Can a home’s 240-volt circuits be bad?
I’ve had 2 electric water heaters fail the same way: Temp/pressure relief valve starts releasing occasionally over a period of months, then one morning I wake up to no hot water and a tripped hi-limit/reset control on the upper thermostat. This time there’s evidence of overheating at the thermostat, with melted plastic and foam, and charred insulation on one of the hot wires to the heating element. I can reset the heater and it will work long enough to heat a batch of water, then trip again. The panel’s 30 amp circuit breaker never trips.
I’m going to replace the heater today under its lifetime warranty (it is only 5 years old), but I don’t want the new one to become the third quick fatality. Since a plumber exhausted the plumbing issues the last time this happened (tested water pressure and installed expansion tank), I started connecting some dots about our 240v power and wonder if this means anything:
1) My water heaters seem to overheat (although they are set to under 120 degrees and I have very soft water with little mineral buildup)
2) My electric range burners sometimes overheat to the point of scorching pans. (I always assumed this was bad range controls, elements or receptacles.)
3) My electric dryer has always seemed to run at the same fairly high temperature, despite its 4 heat settings. Even the lowest “delicate” setting is quite hot. (I always assumed this was just a faulty dryer.)
4) My heat pump had an electrical component failure a few years ago, but seems to run well ever since replacement.
These are all 240v appliances. Could the house have a problem that somehow supplies too much voltage to these circuits? The 120v seems okay (light bulbs seem to last the normal time, and my sensitive electronics have had no problems.)
It’s a 1970s house, standard 100-amp 240v 3-wire electrical panel (although the meter says “CL 200”–not sure if this means 200 amp). I would hope it was wired by a licensed electrician, but I’m not the original owner, and I’ve seen some obvious DIY work in some parts of the house. Also, several years ago the power company re-laid some of the underground cabling because “it had deteriorated in our acid soils”.
Any insights? Thanks for your help.
Replies
I'g guessing the other items are over-sensitivity to the failures. Most appliances are set to run + 10% - 15%. You'd be snapping lightbulbs with astounding frequency like each lamp each month. A Volt Ohm Meter would tell you the voltage you are pulling. Go out and get one if you are suspicious. How about the neighbors? anyone else wasting electricity to heat water with the same problem?
You near a factory? or a big power user? Sometimes voltage is boosted in the AM by the power plant to enable startup on the grid of many industrial locations. It is a pre-emptive strike by the power company to combat the power lag that occurs when 50 and 100 + hp electric motors start up at 7AM each day. Voltage drops in an industrial grid with this kind of load. That is why the utilities charge industrial users for not just the power consumed cumulatively (like our home meters) but also for the Peak usage, and the power factor. Industrial accounts get the message when they get these upcharges to their bill. Often the upcharges are 3x the cumulative power bill per month.
Most likely in your case the electric heating element is running dry, or it was a cruddy electric water heater. When you take out this heater take a couple of tools and remove the heating element. If there is a crusty halo of minerals on the elements then that is the final arbitrator of whether you have minerals in your water. If it just boiled dry (good symptom as to the pressure valve discharging) then the element will only sustain heating without a load for a short period of time.
If you are on a well, possibly your pump is sucking air and filling the tank with air and you are draining the tank below the heating elements.
All speculation on my part, but these are things to check out.
Final PS. Why not gas for the water heater? It is at least 1/2 the price to run.
Thanks for the ideas, Booch.
Most likely "cruddy water heater" is the cause. It was made by that big outfit in Tennessee, sold by Lowe's for about $280. Does that make it cruddy? Others have told me they've had problems with thermostats going bad on these homecenter-type water heaters.
I'm out in a rural residential area, so I doubt it's the industrial effect. And I'm on city water so I don't think air caused it. If the element went dry, would it be dead for good? I'm able to reset the heater and both elements work as long as I keep the thermostat set low. (By the way, the water released out of the TP relief valve was never very hot--I could easily keep my fingers in it. So I always thought excess water pressure was the poblem, not heat.)
Finally, I'd love to use gas, but we have no natural gas line here. Propane isn't much cheaper than electricity for this purpose overall, is it?
