Water Heater Repair, Maintenance and Troubleshooting Q&A
Be sure to scroll down... there may be more than one question on this page!
Is it okay to my drain water heater and shut off gas to it if the house is
going to vacant for 4-5 months? I am always afraid of water leaks.
Most people just turn the water off unless they are concerned with freezing.
Then you should drain down the entire system. However, there is a
potential problem with draining down the water heater for a long period of time
that you might want to consider... rust!
Water heaters are made from steel, which can rust. Even though modern
heaters are lined with a non-corrosive glass-like ceramic. However, this
is not 100% effective because it is impossible to coat 100% of the tank and the
material is prone to cracking during transportation and installation.
The rust is stopped by the use of a sacrificial anode, a long rod of
magnesium, aluminum or zinc that is put into the top of the tank and extends a
few feet into the water. These materials dissolve away more quickly than
steel through a electrochemical reaction (like a common car battery) and the
steel is not affected as long as the anode lasts.
Here is the problem. Draining the water stops the sparing action of the
anode and exposes the steel to the water vapor left in the closed tank.
This can cause increased rust and may decrease the life of the tank.
Though it is not unheard of for leaks to occur in the owner's absence, they
are minimized if you turn off the water to the whole house when you leave so
there is no pressure in the system. Of course, if a visual inspection of
your water heater shows evidence of corrosion or leaks anywhere, you should have
it checked BEFORE you hit the road!
What is the proper way to test the heating element(s) in a water
heater? I have heard they can be tested with the power either on or
off? Is one way better than the other?
To directly test the element, the electricity should be off.
The heating element in an electric water heater works the same as
the heating elements in ovens, toasters and the stove top. The
elements heat up because they highly resist the flow of electricity.
This "resistance" can be likened to friction, causing an
increase in heat.
If the element is broken... meaning the electricity
does not have a compete path to follow through the element... the
element will not heat up. Technically speaking, a broken element
has "infinite resistance" to the flow of electricity and zero continuity.
Resistance and continuity can easily be checked with an inexpensive
multimeter or battery powered continuity tester, available at most
hardware stores or Radio Shack. Turn off the electricity,
disconnect either wire from the element's terminals and test across
the terminals for continuity. If there is no "beep", or no
movement of the pointer on an analog multimeter, you can be sure that the element is
defective and needs replacing.
You can test across the terminals of the element for voltage (with
the electricity on and all wires connected), but the reading you get
may or may not indicate a problem with the element. An "off" or broken
circuit breaker, a defective thermostat or even a loose wire may be
the culprit, not the element itself.
My situation is this: My electric water heater is not working. I get 240V
at the heating element and also at the thermostat. What test can I perform on
the heating element or the thermostat to determine which is faulty without
If you are getting electricity at the heating elements, then the elements are
most likely burnt out. To test them, first turn off the electricity. Now you
must isolate them by disconnecting them from their thermostats. Set your
voltmeter to continuity test, or if that's not an option, set it to test
resistance. If you test infinite resistance, or if the continuity test reads open
circuit, then the element is bad. This is the same test you would use on a
kitchen stove burner or oven element.
If they do prove to be inoperable, chances are you have been heating your
water with one heating element for a while, since it would be unlikely that both
would fail simultaneously. You should notice a dramatic increase in the speed
and efficiency of your water heater after the repair.
If the terms continuity or voltmeter or open circuit don't mean anything to
you, perhaps you should pick up a really great book on appliance repair (pub 9/26/12), Troubleshooting and Repairing Major Appliances.
I have found the book to be an invaluable resource.
What do you think about tankless water heaters? I love the idea. When you turn on your hot water knob, the unit heats water as it enters your house.
There is no tank to collect sediment, or constantly heat water you may not use. Do you recommend them? Have they been on the market long enough
to be proven reliable? My local Home Depot doesn't carry them. Who would I
call, a plumber? Can you recommend any particular brands?
MD from Venice, FL
I think tankless water heaters are great but have some limitations that
make them unsuitable for some users.
