Troubleshooting Your Gas or Electric Water Heater

by on February 10, 2013Karie Fay

Unless you’re into cold showers, the sudden failure of your water heater is likely quite a shock. Looking at the ticket price for a new one, or the repair bill on the old, will undoubtedly give you another shock to top it off. Save your heart – and your pocketbook – by troubleshooting your water heater problem yourself.

How Your Water Heater Works

Troubleshooting your gas or electric water heater could help you save money on repair costsAt the simplest level, your water heater transfers heat to a water source, which then is routed through your plumbing to the site of demand. The picture in your mind is probably the classic tall, cylindrical tank, full of water standing at the ready, typically heated by either natural gas or electricity. Advanced water-heating systems emerging in the American consumer market are gradually replacing the traditional tank-based electric and gas water heaters, however.

Electric heat pump water heaters use energy from the air to heat the water while dehumidifying the air at the same time – a bonus in basements or humid climates. Gas-fueled or electric tankless or demand-type water heater systems heat the water as it flows through the pipes, by means of a heating element, eliminating the need for a traditional tank. The new tankless systems not only last longer than conventional gas and electric hot water heaters, they are much more energy efficient as well.

Until the initial cost of newer water-heating systems drops, standard tank-based gas and electric water heaters will likely continue to occupy most homes. Both operate on the same principles and troubleshooting for both is much the same.

The cold water supply pipe delivers fresh water to your water heater and a dip tube routes it to the bottom of the typically steel tank. When you take your hot shower, the heated water, stored in the tank, flows from the top of the tank and out the hot-water pipe.

Steel water tanks are insulated on the exterior and have a glass-lined interior to prevent corrosion, which is the leading cause of tank failure. Rust will quickly eat through exposed metal, requiring total replacement of the tank itself. An anode rod, made of magnesium, runs down the middle of the water tank in an effort to attract the rust to it instead of the steel. Designed to corrode away, it does, leading to eventual tank failure if not checked annually and replaced as necessary.

Outside of the tank, your water heater has a temperature-and-pressure relief valve, or T&P valve. The T&P valve is located on a pipe that runs from the top of the water heater to about 6 inches above the floor before abruptly ending. The T&P valve is designed to open if either the pressure or the temperature inside your water heater exceeds defined limits. Keep a bucket underneath the T&P pipe to catch draining water if the valve opens.

Every water heater tank also has a drain cock at the bottom of the tank, which allows you to drain water, as well as a water-supply valve on the incoming cold-water supply pipe.

Electric water heaters are generally wired to a 220-volt circuit breaker. An attached thermostat senses the water temperature inside the tank. When your hot shower runs, the temperature drops, and the thermostat closes the electrical current that allows the electricity to flow into the unit. Inside, heating elements conduct the electrical current that heats the water. Once the water temperature again reaches the proper temperature – typically 120, 130, or 140 degrees Fahrenheit, the thermostat closes to break the circuit and thus ends the water heating.

Gas water heaters, in contrast, use a gas burner underneath the tank to heat the water. The fuel is piped from the source to the gas control valve. A thermostat detects the water temperature and opens or closes the fuel delivery to the burner. A thermocoupler – essentially a safety device – ensures the pilot light or spark ignition activates properly before allowing the burners fuel. Gasses produced during combustion flow through and out the top of the tank, into a vent pipe and typically out the roof or sidewall.

As with an electric hot water heater, a gas water heater has the same anode rod inside the tank. The longer the anode, on either gas or electric water heaters, the longer the tank will last. However, since the burner heats the tank itself, the gas-fueled water heater tank experiences greater wear and tear and thus a shorter life expectancy.

The incoming cold water pipe should have a shut-off valve, and a drain valve will be at the bottom of the tank exterior, just like on an electric water heater. The T&P valve operates exactly as it does on an electric water heater.

Water Heater Troubleshooting: Common Symptoms & Causes

From minor inconveniences such as discolored water or water that seems just a little too cool, to a major crisis like ice-cold water in your shower or water pouring out the water heater tank, the problems you may experience with your gas or electric water heater are easier to understand with knowledge of how the hot water actually works. In addition, many of the problems you may experience are common to both electric and gas water heaters. Search for the possible cause and solution by the symptom. For more advanced troubleshooting and repairs, consult a qualified appliance repair technician.

