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How to select and replace thermostat on electric water heater

Resource: How to replace thermostat on GAS water heater
2023
Upper and lower thermostats
thermostat temperature range
Buy residential upper and lower thermostats

Thermostats are interchangeable/ each works with your water heater
89T is discontinued/ replace with Apcom or Therm-o-disc

Buy 90-150° F for residential tank:
Rheem UV11698
Rheem SP11698
Camco 08163
Aprom / 90-150°
Water heater thermostats
Camco thermostats
More thermostats
Test upper thermostat
Adjust temperature using screwdriver. Typical residentail range 115-130°F
Typical bath shower is 104°/

All settings are approximate.
Higher temperatures risk scald.
Commercial water heater thermostatsCommercial only
... upper and lower thermostats

Buy  120-180 degree F
Rheem SP8293 upper / 110-170°
Camco 08314 lower / 180°
Rheem SP8295 lower / 110-170°
Camco 08304 upper/ 180°
Apcom WL6190 Upper 130-160°F
Apcom WH9C lower 135-180°F
Apcom WL6200 Upper 135-180°F

Residential tank thermostat is rated 90-160° F
Residential tank is NOT rated for pressure and temperature of 170-180° water.
Only use 180° F thermostat on commercial water heater that is rated for high temperature

Thermostats are rated for Single phase and 3-phase-non-balanced water heaters up to 480 Volt
Resource
How to change 3-phase water heater to single phase
Read more about 3-phase water heater
CAMCO-therm-o-disc-thermostats.pdf
Commercial-and-residential-electric-water-heater-thermostats.pdf
Electric-water-heater-thermostat-troubleshoot.pdf
Therm-o-disc-59T-66T-thermostat-Bulletin.pdf
All brands of thermostats are interchangeable

$48
for 2 low density 240 Volt 4500 watt elements/  + Upper and lower thermostat


Buy LOW density kit:
Apcom plumbers pack Amazon
110°-160°
Resource
How to replace elements

$35 for 2 high density 240 volt 4500 watt elements + Upper and lower thermostat

Apcom thermostats
Buy HIGH density kit:
Apcom plumbers pack Amazon
110°-160°
Resource
How to replace elements


Low density elements might last longer in hard water 
$45 for 2 high density 240 Volt 4500 watt elements/ + Upper and lower thermostat

Therm-o-disc thermostats
Buy HIGH density kit:
Therm-O-disc high density plumbers pack
Therm-O-disc high density
Therm-o-disc high density / copper element
90°-150°
Resource
How to replace elements
water heater element
Wires attach to either screw on element:
Reset button
Resources
How residential water heater works
How to replace thermostats on electric water heater
How to replace thermostats on gas water heater
Troubleshoot electric water heater
Troubleshoot gas water heater
Take apart thermostatsSee larger
How to make 3 terminal lower thermostat using upper thermostat

If water heater has foam insulation, then replacing lower thermostat with ECO protected thermostat may not be easy.
Take apart upper thermostat and make new lower thermostat that will work for the specific two-water heater diagrams shown above.

Do not remove ECO red reset protection on water heater.

Safety
ECO will trip at 170°F and protects you and protects the tank in event of overheating, and is required for safe operation of heater. Ordinary residential steel water heater tanks are rated for 150°F, but engineered to withstand rupture up to 300°F, assuming tank is not rusted. TP valve releases water at 210°F which is highest temperature allowed for any type water heater, to protect from violent steam explosion that will completely destroy home.

Thermostat failures: Sticking in open or closed position, calibration loss, melted parts, fire etc.