You wrote:
Most likely "cruddy water heater"
Others have told me they've had problems with thermostats going bad
Strange but I have a buddy i helped change his and after 3 years he had to adjust the thermostat to get it to run as it just stopped working. By setting it up a notch it worked again. (Sounds like a bad potentiometer to me)
If the element went dry, would it be dead for good? Hell Yes, electrical heating elements are only as good as the heatsink. That is why they use thermal grease on CPU's to industrial heaters. When the heat doesn't transfer the electricity runs uncontrollably to the "heating element" without the benefit of warming the thermostat or heat sensor that shuts down the electrical circuit that makes the heat. 5 minutes will toast the element as the insulation inside the heating element breaks down and the element shorts to the body of the heater or it burns the element open.
I'm able to reset the heater and both elements work as long as I keep the thermostat set low. Sounds like the thermostat to me, at least that is where I'd look. 4lorn1 seems closer to the mechanisim of these read his post carefully.
Finally, I'd love to use gas, but we have no natural gas line here. Propane isn't much cheaper than electricity for this purpose overall, is it?
Hell yes, Propane is way cheaper!
Theorize with me. We take coal adn burn it to make steam. then we turn a turbine to make electricity. By the time it hits your house 40 percent of the energy in the coal is lost either due to Physics, inefficiencies in the process, or just line loss due to resistance. Physics says each time you change state with energy (chemical to heat to mechanical to electricity to heat ) you lose a little bit. It doesn't matter if you are in a laboratory or a factory the Carnot equation determines the losses at each stage. Simple actions keep entropy at bay. I'd estimate you pay 1/3 the price of electricity. Look at the orange tags on the water heaters at HD if you need proof.Jack of all trades and master of none - you got a problem with that?
That is all true, BUT don't know of a coal buring hot water heater.
And some electricity is generated by water power.
So you really need to check the specifics in YOUR area.
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There comments. Being on a rual line might be worse. I have heard where the power companies boost the voltage up so all of the milking machine will work at 4 pm when they start milking the cows. If would not hurt to call the power company and see if they will put on a power quality recorder for a few days.
Check the water pressure. Some areas run high.
And many water companies are now adding checkvalve or if you have a pressure reducer they act the same way. You have a "sealed" system and when cold water is heated it expands and the pressure goes up. That is the reason to use pressure expansion tanks.
Ok My point on a coal plant is mis stated. As the Midwest is changing to Natural Gas fired plants as well as the wind, Nuclear, even methane generated electricity the fuel point is an idle argument. The fact that coal is extremely abundant compared to other fossil fuels made me select it as the fuel of default.
I reinterate the Yellow Department of Energy tags on every appliance gives the dollars and cents comparison for all types of water heaters. In particular our friend should compare electricity to Gas of any type. BIG difference in the wallet, and in my opinion on the environment.
Excuse the RANT The argument that electricity is cleaner sits in only one area. That is the power company runs a more environmentally efficient power plant than your Briggs & Stratton generator or your fuel powered implement. In many cases this is true, but when we talk about burning Natural gas or propane the argument is not very sound. The fact we have transmission losses costs the environment in wasted energy. 10 to 15 percent is lost to resistance on the power line between the plant any your point of use. Turning fuel into heat and spinning a generator to make electricity loses 40 percent of the available energy in the fuel.
The other points you make on voltage differences and pressure are good. If it helps the homeowner sleep better he ought to start there.
Jack of all trades and master of none - you got a problem with that?
> in wasted energy. 10 to 15 percent is lost to resistance on the power line between the plant any your point of use.
Do you have a source for that 10 - 15% figure? I've heard estimates as high as 50%. This is a really difficult thing to get an accurate number on.
-- J.S.
Jeeze, you are really stretching me on that. I was graduated in 1979. I'm pretty sure the book is no longer in my posession. (the physics book I do have)
We did a Boyscout electrical badge a bit ago with my eldest and the transmission loss was mentioned in that discussion. Being that it was a tour of the Nuclear Power plant in Kewaunee WI, and the current state of powerplant visits I'd bet that source has dried up as well.
Power+transmission+loss "Googled" yields many things. About 1/2 of which I cannot follow, thinks like scatter charts etc.. This is the realm of power problems well known since Edison's day. In fact he was fond of DC as there was less loss over a distance (I think) but the transforming issue made AC the power source of choice. You can't transform DC easily.
Wish I could answer the question more directly. I just remembeer the qualitative information that energy changing state, makes waste. And that transmitting energy also makes waste. I'll bookmark our discussion and when the weekend is over I'll put some effort to finding the complete argument.Jack of all trades and master of none - you got a problem with that?