  • Hot Water is Discolored: Dirty brown or rust-colored hot water usually indicates a build up of rust and sediment inside your hot water heater. Excessive sediments may also make the water take longer to heat and cause popping noises during the heating cycle. The solution is simple – drain the water and flush before refilling.
  • Hot Water Smells: If your water smells like rotten eggs, it indicates an excess of hydrogen, sulfur and bacteria. This is especially prevalent in homes with well water. The magnesium anode rod inside your tank emits hydrogen, while the water supplies the sulfur and bacteria. Treat the problem with two solutions: First, replace your old anode with a new aluminum one, which will lower the hydrogen content. Next, chlorinate your water supply to kill the bacteria. Flushing the tank and rinsing it with chlorine bleach before replacing the anode will help the problem tremendously. Consult a water heater professional for further information.
  • Water Heater is Noisy:Rumbling, rattling and popping noises may be quite normal, although they may startle you, especially in a new home where you aren’t used to the sounds your appliances make. Sure, rumbling may be a sign of sediment and a popping noise may indicate T&P valve stress, but don’t borrow trouble – if everything works properly or if the noise is nothing new, there’s likely nothing to worry about. Keep an eye on how your water heater performs to determine if the sound is, indeed, a symptom of another problem.
  • Hot Water Pressure is Low: When you notice your hot water doesn’t flow as hard as it should, you need to check several possible causes, from the faucet back to the water heater. At any point that the troubleshooting proves too difficult for you to perform, have a qualified professional take over. As with all do-it-yourself troubleshooting, chances are good that the repair bill will still be much lower, even if you can’t find or fix the problem, since you have narrowed down the possible causes. One by one, check the following parts and proceed as necessary:

1. Is the water shut-off valve at the water heater partially closed?

2. Unscrew the faucet aerator, the round tip under the faucet that sprays the water flowing from the tap. Is it clogged with gook or sediment? Soaking the aerator in a bowl of vinegar overnight, then scrubbing with an old toothbrush, should solve this problem.

3. Is the faucet water shut-off valve completely open?

4. Remove and check the faucet supply line pipe. A clogged pipe will restrict water flow as well. Clean or replace as needed.

5. Check the hot water line, leaving the hot water heater, for sediment and debris. Call a professional for assistance with this and internal water heater repairs if you lack the experience and confidence to do it yourself.

6. If the water heater’s dip tube, inside the tank, is clogged, it will also slow the hot water flow, presenting as low water pressure. The dip tube has small drain holes at the bottom that may easily fill with sediment or plumbing sealant and other debris entering the system. Sometimes the dip tube may even break with age. Replacing the dip tube is simple, but you may wish to have a service technician perform the work for you.

  • T&P Relief Valve is Leaking Water: The first thing to assess is just how much water is leaking. A dribble typically points to a totally different set of possible causes than a rush of water from the T&P. For slight leakage, the cause is generally minor and the fix simple:

- A loose or malfunctioning T&P will show as a slight trickle or small accumulation of water. To replace the valve, the tank is first drained before a new T&P is added in place of the old one.

- A flood of water likely indicates that the temperature or pressure inside the tank is too high and the T&P is working as designed. While that’s good news for your water heater and personal safety (the tank will not blow, spewing scalding water), it’s bad news for your floor as gallons of water flood it. Often, it’s the result of a malfunctioning thermostat that allowed the water temperature to rise too high. Consult a qualified professional who has the ability to troubleshoot the water heater thoroughly and safely and guide you to the appropriate solution.

