Upon first landing on the A O Smith water heater home page I thought it was too busy might be difficult to navigate. I still think so.
I checked around and found they have a large confusing array of models with industry typical Energy Factors, tank sizes, and other features. I could find nothing new or exciting on this water heater web site.
I was quite frustrated by the site. It seemed anything worthwhile looking at was in the form of a PDF file, something I don’t care for. I had the impression that the site is more oriented to professional plumbers, not the everyday lay person.
No mention of prices. Typical warranties. Typical features, glass lined, anode protections, long-life 4500 watt heater elements, and they do have brass drain valves… at least that is something. If you have ever had one of those plastic drain valves break off you will appreciate the brass valves.
A. O. Smith, like the other water heater manufacturers claim a super duper self cleaning dip tube. As I have said before, there is no such thing. No dip tube can clean your water heater. Self cleaning dip tubes just don’t do anything.
They have a few tankless water heaters and models specifically for homes with hot water circulating systems and hydronic heating etc. I think it’s time I move on to the next hot water heater manufacturer on my list. Let’s see… Ah yes… this time it’s off to visit Bosch water heaters… well, their web site anyway.
Bill the Hot Water Guy
Wednesday, September 30, 2009
Saturday, September 26, 2009
American Water Heaters
American Water Heaters.
This blog will probably be as much about the American Water Heater website as it is about American water heaters. I figure I might as well evaluate the site. Let’s see which water Heater Company gives us the best user experience, or at least gives me the best experience.
Upon first landing on the home page I found a site that is clear and concise. It’s easy to locate where I want to go and no distractions. They have contact information including 800 numbers with hours of operation listed. So far so good.
I clicked on “Products” in the upper right nav bar, and voila! I landed on the Products page where I could choose between gas, and electric and residential or commercial water heaters.
I clicked on the “Residential Electric” link, and landed on a page of listings of water heaters.
Electric Water Heaters
Basically, they have water heaters holding from 2.5 gallons to 119 gallons in a variety of shapes and sizes. Mostly 30, 40, and 50 gallon models. I took a pretty hard look, and could not find anything other than the standard stuff; TP valve, dip tube, anodes, internally coated tank, etc.
Some of the models advertised dip tubes that promoted self cleaning of the heater. Bunch of nonsense. Several water heater companies claim the same thing about their dip tubes too, but there is no evidence that they do anything.
American water heaters come basically with 6 year, 9 year, and 12 year warranties. I was not able to see any difference in the heaters. I’m sure they are identical heaters, the only difference being the price.
American water heaters also have solar storage tanks with and without backup heating elements, and pre-wired temperature sensors.
The heaters ranged from an Energy Factor of from0.83 to 0.93. Most of the heaters energy factor range from 0.90 to 0.93.
Gas Water Heaters
Next I checked out the residential gas water heaters. The gas heaters product list is a little more complicated than the electrics. There are also tankless water heaters mixed in. I didn’t even know American Water Heaters even made tankless heaters. The energy factor for the gas water heaters ranged from 0.58 to 0.63.
Most of the standard gas models have 6, 9, and 12 year warranties, and again, there seems to be no difference other than price.
American has the American Polaris® High-Efficiency Residential Gas with over 94% thermal efficiency and a stainless-steel tank and full flow brass drain valve. Pretty cool.
You can download the PDF manuals for any model of their water heaters.
The site has all kinds of goodies… a cross reference chart for other manufacturers models, troubleshooting instructions, exploded views, parts lists and more. You can find detailed information about thermostats, with wiring diagrams for all configurations.
Unfortunately they have no prices listed.
Next I’ll look at A. O. Smith water heaters…
Bill – The Hot Water Guy
This blog will probably be as much about the American Water Heater website as it is about American water heaters. I figure I might as well evaluate the site. Let’s see which water Heater Company gives us the best user experience, or at least gives me the best experience.
Upon first landing on the home page I found a site that is clear and concise. It’s easy to locate where I want to go and no distractions. They have contact information including 800 numbers with hours of operation listed. So far so good.
