Electric Water Heater doesn't heat - checked everything, puzzling!

[pgrillo]

I am not a professional plumber. We have had 2 plumbing companies come in and look at this and unable to figure it out. I have done as much testing as possible - and am clueless as to what is happening.

30 Gallon Water Heater. 2 years old, dual element
Suddenly it will not heat water to hot. Get very luke warm water for about 30 seconds, then goes to cold.

Both elements and thermostats replaced by first plumber. A new set of thermostats replaced by second plumber.
Testing procedure and results and comments.

With digital tester

• Voltage reading at top (before top thermostat) is 209 Volts. 0 volts when breaker is turned off
• Top Element and Bottom Elements
  • With power off, remove wires.
  • Get continuity pole to pole
  • Ohm resistance is 14 ohms
  • Checked each pole for a short - no issues
• Power back on
  • Top element. Turn thermostat all the way on, get 209 Volts reading at element
  • Top element Turn thermostat all the way down, get 0 voltage at top element
  • At same time I turn lower thermostat all the way up, and i get expected 209 volts on lower element.
• It appears that voltage readings at each element working properly. top on when needed, and when top is satisfied, power is routed through lower thermostat and ultimately the element.

So, the reality is that the top element which is reading 209 Volts, essentially remains that way and will not turn off, will not heat water to appropriate temp (using 130).
I have adjusted the temp down, and can see that the voltage/current goes off when the thermostat goes almost all the way down to off. Conversely, when i turn the thermostat back up, it kicks on about fairly quickly, indicating that the water is warm only and thermostat recognized it and you can here and measure the voltage on the element.

There is no kind of current regulator placed between breaker and water heater. The above is the extent of any of my knowledge on electricity. Question. Even with a reading of 209Volts and 14 ohms at the element that has been tested for continuity, etc - is it still guaranteed that the full 3100 watts is being drawn? Is there any situation in which that is not the case? Is 209 Volts enough? This water heater is not mine ... my water heater works fine and measures about 211 Volts, so I figured the voltage should be sufficient - and worst case it just takes longer to heat water appropriately.

At wits end, don't want to replace water heater if it isn't the water heater ....

Has anybody seen this odd situation?

regards

 

[Twowaxhack]

I scanned over your post.

You need to check how it’s wired. Make sure with a wiring diagram that it’s wired properly.

The top element should heat first and when it’s satisfied the upper thermostat switches the power to the lower thermostat.

To test if the element is heating properly, you need a test meter that will read AC amps.

Divide the wattage of the element by the input voltage to calculate how much amperage you should be drawing..

From what you’ve posted, you should be drawing 14.8 amps. So 15 amps.
3100 watts divided by 209 volts = 14.8 amps

Make sure your dip tube is intact

Make sure cold is piped to the side of the heater with the dip tube, should be the cold side.

 

[pgrillo]

I scanned over your post.

You need to check how it’s wired. Make sure with a wiring diagram that it’s wired properly.

The top element should heat first and when it’s satisfied the upper thermostat switches the power to the lower thermostat.

To test if the element is heating properly, you need a test meter that will read AC amps.

Divide the wattage of the element by the input voltage to calculate how much amperage you should be drawing..

From what you’ve posted, you should be drawing 14.8 amps. So 15 amps.
3100 watts divided by 209 volts = 14.8 amps

Make sure your dip tube is intact

Make sure cold is piped to the side of the heater with the dip tube, should be the cold side.

Thank you for the input. I think I've covered these issues.

Wiring has been checked many times. I have tested and shown that power switches properly from the top to the bottom. Plumbers checked the dip tube, it is in order. Water heater is only 2 years old, as well.

Power seems to be working properly, switching from top to bottom.
I set top thermostat to max and bottom thermostat to 0, and i get 209 Volts on the top element and 0 Volts on bottom element.
Then set top thermostat to 0 (off) and bottom thermostat to max, and i get 0 volts on top element and 209 Volts on bottom element.

Your note on testing AC Amps is interesting, this is where I'm short on knowledge. I can determine the Voltage and Ohms (resistance) at the element. Doing the math, as you say above correctly it comes out to 3100 watts or just under 15 amps.

Are you suggesting that that is not enough? That even with a reading of 209 volts and 14 ohms - it still may be drawing a lot less than the 3100 watts, and thus not heating the water?

if so, not sure how i test actual amperage - can this be done with a standard multi-meter?

again, thanks for you input/help.

 

[Twowaxhack]

Voltage doesn’t indicate work being done.

Amperage shows energy being consumed.

electric water heaters are simple to work on but you need the right meter.

You need an AC clamp on amp meter. You set it to AC amps then clamp it around one wire of the element. Power on and voltage applied. This should give you an amperage reading .

 

[TomFOhio]

Does your meter have a clamp on device on the meter or seperate. Harbor Freight sells them for people that may check
it once in a while. That is what you need to get amp draw.
Sorry TW you beat me to the draw.

 

[pgrillo]

Thanks, was feeling like i needed to measure actual amps. I'll go out and buy one. Not to get ahead of this but, let's say i get a reading much lower than 15 amps - even though voltage and ohms do not match that. Not much happening between the breaker box and the water heater. What might cause that? Is that an energy supplier issue?

again, thanks a lot for this valuable advice and input.

 

[Twowaxhack]

Then I would suspect a bad element.