  • Water Drain Valve is Leaking: Parts may wear out simply due to age. If the drain cock is dribbling water, draining the tank and replacing it before refilling it with water should fix the problem.
  • Water Heater is Leaking from Unknown Source: If you find wetness around your water heater but aren’t sure where it’s coming from, you need to investigate further. Other than the valves – which you already have eliminated as a possible cause – the water heater may leak from either the pipe leading into the tank or the pipe leading away from it. If you look at and feel these pipes and they are dry, suspect a leaking tank. Most water heaters last 10 to 15 years before failing. Even a slight pinhole in the tank will cause failure. While pipes, valves and many components may be replaced, there is no way to patch a tank. A leaking tank requires total replacement.
  • Takes too Long to get Hot Water From Faucet: Because your hot water supply pipe, emerging from the water heater, constantly contains water, it will cool slightly when you’re not running your hot water faucet. The cooler the temperature surrounding the pipes, the more the water cools. To get fresh, hot water, you must run enough to clear the standing water first. Pipe insulation will help slightly, but the delay is completely normal.
  • Water Heater Runs Out of Hot Water: Sometimes your water heater is simply too small to handle the demand placed on it. The result is running out of hot water. Other possible causes, common to both electric and gas water heaters, include improper installation of a new water heater, leaks in the hot water line resulting in less hot water making it to the faucet, or excessive sediment in the tank, especially in areas with hard water. Dirty-colored water, a noisy water heater, and low water pressure in combination with a lack of hot water are tip-offs that sediment is the problem. While flushing the tank of sediment is a do-it-yourself project for many, consider consulting a service technician for professional assistance with any of these causes.

Troubleshooting an Electric Hot Water Heater

Some problems you may experience with your water heater may occur in both gas and electric models, but the precise causes will vary due to the difference in how electric and gas water heaters work. Still, the troubleshooting process remains the same – search by symptom and narrow down the possible causes. Consult a qualified service technician for further information or advanced repair assistance.

  • Runs Out of Hot Water: If you still run out of hot water and have performed the general troubleshooting, looking for sediment and other common causes, then the problem is likely due to parts specific to an electrical water heater. Among the most common are defective heating elements, faulty or improperly wired thermostats and loose wiring. If the tank is not grounded properly, you may also have hot water supply issues. A qualified service professional has the knowledge and tools to narrow-down the cause and repair, as well as to replace or rewire as needed.
  • Takes too Long to Get Hot Water: After checking the common causes applicable to both gas and electric water heaters, turn your attention to the electrical heating system itself. If the heating elements are too small or the thermostat malfunctions, the water may be not hot enough and sluggish as well.
  • Water is too Hot: The first thing to check, on both gas and electric water heaters, is that your water temperature setting control is at the temperature you desire. For most households, 120 degrees Fahrenheit is adequate and safeguards against accidental scalding. If the setting is appropriate, hold a thermometer under steady running hot water to check the temperature of water delivered. Excessively high water temperature is typically caused by a faulty thermostat or a grounded heating element, meaning the heating element touches the inside of the tank when it shouldn’t. Consult a repair technician for further information and assistance.
  • Electric Water Heater Isn’t Working: If you’re not getting any hot water at all, start with the simplest possible causes first. Make sure the water heater is turned on and that the breaker isn’t flipped or the fuse blown in your home’s fuse or breaker box. If you have a breaker box – most modern homes do – flip the switch completely off and back on again even if the breaker wasn’t thrown. This resets the electronics inside the water heater. Other possible causes include a grounded or out-of-calibration thermostat and loose or faulty wiring as well as a tripped high limit switch. Contact a qualified service technician for in-depth troubleshooting and assistance.

Troubleshooting a Gas Hot Water Heater

After troubleshooting general symptoms and causes for your gas water heater problems, turn to troubleshooting geared specifically to a gas water heater. Although many of the parts that make a gas water heater work are mechanical instead of electric, making some repairs easier, there are more parts. Burners, ignition systems, gas valves and such may all malfunction. As with an electric water heater, consult a qualified repair technician to assist with advanced troubleshooting and repairs you are not comfortable attempting.