I clicked on “Products” in the upper right nav bar, and voila! I landed on the Products page where I could choose between gas, and electric and residential or commercial water heaters.
I clicked on the “Residential Electric” link, and landed on a page of listings of water heaters.
Electric Water Heaters
Basically, they have water heaters holding from 2.5 gallons to 119 gallons in a variety of shapes and sizes. Mostly 30, 40, and 50 gallon models. I took a pretty hard look, and could not find anything other than the standard stuff; TP valve, dip tube, anodes, internally coated tank, etc.
Some of the models advertised dip tubes that promoted self cleaning of the heater. Bunch of nonsense. Several water heater companies claim the same thing about their dip tubes too, but there is no evidence that they do anything.
American water heaters come basically with 6 year, 9 year, and 12 year warranties. I was not able to see any difference in the heaters. I’m sure they are identical heaters, the only difference being the price.
American water heaters also have solar storage tanks with and without backup heating elements, and pre-wired temperature sensors.
The heaters ranged from an Energy Factor of from0.83 to 0.93. Most of the heaters energy factor range from 0.90 to 0.93.
Gas Water Heaters
Next I checked out the residential gas water heaters. The gas heaters product list is a little more complicated than the electrics. There are also tankless water heaters mixed in. I didn’t even know American Water Heaters even made tankless heaters. The energy factor for the gas water heaters ranged from 0.58 to 0.63.
Most of the standard gas models have 6, 9, and 12 year warranties, and again, there seems to be no difference other than price.
American has the American Polaris® High-Efficiency Residential Gas with over 94% thermal efficiency and a stainless-steel tank and full flow brass drain valve. Pretty cool.
You can download the PDF manuals for any model of their water heaters.
The site has all kinds of goodies… a cross reference chart for other manufacturers models, troubleshooting instructions, exploded views, parts lists and more. You can find detailed information about thermostats, with wiring diagrams for all configurations.
Unfortunately they have no prices listed.
Next I’ll look at A. O. Smith water heaters…
Bill – The Hot Water Guy
Monday, September 21, 2009
Residential Water Heaters – A Comparison Between Brands
Residential Water Heaters - Comparing Different Brands of Water Heaters
Water heaters can be a confusing topic, and there is quite a bit of competition between the various water heater manufactures to get you to purchase their brand.
I thought I might take a look at the websites for the various manufacturers to see if there are significant differences between the various brands of residential hot water heaters. Water heaters are a commodity product. Basically they are a tank of water with either a gas burner under them or electric heating elements inside of them. There isn’t really much to differentiate the water heaters from one manufacturer to another, with a few exceptions.
Comparing Brands
In the coming weeks I’ll examine the features of the basic residential models like 40 gallon gas water heaters, 50 gallon heaters, 40 and 50 gallon electric water heaters and I’ll take a look at the energy efficient models as well. I’ll go through the list of manufactures in Alphabetical order, and I’ll also include tankless models if they are produced by that manufacturer.
The manufacturers I will compare are American, A.O. Smith, Bosch, Bradford White, G.E., Marathon, Noritz, Rheem, Rinnai, State Industries, Takagi, and others.
Previous article comparing some brands of tankless water heaters.
Gas water heaters
All gas water heaters (storage type) have a gas burner, tank, flue, thermostat, drain valve, insulation, pressure relief valve, anode rod, dip tube, gas valve, pilot light, thermocouple, and tank insulation. That’s pretty much it for any storage tank type water heater.
There may be some gas water heaters that do not use a standing pilot light, but ignite when the thermostat calls for heat. I know there are commercial units with that technology available, but I am not sure about residential units. I shall find out and report back.
More about gas water heaters.
Electric water heaters
All electric tank type water heaters have a tank, electric heating elements, high limit switch, one or two thermostats, drain valve, anode rod, pressure temperature relief valve, and dip tube.
Electric water heaters are all pretty efficient as far as converting electricity to heat energy, the main difference in electrics being the amount of standby loss.
More information about electric water heaters.
