How can I properly check to see if a water heater element is working?

[blurredvision]

Our 30-gallon water heater has sucked ass for the past year, so the father-in-law tells me definitively that it's the elements. I go buy 2 new elements (they are definitely the right parts, so no worries there), we installed them this past weekend. Now, it seems the showers in the morning are worse and get colder, quicker.

It's just me and my wife, so surely a 30-gallon tank would be sufficient in the morning for her to take a 10-15 minute shower, then allow me to take a 5-10 minute shower about 20 minutes after she gets done.

What is the correct way to see if an element is even working? I thought about putting a meter up to the wires that are feeding power to the elements, but would that tell me anything about the element itself? I'm hoping there's an easy way to check them without having to drain the entire tank again, but I'll do it if I have to. If it doesn't plug into a wall socket, I'm pretty dumb about electricity and exactly it "works".

 

[Modelworks]

1. check the power to each element, if there is no voltage on it, then turn the thermostat up to see if that turns the element on, if not its a bad thermostat, the voltage should be 120 or 200+ depending on what kind of heater it is.
2. turn off the breaker to the heater.
3. remove the wires off each element.
4. change meter to ohms setting, measure the connections on each element, you should get a reading of less than 1000 ohms., if not the element is bad.

I suspect its the thermostat.

 

[FoBoT]

if you already replaced the elements, then either you left a loose wire or the thermostat is borked

 

[Pepsei]

go with tankless water heater....

 

[bctbct]

Did you try flushing the WH to see if the bottom is full of sediment? That can cause lower temps.

 

[amdskip]

Originally posted by: bctbct
Did you try flushing the WH to see if the bottom is full of sediment? That can cause lower temps.

Yep, if you have a calendar, setup a reoccurring appointment to drain the water heater once a year.

 

[FoBoT]

i have to flush mega crap loads of white rock like stuff out of my tank about every 9-10 months
the water here is loaded with calcium or something

OP probably would have noticed when the lower element was changed out, if it was really bad/built up

 

[blurredvision]

Originally posted by: Modelworks
1. check the power to each element, if there is no voltage on it, then turn the thermostat up to see if that turns the element on, if not its a bad thermostat, the voltage should be 120 or 200+ depending on what kind of heater it is.
2. turn off the breaker to the heater.
3. remove the wires off each element.
4. change meter to ohms setting, measure the connections on each element, you should get a reading of less than 1000 ohms., if not the element is bad.

I suspect its the thermostat.

Thanks a lot...what do I need to buy, a multimeter? Anything special I need to look for in buying one? I've never shopped for one before, I don't know what options (if any) are out there.

Originally posted by: FoBoT
OP probably would have noticed when the lower element was changed out, if it was really bad/built up

I obviously haven't seen many water heater elements in my lifetime, but the lower element didn't look particularly bad. It obviously had some build-up on it, but my father-in-law seemed to think both elements looked fine, and from what I've been told, he's had many battles with water heaters over the years...he knows his stuff. Unfortunately, though, he lives over an hour away, so I can't always ask him to come take a look at it, hence my asking here .

 

[Sasiki]

This multimeter is fine. I have one just like it.. works great for checking standard 110v outlets and such. For $22, can't go wrong.
http://www.lowes.com/lowes/lkn...81-GDT-185A&lpage=none

 

[Modelworks]

Originally posted by: blurredvision
[
Thanks a lot...what do I need to buy, a multimeter? Anything special I need to look for in buying one? I've never shopped for one before, I don't know what options (if any) are out there.

I think this is the best deal out there.
But it ends on 3/1/08
http://www.sears.com/shc/s/p_1...00P?keyword=multimeter
Includes meter + AC voltage detector.

It does everything you need and more and is only 15.00

 

[drnickriviera]

If everything test fine electrically, i'd look at the dip tube. It's a tube on the cold water side that puts the incoming cold water at the bottom of the tank. If it's broken off or missing, you're essentially sucking the cold water off the top of the tank.

 

[blurredvision]

Thanks a ton guys...this is ATOT at it's best.

 

[Paperdoc]

Here's the way many electric 2-element water tanks work. Most work off a 220 Volt supply at 20 amps, so that's about 3000 W or a bit more available. But each element itself is rated at 3000 W, so they can't both be on at the same time. When started up cold, the thermostats turn on ONLY the upper element to heat the upper part of the tank. Now cold water flows into the tank through a long tube down to the bottom, and then up to the outlet at the top. Since hot water tends to rise in the tank, that's where the hottest water is, near the outlet. But once the upper thermostat senses the temperature up there is hot enough, it hands over control to the lower thermostat / element system. That system heats the lower part of the tank until it, too, is hot enough. Then it turns itself off and on as the tank sits idle, keeping the whole tank hot.

Now someone starts to use lots of hot water. At first the lower thermostat calls for more heat. But eventually the upper thermostat senses it is too cool, and it takes control again, shutting off the lower system and heating the upper part of the tank closest to the outlet. This continues until the hot water user quits, and the upper part of the tank returns to its setpoint. The whole cycle continues.

If you have some hot water, but it does not last long, it could be either one of the elements, one of the thermostats, or a wiring fault.

Step 1: Check the supply voltage. With everything connected normally, CAREFULLY (don't touch any live wires!) check the voltage coming into the water heater top thermostat from the supply cable from the breaker panel. It should be about 220 volts AC across the supply. If it is substantially less, your problem is in the breaker or the supply cable. Considering that you say you have some hot water at the start, this seems a less likely problem - most supply line trouble would give you no voltage (and no hot water) at all.

Step 2: Disconnect power to the tank for safety, then do what blurredvision says: disconnect each element and check its resistance. A 3000W heater designed for 220 volts should have a resistance around 16 Ohms. Replace if necessary, re-check and reconnect.

Step 3: Assuming the tank is hot, and with all the electrical connections hooked up normally, CAREFULLY (again) measure the voltage across each element - it will be either nothing or about 220 volts AC. Now open up a hot water tap and let it run to drain continuously. Keep checking the voltages. You should see the lower element come on first, but then it will go off and the upper one will come on. Shut off the tap and watch the voltages change again as the tank heats up. If no voltage appears at one element when it should, you have found the area with a flaw either in the thermostat that feeds it, or in the wires. Don't forget that the lower thermostat and element get their feed from the upper one. So if the lower system does not ever get power, check the wires and output terminals from the upper thermostat to be sure power is being supplied from there.

 

[KK]

We just had to replace our dip tube. We would have hot water but it would only last for about 4-5 minutes before going to luke warm. It was easy to replace and the dip tube was only 10 dollars shipped from the manufacture, rheem. Works like a charm now, only issue is that the old diptube complete was detached and flushing it a few times we still have pieces of the dip tubtube clogging the aerators and shower heads, this will diminsh as the diptube remains clear out of the tank.

 

[NL5]

Yep, as others have said, probably the dip tube......

 

[imported_Baloo]

30 gallons is not sufficient for a 10-15 minute shower, and another 20 minutes later. Holy bejesus! 10 to 15 minutes? Do the math. At about 2 gallons per minute, that's 20-30 gallons. If you do not have a legal shower head that limits the flow, usage is higher. Twenty Minutes is far short of the time an electric water heater needs to heat the cold water in the tank after your wife get's out to 110+ degrees. You need several hours for that. Your elements are working fine, you need either to get a bigger water heater, a second water heater, an on-demand tankless water heater, or have you wife spend less time in the shower.