But there’s no need to guess. Get an AC amp meter and while you have voltage at the element clamp the meter around one element wire and read AC amps. Then do your math. If it’s lower that expected. Replace the element.

You should check voltage by touching each probe to your two hot wires at the same time.

 

[pgrillo]

rechecked voltage. checked current using clamp meter while live. It reports 15 amps running through wire on element. Checked first top element with voltage active, then bottom element after turning top thermostat down and bottom up forcing a voltage reading on lower element. 15 amps on both.

So still stumped, where is the energy going? not heating the water...
Had replaced both elements already, and was seeing this with previous elements as well. Could do it again... I'm at a loss...

 

[Twowaxhack]

If it’s pulling 15 amps then it’s heating the water. That amperage proves electricity is being used, if electricity is being used by the element then it has to be heating.

Turn the cold water off to the heater and go to a hot water faucet and bleed the pressure off. The water should stop after the initial surge.

Make sure that happens.......report back.

If it never stops then you have a cross connection between hot and cold.

Are you sure you don’t have a hot water leak ?

 

[pgrillo]

turned off supply to heater, nothing comes out of any of the hot water faucets. seems good.

leak.. which I've been thinking about.
small condo, 1st floor slab. 3 sinks and two showers. Haven't seen any indication of a leak. But yeah, that's still a question. Not sure how to check if it's hidden.
I can get a plumber in here to check. I believe they can check for a leak using some sort of pressure on system? Does that make sense?

 

[TomFOhio]

Are any of your floors extra warm??

 

[Twowaxhack]

Turn the cold water off to the water heater again but DONT relieve the pressure……

Wait about 10 minutes and then turn the cold water to the water heater back on…..

If you hear a “ swoosh “ of water filling the heater, then you have a leak.

 

[pgrillo]

Turn the cold water off to the water heater again but DONT relieve the pressure……

Wait about 10 minutes and then turn the cold water to the water heater back on…..

If you hear a “ swoosh “ of water filling the heater, then you have a leak.

Where do old retired software engineers go to die? They show up in a plumbing forum trying to figure things out and is clueless .. that would be me, ha ha.

That's interesting suggestion, it relates to my next thought on how to confirm a leak.

Earlier I was asked to turn the cold water off to the tank, then open a hot water faucet - and it should not deliver any water? It did not.
If that is the case, why would it not be the case that if i turn the cold water off to the tank, that any leak in the system would likewise stop? Just wondering.

I can do that first test ... I was thinking if my above thought was true (and it appears it isn't based on your suggestion) I could turn the cold water off, the water would stay in the tank, and then would be heated to temp and eventually heater turns off, hot water in the tank - until I let cold water back into the tank to force hot water out - along with the leak.

 

[Twowaxhack]

The water heater uses cold to force the hot out of the heater.

If you turn the cold water off to the heater the system should stay pressurized.

If you turn the cold water valve off to the heater and the hot system has a leak the pressure will drop to zero.........then when you turn the cold water valve back on you will hear the system pressurize.

If you don’t have a leak you will not hear water filling the tank.

Of course you can’t turn on any hot faucet in the mean time.......

If you do have a leak on the hot side, leaving the cold water off to the heater for a couple hours should allow a full tank of water to heat up. Once you turn the cold water valve back on then you can use it......of course the leak will also be consuming your fresh heated tank of hot water.

 

[Twowaxhack]

If you have a water meter you can also watch for leakage at the meter. You can turn the cold water valve off to the heater and watch the meter stop registering the leak, then when you turn the valve back on the meter will show the leak again.

 

[RS]

What country are you in? All the residential water heaters I've dealt with are either 120 or 240 volts? It should have the required voltage on the label. But even the lower voltage should heat the water to the setpoint eventually.
You need to find some one to troubleshoot the problem and not just change parts.

 

[pgrillo]

What country are you in? All the residential water heaters I've dealt with are either 120 or 240 volts? It should have the required voltage on the label. But even the lower voltage should heat the water to the setpoint eventually.
You need to find some one to troubleshoot the problem and not just change parts.

St Petersburg, Florida. This water heater problem that reads 209 Volts is at moms condo. I have a place here too, and I get about 210 Volts. So, I suppose not so uncommon here. Still, pulling 15 Amps should be sufficient, even if it takes a bit longer.

 

[psklein578]

Sounds like you need an electrician. Maybe you have a bad breaker for the water heater in the panel.

 

[pgrillo]

Sounds like you need an electrician. Maybe you have a bad breaker for the water heater in the panel.

The issue at hand has been no hot water, barely warm at best. As I mentioned, another water heater registers 210 Volts and I get perfectly hot water. At this point it's looking like a leak, and that's unfortunate because it'll be real difficult finding where with condo on 1st floor slab.
But first I need to confirm which I'll be doing this morning.

I have a feeling that the low voltage is the local power company issue. I may look into that separately, but like I said it doesn't result in no hot water, it's still pulling over 3000 watts which slows it, but still hot enough.

 

[wpns]

What country are you in? All the residential water heaters I've dealt with are either 120 or 240 volts? It should have the required voltage on the label. But even the lower voltage should heat the water to the setpoint eventually.
You need to find some one to troubleshoot the problem and not just change parts.

208 is the voltage you get across two phases of a 3-phase system. Most (all?) “240-volt” appliances work just fine on 208, it’s not that uncommon.