Propane is a good deal. Local costs are about $1.50 gallon bulk delivery right now. At 92,000 Btu/gal that is $16.30 a million Btu. With an 80% efficient WH, $20.38 in the water. Local residential electric is $0.11/kWh or $35 a million (3,413 Btu/kWh). Electricity is almost 100% efficient.
A figure that DOE uses for electric transmission losses nationwide is 7%. Fuel to Wire effieciency of a modern coal fired plant can be as high as 43-44%. In plant auziliaries will consume 5 to 8%, (things like boiler feed pumps, cooling tower pumps and fans, forced and induced draft fans, etc). Thus by the time the electron hits your meter the energy is packs is down to about 30%. (For energy studies we generally use a source energy figure of 11,000 Btu/kWh or 31%. Modern gas fired combined cycle gas turbine generators have initial efficiencies near 60% and plant auxiliariy uses are less.
Edited 5/23/2003 12:32:03 AM ET by JANATION
What's the "big outfit in Tennessee"?
I am likely buying an electric HW heater tomorrow for my parent's place. I get a decent price from my plbg wholesaler but am sort of on the outs with them over a toilet issue and was thinking about hitting Lowe's.
remodeler
I bet he is referring to State Industries. Plant is located near Nashville.
Actually the Lowe's water heaters I got were made by US/Craftsmaster in Johnson City, TN. The one I got last week was branded Whirlpool.
It's 50-gallon electric with lifetime warranty on parts and tank for $278. It has some "fancy electronics" on top instead of the simple thermostat wiring, which worried me a little. But so far it's working fine, and with the warranty I guess I can't complain. I did replace the cheap plastic draincock with my own 3/4" ball valve so periodic draining/flushing will be more effective.
Good luck!
Russ is it to late to swap out the ball valve with a boiler drain cock?
Less problems down the road. Ball valves seem to break down early in their lives under prolonged heat, pressure and with infrequent use.
Hmmm. Thanks for the tip. I actually got the idea for using the ball valve from an article in Fine Homebuilding magazine (Nov 97 #112). I wonder if anything was published in a later issue to refute the idea. I don't think I ever saw anything.
Is a hefty full-port all brass valve going to be that bad?
Kind of off topic, I wonder if the FH back issues on CDs contain all the followups, corrections, letters, and other dialog referring back to original articles. If all that was indexed on the CD, threaded similarly to these forums, that would be valuable.
Don't know the CD for FHB. Never been there.
I changed out two ball valves after they failed. Seemed as though the minerals and other sediment type crud scored the seat and ball when the WH was flushed. My guess is the gunk that had built up against the ball and was baked in scored everything when the valve was opened.The valves just leaked some afterwards.
The drain cocks I put in have been trouble free for years. One was on my WH [9 years] and I took off the SS bodied valve that I had put on. I put on 600 WOG boiler drains in place of the ball valves.
Where do you get the drain cocks? Make and model? I just got finished replacing the plastic POS on mine with a Red-White 3/4" full bore brass ball, after draining the tank completely and even scraping and flushing the crud out the hole using a coathanger. At least I no longer hear the bubbling sound when I turn on the hot water.
-- J.S.
Every body that sells ball carry boiler.
I used a Watts. Part number unknown.
Super wide range of configurations.
I got mine at the local wholesaler, about 6 bucks.
600 is the psi rating and WOG stands for Water, Oil, Gas.
Numbers go to 2500 and letters to WOGS before you get really serious.
Bigger numbers - better valve. Imports just don't cut it.
If you want to clean the bottom of the tank again use an over sized weapons brush with a hook bent in it. Coat hangers are a little rough on the glass lining. Trickle the water as you drag the gunk out. Kiss the brush good bye.
Thanks -- I'll get the Watts for when we're ready to move the WH.
-- J.S.
There are many seemingly contradictory pieces of evidence but none that you cite are strong evidence for voltage problems. Electric water heaters are relatively simple and very rugged.
First it is vital that the water heater not become a run away boiler. If it did the tank could explode. This sort of failure can be catastrophic. I have seen photographs of the aftermath. A set of stairs leading up to a bare slab. The house was blown apart. There are a few interlocking and redundant safeties designed to keep this from happening.