They were originally designed to be used in situations where a tank is
undesirable and/or inefficient, such as a building with very minimal hot water
demand. They are more commonly used overseas than in the US, probably because we
are not as attuned to the economy and space saving attributes of these water
Since the water is heated as needed, there can be tremendous savings over
tank units that by design keep the water hot 24/7. And there are other more
conventional alternatives that may be as good or better. For example, the energy
(and dollar) savings are diminished or even nonexistent if the alternative is a
hot water system integrated into your gas or oil heating system. If the price of
gas or oil is especially low in your area, a standalone tank unit using these
fuels may be competitive if you take the extra effort to superinsulate the tank
(via wrapping the tank with insulation) and keep the temperature down to under
There is a trade-off you must understand before making a purchase decision on
a tankless water heater. Tank-type water heaters can supply enough hot water to
run multiple hot water appliances or showers at the same time, provided you buy
a unit with sufficient tank size for your projected usage and the size of your
household. Tankless heaters, on the other hand, have large drop offs in water
temperature as the flow through them increases. This is because of the way they
work. The elements in a tankless water heater can heat water up to an adjustable
maximum temperature, based on an assumption of the water flow through it and the
temperature of the water coming into it. As the incoming water temperature
drops, so does the outgoing temperature of the heated water. Of course, you can
install more than one tankless water heater in your home, to serve different
"zones", to solve volume problems.
One the positive side, with a tankless unit you never run out of hot water.
We all know the frustration of having the stinking hot water tank run out of
heated water during that critical final rinse! You know... the one that really
There are a number of companies online that sell these units. I cannot give a
product recommendation, but I suggest that you get the written manufacturer's
performance stats on a number of them before making a purchase decision. Another
possible source of information would be a hardcore plumbing supply house, rather
than a home store.
What are the signals that a water heater would give that it is time to
replace it. I built the house in the spring of 1985 and I still have the
original water heater. This water heater has never been drained, shortly after
it was installed the pressure valve leaked and was replaced, and I have been the
only person living in the house up until Sept 1997 when my mother moved in with
For about the past 3 months I have noticed that the pressure valve has
been leaking a little water, so when my brother came up for Xmas I asked him to
change it because it appeared it was slowly getting worse. Both the pressure
valve and the galvanized metal nipple showed a considerable amount of junk in
them. I replaced both.
The only noise I have ever heard from the water heater is a rumbling when a
faucet is turned on while the water heater is heating water.
BO in the Mojave Desert, CA
There is no tried and true way to know precisely when a water heater needs
replacement. Obviously, a leak in the body of the heater requires immediate
replacement. If there is a major malfunction, such as complete or partial loss
of hot water supply, leakage around plumbing fittings, or the appearance of
excessive corrosion on the heater body itself or at the heater's plumbing
connections, AND the unit is over 8 years old, replacement may be preferable
over repair (if a repair is possible, that is). I would leave this up to your
budget and repair skills.
All the active parts and most of the plumbing parts… the heating elements,
thermostat, anode rod, and the various valves… are designed to be replaceable.
The main obstacle to disassembly is corrosion. A water heater corrodes more
quickly than other plumbing fixtures because of the constant higher than room
temperature it operates at, and the fact that sometimes the water heater acts as
an electric ground, accelerating this corrosive process. Corrosion makes
replacing any parts chancy, since the replacement may leak, necessitating the
replacement of the entire heater.
So, like a conscientious Boy Scout, be prepared for the possibility of
replacement even when the repair seems simple and straightforward. So it goes
In your specific case, with a water heater over 13 years old, repairs are
probably not cost effective, since the life expectancy of a water heater is only
8 to 12 years. As they age, they become less efficient. This is true for all
heaters, but more for electric types. Modern water heaters have better
insulation and are more efficient "out of the box", so you may notice
dramatic savings in fuel and/or electric costs by replacing it.
I have a 40 gallon gas water heater. It is leaking at the base of each pipe
going into the top of water heater. Is this a problem with the water heater when
there is no leaking from the bottom?
C.M. from Lees Summit, MO
From your description it appears that you are getting leakage around the
threads for the in-and-out water supply lines into the heater. When this occurs
shortly after installation, it is an installation snafu. However, most leaks
that occur after years of service are caused by chemical corrosion that has
"dissolved" the threaded fittings. The corrosion is softer than the
original metal allowing water to seep around the threads. Eventually, the
fitting will begin to spray water. Therefore, even though you are not in
emergency mode as yet, this problem must be taken care of A.S.A.P. The leakage
may or may not be correctable, depending on the severity of the corrosion. Be
prepared… the only repair option may be replacing the water heater.
Most water heater connections are not designed to be taken apart without
cutting the pipes so a rescue operation will involve pipe cutting, disassembly
and examination of the fittings to determine whether or not they can be saved.
