my water heater sprung a leak through the upper heating element , It flooded
the space between the tank & casing (& laundry room). I drained the tank &
replaced the element, It still is not heating water.
is it likely that the lower element is also fried , & wouldn't it still heat
water if it was? what else could be my problem? I wonder if the water fried
the switch. should I just replace the whole WH?
It is likely that the incident led to the associated circuit
breaker tripping or the fuse blowing.
Any electrical equipment which may have been splashed or
soaked by the leak should be examined and tested and
replaced if necessary.
The other element will not have been affected by the
incident - unless its terminal assembly got wet.
If you are asking these sorts of questions - you ought to be
getting qualified assistance. 200+ volt circuits with water
and plenty of earthed exposed metalwork around is not a good
place to learn about investigating electrical faults.
Firstly, if there is a risk that the part of the thermostat
outside the tank (the part containing the terminals) got
wet, use a megger between the terminals and metal jacket to
check that the insulation has not been degraded.
Next using a continuity tester, check that you have
continuity between the terminals at room temperature.
Next heat the metal jacket of the thermostat up to and above
its trip setting, whilst monitoring the continuity between
terminals. A water bath with a thermometer suspended freely
in the water is the best heating medium. The thermostat
should open at the set temperature, as shown by the
continuity tester and thermometer. Obviously, only immerse
the metal-jacketed part of the thermostat in the water.
The possible faults are:
1) If the terminal area got wet, degraded insulation.
Replacing the thermostat is the safe option.
2) If a very high fault current flowed at the time of
failure, the contacts may remain permanently open (no
heating) or permanently shut (boiling water). Replacing the
thermostat is the only option.
Of those, 1) is highly likely if the terminal area did get
wet. 2) is very unlikely - the circuit breaker/fuse should
have tripped preventing this.
It is far more likely that you have no power at the unit
(fuse blown or circuit breaker tripped ) than that the
thermostat has failed due to a failed heating element.
thanks for the tips...
I did some Google research & what I found said to check for voltage at the
upper element, if there's no power there (but there is at at the
thermastat ), than the upper thermostat needs replaced. it doesn't submerge
into the tank, it is only against the outside of the tank.
what is your problem dickwad?
I know several union electricians, I could get free help if I wanted to bug
one of em. I am pretty sure I can handle it.
If you don't have anything helpful to say, shut the fuck up.
thank you for your time.
BTW: I changed the thermostat & It's up & running.
Glad it is working.
Contact (surface mounted) thermostats for electrical water
heaters aren't generally a good idea - if the thermostat
comes loose or otherwise has bad thermal contact with the
tank, the water temperature can rise to very dangerous
temperatures. Not only can any hot water user get badly
scalded, the water could boil and overpressurize itself or
another part of the system. They are more applicable to an
indirect heating system (with,say, a primary circuit with
its own upper temperature limit) as an additional, rather
than the only, temperature setting.
If it were me and I had to use a surface mounted thermostat,
I would either:
install two in series, both set to the required maximum
temperature. That way, if one thermostat fails, the other
will stil protect people and property.
add a thermal fuse clamped to the hot water outlet pipe,
again in series with the heater circuit. Choose one that
will limit water temperature to safe values.
The latter is my preference as they are far, far more
reliable than thermostats - which is important for this
As for your rather unkind comments to one poster - the guy
was giving sensible advice. Lots of people do kill
themselves attempting to do what you did. For all we know,
you could be seeing if the circuit is live by sticking your
fingers in the socket...
theses things are on almost all electric water heaters,
you >can readily buy
They are absolutely safe used on a secondary, indirectly
heated, hot water system. So on a standard central-heating
system which also heats the water, they are ideal. That is
why you see so many of them for sale - they are intended to
be used for such systems, which are commonplace. At the very
worst, the hot water temperature could rise to the
temperature of the primary circuit.
They are not safe enough to use to control a direct heating
source - such as an electrical immersion heater. Even if you
install them perfectly, if ever they get knocked, they can
lose good thermal contact with the tank and the tank
temperature can then rise to scalding or even boiling point.
So, sorry to disagree with you - but my views still stand.
It may be different in the US than the UK, as I assume you
are. Here, an electrical immersion heater would almost
invariably be controlled by a tube thermostat.
Now the various other US-based contributors to this group
haven't commented on this aspect - so you may be right that,
in the US, it is normal to control an electrical water
heater using a surface mount thermostat. Your surface mount
thermostats may be different - ours are typically held in
place by a spring band around the tank. They are relatively
easiy to displace and often are - as the tanks are typically
in an airing cupboard used by the householders to dry
clothes on or near the tank.
We do get a lot of children badly scalded in the UK from hot
water coming out of the tap at too high a temperature. Often
that is because the surface mount thermostat has become
displaced and the hot water has risen to the boiler primary
circuit temperature, which itself has been set higher than
advisable. This is, of course, for an indirectly heated tank
and not an electrically heated one.
Water coming out of a tap (faucet?) at anything approaching
190 degrees could cause horrendous injuries, as I am sure
Thus, under UK conditions, I would certainly want a
secondary protective device to limit hot water temperature,
in addition to a surface mount thermostat.
In the UK, an electrical water heater controlled by a
surface mount thermostat would probably be a diy-install -
no heating engineer would do this. So, had you been in the
UK, I would suspect that your original installation had been
installed by a previous owner and not a professional.
I just wanted to make sure that you knew the risks and what
will happen should the surface mounted thermostat get
knocked out of place.
Yes, our tanks are a bit different. They are made of copper,
for a start - so they don't need sacrificial anodes. The
thermostat slides into a tube built into the heater itself.
We do have surface mount thermostats but they are only used
to control an indirect heating system - these diagrams show
This is our versions of a surface mount thermostat:
Yours come with a secondary trip mechanism in the case of
over-temperature. Much safer than ours, which don't have
this, ass you can see. Also ours aren't protected behind a
metal plate - they are just pulled onto the tank by a spring
going around it. It is very easy to knock ours out of place.
So the chances of one of yours losing close mechanical
contact with the tank sounds to be a lot less than one of ours.
I can see now that it would be quite hard to add an extra
thermostat to your system- with our system it is very easy.
Thanks again for that. I would be much happier using one of
your surface mount types than one of ours! But your type
aren't available here.
I have to admit it, it looks as though the US system is better than the UK
UK immersion stats often fail closed resulting in boiling 212 degree f ( 100
degree cent ) coming out of the taps.
The water system cannot be over pressurised.