Rheem electric water heater model 71 305

Check water line going to heater for a cut off valve. If there’s not one, have a plumber add one unless you want to cut water off to entire dwelling.

Add an extrol expansion tank to the piping. You can get one for about thirty dollars from the hardware store.

Copy following link for FV lockout:
http://waterheatertimer.org/How-to-troubleshoot-gas-water-heater.html

GE water heater made by Rheem has a glass vial called TRD.
http://waterheatertimer.org/How-to-repair-Rheem-TRD.html

Copy following link to troubleshoot and see service manual by type of gas control valve:
Rheem does not post service manuals
http://waterheatertimer.org/How-to-troubleshoot-gas-water-heater.html#intellivent

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Drain valve should be located on bottom of water heater.
http://waterheatertimer.org/Water-heater-will-not-drain.html
http://waterheatertimer.org/images/Marathon-drain-valve-2.jpg
http://waterheatertimer.org/How-to-replace-water-heater-drain-valve.html

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Question posted under Rheem water heater.
Model number and gas valve are unknown. Add a comment.

Following information applies to typical tank-type gas water heater, and does not apply to tankless water heaters, boilers, indirect heaters, solar water heaters, etc or for electric water heater.

Electric water heater ECO is located on upper thermostat.
Open top cover and ECO can be reset by pushing in red reset button,
Or ECO can be replaced by replacing thermostat. Add a comment.

Open following link to see typical tank-type gas water heater ECOs:
http://waterheatertimer.org/images/Intellivent-ECO-900.jpg
http://waterheatertimer.org/images/Typical-gas-valve-500.jpg

The ECO will trip at 180-200 degrees F.
This happens when the thermostat fails, then the burner stays on, and the water will continue heating.

With most water heaters, the ECO is one-time use device and the gas control valve is replaced.
Some water heaters have resettable ECO, but the overheating problem has to be solved.
Each water heater is different.
Contact Rheem or read manual for correct procedure.

If you have intellivent gas control valve, open following links for typical service manual:
http://waterheatertimer.org/How-to-adjust-temperature-on-water-heater.html#intelli
http://waterheatertimer.org/pdf/Intellivent-service-manual.pdf

More resources:
http://waterheatertimer.org/How-to-install-gas-water-heater.html#troubleshoot

Shut off the water supply valve over the heater. Shut off the electric or gas to the heater.
If you have any house or basement water valves below the level of the heater, open them and open a valve that is higher to vent it.
If necessary, open the drain at the bottom of the heater and using hose or buckets, lower the level below the relief/thermostatic valve. Be careful, the water is hot and softens even heavy hoses.
Once the water level is down, unthread the downtube (if there is one) from the discharge of the relief valve, unthread the relief valve from the heater and either dope/tape the threads or replace the relief valve.

Write back with any questions.

You have electric water heater.
Electric water heaters are fully repairable by homeowner, excluding hybrid type.

Rheem electric water heaters:
http://www.rheem.com/products/tank_water_heaters/electric_water_heaters/
Rheem fury series manuals and models
http://www.rheem.com/product.aspx?id=09DF2BDD-5E11-4D32-B574-84ACFB8A4619

Age of Rheem water heater is shown first 4 digits of serial number located on side of tank: for example 0705 means July 2005.
Serial number also shows model number & wattage of elements in case you need to buy new generic 4-bolt type 4500 Watt element from hardware store.

A) If your water heater receives very cold incoming water, it may not heat fast enough to keep tank warm.
Add a tempering tank.
http://waterheatertimer.org/Tempering-tank.html
Add insulation over entire water heater except TP valve. Insulate pipes completely.
Read more information:
http://waterheatertimer.org/9-ways-to-save-with-water-heater.html

B) 40 or 50 gallon water heater is 240Volts and tank will have 2 access panels on front.
Rheem ships all water heaters with 4500 Watt elements.