It may take nothing more than wrapping the threads of the threaded connector
with a few layers of Teflon pipe wrap and reassembling it. Then again, if the
corrosion has deeply pitted the fixed connector on the water tank, it may leak
when reassembled no matter what you do! Worst case… disassembly might even
damage the tank!
Since reattachment of the pipes will be pretty much the same for an old or a
new water heater, you should give some serious thought to replacing it now. If
the heater is ten or more years old, you have reached the end of its useful life
and would probably be better off getting a new one. Old water heaters, even if
they don't leak, tend to be less energy efficient. Even if you have been
diligent in draining the heater annually to remove energy-stealing sediment from
the tank, buildup of hard scale in the tank still robs you hard-earned money 24
hours a day!
Over a few years a new heater will probably pay for itself in energy
savings... with the added benefit of you NOT having to clean up the soggy mess
of a major water heater failure.
My pilot light won't stay lit on my hot water tank and I've been told it is
the thermocouple. I am very handy with most things around the house and would
like to try and install this myself. It is only a $6.00 part and yet they want
$40 to install it! Could you tell me the steps to installing a thermocouple. I
have the bottom cover off the tank and am familiar with where the pilot light
is. Could you please walk me through this?
This is one of the less dangerous gas appliance repairs since you do not have
to disconnect any gas lines. As a disclaimer, I am hesitant to encourage
inexperienced people to do their own gas appliance installations and repairs
because of the danger involved. Plumbers have special safety procedures and
tools to minimize the risk of explosion or fire.
First things first… turn off the gas at the main shutoff. If the heater has
been running let it cool for at least 20 minutes.
The thermocouple is located near the pilot light. It is designed as a safety
feature that automatically turns off the gas supply should the pilot go out. It
works by generating a small amount of electricity when heated, keeping the gas
valve open. The gas control valve is essentially a "dead man
switch"... if the electricity stops flowing, the switch opens and the valve
I cannot tell you the exact location or appearance of the thermocouple, but
if you purchase an exact replacement you should be able to visibly find it,
since it will be in plain view behind the inspection plate.
There is a tube attached to the thermocouple that must be disconnected from
the gas control valve. Once you unscrew the nut holding the tube in place, you
will be able to slide the thermocouple out of the bracket on which it rests. If
there is another fastening method, it should be obvious by visual inspection of
the old thermocouple.
The new thermocouple is installed by the reverse procedure... slide it in
place and then attach the thermocouple tube to the gas control valve.
If the new thermocouple does not attach exactly like the old one, stop the
repair and call or visit your parts supplier to be sure that you have the
Hope this is helpful... and be careful!
I watched the installation of a "Hot water Circulation Pump" on a
TV handyman show. I would like to procure one or two, but can't find a source.
Would you have any info on this device?
The device is a small pump installed under the sink of the bathroom furthest
from the hot water heater. It is connected to an electrical switch mounted under
the counter. It comes with flex hoses for easy connection into the water lines.
When the switch is pushed the pump circulates the hot water back to the cold
water side for a few minutes. This eliminates having to waste water for several
minutes until it is hot enough to use.
DB from Winter Park, FL
I heard of this type of recirculation system at least 20 years ago, though not
as a kit, in the days of the (shudder) energy crisis! Its availability was
proportional to the creativity of the plumber...in other words, an
improvisational job. I have wanted to try this project myself, as I have a
similar problem to yours. Having a very adequate well system in my own home, I
never felt pressured to institute extensive conservation measures (even if the
project seemed like fun). However, I know everyone is not as fortunate as I am
in this regard.
Let's walk through the concept, and see how you could build one yourself with
commonly available parts, and then discuss the "kit" .
First, the pump. The choice of the pump is critical. In a long ranch-style
home with one floor, the "head"... the height the water has to be
raised by the pump... is not very critical. However, a large multi-floor dwelling
will need a pump that can push the water from water source to the second (or
third) floor. This rise can be over 16 feet. The pump also must be able to
handle very hot water. Not all pumps are designed to handle water over 120
degrees. So the pump of choice would probably be a solar hot water system pump.
These run from $100 to $200.
The real trick in this project is to lace your return piping back to the cold
water inlet side of the hot water heater. This will require some ingenuity and
probably some minor demolition!
