Troubleshooting an electric water heater and how fix heating problems
Electric water heater troubleshooting is easy when you
understand the heating process, know plumbing and
appliances. What you need
to know before doing any repairs is how electric water heater works and
what are the main components.
This is a heating expert guide written especially for
troubleshooting electric water heaters with 30, 40, 50 gallons
capacity and larger ones, for residential use.
Electric water heater elements and how they work
Cold water from house plumbing enters the heater tank, through the dip tube and fills the tank from bottom up.
The upper thermostat with pre-set temperature calls
for heating and turns on the upper heating element to heat the
water.
Water is getting warmer and when it reaches
the set temperature the top thermostat switches power to the
bottom thermostat and it applies power on the bottom heating element
until it reaches the set temperature.
If
the hot water in the top of the heater tank is too high the red
button will trip and cut the power to both heating elements.
Once
you open the tap for shower or dishes, hot water is drawn from
the top of the unit, through plumbing to the opened faucet.
For draining and tank flushing, there is a drain
valve
at the bottom of the tank.
Inside the heater tank, there
is sacrificial
anode rod that prevents corrosion due to the heating process. It is
replaceable.
Now,
when you know the basics, it is much easier to do electric
water
heater troubleshooting. We will assume during this presentation that
electric heater was properly installed and was function correctly
before the problem occurs.
Problems and troubleshooting described below are related exclusively
to electric heaters, tank type. For water heaters troubleshooting
repairs with common problems, for both gas and electric units go back here.
Note:
Basic electrical knowledge is necessary to safely trouble shoot an
electric water heater.
Troubleshooting
Electric water
heater
troubleshooting - problem #1: No hot water
Solution
and how to repair:
Check is there a power at all; the main switch might be
off. If
you suddenly have no hot
water, your water usage may be exceeded the tank capacity. If that is
the
case, wait for the heater to recover.
Another solution might be; try pressing the red, reset button on the
upper thermostat. If after 10 min you still don't have hot
water,
check is electricity being delivered to the appliance; check
the
heater's pair of circuit breaker in the breaker panel.
If
breakers are ON, check if there is a voltage using the voltage
tester, at the input terminals of the upper heating element.
If
there is no voltage the thermostat has to be replaced; if there is
voltage the heating element needs replacing.
Other possible causes might be as follows:
Improper wiring - rewire per wiring diagram found in
the user manual
Shorted wiring - rewire
Circuit overload - reduce load or provide adequate
circuit
Grounded element or thermostat - rewire
Heat build-up due to loose wire - tighten wire
connections
Defective high limit switch - replace
Electric water
heater
troubleshooting - problem #2: Slow recovery,
takes too long to reheat
water
Solution
and how to repair:
If your electric heater was running for too
long, the odds are insufficient hot water for your shower and if it is
happening often, you have an undersized heater. Depending on
the recovery rate, you have to wait for a while for water to be
reheated.
Another cause is that the thermostat is set too low especially in the
winter time and in the cold room, where simple solution
is to increase the temperature, not to high, as the too hot
water
can lead to scalding and burns.
Your lower heating element or lower thermostat also might be faulty so
you
have to replace them.
If the scale is formed on the heating elements because of the hard
water action, the contact surface between fully immersed elements and
water is decreased and needs to be cleaned.
Improper, loose wiring or thermostat is not installed properly.
Thermostat has to be installed flush
with the tank so it cannot read the temperature accurately.
As
the electrical heating elements are used over months and years
of work, water condition in your home and area plumbing (hard water)
caused the buildup of scale and mineral sediments on
electrical heating elements.
Note: recommendation is to do the preventive maintenance and flush heater regularly.
To fix a problem, remove and clean heating elements from the
scale buildup. If it doesn't help, replace them.
Another
solution is to install low-watt density heating elements with
a
larger contact surface to transfer heat to water more efficiently.