Heat pump water heaters
I'll also be examining heat pump water heaters as I run accross them. They are very efficient at heating water but are pricy. More about heat pump water heaters... Heat Pump Water Heaters
Miss-leading statements
When I see glaring errors or miss-leading statements on the web sites I may very well make note of them as well. I find it very irritating when web sites miss-lead the visitors.
Stay tuned, American water heaters is the first water heater product review I will do, and I should have it up by tomorrow…
Bill the Hot Water Guy
Water heaters can be a confusing topic, and there is quite a bit of competition between the various water heater manufactures to get you to purchase their brand.
I thought I might take a look at the websites for the various manufacturers to see if there are significant differences between the various brands of residential hot water heaters. Water heaters are a commodity product. Basically they are a tank of water with either a gas burner under them or electric heating elements inside of them. There isn’t really much to differentiate the water heaters from one manufacturer to another, with a few exceptions.
Comparing Brands
In the coming weeks I’ll examine the features of the basic residential models like 40 gallon gas water heaters, 50 gallon heaters, 40 and 50 gallon electric water heaters and I’ll take a look at the energy efficient models as well. I’ll go through the list of manufactures in Alphabetical order, and I’ll also include tankless models if they are produced by that manufacturer.
The manufacturers I will compare are American, A.O. Smith, Bosch, Bradford White, G.E., Marathon, Noritz, Rheem, Rinnai, State Industries, Takagi, and others.
Previous article comparing some brands of tankless water heaters.
Gas water heaters
All gas water heaters (storage type) have a gas burner, tank, flue, thermostat, drain valve, insulation, pressure relief valve, anode rod, dip tube, gas valve, pilot light, thermocouple, and tank insulation. That’s pretty much it for any storage tank type water heater.
There may be some gas water heaters that do not use a standing pilot light, but ignite when the thermostat calls for heat. I know there are commercial units with that technology available, but I am not sure about residential units. I shall find out and report back.
More about gas water heaters.
Electric water heaters
All electric tank type water heaters have a tank, electric heating elements, high limit switch, one or two thermostats, drain valve, anode rod, pressure temperature relief valve, and dip tube.
Electric water heaters are all pretty efficient as far as converting electricity to heat energy, the main difference in electrics being the amount of standby loss.
More information about electric water heaters.
Heat pump water heaters
I'll also be examining heat pump water heaters as I run accross them. They are very efficient at heating water but are pricy. More about heat pump water heaters... Heat Pump Water Heaters
Miss-leading statements
When I see glaring errors or miss-leading statements on the web sites I may very well make note of them as well. I find it very irritating when web sites miss-lead the visitors.
Stay tuned, American water heaters is the first water heater product review I will do, and I should have it up by tomorrow…
Bill the Hot Water Guy
Monday, September 14, 2009
Saving Water and Saving Energy - Human Behavior
Saving water and saving energy in a residential home setting, is largley a behavioural problem. If you observe how people use thier water for instance, you can spot wasteful behaviors all over the place.
Yard and lawn watering behaviors that don't save water
There are the obvious wasteful behaviours, such as watering the lawn at the wrong time of day, or over watering, and even watering the sidewalks and streets. The behavior in these cases is I guess, lazyness. All are easily corrected, but require someone to take the corrective action.
Low flow fixtures VS. behavior - To save water and energy
Once of the most often used water conservation methods or device is the low flow fixture. Low flow fixtures are a double edged sword. They can provide significant savings, and in turn can inadvertently cause a lot of waste.
For example, low-flow fixtures limit the maximum flow rate available from the fixture. This translates to lower water velocities through the pipe, and thus require a longer wait for hot water. However, a common reaction for those people who have very long pipe runs, is to turn on the hot water in the shower and go do something else while the shower gets hot. When they return, they often return to find hot water running down the drain.
Depending on how long the water ends up running before the human returns to use it, the savings in water is negatively impacted, and can even end up wasting more water than if the low flow fixture had not been used to begin with.
In the previous scenario energy is also being wasted. The cost of heating water is much higher than the cost of the water being heated. Running hot water down the drain is very expensive in terms of money savings... or loss!