The connection is not extremely difficult but does require some plumbing skills
and electrical skills. The pump (outlet side) would be installed on a T-fitting
on the cold water line to the hot water heater, regardless of the type (tank or
furnace-fed). One pipe would have to be run from the faucet side of the hot
water shutoff all the way to the inlet side of the pump, forming a loop. The
pump acts as a one-way check valve so cold water can't be drawn up to the hot
As far as the electrical wiring goes, these pumps draw around one amp at 115
volts, meaning you should be able to connect it to an existing circuit in the
bathroom. I would put a switch near the pump as a shutoff. The pump
documentation should help you determine the type of wiring necessary for the
switch you locate under the bathroom sink. Also, I would use a standard
electrical wall-type switch in an electrical box under the sink. You will get
better service life than a push-type switch. Also, you will be able to tell if
the pump is on or off at a glance! If you wanted to get really exotic, and also
protect yourself from having the pump run too long... which would be a real
waste of hot water... you could use a timer switch instead.
There is a company on the web that sells this system in kit form. It is
called the Metlund Hot Water D'MAND System at
There are advantages to this kit
over a pure D-I-Y job. They supply a flexible copper tubing to speed
installation and temperature sensitive relays that automatically turn off the
pump when the hot water reaches the faucet. This system can also be used at
intermediate faucets on the line (such as in the kitchen or other bathrooms) by
installing a separate switch and relay under each sink. It has a low voltage
switch system, making the additional wiring easier because of the smaller wire
size used, along with reduced shock hazard at the remote bathrooms... a good
idea if you have kids.
They have a great schematic of the layout of these systems at the web site, that
is worth looking at if only out of curiosity!
I own a condo that is about 11 years old and my water heater is located
upstairs and I'm worried that it may burst and do some serious damage to my
place. I have had a few neighbors have their water heaters burst and had to
replace them. Would it be wise to replace mine?
The average life expectancy of a water heater is 8 to 12 years, though some
units last significantly longer. If I were you, I would begin shopping for
a new one before you pay for it twice! I must also stress the importance of having a drainage pan installed under
the new hot water heater. The pan functions as a catch basin for any
leakage. Many contractors install water heaters in attic spaces in condos,
especially in smaller units where living space is minimal and basements are
nonexistent. Unfortunately, they often do not install the pan, so any
leakage can be damaging or even catastrophic for the homeowner.
The pan has a drain built into it, which can be run into your plumbing drain
system or even to the outside of your home. This would be determined by the
code requirements for your area.
Our house is 4 years old. Recently we have been having problems
with our hot water heater. Sometimes the water is not hot. The pilot
light is on, the temperature is set correctly. Is it possible we need
to replace our hot water heater already? Someone told me there may be
sediment in the bottom of it. How do you take care of this without
getting into major expenses. Looking forward to your answer. Thank you
KD from a distant star
There is an article at the site on draining sediment out of water
Draining the tank in a gas water heater will improve the efficiency of
the heater if you have a significant accumulation of sediment. The
layer of sediment acts like insulation, slowing down regeneration…
the speed at which your water heats up.
It should be noted that sediment does not have a significant effect
on the efficiency of electric water heaters because the heating
elements are located above the bottom of the tank.
If draining the sediment does not improve the function of your
water heater, you should bring in a service person to examine it. I do
not encourage do-it-yourselfers to experiment on gas appliances.
I have a problem with the temperature of the water in my home. I
have a hot water heating system, and my water is heated by the same
furnace. I do not have a hot water tank. Instead, the water comes
directly from the furnace. According to my oil burner company, I must
keep the temperature of the water in the furnace above 140 degrees or
my heating system will not work properly. This seems to be extremely
hot and I am concerned that my little one (when he is old enough to
reach the faucet) may burn himself. Should I insist he lower the
PB from Scranton, PA
You are without-a-doubt correct to be concerned about your water
temperature. Back in the good old days, it was not uncommon for water
heaters to be set at 160 degrees, more than hot enough to cause
immediate severe scalding burns! Nowadays, the standard setting for
hot water is between 110 and 120 degrees.
However, I would advise against changing the water temperature of
your furnace. Your furnace guy (or gal) is absolutely correct…
lowering the temperature will radically change the built-in efficiency
of your furnace and of your heating system as a whole.
Think about it… if you lower the temperature of the furnace, the
temperature of the water circulating through your radiators will
likewise be lowered. This will in turn increase the amount of time it
will take for your home to be heated. All things being equal, it takes
the same amount of oil to keep your home at a certain temperature
regardless of how hot the water is. Therefore, your oil burner will
have to cycle on and off more often to maintain this lower temperature
because it will take longer for the temperature to rise. This will
cause increased wear and tear on the furnace without any gain (or even
a loss) in efficiency. The most inefficient moment in your furnace's
operation is when it first starts up!
