My Daughter Needs Help With Her Electric Water Heater (I'll leave it there)

Steve Thompson (Taco)

She has a Bradford White electric water heater in her house that keeps tripping the breaker. Replaced the heating element, both top and lower t-stat control, had it re-wired and replaced the properly sized breaker - and it still trips.

I shot my mouth off that being in the industry I could get some expert advice. Can any of you experts give me some ideas on the cause/solution?

Figured if anyone might know it be yous guys...

Tinman

Intermittent short to ground?

Robert O'Brien

Replaced both elements?

Tinman

Not big on parts replacement. Was it proved that both elements aren't banging on at the the same time?

Gordy

Which element was bad Both? visibly bad, or failed an ohm check?

Breaker trips right away. or does the heater run for a bit then trip breaker?

BobC

Does the breaker trip at any given time or is it truly random? Were both upper and lower elements replaced?

It may take some sleuthing about with a ampprobe.

Bob

Ironman

If the WH is NOT drawing more than its rated amperage (19a for 4500w), then the issue is in the wiring, the breaker or the panel. It could also be a chafed wire in the heater.

Please get a tech that knows how to diagnose with a meter instead of a parts changer.

lchmb

"had it re-wired" as in the unit or power from the unit to the panel? Amp clamp and a meter could help solve it..where's she located? I help family (consider that anyone in this lovely buisness) free

Steve Thompson (Taco)

Wow, you guys are really awesome. I'll break out my troubleshooting meters tomorrow.

The wiring was replaced between the heater and the panel by my son, who is a journeyman electrician. He's really good at electrical stuff, (yes, I'm biased) but not "an expert" on electric water heaters (nor was the last service guy that looked at it).

She's up in Calgary - might be something with the metric power :-).

Steve Thompson (Taco)

BTW, the heater runs for a while then the breaker trips. My spidey sense is thinkin something happens when the heater is satisfied.

BobC

Anything in the chain is suspect, pull any wiring away from ground and consider it could well be a thermostat as well as a heating element.

They are on 60z so it looks like metric power is absolved in this instance

Bob

JUGHNE

If cold or cool start, top element heats upper 1/3 of tank then switches to the lower element which could be shorted out.

Or wiring controls wrong running both elements at same time.

Gordy

Do an ohm check on bottom element.

hot_rod

Check the wattage on the elements 4500 to 5500W will hold on a 30 amp circuit, 6KW may not, depending on your actual voltage.

ChrisJ

From what I recall a hardwired appliance such as a water heater is subject to 20% derating so a 30A circuit shouldn't be driving more than 24A or 5760W @ 240V.

I believe this is because under certain conditions, such as high ambient the breaker could trip prematurely.

Zman

Stephen Minnich said:

Not big on parts replacement. Was it proved that both elements aren't banging on at the the same time?

This is where I would start. That or an intermittent ground, possibly a damaged wire.

JUGHNE

If this has been in use for a while and is a new problem, my bet is on a bad lower element.

Gordy

Steve was there a lot of sediment in the bottom of the tank when you changed the lower element? If so did you clean it out?
You probably would have noticed from a painfully slow drain.

What happens is sediment builds up to the lower element, and does not allow enough water around the element there for it rapidly burns out.

Another thing to try is a lower density element if the bottom one is burned out again. Low density elements are longer have the same output, but do not get as hot.

SWEI

While you're at it, replace the boiler drain with a full port ball valve. This will make clearing the accumulated scale actually possible.

hot_rod

How old is the tank? At some point replacing all the elements, wiring, controls, drain cock, etc... just saying

kcopp

hot rod said:

How old is the tank? At some point replacing all the elements, wiring, controls, drain cock, etc... just saying

Really... at some point a new tank may be a whole lot easier/ less of a headache that chasing a bad part.
Unless they like the challenge... thats cool too.

Tinman

I get what you guys are saying but in terms of parts, there's only a few on an electric water heater.

Harvey Ramer

The sequencer at the top element is a double throw and won't allow both elements to operate at the same time.

First thing to do is verify the current draw of the circuit is correct. Check both legs. They should be the same.

If they are correct, check the breaker. If it is warm/hot to the touch when it trips, it's tripping on current draw. Bad breaker. If it is cold when it trips, it is tripping on a fault.

Finding a fault or excess amp draw, will require a continuity tester. Disconnect the electrical cable in the junction wiring box but leave the equipment ground connected. Check for continuity between both heater wiring leads and ground. Ohms reading should be infinite.
Remove wires from upper element. Check the resistance of the element and verify against the wattage. Check for continuity between both terminals on the element and equipment ground. Should be infinite. Check for continuity between wire leads and from each lead to ground. Should be infinite.
Repeat on lower element.

If you don't find the problem with this procedure, go take a nap. When you wake up, go buy a new water heater.

hot_rod

All tanks leak at some point, if the tank is 10 years old, and has seen a lot of hard water, and the bottom is filled with sediment??

Be a nice dad and buy her a new tank

Paul48

Nowadays...after 7 years, you're on borrowed time.

BobC

If you flush it regularly and replace the anode rod every 3-4 years you can extend it's working life.

Bob

Paul48

That requires a discipline, and personally, I'd rather shove $2 a week in an envelope, and go fishing instead.

JUGHNE

Just to remind myself the blessings of having good water:
Our 1994 tank that may have been drained 5 times in it's life here and still looks good.
The 1984 NG water heater that a lady wants me to change because it sounds like a coffee pot, no leaks. Never been drained, can't open the valve. Had it been drained she would never know it is down there except for the failed T-couple last week.