Save Water - Behaviors in the Bathroom
Studies have shown that 80 percent of the time a typcal hot water draw occurs at a bathroom sink, the hot water doesn't make it all the way to the fixture. Most of us are guilty of this behavior... impatience... we turn on the hot water to wash our hands and we can't wait for the hot water so we start washing, only to finish about the time the water starts to warm up.
If you don't end up using the hot water, and all you've done is filled the pipe with hot water which will then cool off, then you have essentially wasted the energy. Better to not use the hot water faucet at all.
There are a whole lot of behaviors in the bathroom that can lead to wasting water, things like letting the water run while you brush your teeth, especially warm or hot water, running water whle you shave, lingering in the shower, etc.
The laundry room and saving water and energy
The obvious answer to saving water in the laundry room is to use the smallest load setting possible while still having enough to get the clothes clean. Using cold water instead of warm or hot saves energy as well.
Save water in the kitchen
The kitchen also suffers from human behavior caused water wastage. Single handeled faucets along with human habits are a contributor to energy wastage. If you don't swing the handle all the way to the left when drawing cold water, then you are drawing some hot water as well... a waste of energy.
Running the hot water to get your dishwasher really hot water is wastefull of water, running water to rinse dishes thouroughly, even hot water, when your dish washer doesn't need pre-rinsing, etc.
Save water and be energy efficient
There is one solution to several of these water saving problems... a demand hot water system of course. In the bathroom it will save energy and water by eliminating running water down the drain while you wait for hot water to arrive as discussed earlier.
In the kitchen it can eleminate the wasted water that you run to get hot for your dishwasher etc.
When you really do need hot water you get it more quickly and without wasting any water which saves you additional energy. It's the perfect companion for low flow fixtures!
Yard and lawn watering behaviors that don't save water
There are the obvious wasteful behaviours, such as watering the lawn at the wrong time of day, or over watering, and even watering the sidewalks and streets. The behavior in these cases is I guess, lazyness. All are easily corrected, but require someone to take the corrective action.
Low flow fixtures VS. behavior - To save water and energy
Once of the most often used water conservation methods or device is the low flow fixture. Low flow fixtures are a double edged sword. They can provide significant savings, and in turn can inadvertently cause a lot of waste.
For example, low-flow fixtures limit the maximum flow rate available from the fixture. This translates to lower water velocities through the pipe, and thus require a longer wait for hot water. However, a common reaction for those people who have very long pipe runs, is to turn on the hot water in the shower and go do something else while the shower gets hot. When they return, they often return to find hot water running down the drain.
Depending on how long the water ends up running before the human returns to use it, the savings in water is negatively impacted, and can even end up wasting more water than if the low flow fixture had not been used to begin with.
In the previous scenario energy is also being wasted. The cost of heating water is much higher than the cost of the water being heated. Running hot water down the drain is very expensive in terms of money savings... or loss!
Save Water - Behaviors in the Bathroom
Studies have shown that 80 percent of the time a typcal hot water draw occurs at a bathroom sink, the hot water doesn't make it all the way to the fixture. Most of us are guilty of this behavior... impatience... we turn on the hot water to wash our hands and we can't wait for the hot water so we start washing, only to finish about the time the water starts to warm up.
If you don't end up using the hot water, and all you've done is filled the pipe with hot water which will then cool off, then you have essentially wasted the energy. Better to not use the hot water faucet at all.
There are a whole lot of behaviors in the bathroom that can lead to wasting water, things like letting the water run while you brush your teeth, especially warm or hot water, running water whle you shave, lingering in the shower, etc.
The laundry room and saving water and energy
The obvious answer to saving water in the laundry room is to use the smallest load setting possible while still having enough to get the clothes clean. Using cold water instead of warm or hot saves energy as well.
Save water in the kitchen
The kitchen also suffers from human behavior caused water wastage. Single handeled faucets along with human habits are a contributor to energy wastage. If you don't swing the handle all the way to the left when drawing cold water, then you are drawing some hot water as well... a waste of energy.
