The Tank › Can I replace 3800watt 208V Anod with a 4500 or 5500Watt
- December 12, 2010 at 12:31 pm #14706ToddoParticipant
I have a Miser 5 kenmore. It appears from the expiration on the label it is at least 22 years old. Not to bad. I have checked the anode and it test good by ohms testing. I have not opened it up to see how the anode looks. The reason for my inquiry is first my electric bill has really gone up over the last 8 months “like double” So I started thinking my anode was bad. Oddly enough in this short time before i even checked the Waterheater the breaker on the thermostat popped. I reset it no problem since. Of course I am wondering why it popped. I did notice while checking the water heater there was 2 drops of water at the insertion point of the anode but nothing close to the electrical. I was thinking I need to replace the element, or Replace the Waterheater?? I was looking at tankless waterheater for the small price but it requires 100am breaker. My main breaker is 2 70amp tied together. If anyone knows is this equal 70amp total or 140amps. So back to my original question if I was to replace the Anode can I replace it with a higher 4500 or 5500 watt even thou the tank says 3800 max. Would I save money with a tankless over buying just a new water heater? Price is the same. Looking at the titan tankless. Thanks sorry for the long post.December 12, 2010 at 8:01 pm #14709AkBrianParticipant
What your asking about is an “element”, the anode is a stick of aluminum or magnesium immersed in the water to prevent corrosion of the tank. I’m a noob here, so others can better address your basic question, but I can tell you this;
amps=watts/volts , so…
5500/240= ~23 amps
Good practice is to not exceed 80% of a circuits rating. So..
23/.80= ~29amps, so if 5500watts elements are used it should be on a 30amp 240volt breaker.
Using the 80% guideline, your 70 amp main breaker should not see more than..
70 x .80= ~56amps continuously.
So you should not have more than 56 – 23 = 33 amps of OTHER load continuously on either leg of your service.
I’m sure if I made an error somewhere here, others will point it out. You should be able to do the math for the 4500 option. Note, I’m not addressing concerns related to the tank itself in my response, others know more than me in that regard.
BTW, I have the same problems due to an old 100 amp service entrance that has two pairs of 60 amp fuse disconnects, it’s a pain to deal with. The joy of living in a 1930 house.
Noting your title, if you live in a single family residence then you very, very likely have a 120/240volt service, not 120/208volt service. 208 volts is common for commercial 3 phase electrical services.December 12, 2010 at 8:12 pm #14711energyexpertParticipant
Your post confuses me quite a bit.
The anode is the sacrificial rod designed to “rust away” to prevent the steel tank from rusting. Anodes have nothing to do with heating.
The “breaker on the thermostat” is not a breaker but a bi metal temperature sensor designed to interrupt all power to the WH if overheating occurs. A stuck thermostat or cracked element (which will continue to heat after the thermostat opens one leg of power) can cause overheating.
After 22 years unless you had nearly distilled water the anode is almost certainly gone.
A volt ohm meter will tell you if the elements are good. With power off, 3800 watt elements should read 15.2 ohms screw to screw and infinity screw to ground.
Manufacturer may have used #14 AWG MTW (105C) wire internal in the WH which will work for 3800 or 4500 watts but not 5500. Also the WH circuit from the breaker may only be #12 AWG which is good for only 3800 not 4500 or 5500.
Tank less electric. If you only have a double pole 70 as your main you will have to upgrade your service to 200 amps. 100 amps at 240 volts = 81,912 BTUs/hour. This may sound like a lot but if your water inlet is 35 F and you raise it to 110 F you only get 2.2 gpm; a rather merger shower by most standards. And what if someone opens a hot tap somewhere else?
My utility, Progress Energy, commits on their website about tank less electric WHs. Sometimes two or more houses share a step down transformer. If you install a tank less electric WH and your neighbor has complaints (lights dimming, etc.) the utility will upgrade the facilities and charge the tank less WH owner for these upgrades.
If you want to increase recovery change the lower thermostat to an upper thermostat then pull a separate circuit to feed the lower thermostat directly. Then each thermostat can operate independently of the other or at the same time.
But if you are thinking about keeping/upgrading your current WH changing the anode is a must.
DavidDecember 16, 2010 at 12:13 am #14731ToddoParticipant
I first want to say thank you and sorry about my confusing post 🙂 . I actually had no idea what an anode was I assumed an anode and an element was the same. I have now researched it more and wow. I definitely have to check this ASAP.
Akbrian: Thank you for the info on the breaker and how to calculate load. So basically two 70amp breakers tied together are are still only 70amps not 140amps. As for total load not a problem. I live in Hawaii, I don’t use A/C and really only other large appliance is the stove. I tested the Element Ohms read 4.5. My water heater only has one Element so it is still good. I will need to check the Anode condition. If the anode is bad and It has been 22 years. Should I replace the anode or the entire WH before the tank fails?
Energyexpert: I will check the anode ASAP. I assume 4.5 ohms is a good reading for the element. Is there anyway to tell if the element is cracked. Would this create a higher resistance reading? I did turn down the temperature and it has not set off the overheat sensor again. I believe Hawaii water is pretty low in minerals and that could be to my success of 22 year old WH. From your post about the tankless heaters and electrical service is appears I will have to if I choose to replace stick with the tank heaters. I do appreciate the information. I never knew there was so much about WH. I will consider a timer on this one or a new one.
I appreciate the responsesDecember 17, 2010 at 4:31 am #14737energyexpertParticipant
Can you give us the nameplate data from your WH? Here in the “48” most residential WHs are wired at 240 volts and have outputs of 3800, 4500, or 5500 watts with 4500 being the norm by a wide margin. The respective ohms for these elements are 15.2, 12.8, and 10.5 ohms.
4.5 is very low unless wired at 120 volts. If 120 volts is the supply voltage on 4.5 ohms then output will be 3200 watts.
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