Electric Water heater problems

I am having problems with my waterheater decreasing the amount of water as I take a shower, meaning the longer the shower is the less hot water I have. Talking to some people I thought it was one of the elements, I tested both meters with the power off and one wire disconnected and they both read infinite to the mounting bolts and around 15 ohms across the terminals. Do these readings sound right, the stuff I read on the web said it should read what I meausred. Any other suggestions the only things I can think of is the thermostats, or there is allot of crud in tank. Is it a good idea to drain the water heater and refill it to get rid of any build up? Also everything I read said to test the thermostats but I can't find any instructions on the procedure to test these. The model is a Richmond Miser model #8V5-2C 220V 50 gallon. Thanks for your help
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You really should do that about once a year, A lot of people never do tho....... I would give it a try, I think if there is a lot of crud around the heating elements it will not heat properly.
Although the Soon to be X Girlfriend said she never did it, and her mother never did it , in the 12 years they had the water heater, so I guess that makes it right......LOL Tony D.

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You don't need to drain it completely, just open the bottom drain and let it run until clear.
John

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Mike P wrote:

Less what? Are you describing flow rate or temperature?

Your element resistance measurements are quite normal.
IMHO crud buildup in electric water heaters doesn't cause anywhere near as big a problem as it does with gas heaters, and I've never seen much buildup on electric heater elements I've pulled. I think the big problem crud causes with gas water heaters is that it forms a thermal insulating layer on the bottom of the tank which can let the flame overheat the tank bottom and also interferes with transfering the BTUs to the water.
If you're experiencing a "too soon" decrease in water temperature, you should check the dip tube on the heater's cold water inlet. That's a pipe (usually plastic) which directs the entering cold water to the bottom of the tank. If that tube falls loose, the cold water enters at the top of the tank and finds its way over to the hot water outlet too quickly.
You can usually see the dip tube through the upper element hole with the aid of a flashlight. If you can push on it with a thin stick and it doesn't flop around loosely, then it's likely ok. The "proper" way to check it is to disconnect the cold water inlet piping from the tank and lift the dip tube up out of the inlet port.
Good luck,
Jeff
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Jeff Wisnia (W1BSV + Brass Rat '57 EE)

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Mike P wrote:

I doubt if it is the crud in the tank, but draining it (not the tank, just the crude, generally a few gallons) is not a bad idea. Some is likely to not drain out, but you should be ahead. The only down side is sometimes the cheap valves they put on those things go bad, especially if the have not been opened in years.
A thermostat is a good chance. Next time someone is taking a long shower, check for voltage (240V) at each element. If you get it on both, that will eliminate that one.
Another issue would be the dip tube.
One last issue, is you are just using too much hot water and the tank can't keep up. Most likely a problem if you don't have flow restricted shower heads.
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Joseph E. Meehan

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Thanks for the help Ok to answer a few questions, the water pressure stays the same I just find myself having to keep adjusting the faucet to keep the shower at a reasonable temperature. It didn't do this until recently. I usually take like 10-15 long showers at the most and as the only person living here with a 50 gallon tank, and the shower as the only thing running first thing in the morning I find it unlikely that I am using all the hot water that quick. I did drain the tank out today and even filled it partially and redrained it to make sure that it was flushed well and the problem presists. I am going to check the thermostats tomorrow and get a voltage reading on them and then if that looks right I will pull the elements and look inside at the dip tube, and maybe change out the elements while I am at it providing they aren't too expensive.
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Mike P wrote:

First, crud in the bottom is bad, but it doesn't stop water heating until it builds up so high that it touches the bottom element and then it can cause the element to burn out. Try to drain some water out of the tank if you want, but if you have hard water you won't get much out with a regular valve; the only way to get really bad build up out is to take out the bottom element and vacuum the stuff out through the element hole.
Second, lots of water heaters never had dip tubes and they worked just fine, so something with the dip tube is not likely to be your problem but could be. Third, we assume you have at least two elements in the hot water tank. A 50 gallon tank should deliver water hot enough to burn you for as long as you want to take a shower unless you have an unrestricted outlet. (assuming the thermostats are set at 130 to 135 F degrees.) The standard 2 gal per minute restriction will certainly deliver plenty of hot water.
Fourth, water heaters are pretty simple but you have to understand how the electricity is routed sequentially to one thermostat and one element and then through the other thermostat and to the second element when there is high demand (temperature in the tank decreases). All you need is the electrical diagram and a test light(120 V to ground)to see if electricty is going through the thermostats and if it is going through the heating elements. But you probably need a check list to understand what you see.
For just testing the thermostats, turn the power off, disconnect one wire at a thermostat and test for continuity across the two terminals with your ohm meter. If you don't get continuity then turn the thermostat lower (assuming that the tank is hot) until you get continuity. If the tank is hot and you still can get continuity, the thermostat is bad.
Send me a private email if you wish and I'll send you an old test diagram and procedure (warning, it's a little slow if you have a regular modem like I do).
Good Luck.
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