Running the hot water to get your dishwasher really hot water is wastefull of water, running water to rinse dishes thouroughly, even hot water, when your dish washer doesn't need pre-rinsing, etc.
Save water and be energy efficient
There is one solution to several of these water saving problems... a demand hot water system of course. In the bathroom it will save energy and water by eliminating running water down the drain while you wait for hot water to arrive as discussed earlier.
In the kitchen it can eleminate the wasted water that you run to get hot for your dishwasher etc.
When you really do need hot water you get it more quickly and without wasting any water which saves you additional energy. It's the perfect companion for low flow fixtures!
Friday, September 4, 2009
Tankless Water Heater Savings
After my last blog, I got an email from a friend of mine, who is involved with the installation and sales of tankless water heaters. Here is what he wrote:
Bill,
I read all of your blog interesting but very negative on tankless, don’t agree with all of it but well written. where are the heating efficiencies, for example tank water heater is only 40 to 55 % efficient vs. 82 to 94% how about the clean water you get without all the junk from the tank, I have attached a picture from a tank that was only 10 years old, take a look. LOL. At the end what is more costly and important 10 to 20 sec. Additional delay of getting hot water and may be 2 gallons of water or the inefficiency of the tank water heater and the additional energy wasted and environmental impact. Oh well, I could go on. LOL
Al
So in response to Al’s email…
First off, who has a 40 to 55% efficient water heater?
I poked around on the internet looking at water heater efficiencies, and could not find any water heater with an energy factor of less than .56. Most were .60 or more. (I presume we are talking about the energy factor when we refer to efficiency.)
I took a look at the tankless water heater specs and I found that most tankless units had energy factors of about .82. The highest I saw was .92, but I didn’t spend a lot of time looking so I probably just didn’t come across those .94 units.
So before moving on, I would like to say that using 40 to 55 percent efficiency for tank type water heaters is on the extreme low side. 60 percent efficiency would be the most common storage efficiency from my limited research.
I visited the ACEEE – (American Council for an Energy-Efficient Economy) who I think you could say is an independent 3rd party. They have a comparison table comparing Life-Cycle costs for the various types of water heaters.
Interestingly they recommend looking for a gas storage water heater with a minimum energy factor of .63 and they state that the highest is .67. Quite a bit higher than 40 to 55%.
From their table, a conventional gas storage water heater with a EF of .60 has a yearly cost of $350, and a tankless water heater with an EF of .80 has a yearly cost of $262.
As you can see the difference in yearly energy cost is 350 – 262 = $88.00 a year, or about $7.33 a month. A tad more if the efficiency was .82 as I was finding.
For me, $8.00 a month is definitely not worth the potential problems associated with tankless water heaters, and the changes in behavior I would have to make, like giving up that “trickle” of warm water I use when I brush my teeth. I hate cold water on my teeth!
As for the pictures of the corroded old water heaters… here are my thoughts. First, since I usually drink cold water, I am drinking the water from the water main. Since the water passing through the water heater also came from the same source of water, then it must be even cleaner than the cold water if it leaves all that stuff in the heater.
All that sediment and those deposits are just minerals that have come out of the water as it was heated, and you consume those same minerals every time you drink the cold water. So I don’t see a problem.
By the way, in areas with high mineral content many of the tankless water heater manuals instruct you to clean out your heat exchanger periodically. It seems the hard water is hard on tankless heaters too! Cleaning the heat exchanger on a regular basis does not sound like something I would want to do.
Metlund D’mand systems, our main competitor and the big guys on the block as far as sales go state that the savings from a demand hot water system from reduced water consumption and reduced sewage fees amounts to about $150 a year for a typical home with a natural gas water heater.
Gee… that’s more than the tankless water heater saves to begin with. If Scottsdale Arizona is offering rebates of $200.00 for homes that install demand hot water systems they must feel that the wastage of water from residential hot water plumbing systems is significant.
If you are really concerned about environmental impact, then you should put a hot water demand system on your tankless unit and more than double the monetary savings and reduce both energy consumption and water wastage. Pumping and treating water and pumping and treating sewage consumes energy as well.