  • Runs Out of Hot Water Quickly or Reheats Water Slowly: If you have eliminated generic problems such as improper temperature settings, a defective dip tube or an undersized water heater, the problem is often either a defective water temperature thermostat – requiring replacement of the gas control valve – or the burner orifice is dirty and clogged, fixable with a simple cleaning. Other possible causes include low gas pressure, an excessively dirty vent flue or a downdraft through your flue. Downdrafts – air coming down your flue pipe – may be periodic and require you to simply relight your pilot light for normal operation to continue. If the downdraft continues, or if you suspect an obstruction in the flue from things such as leaves, bird’s nests or excessive soot, inspect the flue from the point it exits the house. The end of the pipe may need to be raised to prevent a downdraft, the flue may need cleaning, and the cap covering it may be loose. Consider cleaning the flue yourself, if necessary, or consult a professional for expert assistance.
  • Water is Too Hot: After checking your temperature control setting to ensure it wasn’t accidentally raised, suspect a thermostat problem. Replacing the thermostat is fairly inexpensive and takes only a few minutes for a professional.
  • No Hot Water: Always check your fuse or breaker box to ensure the power is on to the water heater. Although it’s gas-powered, an electronic ignition requires a small amount of current. Check the pilot light to see if it is lit and relight if necessary. If it fails to stay lit, troubleshoot the pilot light failure as well.
  • Pilot Light Won’t Light: If the gas control knob is open, allowing an adequate gas supply to the pilot and burner, then the pilot light orifice or tube may need cleaning or replacement. A loose or defective thermocoupler will also prevent your pilot light from lighting. Air in the gas line may prevent lighting as well. Even a defective gas valve will prevent proper pilot light operation. Consult a service technician for further information or assistance.
  • Pilot Light Won’t Stay Lit: Just as frustrating is a pilot light that simply won’t stay lit. Sure, you may be able to relight it and get the entire tank up to temperature right before using your hot water, but that’s a hassle. The most common causes include a loose or defective thermocoupler, a vent downdraft, clogged flue or pilot light assembly or improper gas pressure. Perform those repairs you feel confident about and consult a service technician for advanced repairs and troubleshooting.
  • Burner Flame Problems: Whether it won’t stay lit, the flame is too high or yellow, the flame appears to float or even emits a noisy, whistling sound, the causes tend to be the same. Dirty orifices, faulty thermocouplers, clogged flues and improper gas pressure are the typical culprits. While cleaning many of the parts is fairly simple, ask a qualified professional for advanced help.
  • Soot or Scale on Water Heater or in Flue: Soot and scale are the products of combustion. Soot should flow through the flue and exit the home. Excessive buildup of either indicates problems with combustion or an obstruction inside your flue. Clean the flue, similar to a chimney, and keep chemicals away from your water heater. Ensure your gas water heater has an adequate supply of air for ventilation. Consult a repair technician for further assistance.

Preventative Maintenance

While it’s inevitable that your water heater will eventually die, proper maintenance will normally help prolong its life, as well as increase its energy efficiency. The Department of Energy suggests you insulate your water heater – taking care to avoid covering the thermostat on an electric model or the top, bottom, burner and thermostat on a gas model – as well as the first 6 feet of both hot and cold pipes connecting to the water heater.

Inspect your hot water heater completely at least once a year. Performing the inspection during your routine fall or winter maintenance will help you remember to do it. Draining a quart or two of water from your tank a couple times a year will help remove sediment, and checking the T&P valve once a year will help spot malfunctions before they happen.

With any luck, cold showers will be a thing of the past – unless you specifically want one!

{ 40 comments… read them below or add one }

sarah May 17, 2014 at 4:05 pm

I replaced my electric water heater 6 months ago due to brown, thick water leaking from the top in 2 places. The new tank is doing the same thing. Is it rusted already? I can’t afford another tank

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Steve McKay January 22, 2014 at 3:02 pm

Hello,
I live in a town house development in carver Ma, these condo’s/townhouses are brand new (6 yrs old) My girlfriend and all of our neighbors bought them brand new and have been the only owners, in 6 years living there, are first tank lasted 4.5 years, in the last year and a half I ve been through 3!! water heaters, this has happened to 6 of my neighbors as well. The property manager says he has no clue why this would happen. One of our friends replaced his this past Aug/12 and his already went again last week. We are looking for answers and any insight would be greatly appreciated

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Karie Fay April 15, 2014 at 11:55 pm

Hi Steve,

Wow – that sounds crazy! And expensive too. I wish I could be of more help, but I can only make some wild guesses. Have you checked the sediment levels inside the water heater? Do you do periodic maintenance (such as draining some water from the tank and cleaning the burner components, etc.). I would try to do everything I could to increase the water heater life. I would consider picking the brain of the local service technician as well. Can I assume they are all the same brand water heaters? What part goes out — or does it vary? Feel free to give me more information!