So instead of focusing on the furnace as the culprit, you can take
measures to lower the faucet hot water temperature AFTER it leaves the
furnace. This is done through the installation of a "mixing
valve". A mixing valve is a simple thermostatically-controlled
mechanism that mixes a little cold water with the hot water to lower
the temperature. Mixing valves are adjustable to product the desired
water temperature, but it is wise to use a thermometer to verify the
temperature at the tap. Installation does require some plumbing skills
such as pipe cutting and soldering, but the end result is worth it!
I have a gas hot water heater and I am having a problem lighting the pilot
light. For some reason the pilot does not stay lit when I turn the switch from
"pilot" to "on".
CP from Plainfield, IL
There is a safety device called a "thermocouple" in all gas furnaces and
water heaters that utilize a pilot light. The thermocouple generates an
electrical charge when heated, opening a valve which fuels the pilot flame.
Should the pilot light go out, the thermocouple cools quickly and the pilot
valve closes, preventing your home from filling with gas. The pilot position on
your valve switch essentially overrides the thermocouple, allowing you to light
There should be specific instructions for lighting the pilot light somewhere
on the unit, but if not, here is the generic procedure. First, turn the manual
gas control knob to "pilot". This position allows gas to flow to the pilot so
you can light it. You will notice that the knob is spring loaded and turns off
as soon as you release it. Once the pilot flame ignites, hold the knob in the
pilot position for about 30 seconds so that the flame thoroughly heats the
thermocouple. If the thermocouple is working properly, when you release the
manual valve, the pilot will remain lit. Turn the knob to the "on" position so
that gas can now flow to the main heating elements.
If this procedure fails, try holding the control knob open for up to a
minute. If the pilot light still refuses to stay lit, you may need to either
adjust the pilot light or replace the thermocouple. Both of these procedures are
fairly easy, safe and do not require you to disconnect any gas lines.
One of the books in our bookshop, Troubleshooting and Repairing Major Appliances, has a
great description of these repair procedures, as
well as repair and maintenance info on other appliances.
I have hear that there are products on the market that you can attach to
your shower head to produce instant hot water. Can you tell me some
manufacturers that make such a product and where they are located?
Instant hot water showers are available in many parts of the world. Actually,
the concept is ingenious. Instead of the intricate plumbing and wasted water
normally associated with showers, only one pipe... cold water... leads to the
heating unit which is conveniently located right inside the shower enclosure.
All adjustments for temperature are made at the heater which means instant and
fairly consistent water temperature with no wasted water or electrical power!
They are not available worldwide, though, in part due to a low product demand
in water-and-electrically-rich countries. For example, Alpha Electric, one of
the links below, currently exports to Australia, Singapore, Thailand, Indonesia,
Philippines, Vietnam, Fiji and United Arab Emirates. I could not find a company
that exported to the Americas.
These units currently aren't engineered to meet the strict electrical codes
in some countries. In the US, for example, electrical codes current don't allow
for any household-current electrical devices within shower enclosures. To get
these "instant showers" approved and the applicable electrical codes changed
would undoubtedly be a costly political battle. Also, the voltage requirements
may not be compatible with your own local power grid.
Here are three links to companies on the Web that offer these specialty
This sort of sensible alternative to central water heating will only occur
when governments... spurred on by public opinion... start encouraging reasonable
conservation through the use of these and other energy-saving devices.
For the first time in 10 years my gas water heater is dripping a small
amount of water out the relief valve discharge line onto the basement floor. Is
this ok or do I need repairs?
KO from Newnan, GA
Consider this little drip a polite warning sign that some repairs may be in
order. If you have not noticed any other changes in the system... unusual
increase in the temperature of the water, for example... then the valve is most
likely the culprit.
The only way that a water heater can become dangerously overpressurized is if
the thermostat(s) did not turn off the heating elements (in an electric unit) or
gas flame (in a gas unit) at the temperature setting of the water heater. This
can cause the water in the tank to overheat or even boil!. The valve is supposed
to open under these extreme conditions to protect the damage to the tank or to
your plumbing fixtures by relieving the pressure.
By your description, this does not sound like an emergency situation but it
could eventually turn into one. I would suggest having the pressure relief valve
replaced at your earliest convenience.
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