Subtract that extra gallon or two of water from the savings provided by the increased efficiency of the water heater, and environmentally the tankless water heater doesn’t look so good. Just my opinion of course.
So Al, perhaps I have miss-interpreted your numbers, perhaps you weren’t referring to energy factor with your efficiency numbers?
That’s all for today folks…LOL…if anyone reads this blog.
Bill
Bill,
I read all of your blog interesting but very negative on tankless, don’t agree with all of it but well written. where are the heating efficiencies, for example tank water heater is only 40 to 55 % efficient vs. 82 to 94% how about the clean water you get without all the junk from the tank, I have attached a picture from a tank that was only 10 years old, take a look. LOL. At the end what is more costly and important 10 to 20 sec. Additional delay of getting hot water and may be 2 gallons of water or the inefficiency of the tank water heater and the additional energy wasted and environmental impact. Oh well, I could go on. LOL
Al
So in response to Al’s email…
First off, who has a 40 to 55% efficient water heater?
I poked around on the internet looking at water heater efficiencies, and could not find any water heater with an energy factor of less than .56. Most were .60 or more. (I presume we are talking about the energy factor when we refer to efficiency.)
I took a look at the tankless water heater specs and I found that most tankless units had energy factors of about .82. The highest I saw was .92, but I didn’t spend a lot of time looking so I probably just didn’t come across those .94 units.
So before moving on, I would like to say that using 40 to 55 percent efficiency for tank type water heaters is on the extreme low side. 60 percent efficiency would be the most common storage efficiency from my limited research.
I visited the ACEEE – (American Council for an Energy-Efficient Economy) who I think you could say is an independent 3rd party. They have a comparison table comparing Life-Cycle costs for the various types of water heaters.
Interestingly they recommend looking for a gas storage water heater with a minimum energy factor of .63 and they state that the highest is .67. Quite a bit higher than 40 to 55%.
From their table, a conventional gas storage water heater with a EF of .60 has a yearly cost of $350, and a tankless water heater with an EF of .80 has a yearly cost of $262.
As you can see the difference in yearly energy cost is 350 – 262 = $88.00 a year, or about $7.33 a month. A tad more if the efficiency was .82 as I was finding.
For me, $8.00 a month is definitely not worth the potential problems associated with tankless water heaters, and the changes in behavior I would have to make, like giving up that “trickle” of warm water I use when I brush my teeth. I hate cold water on my teeth!
As for the pictures of the corroded old water heaters… here are my thoughts. First, since I usually drink cold water, I am drinking the water from the water main. Since the water passing through the water heater also came from the same source of water, then it must be even cleaner than the cold water if it leaves all that stuff in the heater.
All that sediment and those deposits are just minerals that have come out of the water as it was heated, and you consume those same minerals every time you drink the cold water. So I don’t see a problem.
By the way, in areas with high mineral content many of the tankless water heater manuals instruct you to clean out your heat exchanger periodically. It seems the hard water is hard on tankless heaters too! Cleaning the heat exchanger on a regular basis does not sound like something I would want to do.
Metlund D’mand systems, our main competitor and the big guys on the block as far as sales go state that the savings from a demand hot water system from reduced water consumption and reduced sewage fees amounts to about $150 a year for a typical home with a natural gas water heater.
Gee… that’s more than the tankless water heater saves to begin with. If Scottsdale Arizona is offering rebates of $200.00 for homes that install demand hot water systems they must feel that the wastage of water from residential hot water plumbing systems is significant.
If you are really concerned about environmental impact, then you should put a hot water demand system on your tankless unit and more than double the monetary savings and reduce both energy consumption and water wastage. Pumping and treating water and pumping and treating sewage consumes energy as well.
Subtract that extra gallon or two of water from the savings provided by the increased efficiency of the water heater, and environmentally the tankless water heater doesn’t look so good. Just my opinion of course.
So Al, perhaps I have miss-interpreted your numbers, perhaps you weren’t referring to energy factor with your efficiency numbers?
