Question about Water Heaters

# Electric Water Heater blows fuse, but only every few years

Electric water heater has two 4500w elements. Fuse box has 3 wires (white/black/red) with a 25A old-style glass fuse for each. Every few years (yes, years, no more often than that) one of the fuses blows for no obvious reason. One time it was the red wire, the last 3 times it has been the black wire. Any idea why this is happening? Bottom line: I don't know what size fuses to use. I calculated A (amps) = W (wattage) divided by V (volts): A = 9000 / 120 = 75A, split equally among 3 fuses at 25A each. Is that how it works? Should I be using 30A fuses? Should I be using 240V in the calculation instead of 120V? Is it a bad idea to use one 30A fuse and two 25A fuses, if I don't have 3 of each? Thank you.

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• Water Heaters Master

Your residential water heater is not 9000 watts. Or it would blow the fuse every day and melt the wire. Instead, you have dual-element non-simultaneous 4500 watt water heater.
http://waterhatertimer.org/How-it-works.html
http://waterheatertimer.org/Figure-Volts-Amps-Watts-for-water-heater.html
Look at label for 'total connected watts'
http://waterheatertimer.org/images/Whirlpool-energy-smart-watt-rating-IMG_2600.jpg
25 amp breaker or fuse and 10 gauge wire is minimum acceptable for 4500 watt water heater.
http://waterheatertimer.org/Color-code-wire.html
Troubleshoot blowing breaker or fuse:
http://waterheatertimer.org/How-to-troubleshoot-electric-problems-with-water-heater.html#trip-breaker
Why does it blow fuse once each year?? I don't know.
Fuses and breakers trip when overheating occurs on wire.
Each fuse or breaker is rated for heat, and over time, it will get hot and then cool and then get hot again ... this action weakens fuse or breaker.
To solve problem: install 3500 watt elements (and clean sediment out of tank). Wire will run cooler, and fuse will last longer. Whole fuse box will demand less power, and run cooler, and will last longer as a result. So there is less stress on electric service panel.
http://waterheatertimer.org/How-to-replace-water-heater-element.html
3500 watt element will heat water to same temperature, but takes longer. For example: 4500 watt heats 21 gallons per hour, while 3500 watt heats 17 gallons per hour.

Posted on Apr 29, 2013

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Posted on Jan 02, 2017

ha ha ah

Posted on Oct 30, 2009

Your 220v hot water heater does not need the neutral(white) wire coming in. Bare wire goes to ground -green headed screw. Black goes to black, Red goes to red. White gets teminated with a wirenut or some electrical tape.

Posted on Jan 25, 2010

Hello,You are correct! Black/blue=black & Yellow=white 220volt single phase power.There are 3 wires for 3 phase power connection NOT the case in a home.Also an "off peak"timer option would use (black) only controlling the bottom element and (blue) controlling the top element.

Posted on Apr 21, 2010

Testimonial: "thank you I finally have hot water!!!!!"

SOURCE: Atwood 6 gal water heater

There should be an internal reset button.

Posted on Feb 08, 2011

Call Rheem
1-800-432-8373
They might ask you to contact the installer. If you installed it yourself ... well that is problematic. For example if vent condensation drain was not installed correctly, the condensation can drip down into the unit causing acidic water that will shorten life of heat exchanger.
Make sure there is affordable qualified service in your area before buying tankless water heater.
Avoid wallet thickness error.
http://waterheatertimer.org/pdf/Tankless-WT-Error.pdf
http://waterheatertimer.org/Troubleshoot-Rheem-Tankless-water-heater.html
Don't forget to keep up with yearly maintenance, and tankless cannot be exposed to more than 11 grains hardness in water.
http://waterheatertimer.org/pdf/Tankless-maintenance.pdf
And if you need a service manual for your Rheem tankless, well that is problematic since Rheem does not have service manuals ... might try reading Bosch or Bradford white service manuals.

Posted on Jul 31, 2012

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## Related Questions:

### Have 40 gallon electric hot water tank 10 gauge wire 20 amp double pole breaker federal pacific fuse box red black ground wire shows power on 2 hrs now not even Luke warm water what could be wrong

I'm an electrician and can help. Federal Pacific equipment is tough stuff. The company went out of business decades ago - due to faulty equipment they made. Aside from that..