Thermostat temperature calibration is approximate in all thermostats.
Typically, bi-metal thermostats have triggering range from 5 to 15° for SPST (single element tank) and 17-27° (double-element tank) for SPDT.
Tank temperature can drop considerably before thermostats begins to heat water, and manufacturer says 'it's normal'.
Wide range can be annoying if you run low of hot water: Install new thermostat for better results.
Close range can cause TP to release water after several short draws of water from tank... because top of tank is already hot but added cold water activates thermostat and lower element makes more hot water that causes top of tank overheat.
Resources:
Ways to get more hot water
Therm-o-disc thermostat protectors Thermostat protectors/ for therm-o-disc upper and lower thermostats
Terminal protectors for therm-o-disc// Does not fit Apcom style
Protectors are important when inspecting water heater and pushing reset button without risk of electrocution
Never stand on wet surface or outdoor soil... always put down dry boards to stand on
Do not touch or lean into anything made of metal when working on water heater that has power.
Never touch wet water heater or water heater that was flooded... make certain power is OFF

Buy:
Camco 08113 Upper  thermostat shield
08103 Lower  thermostat shield
08130 kit with both thermostats and shields

Replacement steps start here
220 Volt circuit breaker
Power if OFF
Do not empty water out of heater
Turn power OFF
Turn off 20 or 30 Amp circuit breaker to 240V water heater See basic water heater wiring diagram
Or 20 Amp circuit breaker to 120V water heater

Check label on side of water heater for appliance voltage Figure volts amps watts
Wattage is stamped on end of element see example

water heater element
Never assume power is OFF/ Use non-contact voltage tester
Use non-contact voltage tester on timer, on wire, on outlet to see if power is present.
Press button on tester, if single beep then no power is present. If continuous beep then power is present.
Never stand on bare ground, always stand on dry boards, do not hold or touch anything metal when working on timer or water heater that has power, tape tester leads to wood sticks, never touch wet water heater, or flooded water heater, or timer that had a short or fire without turning power OFF.

Buy:
Multimeters at Amazon
Buy non-contact voltage tester at Amazon
Electric testers at Amazon
Shop Amazon - Industrial and scientific
Shop Amazon - Industrial Electric Products
Test water heater
How to find age of water heater
How to use ordinary tester/ 120, 208, or 240V:
Stand on dry boards
Never touch wet water heater unless power is OFF
Tape tester leads to wood sticks

1. Test black wire to ground wire

2. Test black wire to white wire

3. Test white wire to ground wire

If indicator lights up, then electricity is present.
water heater thermostats
Newer tanks have foam insulation that may need to be cut back. Insulation must be re-installed.
Do not empty water out of heater
Not necessary to wait for water to cool. Can be done with hot water inside tank.
Power must be OFF.
Use screwdriver to remove covers and insulation from tank

Some 240Volt tanks have single access door and single thermostat
Buy new parts that match old
Buy parts at hardware store
Thermostats and elements are generally interchangeable between brands of electric water heater
Exception is Whirlpool energy-smart shown lower on page.

Thermostats usually covered with plastic protector shield.
New protector shield packaged with some new thermostats
Purpose of protector is to protect homeowner from electrocution when pushing reset button or adjusting temperature when power is ON.
Older heaters may not have plastic shield.
Buy:
Upper element terminal protector
Lower element terminal protector
Take photo of wires ... before starting
Take photo of wires or draw picture showing location of each wire
Replace water heater thermostat
Larger image
See large image of overall wiring diagram
Wire colors can vary
Take photo of wiring before starting.


See upper thermostats showing numbers
Steps to replace thermostat
Instructions are same for both upper and lower thermostats
Power is OFF, and tested that power is off using steps above