Good luck,
Karie Fay

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Sam Mehr January 19, 2014 at 10:41 pm

I have gas Rannia tankless water heater and it 5 years old. The past two days when the water heater is running the unit shut off and will not come back on for several minutes. Can someone tell me what is cause this to happen
Thanks
Sam

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Jason January 7, 2014 at 7:14 am

I just had a new hot water heater installed and now every time someone is in the shower and a faceut is turned on elsewhere in the house it either goes cold or hot in the shower. This never happended before the new heater was installed.

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Janet January 2, 2014 at 9:49 pm

I had a new 40 gallon Ruud hot water installed a couple of days ago. It will not produce hot water. The plumber came out and he tried several things after talking to the place where he purchased it and the manufacturer, but nothing changed. He checked the gas line which had some particles in it and he cleaned that out and the flame was quite blue so he thought that fixed it but it didn’t. He told me to turn off the cold water going into the tank and then after an hour to turn the col water back on and see if there was hot water. The water was hot until I took a shower and when my daughter try to take a bath the water was warm again. Can you tell me if the cold water going into the heater is causing a problem with the heater not making hot water. This

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Janet Reply January 21, 2014 at 12:15 am

You probably have a hot water leak. It could be under the foundation. Did you ever figure this out?

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priscilla sydnor December 8, 2013 at 9:26 pm

can water in a gas line stop the tank from working, staying lit

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Karie Fay April 15, 2014 at 11:46 pm

Hi Priscilla,

Did you ever determine your problem? To answer your question, yes water would stop the gas from burning. This can happen in automobiles as well. The gas gets wet and the car runs poorly. Has your gas line been exposed to water? A more likely cause is a bad thermocouple or a bad gas valve. I suggest having someone take a look at it for you.

Hope that helps,
Karie Fay

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Lonnie December 1, 2013 at 8:59 pm

I have a ambassador on demand water/floor heater the water putt of it was working great until I turned some valves to get the floor heat going then everything went cold. I have shut everything down pressed the reset button and tried to fire it back up but don’t know if I am doing things wrong I don’t have a manual and flying by the seat of my pants. Can you help me with some tips?

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Mark Rehorst November 20, 2013 at 1:21 pm

I plan on going away on vacation for 45 days this winter. I’m still going to heat the house, but plan on turning off the water supply to the house. I have a gas water heater and am wondering if I am better off turning off the water heater completely or just putting it on the “vacation setting”? I’m not draining the water heater, just turning off the water valve at the main. I’m doing this just in case of a bursting pipe.
Please provide advice. Thanks!

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Karie Fay April 15, 2014 at 11:49 pm

Hi Mark,

The next time you go away for vacation, if you don’t want to drain your water heater, by all means use the vacation setting! It will help conserve energy while keeping the pilot light lit. It’s a convenience thing as well — when you get home, all you have to do is turn it back up to the temperature you wish (standard is 120 degrees F).

Hope you enjoyed your getaway!
Karie Fay

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Vicki November 17, 2013 at 7:43 pm

Our water heater has been putting off a weird smell off and on when it’s heating water and there is heat coming from the top of it. Is this normal? Thank you!!

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ibrahim November 15, 2013 at 6:45 pm

My gas and electric heater is heating up too fast so the damper close and make heater shut off .I bleed the lines and from yhe overflow valce a lot of ste come out ..what could be the problem

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RON October 31, 2013 at 6:43 pm

I have a gas A.O Smith water heater and although the pilot is lit and stays on, the burner will not fire up. The knob is on the “ON” position, but when I turned on the faucett the water is warm but the burner is never on. What could be the problem?

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Karie Fay November 15, 2013 at 11:57 pm

Hi Ron,

If your pilot stays lit, I would expect the thermocouple is still good. However, it is a cheap, easy fix to eliminate the possibility that I am wrong. :) You might try cleaning the flame sensor as well. Other more likely possibilities are a dirty burner system, inadequate gas pressure (ask the gas company), poor air intake or a bad gas control valve thermostat.

If you feel comfortable and know the safety procedures, you may be able to troubleshoot these problems yourself. If not, contact a professional.