There may be no power out of the breaker, bad connections between the breaker and water heater, bad thermostat, bad hi temp sensor, bad heating element and more. I wrote the article linked below - that will help you find and fix any of these problems and more - assuming you have the equipment and ability to work on electric water heaters. If not - call a licensed electrician.

How to Repair an Electric Water Heater

Jun 05, 2015 | Water Water Heaters

### Can I run the hot water heater with a generator

Yes.
Ordinary electric water heater can run on any voltage from any direction (excluding volt/amp ratings below what can heat element coil).

Voltages include single-phase, split phase, and 3-phase residential/commercial voltages with either 50 or 60 Hz.
http://waterheatertimer.org/How-to-wire-water-heater-for-120-Volt.html
http://waterheatertimer.org/How-to-wire-water-heater-thermostats.html#3-phase

Install line fuse.
30 amp fuse would be required to prevent wires from overheating, and eliminate fire hazard.

This information does NOT apply to energy-smart electric water heater with box on top of heater, or newer energy smart with electronics, or to hybrid water heaters, or heat pump water heaters with delicate electronic circuitry.

Why it works like this:
Ordinary electric water heater thermostats are mechanical bi-metal switches and respond to tank temperature, and are not operated by electricity.
Ordinary generic elecrtic water heater thermostats switch electricity on-off using mechanical bi-metal switch.
Heat elements are simple coil of thermal wire that gets hot when voltage is applied.
The element will get hot when power is applied.

Oct 29, 2012 | Rheem 40 GAL ELEC TALL Water Heater 6YR SC...

### We purchased a new electric hot water heater we installed it on a 220 line and we are not getting no hot water

check with a vom set on high voltage setting. for power... black wire to black wire,, white wire to red wire on heater ground wire to tank ..on 220v there is no neutral like on 110volts..check red reset button under top panel / control push on it resets it,,,

Apr 17, 2011 | Whirlpool Water Heaters

### Can i replace 4500watt elements with 5500watt on a 606 model

1) Manufacturer's warranty will be voided, and I've never seen recommendation that suggests better heating or saving money from replacing 4500W with different wattage element.

2) That being said, you have 240V water heater.
4500Watts divided by 240 = 18.75 amps
5500Watts divided by 240 = 23 amps

20 amp circuit breaker with 12 gauge wire is rated for 80% of load = 16amps
30 amp circuit breaker with 10 gauge wire is rated for 80% of load = 24amps.
http://waterheatertimer.org/Figure-Volts-Amps-Watts-for-water-heater.html

3) You can use 5500Watt element if you have 30 amp breaker and 10 gauge wire.

Feb 15, 2011 | RELIANCE ELECTRIC WATER HEATER

### Is the lower element suppose to have two legs of 120 to it? Or do i need to move a wire up top to make it 240? as it is on top element.

You have water heater with two elements.
Two-element water heaters are 240Volts.

1) Lets talk about what makes a 240Volt circuit
See basic water heater circuit:
http://waterheatertimer.org/B220C.html

Open link, and illustration at top of page is your water heater circuit

Notice that two insulated wires come from the circuit breaker and go to the water heater.
These two wires are 120volt each. When these two 120Volt wires combine, they create 240Volts
These are called hot wires because they come from the hot busbars.
There is also a bare copper wire that comes from neutral busbar.
The bare copper wire is a safeguard, and is not necessary for the 240V circuit to work.

Inside each circuit breaker box is 1 neutral busbar, and 2 hot busbars.
Open image below, and it shows typical residential breaker box
http://waterheatertimer.org/images/Inside-Main-Breaker-Box-420.jpg

In a residential home, each circuit takes two wires to complete the circuit.
For 120Volt circuit, you need 1 neutral wire and 1 hot wire to complete the circuit. These are usually a black and white wire. The bare copper wire is a safeguard.
For 240Volt circuit, you need 2 hot wires to complete the circuit, and each hot wire comes off a different busbar. These can be a black and white wire, and sometimes a black and red wire. The bare copper wire is a safeguard.

With a 240Volt water heater the two hot wires connect to the black and red wires located on top of water heater.