Narrow down the suspects:
C) Water heater has some hot water.
This tells us upper element is working.
And that water heater electricity is working.
And that reset button is not tripped.
And that heater is not experiencing run-away overheating event.

That gives us 3 solid suspects.
1) lower element is burned out. Test lower element using inexpensive multi-meter from Home Depot.
http://waterheatertimer.org/How-to-test-water-heater-element.html
Replace element with same wattage shown on label, and clean out sediment:
This will restore water heater to full 99% efficiency.
http://waterheatertimer.org/How-to-clean-sediment-out-of-electric-water-heater.html
http://waterheatertimer.org/Clean-sediment-out-of-water-heater.html

2) Upper or lower thermostat is bad. Replace both thermostats for about $25.
http://waterheatertimer.org/How-to-replace-thermostat-on-electric-water-heater.html
If you want to test thermostats and all parts before replacing anything:
http://waterheatertimer.org/How-to-troubleshoot-electric-problems-with-water-heater.html

3) Burned or shorted wire. Turn off power. Open covers on side of tank. Remove insulation. Inspect parts for signs of high heat and burning. Especially lower element. Tighten any loose wires. Replace part that shows signs of burning.
Put insulation and cover back over thermostats so cooler outside temperature doesn't cause thermostat to misread tank temperature.

Rheem 4500 watt element

You have electric water heater.
Electric water heaters are fully repairable by homeowner, excluding hybrid type.

Rheem electric water heaters:
http://www.rheem.com/products/tank_water_heaters/electric_water_heaters/
Rheem fury series manuals and models
http://www.rheem.com/product.aspx?id=09DF2BDD-5E11-4D32-B574-84ACFB8A4619

Age of Rheem water heater is first 4 digits of serial number located on side of tank: for example 0705 means July 2005.
Serial number also shows model number & wattage of elements.

A) If your water heater receives very cold incoming water, it may not heat fast enough to keep tank warm.
Add a tempering tank.
http://waterheatertimer.org/Tempering-tank.html
Add insulation over entire water heater except TP valve. Insulate pipes completely.
Read more information:
http://waterheatertimer.org/9-ways-to-save-with-water-heater.html

B) If cold outside temperatures are not to blame, your water heater may have a bad thermostat or bad lower element.

C) 40 or 50 gallon water heater is 240Volts and tank will have 2 access panels on front.
Rheem ships all water heaters with 4500 Watt elements.

Narrow down the suspects:
D) Water heater has some hot water.
This tells us upper element is working.
And that water heater electricity is working.
And that reset button is not tripped.
And that heater is not experiencing run-away overheating event.

That gives us 3 solid suspects.
1) lower element is burned out. Test lower element using inexpensive multi-meter from Home Depot.
http://waterheatertimer.org/How-to-test-water-heater-element.html
Replace element with same wattage shown on label, and clean out sediment:
This will restore water heater to full 99% efficiency.
http://waterheatertimer.org/How-to-clean-sediment-out-of-electric-water-heater.html
http://waterheatertimer.org/Clean-sediment-out-of-water-heater.html

2) Upper or lower thermostat is bad. Replace both thermostats for about $25.
http://waterheatertimer.org/How-to-replace-thermostat-on-electric-water-heater.html
If you want to test thermostats and all parts before replacing anything:
http://waterheatertimer.org/How-to-troubleshoot-electric-problems-with-water-heater.html

3) Burned or shorted wire. Turn off power. Open covers on side of tank. Remove insulation. Inspect parts for signs of high heat and burning. Especially lower element. Tighten any loose wires. Replace part that shows signs of burning.
Put insulation and cover back over thermostats so cooler outside temperature doesn't cause thermostat to misread tank temperature.
Rheem element

If you are reffering to the drain valve at the bottom of the hot water tank. It may be leaking due to the O ring being cracked or worn out. You can either drain the tank and replace the valve or you can buy a hosebib brass cap and thread it on the existing valve. There is no cause for alarm when doing this as this valve is just to drain the tank when replacing your hot water heater