Hope that helps,
Karie Fay

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SVIENS October 30, 2013 at 9:52 am

HOW DO I LEAVE MY UNIT AND HOT WATER GAS HEATER WHEN AWAY FOR 6 MONTHS
WILL BE LEAVING THERMOSTAT LOW, BUT IF I TURN OFF WATER HEATER WILL IT STILL HEAT THE HOUSE? Live in New England It is called Hydraelectric

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Karie Fay November 15, 2013 at 11:40 pm

Hi Sviens,

I am a little uncertain the specifics of your situation — and I have never heard of Hydraelectric. Is that the type of water heater? And am I correct that your gas hot water heater also heats your house?

If that’s true, then without knowing more about your situation I would have to say I would leave the hot water heater on while I was gone. It doesn’t consume much energy, especially if the temperature is reduced. And if it generates the heat in your home, then you won’t have heat in your house if you turn it off completely. Especially in New England, I don’t think you want to take that risk at this time of year.

Hope that helps,
Karie Fay

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Diane October 25, 2013 at 1:08 pm

Just had new water heater installed. Now when someone is in shower and another faucet is turned on, shower person gets blast of cold water until other faucet is turned off. This never happened before new water heater was installed.

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Karie Fay November 15, 2013 at 11:35 pm

Hi Diane,

Are you still suffering through cold showers? You didn’t give many details about the type of water heater or the size. I assume it was comparable to the old one? Who installed it?

There’s a couple possible causes, but I would guess you have low hot water pressure. From what I understand, this often becomes apparent after plumbing work such as a new hot water heater.

Try checking if there’s a shut off valve on the pipe leaving the hot water heater and make sure it’s totally open first. Then, look at the aerator screens and faucet openings for every fixture, including the tub and shower. Sometimes these get clogged with hard water minerals and sediment and gradually restrict your water pressure.

If this doesn’t solve it, it could be in a pipe itself. That involves looking first at the pipe-to-hot-water-heater connection (there’s a nipple there that often gets clogged) and working backward. You may wish to pick a plumber’s head, or do a little research into “low hot water pressure” to find specifics to try yourself.

Hope this helps!
Karie Fay

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Teresa Mc October 23, 2013 at 5:06 pm

Question I turned the gas heater on this morning and now it sounds like water is dripping in the heater vents? Should I be concerned?

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irene estrin October 23, 2013 at 7:37 am

My heating system is gas powered hot water heater. 1st and 2nd floors are controlled by separate thermastats. I see piping coming off the top of the heater to the second floor and the first floor and the valves are opened to both floors. I turned the heat on both floors, but the hot water does not go up to the second floor (I have hot water on second floor in the bathroom though). The thermastat on the second floors seems to be working. What could be the problem?

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DALE COOK October 8, 2013 at 11:21 am

What causes air to get in the hot water and not in the cold water and what can be done to correct the situation?

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Karie Fay November 15, 2013 at 11:25 pm

Hi Dale,

Thanks for the question. Wow, you have me stumped. Generally you would expect if there is air, it will be in both the hot and the cold water as well. So you would tend to think it’s coming from the water heater, wouldn’t you?

Just on the off chance that it could be this simple, try checking your water line coming into your water heater. Look for a water valve control (a shut off). Is it fully open? Restricting the flow of water supplying your hot water heater may introduce air into the system.

If that doesn’t help, I would suggest contacting a professional. You don’t mention if you have a well or city water, and I can’t be certain of your setup. Depending on many factors, it could be anything from a valve malfunctioning to things I probably am not even imagining.

Good luck,
Karie Fay

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Lisa Horneman September 19, 2013 at 11:50 pm

My water heater is turning off the circuit breaker. Firstly it started only doing it through the day (which was odd as it is only run during off peak times) now it switches off throughout the night. It will only switch off once usually between 12-2am and once I turn it back on again it does not short.
I have had the circuit breaker replaced, the element replaced although the second element was not as it was disconnected from the booster (this is what I am being told anyway). Any ideas of what could be causing this please?

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jimmy popejoy September 5, 2013 at 1:55 pm

Hello, My elderly neighbor called me over about his high electric bill, we started checking out things and seems to be pointing to the Electric water heater. When heater breaker is shut off the meter slows. We adjusted thermostats lower and heard audible clicks as if to be off, but turn breaker back on and meter speeds up. Both thermostats seem to be working properly. We have monitered meter for 2 to 6 hours and it does not slow down unless breaker is off. Scratching our heads.