2) Let's talk about wiring inside a water heater.
http://waterheatertimer.org/images/WH-w-combined-530.jpg

Open image on link above, and it shows your 240volt water heater wiring.
The 2 hot wires from breaker box connect to the red and black wires on top of heater.
Inside each water heater, the wires are color-coded and will appear the same, or nearly the same, as shown on link above.
As long as your wiring appears like the image, and the hot wires from breaker box connect correctly, and the circuit breaker is working fine, then your water heater will work.

Add a comment any time.

3) More electric water heater links about water heaters, thermostats and tank wiring:
http://waterheatertimer.org/How-electric-water-heater-works.html
http://waterheatertimer.org/How-water-heater-thermostat-works.html
http://waterheatertimer.org/How-to-wire-water-heater-thermostats.html

Dec 28, 2010 | RELIANCE ELECTRIC WATER HEATER

### I replaced the heating elements(2) and switiches(2) on my Rudd electric hot water heater. Model PES 40-2. The switghes came with several wiring diagrams.(universal) Can I get a diagram specific to my...

Residential water heaters USUALLY follow same diagram unless water heater is wired for other purpose. Multiple diagrams on instructions show available options. Take photo of wiring before removing wires on any electrical device.
Upper element.
Black wire from top of heater connects to #1 top left screw.
Red wire from top connects to #3 top right screw.
Blue wire from upper element connects to #4 middle screw on right side
Red wire from lower element connects to #4 middle screw on right side
Yellow wire from upper element connects to #2 lower left screw
Black wire from lower thermostat connects to #4 lower right screw
Upper element: Yellow and Blue wires connect to either screw
Lower element: Red wire from top connects to either screw
Lower thermostat: Black wire from top connects to top screw
Short wire between lower thermostat and lower element

http://waterheatertimer.org/images/Water-heater-wiring-w-numbe.jpg
http://waterheatertimer.org/images/Thermostats-numbered-divided-500.jpg
http://waterheatertimer.org/How-to-wire-water-heater-thermostats.html

Sep 18, 2010 | Whirlpool Water Heaters

### OUR WATER HEATER IS BLOWING FUSES ..

1) Turn off power before touching water heater that is shorting or wet or was flooded.
2) Circuit breakers & fuses blow because of heat. A short will cause heat. Tighten screws on terminals inside box, listen for crackling sound/burning smell from loose-fitting parts.
3) Easy test for circuit breakers: move water heater wires to another same-size breaker. If same-size does not blow, then problem is breaker.
4) A short between fuse box and water heater could be gnawed electrical wire. Inspect wire.
5) Wires have size markings. 5500 watt water heater needs #10 wire. 4500 watt water heater needs #10 wire but can work with smaller #12 if distance is not long. See label on side of heater for wattage, voltage, etc. Element wattage is water heater wattage even with 2 elements.
http://waterheatertimer.org/Figure-Volts-Amps-Watts-for-water-heater.html
6) Short inside water heater can be elements or thermostat. Open covers and inspect parts for burning. Screws should be very tight against copper wire. Sediment could fill bottom of water heater cause lower element to short.
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http://waterheatertimer.org/How-to-troubleshoot-electric-water-heater.html

Sep 16, 2010 | Little Giant Water Heaters

### Wiring an electric water heater

Hello,You are correct! Black/blue=black & Yellow=white 220volt single phase power.There are 3 wires for 3 phase power connection NOT the case in a home.Also an "off peak"timer option would use (black) only controlling the bottom element and (blue) controlling the top element.

Apr 21, 2010 | Rheem 40 GAL ELEC TALL Water Heater 6YR SC...

### Rheem 50 Gal two 4500W heating element - not enough hot water

one element is off peak and one is boost could be thermostat or ripple controller in fuse box or one dead element

Apr 19, 2010 | Rheem 50 GAL ELEC TALL Water Heater 6YR SC...

### Little amount of hot water

Quite likely a bad element. There are two in electric HW heaters. Often the bottom one will fail so you only end up with the upper half heated up.

You can check it with a digital volt meter if you have one.

with the power off at the breaker box, you can remove the wires from the element and (using the ohm (resistance) setting) check across the terminals. it should read around (4500W/240V = 18 ohms).

How old a HW heater? might be time to replace it...

Peace,

Mar 05, 2010 | Water Heaters

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