements are compatible with your system.
 

Sarg

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I just saw this yesterday :
Per the internet:
Marathon upper elements are 4500 watt for slightly faster heating, while lower elements are 3800 watt to help prevent burn-out.
 
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