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John Bird August 4, 2013 at 4:18 pm

Have just replaced the T&P Valve as corrosion had eatern away the inlet valve of the T&P, and mains water was flowing into Hot water tank non stop causing hot water to overflow out the drain pipe. Even with a NEW T&P fitted the mains water is still flowing and HOT water is running out of the drain pipe, if not the T&P valve what else could be wrong? Have checked mains water pressure and it is half the rated T&P valve rating.

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Karie Fay August 23, 2013 at 12:47 pm

Hi John,

If I understand your problem correctly, the water flowing in is from the “thermal expansion control valve” that’s part of the shutoff. If so, it might be because the heater’s thermostat or gas control valve failed, making the tank get too hot. I particularly suspect that since the temperature and pressure relief valve needed replacement. IF the heater is indeed running too hot, fix that cause. But the thermal expansion control valve (a colored valve near the heater on the water pipe itself) may be bad.

Hope that helps,
Karie Fay

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Iggy Ortiz July 30, 2013 at 5:14 pm

I have a new water heater and we have been on vacation for a few months so we had the Gas turned off while on vacation. We just had the city come out and turn the gas back on so that we can take our warm showers. Now we have a slow leak coming out the side and down the long pipe. How do we stop this? Is this caused by pressure that’s building up because it was off for a while? What do you recommend?

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Karie Fay August 9, 2013 at 12:59 am

Hi Iggy,

I can’t be certain at this time what caused it. I will say that I suggest having a professional service it for you. When it comes to gas, it’s just too dangerous to DIY unless you know what you are doing.

Good Luck,
Karie Fay

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Earl Biedermann July 28, 2013 at 8:58 pm

We just installed a tankless heater. Like an above poster we are having trouble with the water staying heated. We get apx 30seconds of hot water and then it is gone! The flames are running but I did notice they star high and just as the water starts to cool the flames die down to about hal of what they were. Any idea what might cause it? We hadgas and water pressure checked and all is good there.

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Karie Fay August 9, 2013 at 1:03 am

Hi Earl,

Have you checked all your settings? Specifically, take a look at the valve set temperature and the flow rate. Just like a tank-style water heater, you need to set the temperature. I would start there. Your installer should also be able to give you more information.

Hope that helps,
Karie Fay

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Joe Cam June 11, 2013 at 3:52 pm

Trying to figure out a problem with my parents gas hot water heater. I was over visiting today and heard a loud knocking noise sounding as if it was coming from the pipes. They have two rudd hot water heaters each 65 gallons. They are heated by gas and are vented. The main water supply line coming into the top of the unit, was making a noise. I noticed the motor to the vent was unplugged. When I shut off the valve to the water supply line the noise stopped. I waited about 5 minutes, plugged in the vent motor and turned on the valve for the supply. It seemed to quiet down. I don’t know if this was a back pressure problem or not. Mom called her plumber earlier today who said it’s due to the outdoor sprinkler system which is set up on a submeter and no where near the hot water heater supply lines. Any suggestions on what could be the cause of this knocking noise. It just started the other day. Any help would be appreciated.

Thanks,
Joe

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Michelle July 22, 2013 at 8:02 pm

I have knocking noises and consulted a plumber. He stated that there is lime build up inside of the unit caused by the water.

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Karie Fay July 25, 2013 at 9:03 pm

Hi Joe,

Banging or knocking near a water heater can indeed arise from sediment in the tank. However, given you mentioned the vent was unplugged, I wonder if it has more to do with air pressure, or even a type of water hammer.

I would suggest you try to purge the system of air, and make sure you have a “pressure reducer” that prevents air and water from competing, causing any knocking sounds. It sounds possible to me that if the sprinkler is working, when it comes on and off it affects the water supply, which shows at the water heater as you noted. However, it’s best to get a second opinion from another reputable plumber. There’s several possible things going on. I wouldn’t just let it go, however. Noises like you describe are not normal.

