Electric hot water heater giving luke warm water.


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Old 06-11-08, 08:04 AM
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Electric hot water heater giving luke warm water.

I read enough on here yesterday to do some basic trouble shooting but I couldn't quite figure it out.

This is a family members house that has some creative plumbing. They get their hot water from the on demand coil in the winter and the electric tank in the summer so they just discovered the tank heater has a problem in the last few days once the boiler was shut down.

both elements ohm out to about 12.8 ohms for a 4500 watt 240V coil. No wiring diagram so I couldn't quite figure out the whole wiring scheme but I was not getting 240 on either element even though we have a short burst of hot water followed by warm water for a short while. It was clear the lower tstat was acting strangely as I could get 240 on it by tapping it hard. So that was replaced. Now he is getting warm water for a bit longer but not up to what it should be. The heater is at least 15 years old and is a More-Flo?

I never did see 240 on the upper element but I couldn't tell if that was because it had reached temp or not. I couldn't really feel any heat on the outside let alone a variance between top and bottom. We were going to throw a top tstat in just to see what happens but I thought I'd check here first. I hate throwing parts a problem due to ignorance. I saw the dip tube mentioned a few times but I have no idea how to test that. I'm guessing the tank has never been flushed either.

So how should I go about testing the top tstat? Would shutting it down completely for a few hours and then checking for 240 on power up work? Dip Tube? Overall the body of the heater looks pretty good with no major rust. This house will need a serious upgrade soon to the overall system but for the moment I just need to get them hot water.

Thanks -
 
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Old 06-12-08, 05:11 PM
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No ideas at all on the upper tstat or dip tube?
 
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Old 06-13-08, 04:40 AM
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Yep, dip tube would have been my first guess, since it is warm and not completely cold.
 
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Old 06-13-08, 04:54 AM
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Originally Posted by Just Bill
Yep, dip tube would have been my first guess, since it is warm and not completely cold.
OK - I'll search dip tube - but somehow I get the feeling that means new water heater time.
 
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Old 06-13-08, 07:50 PM
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A 15 yr old water heater is tired and wants to be put to bed forever

Either you have great water, or your tank is ready to blow any time now.
 
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Old 06-14-08, 04:26 AM
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OOppppsss, I missed the part that it is 15 yrs old. Don't put too much time/money is trying to fix it. Life is about at an end. Dip tube is cheap and fairly easy to do yourself(if you can solder), and have you flushed the tank??
 
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Old 06-14-08, 02:55 PM
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speedy72,

First off, a 15 year old WH isn't worth putting anything other than MAYBE a little time into. Replace it.

That said, you won't find a wiring diagram on the WH -- follow the one on the back of the package that the thermostats come in. But, UNLESS somebody has messed with it over the years, the wiring will be the same as it came from the factory.

A bad dip tube won't give you warm water, UNLESS it's split and allowing cold water to leak into the top of the tank. I've seen that ONCE in about 1,000 WH's, and my Dad (a 40 year plumber) had never seen it. (Chances are pretty slim!!)

Since the complaint is "warm water temp.", I tend to think that the problem lies in the "creative plumbing" that allows the boiler to be used in the winter and the tank in the summer. My guess is that cold water is being pulled from the boiler (which is shut down in the summer) and mixing with the hot water from the tank. You need a shut off valve in the system so that the water from the boiler can be turned off in the summer when the boiler is shut off. (I'm assuming that this "boiler" is the furnace.)

As far as the 230, or 240 volt reading on a WH, the only place you'll find that is across the 2 incoming phases of power. (The red wire and the black wire at the top of the upper thermostat.) One leg swings to a negative 115 or 120 volts while the other one is going to a positive 115 or 120 volts. (There is no neutral in a WH.)
 
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Old 06-14-08, 04:49 PM
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Well it seems to have fixed itself for the moment. I don't know it it's electrical or something dislodged or what. Maybe just the overall increase in the incoming temp is allowing it to limp along. but no complaints of hot water shortage since the second day after we changed the lower stat.

I agree it's not worth much time but this is an old PA dutch family. If you know anything about them they will happily spend four times as much time fixing something rather than throw it out. Frankly we could use a bit more of that mentality in this day and age. Our water is excellent here. Really Excellent. My bathroom is 40 years old with almost zero scale.

I doubt the creative plumbing has anything to do with it. It's been that way for a few decades or more now. the house is plumbed so you can get hot water from the boiler, water heater or the home made wood stove with a massive heat exchanger welded to the top. I'd have to look at the plumbing again to see how it's done. I don't know how efficient it actually is but it's worked for a long time. I believe the water heater is the last in the change but has a bypass so you can use it as a storage/buffer tank or bypass it altogether.

240 only at the incoming T-stat? That doesn't make sense to me. I should be able to read 240 across either element when they are heating. I did read 240 on the lower stat, just not the upper, which may or may not have been up to temp.

My vote is to dump the electric tank anyway and use the boiler to heat a quality hot water storage tank.

The problem is the boiler is about 40 years old now so the plan is a whole new system in the next ten years.
 
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Old 06-14-08, 05:37 PM
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I am a firm believer in not replacing until need be, but in the case of a water heater, the older it gets the likely hood of a leak is greater. Which increases the chance of a major water problem. Just being cautious.

As far as the 40 year old boiler is concerned. I would say it probably has poor efficiency. So in the long run it is worse for the environment and your pocketbook every day that system is in service. At today's price of oil I would be looking sooner than in 10 years for a new system. newer boilers run cleaner and cooler.

I am not trying to sell anything here, just trying to show you the facts.
 
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Old 06-14-08, 06:05 PM
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Originally Posted by plumbingods
I am a firm believer in not replacing until need be, but in the case of a water heater, the older it gets the likely hood of a leak is greater. Which increases the chance of a major water problem. Just being cautious.

As far as the 40 year old boiler is concerned. I would say it probably has poor efficiency. So in the long run it is worse for the environment and your pocketbook every day that system is in service. At today's price of oil I would be looking sooner than in 10 years for a new system. newer boilers run cleaner and cooler.

I am not trying to sell anything here, just trying to show you the facts.
I'm in agreement but it's not my call or my house. I just happen to be the family member that has some experience with this stuff. Oddly enough it's a member of this forum that has done the service on the boiler the past few years. The boiler is just new enough to be reasonably efficient and does have a relatively modern burner on it. 40 years is probably an exaggeration. 30+ is probably more accurate. The reasons for not replacing have little to do with mechanical logic and everything to do with upsetting the Matriarch's routine as little as possible. After all the system was "just put in" Yea, when I was just out of diapers.

Before the next system is put in it is hoped insulation and other changes can be made to lower the load and size of the mechanicals. That is not something that can be done now for the above reasons.
 
 

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