Anode rods are just about never changed. Did change some on comm heaters once, 320,000 BTU lasted 25 years , changed tanks because glass lining was breaking down inside tank.

hot_rod

Reminds me of that Muck Vac tool that hit the market years ago. You fished it down a top connection to suck out all the sediment in HW tanks. Promoted to increase efficiency and extend tank life. Turns out in some cases the tanks failed shortly after the expensive and time consuming vac job. The sediment was the integrity of the tank.

If you compare the weight of a modern tank to an 10 or 20 year old one they certainly have "shrunk" the tank and coating thickness probably.

Gordy

Seems to be a lot more lime scale debris on the bottom of electric water heaters. Water qualities being the same as for a gas fired one.

ChrisJ

hot rod said:

Reminds me of that Muck Vac tool that hit the market years ago. You fished it down a top connection to suck out all the sediment in HW tanks. Promoted to increase efficiency and extend tank life. Turns out in some cases the tanks failed shortly after the expensive and time consuming vac job. The sediment was the integrity of the tank.

If you compare the weight of a modern tank to an 10 or 20 year old one they certainly have "shrunk" the tank and coating thickness probably.

Figures.
My grandfather had a cheap 30 gallon atmospheric heater go 30+ years.

Now you spend $1000+ on a power vent model and expect it to die in 10.

SWEI

Gordy said:

Seems to be a lot more lime scale debris on the bottom of electric water heaters. Water qualities being the same as for a gas fired one.

Smaller HX area = higher ΔT and faster scale accumulation. As the element heats up and cools down, it expands and contracts, breaking off the scale, which falls to the bottom. If you look closely, you should see a curved profile on the scale flakes. It only takes a bit to clog the drain valve, but they will pass easily through a ball valve.

Gordy

Exact discription Kurt.

JUGHNE

Or because the entire bottom of a gas heater is heated up then for the first few years the movement of the water just above the fire puts sediment & scale in motion and some of it passes out of the tank with use. Eventually the scale overpowers the convective power of the water and settles down and eventually talks to you like the coffee pot.

The deceiving tanks that remain silent are with the power burners on top shooting down thru the center heat exchanger.
All the junk settles to the bottom and with no fire under it to boil the steam out of the junk there are not warning noises. One AO smith power vented tank had 6" of sediment inside and never made a sound.

Gordy

I have an electric in my rental property. I went through a very similar thing Steves daughters is doing. Of course with a tenant the worst is no hot water, and with the painfully slow drain from sediment build up the first couple times I just replaced the element to get them going. Then the bottom element burn out became more frequent.

All wiring checked out. So the last time it took place the tenants went out of town. I took the time after the drain down to suck out the sediment best as I could through the element port, and installed a low density element. No trouble since.

So my theory is since the regular element always worked then it has to be the sediment that builds up to the bottom element , and does not allow enough water around it there for it over heats. The low density element was just a precaution so when the sediment builds up it will not burn out as fast.

SWEI

JUGHNE said:

One AO smith power vented tank had 6" of sediment inside and never made a sound.

Similar experiences here. As long as we get to them early enough, flinging the ball valve open under line pressure, then closing, repressurizing, and repeating will often clean them out. It's common to net about a shoebox worth of cal-mag from this.

I have seen several fully drained tanks that weighed well over 200 pounds. They were not savable.

ChrisJ

Is my Bradford White 50gal power vent designed like that? I assumed it was just a normal 50 gal tank heater slightly modified?

Steve Thompson (Taco)

OK - the saga continues... (BTW, my issue is if we replace the heater there is no guarantee it will fix the problem).

First, thanks to Dustin and the tech service department at Bradford White - really excellent crew.

Here's where I'm at. Elements ohm out correctly. Lime scale removed (there was a lot). Both 4500 watt (per spec) elements replaced again. Cycled the t-stats - only one element on at a time. 17.7 amps (both are the same) measured at the element and mains going into the heater. No loose or damaged wires. T Stats were replaced a few months ago.

30 Amp breaker replaced and moved to a different position in the panel. 4' of 10 ga new wire between the panel and the heater.

BW and I believe strongly it is a power supply issue but there is nothing common happening when the breaker trips (different times of the day, nothing coming on at the same time etc).

Now what? My daughter is starting to think there is a ghost in the house :-)...

I'm thinking on monitoring the power - opinion?

JUGHNE

So you changed everything but the water heater tank itself?
The internal wiring of the tank is usually buried in the foam insulation of the tank itself. Not impossible that one of those is leaking to the tank. As the temp changes the wires move ever so minutely. A megohmeter test of the wires at the top of the tank shell may show something. I would do this when water is hot and operate the T-stats to pick up the elements, top and bottom. It seems though that if this is the case the smoke would escape out of the heater eventually.

Simpler thing is: loose wires on the breakers will heat up and transfer that heat into CB causing a trip......but I'm sure you have checked that when installing new CB.

ChrisJ

Is there any special reason to not just replace the entire heater at this point?

We tried to fix an intermittent problem my dad's 50gal bradford white power vent heater had and after 3 attempts failing he had enough and replaced it. He needed to depend on it and didn't feel like playing games. It was only 6 or 7 years old too.

ratio

These oddball power issues make me want to pull my hair out!

Are you near any kind of commercial buildings, that may share the power transformer? A large load starting down the street might screw up the power factor right when the water heater thermostat closes. I've asked & asked for my boss to get us a power logger, but the good ones are ...quite expensive. Fluke has a cute one that I'd get myself if I didn't do predominantly 3 phase work.

The megger on the internal wiring is a good thought. I've found intermittent shorts to ground with it, even when it shows clear with a multimeter. Much more effective than replacing the fuse again and again.