Hope that helps!
Karie Fay

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squirrel4207 June 9, 2013 at 6:08 pm

i have a tankless water heater on a well water system. that for some strange reson seems to fluctuate from ice cold to burning hot within about 5 to 10 minute inccrements when i shower.. why and what could be wrong with my system? closest i can figiur. my heater is steaming the water at some point causeing a vapor lock . sorta.. but i cant ajust the temperature or anything on it

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Karie Fay July 25, 2013 at 9:16 pm

Hi Squirrel,

There’s several possible reasons a tankless water heater will fluctuate between ice cold and scalding hot while you are running hot water. You might have too low of water pressure (someone else running hot water, an undersized WH — you need minimum 30psi water pressure) or you may have restricted hot water flow, caused by hard water deposits clogging your shower head for instance (does it happen in the kitchen if you run the water for a while?) You can dissolve hard water scale with vinegar and a little elbow grease.

I would also check the inlet filter screen — it might be dirty, preventing good flow. The filter is at the bottom of the unit, and removes and cleans easily (or replace it if preferred).

Problematic plumbing may cause the problem too. A faulty mixing valve, incorrect plumbing installation, or incorrect water heater settings (check the valve set temperature and the activation flow rate). To check the flow rate, measure the fill time — if it’s longer than usual you know that’s the issue.

Your manufacturer’s product manual should have detailed instructions concerning these parts.

Hope that helps,
Karie Fay

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robert parsons May 25, 2013 at 8:44 am

I just had a local professional install a new Whirlpool gas hot water heater. Now, the strangest thing is happening. Each facet in the house will run cold, or slightly mixed water. If I turn on a shower, it might run hot, then if I run the kitchen facet the hot water in the shower runs cold. This continues throughout the whole house, cold – hot – sometimes no hot. Cold seems to be the only steady temperature that stays continuous.

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Karie Fay June 2, 2013 at 8:01 pm

Hi Robert,

Is your new Whirlpool a tank-based heater, or is it tankless? With a tankless system, the temperature of water in your pipes can fluctuate as you use hot water, then turn it off, then turn it on again — the water in the pipes cools down as it is sitting, so the first burst of water you get is cool. Also, tankless water heaters have a flow rate — if you don’t run your hot water fast (open your faucet) enough, the heater turns off, so what you get through your hot water tap isn’t getting heated at all.

If it’s a traditional tank water heater, there’s a few possibilities. One is that something broke loose inside your pipes during installation – a piece of solder for instance — restricting the flow of hot water. You could try opening a hot water faucet in your kitchen or bath, then, while the hot water flows, close the shut off valve located at the water heater. Repeat several times — it might work the obstruction loose (if this is the cause).

Another possibility is a bad mixing valve. A mixing valve is a device that allows a given amount of hot and cold to mix in order to get different water temperatures. You’ll see these on single-handle faucet fixtures, for instance. They can also be somewhere along your plumbing lines. Homeowners may install them to divert the hottest water to a given fixture, for instance.

To troubleshoot this cause, simply turn off the cold water entering your water heater, via the shut off valve. Next, turn on a hot water faucet. If water continues to flow — hot water especially — then you have a bad mixing valve between that fixture and the water heater. (Next you have to pinpoint where, if not the fixture itself.)

It’s also possible you have a problem with your water heater’s dip tube. A dip tube is a small pipe that runs underneath the cold water inlet and forces the incoming cold water to flow to the bottom of the tank, where it’s heated. When you run hot water, it is drawn from the top of the tank where the warmed water sits. IF the dip tube dislodges, breaks, or is defective, as your run hot water the water heater begins to refill with cool water which is at or near the top, instead of where it should be at the bottom.

The way to verify this is to turn off your cold water supply, disconnect the cold water inlet pipe at the top of the water heater, and pull out the dip tube to inspect it. It’s fairly simple to do, and the part is only a few dollars. Any damage should be obvious.

I still come back to pressure as my number one suspect given that when you turn on another faucet, your shower runs cool. It could turn out to be crossed plumbing lines or something else I am not thinking of. I would urge you to contact either the installer or even Whirlpool — I assume it’s under warranty still. In addition, a professional should have a satisfaction guarantee and be willing to make sure it is working correctly.

Hope this helps,
Karie Fay

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Morris J. Peterson April 21, 2013 at 6:30 am

Water heaters are needed to be check at least once year. Just as you think your unit is still operating doesn’t mean you don’t have to maintain its cleanliness and safety precautions. Having a plumbing inspection for your home is a must to ensure safety and cleanliness of your unit.

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