That’s all for today folks…LOL…if anyone reads this blog.
Bill
Wednesday, September 2, 2009
Electric Water Heater Problems - Storage Tank Type
Electric water heaters and the electrical problems they can have are today’s topic. The electrical system for an electric water heater is fairly simple, and easy to trouble shoot.
A typical water heater will have two heating elements and two thermostats plus a high limit switch.
Let’s start with the high limit switch. The high-limit switch is a thermal circuit breaker. When it gets too hot, it will trip, and a red button will pop out. So if suddenly you have no hot water, the first thing you might want to check is that red button. Push it in and see if that gets the heater going again.
There are two thermostats on a typical unit, one near the top and one near the bottom. The thermostat near the top of the tank is like a temperature controlled single pole double throw switch. That means it is either feeding electricity to the top heating element, or if it is off, it is directing the electricity down to the lower thermostat.
Understanding the operation of the heater will help in troubleshooting. Let’s assume that you just filled the bathtub with hot water, and so your water heater is basically full of cold water. Both the upper and lower thermostats will be turned “on” because the temperature will be below the set points of the thermostats.
Electricity will flow from the mains through the upper thermostat and into the upper heating element, through the element, and back into the mains.
Once the water in the top of the water heater has reached the set point on the upper thermostat, the upper thermostat will shut off the electricity to the upper thermostat, and send it down to the lower thermostat.
The lower thermostat is “on” since it has not warmed up above the set point. Because it is “on” it sends the electricity to the lower heating element and the electricity flows through the element and back to the mains.
When the water in the lower part of the electric water heater reaches the set point temperature of the lower thermostat it shuts off the electricity to the lower element and nothing else happens until the water in the heater lowers below one or the other set points.
Electric Water Heater Troubleshooting
If you have no hot water:
As I mentioned earlier, the first thing to try, in my opinion, is the high limit switch. Push the button and see if the heater begins heating the water.
If that does the trick, the next thing you need to worry about is why the high limit switch tripped in the first place. Did the water temperature get too high? If so why?
A defective upper thermostat that sticks in the “on” position is one thing that will cause the high limit switch to trip. Also a defective high limit switch could be the source of the problem.
Certain usage patterns (frequent small draws) can cause what is known as “stacking” where the water at the very top of the heater gets hotter than it should.
If the high limit switch button is not popped out or if pushing it has no affect, then it’s time to move on to checking the heating elements.
Testing Electric Water Heater Heating Elements
The first thing to do is of course; turn off the electricity to the water heater.
Next you need a simple ohm-meter. Like a cheap Radio Shack multi-meter.
Disconnect one of the two wires to the heating element and then read the resistance between the two heating element terminals.
The heating elements should have an electrical resistance of less than 50 ohms. You don’t have to worry about the amount of resistance though, it will either have some resistance, or it will have an infinite amount. If the needle moves, the element is ok. If it doesn’t, the element is burned out.
If the heating elements are ok, then it’s most likely a bad thermostat. Check and make sure none of the wires are broken or loose under a terminal.
Testing the Thermostats
The electricity comes into the water heater and goes directly to the high limit switch… usually the top two terminals on either side of the high limit switch. Normally the high limit switch is stacked above the upper thermostat.
The upper thermostat has one wire that connects directly to the upper heating element, and one wire that connects to the high limit switch. It has another wire that goes down to the lower heating element.
With a below set point temperature in the water heater, the high limit switch should be sending electricity to the upper thermostat, which should in turn be sending it to the upper heating element.
With the electricity still turned off to the water heater, check the resistance between the top wire that goes from the high limit switch to the mains, and the high limit switch terminal that leads to the upper thermostat. The resistance should measure zero. If not, the high limit switch is bad. (or the red button needs to be pushed in)
If it does read zero, then check the resistance between the terminal on the upper thermostat that connects to the high limit switch, and the terminal that lead so the upper heating element. It should read zero. If not, the upper thermostat is bad.
To check the bottom thermostat check the resistance from the lower thermostat terminal that connects to the upper thermostat, and the terminal that goes to the lower heating element. It should read zero. If not the lower thermostat is bad.