The electrical heating elements are controlled by thermostats. When the temperature of the water reaches the set point these are designed to stop the flow of current to the elements. There is also a high limit switch that has to be reset when the tank temperature approaches dangerous levels. This, when triggered, cut power to the elements. If both of these should fail the temperature and pressure, T&P, valve is designed to vent water and pressure from the tank well before its burst strength is reached or the water can turn to steam.
The T&P valve blowing off might indicate a faulty valve especially when you say the water comes out relatively cool. On the other hand you might be catching the aftermath of a situation the T&P was designed to stop. If the temperature and/or pressure build up the T&P is supposed to vent. The valve might be doing its job and then just not reseating. A small flow could continue for some time. Here again a newer valve might close more reliably.
It sounds like the thermostat/s are not working. Either they are worn or damaged or they are being bypassed. Bypassing can happen, a relatively rare problem, if the elements are damaged and are shorting to ground or the other element. This can mean they are always on. This may mean that the limit switch on the thermostat is dong its job.
Of course all of these symptoms could be caused, or be made worse, if the tank is limed. The elements, limit switch and thermostats are all designed to be exposed, through the tank wall for the controls, to a large volume of water. Liming can compartmentalize the tank. The elements can be surrounded by just a fraction of a gallon of water. When the element, oversized for so small a volume of water, turns on it boils the water. The overheated and rapidly expanding volume hits the limit switch it can trip and the steam can raise the pressure enough to blow the T&P. Lime particles can also prevent the valve from seating correctly. A heavily limed tank is best replaced.
If this water heater is more than a few years old, unless it is a premium model it might be best to install a new one. Lifting the ground and checking for voltage between the tank and ground will often tell you if the elements are leaking voltage. If a ammeter is handy it could be used on the connected ground to check for much the same thing but current in this case. A zero reading on both of these would be ideal. A bit of leakage is normal, especially on older or large commercial models. Anything more than just a bit is a sign that one, or both elements, are damaged and need replacing. This will also allow you, once the tank is drained, to check the inside of the tank, a small flashlight and mirror helps, for lime, rust and the condition of the anode.
Thermostats are easy to check and replace. You run hot water from a fixture and listen with your ear to the tank. You will hear a slight hissing sound as the element kicks in. Wait and, if it is working the thermostat will turn off the power when the water is hot enough. Check a second thermostat, the upper one, by bypassing the lower control and running the same test. Either or both thermostats are easy and cheap to replace. It just takes time. If the tank is sound and fairly new, and your sure it's not limed replacing a damaged element can be done without draining the tank. With a bit of dexterity only a few onces are lost.
You mentioned charred insulation on the wire/s to the thermostat. This is most likely cause by a loose or poorly made connection not the tank overheating or anything but very extreme over voltages. This heating, if it is close to the limit switch, could cause the limit to trip even when the tank is working normally.
Just a suggestion on the T&P valve.
Our water heater was going through about 1every year to year and a half. They'd just pop open for no apparent reason, and they never seems to seal right once they've opened. The second one I replaced, the plumbing supply store guy recommended I put in a small pressure tank on the hot water side of the water heater to cushion hot water expansion. He said that if you have that problem a lot it's often because of pressure build up in the tank as the water heats & expands. Eventually, pressure hits the point the valve opens.
The tanks only cost $15-20. Seems like a good idea on all water heaters to me, though it's probably overkill. But, the stupid valves cost $10 each, and the mess is a pain, so I look at it as cheap insurance.
Here's the followup to my original post--it's not a power problem, but at this point I think I'd rather heat my water in a clay pot over an active volcano!
Yesterday I installed the replacement water heater (the warranty really paid off here--got a new Whirlpool from the homecenter, continuing the lifetime warranty with no hassles other than my labor.) We took our two hot showers this morning and were happy. But I just came home for lunch and found the new T&P relief valve releasing water again, just as with the old heaters!
I quickly measured the pressure at the heater's drain at 160 psi. Then at the nearest faucet I measured temperature at 118F degrees (just under where I set it). So obviously there's a pressure problem, as opposed to overheating.
But this puts me back where I started last year, when I hired a plumber to track down the problem: He tested my water pressure, said my pressure regulator was fine at about 50 psi. He installed a 2-gallon expansion tank on the cold side of the water heater. I later changed this to 5-gallon when the smaller one didn't do the job. The larger one worked fine until a few weeks ago, and it's the one I'm reusing now. (I made sure it was still pressurized at 50psi first.)
So now I'm baffled as to how I can have pressure buildup as the water heater heats a batch, even though I use a an oversized 5-gallon expansion tank (2-gallon should be fine for a 50-gallon heater, according to that plumber as well as the heater's instructions).
Two questions:
1) This new water heater came with "heat trapping" water connections. I believe these are little balls that somehow "seal" the water inlet/outlet to prevent hot water from convecting out of the tank. I know I'm missing something here, but what's to prevent them from sealing so well that the expanding water is trapped in the tank, unable to reach the expansion tank?
2) I can't think of anything else to try. I could replace the pressure regulator on my main water line, but if high city pressure is getting through this regulator sometimes, why does it always coincide with a water heating cycle?
And thanks to all for your previous thoughtful responses.
Have you tried asking whirlpool for ideas?
Now I'm really curious. I was told the pressure tank should be on the hot water side of the water heater. And I havn't a clue what a heat trapping connection is.
WetHead?? Do you install pressure tanks on water heaters? I saw the picts of your radiant heating system with one (Very Nice), but is it anywhere near standard for WH's?
The heat traps will not keep the pressure in the tank. They are not check valves. What is the pressure charge on your expansion tank? It should have a bladder in it with an air cushion. Are you sure the air cushion has not leaked out? It your heater has a blocked cold water line from the water supply...check valve or such, high pressures can be developed by the expansion of the water while it is heated. That is not really a problem with your heater, it is a problem with your plumbing.
Bill
Whirlpool doesn't have anything on its website about the heat-traps, but Rheem does:
http://www.rheem.com/Documents/ResourceLibrary/TSB_Common/1214.pdf
I was beginning to think my cold-side trap was blocking the expanding water from reaching the expansion tank, but this Rheem document says the seats have bypassess to allow for expansion. This confirms what you stated, WRHoover. And it doesn't make sense that these things are at fault, else every water heater using them would be blowing its T&P valve. (But the what-iffer in me asks, "Can I have a bad fitting whose bypass is stuck closed?")
As for the expansion tank, it's less than a year old and I tested it when the system was pulled apart yesterday--pressure in the air bladder was still 55psi, same as my water pressure. And there's nothing between the expansion tank and the cold water inlet of the heater--except that heat trap fitting.
BillyG, I too have seen conflicting info on where to install the expansion tank. My plumber put it on the cold side, and the water heater instructions confirm this. But putting it on the warm side would seem to avoid any heat-trap problems.
I still don't know what to try next. I need a beer.
The plumbing supply guy who recommended I add one couldn't remember, so he looked it up. The color brochure he found showed it placed on the hot water side. Which makes more sense to me, as it wouldn't have to deal with the valve you're talking about, and it's the hotwater that expands. But, not being a plumber I'm not sure this is correct.
Maybe it really doesn't matter. When water pressurizes it exerts equal pressure in all directions. You've complied with your water heater instalation instructions anyway.
I believe putting the expansion tank on the cold side is the correct place to put it...it likes cold water a lot more than hot water. I hate to tell you this...water heaters with heat traps have the traps on both the inlet (cold) and the outlet (hot).
One way to check the heat trap issue is the remove them and see if the system works OK.
Water boils at 212 F considering normal pressure in the air. in a pressurized system it would be even higher than that. To that point It isn't your setting of 160 nor the electricity.
Did you do the hookup? Possiblty do you have the inlet and the outlet pipes reversed? Could be trapped air in the tank but it would be the first time I heard of that.
Why do you have a pressure tank with city water?
What is with the pressure regulator? All you do is restrict pressure you don't make it with a regulator.Jack of all trades and master of none - you got a problem with that?
Final resolution from the original poster:
It was a bad pressure reducing valve (PRV) that caused the T&P relief valve to release water. I installed a repair kit for my Wilkins PRV and all problems have disappeared for several days now. (I was impressed that Wilkins still supports this 12+ year-old PRV. Just about all the guts of the valve are included in the kit, for about half the cost of a new valve. Took less than an hour to install.)
Lessons learned:
1) Pressure reducing valves are not maintanence-free.
2) Contrary to what my plumber said, they are not a go/no-go item. Mine tested at good pressure most of the time, but let pressure gradually build when water was not used for long periods, like overnite. Eventually the expansion tank could absorb no more, so the T&P valve released.
3) The heat-trap fittings work fine and don't interfere with expansion tanks on either the hot or cold side.
Thanks to everyone for your help!