That’s it. You should have found the problem by now if it is electrical in nature.
A typical water heater will have two heating elements and two thermostats plus a high limit switch.
Let’s start with the high limit switch. The high-limit switch is a thermal circuit breaker. When it gets too hot, it will trip, and a red button will pop out. So if suddenly you have no hot water, the first thing you might want to check is that red button. Push it in and see if that gets the heater going again.
There are two thermostats on a typical unit, one near the top and one near the bottom. The thermostat near the top of the tank is like a temperature controlled single pole double throw switch. That means it is either feeding electricity to the top heating element, or if it is off, it is directing the electricity down to the lower thermostat.
Understanding the operation of the heater will help in troubleshooting. Let’s assume that you just filled the bathtub with hot water, and so your water heater is basically full of cold water. Both the upper and lower thermostats will be turned “on” because the temperature will be below the set points of the thermostats.
Electricity will flow from the mains through the upper thermostat and into the upper heating element, through the element, and back into the mains.
Once the water in the top of the water heater has reached the set point on the upper thermostat, the upper thermostat will shut off the electricity to the upper thermostat, and send it down to the lower thermostat.
The lower thermostat is “on” since it has not warmed up above the set point. Because it is “on” it sends the electricity to the lower heating element and the electricity flows through the element and back to the mains.
When the water in the lower part of the electric water heater reaches the set point temperature of the lower thermostat it shuts off the electricity to the lower element and nothing else happens until the water in the heater lowers below one or the other set points.
Electric Water Heater Troubleshooting
If you have no hot water:
As I mentioned earlier, the first thing to try, in my opinion, is the high limit switch. Push the button and see if the heater begins heating the water.
If that does the trick, the next thing you need to worry about is why the high limit switch tripped in the first place. Did the water temperature get too high? If so why?
A defective upper thermostat that sticks in the “on” position is one thing that will cause the high limit switch to trip. Also a defective high limit switch could be the source of the problem.
Certain usage patterns (frequent small draws) can cause what is known as “stacking” where the water at the very top of the heater gets hotter than it should.
If the high limit switch button is not popped out or if pushing it has no affect, then it’s time to move on to checking the heating elements.
Testing Electric Water Heater Heating Elements
The first thing to do is of course; turn off the electricity to the water heater.
Next you need a simple ohm-meter. Like a cheap Radio Shack multi-meter.
Disconnect one of the two wires to the heating element and then read the resistance between the two heating element terminals.
The heating elements should have an electrical resistance of less than 50 ohms. You don’t have to worry about the amount of resistance though, it will either have some resistance, or it will have an infinite amount. If the needle moves, the element is ok. If it doesn’t, the element is burned out.
If the heating elements are ok, then it’s most likely a bad thermostat. Check and make sure none of the wires are broken or loose under a terminal.
Testing the Thermostats
The electricity comes into the water heater and goes directly to the high limit switch… usually the top two terminals on either side of the high limit switch. Normally the high limit switch is stacked above the upper thermostat.
The upper thermostat has one wire that connects directly to the upper heating element, and one wire that connects to the high limit switch. It has another wire that goes down to the lower heating element.
With a below set point temperature in the water heater, the high limit switch should be sending electricity to the upper thermostat, which should in turn be sending it to the upper heating element.
With the electricity still turned off to the water heater, check the resistance between the top wire that goes from the high limit switch to the mains, and the high limit switch terminal that leads to the upper thermostat. The resistance should measure zero. If not, the high limit switch is bad. (or the red button needs to be pushed in)
If it does read zero, then check the resistance between the terminal on the upper thermostat that connects to the high limit switch, and the terminal that lead so the upper heating element. It should read zero. If not, the upper thermostat is bad.
To check the bottom thermostat check the resistance from the lower thermostat terminal that connects to the upper thermostat, and the terminal that goes to the lower heating element. It should read zero. If not the lower thermostat is bad.
That’s it. You should have found the problem by now if it is electrical in nature.
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