Use digital camera and take photo of wires or draw picture showing location of each wire
Remove wires from thermostat
Thermostat is held in place by metal spring that snaps over ears on thermostat
Pull back metal spring on both sides (make a tool using piece of coat hanger wire)
Slide out old thermostat
Put new thermostat in place, wiggle thermostat around to make sure it is held flat and tight against tank by metal spring
Thermostat reads temperature through surface of metal tank
Use screwdriver to adjust temperature
See images showing how to adjust temperature to 120° (or higher if hot water runs short)
Re-connect wires <> tighten screws very firm against copper wire
Important .... Push-in red reset button firmly to make sure it is engaged
After thermostat is replaced, put factory insulation back over thermostat
Insulation must cover thermostat to avoid higher water temperatures than desired set point
Tank must be full of water or elements will instantly burn out
Turn power ON
Put ear against water heater to hear bubbly fizzing sound that says water heater is 'on'
If tank is fully heated, water heater will not turn on. If tank is partially heated, then lower element will turn on. If tank is cold, then upper element will turn on. How it works
Put access doors back on tank
Access doors and insulation are required for thermostat to read correct temperature

If water heater is still not working, see troubleshooting
Burned thermostat
Burned thermostat

What caused it?
Electricity found path from terminals on thermostat to bare metal tank. But fire did not spread because tank factory-installed covers and insulation were on side of tank
Always connect ground wire to water heater
Always keep insulation and cover installed on tank.
Inspection finds Burned thermostat or melted wire
Turn power OFF
Replace part
Test wires


Test wires with Multimeter
Buy:
Multimeters at Amazon

Resource
How to test water heater wires
Fire safety Fire safety

All wires must be same gauge (same diameter). Or connect different gauge wires using push-on wire connectors
Only copper wire used.
Solid wire only. Never use stranded wire.
Only copper under screw plate, no insulation under screw plate.
Maximum 2 wires under screw plate.
Wires must be fully inserted under screw plate. And screw plate very tight against wires.
Wires cannot run over top of thermostat or elements, and must be pushed aside.
Wires can run over top of other wires, but not at point where wires are making connection to either element or thermostat.
Use push-on wire connectors when wires are too short

Buy:
Push on wire connectors at Amazon
Red 3P connector (shown) for 10-14 gauge wire
Yellow 4P for 12-18 gauge wire
Push on wire connectors
Back of thermostat Thermostat must sit flat against tank
Wiggle thermostat to make sure it sits flat against tank
Thermostat sits flat against tank wall so temperature reading is accurate and water heater is protected from overheating

Access doors and insulation must be put back over thermostat to avoid higher water temperatures than desired set point, which leads to overheating, which will trip ECO reset.

See larger
Double-check thermostat wiring
Compare wiring with illustration

Resources:
How to wire thermostats
How water heater thermostats work

Red reset button:
ECO energy cut off turns off power to water heater when temperature reaches 150°-170°
Test upper thermostat Adjust temperature on thermostat using screwdriver.
Recommended temperature is 120 degrees F for efficiency and to avoid scalding water.
If home is running short of hot water, turn temperature up.
Thermostat settings are approximate. Calibration is different for each thermostat. Use cooking thermometer to measure water temperature when exact temperature is needed.

Problems from high temperature setting include higher bill, faster sediment build-up.
Minerals can distill out of water when water is above 140 degrees.
Water expands with higher heat. TP valve releases water. Pressure should not exceed 80 psi.
Resources:
How to adjust water heater temperature
9 ways to save with water heater
Test and replace TP valve.
Install expansion tank.
Inspect for leaks once per year.
Test for high water pressure over 80psi that can damage tank and pipes
Formulas and terminology
Insulation and cover must be over thermostat.
Exposing thermostat to cool room temperature will cause tank to overheat.
Thermostat cannot read correct temperature unless covered correctly.

Buy:
Upper element terminal protector
Lower element terminal protector

Resource
Troubleshoot electric water heater
Water heater leak Inspection finds leak/ rust around element

Resources:
Replace element and gasket
Inspect anode rod
Leaking water heater resources
How to install electric water heater
circuit breaker Circuit breakers/ push fully OFF / and then fully ON
Water heater is tripping breaker
How to replace circuit breaker
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How to reset circuit breaker
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Circuit breakers
How to install subpanel
Why you need ground wire
Match breaker and wire size
How to wire subpanel
See inside breaker box
How to wire safety switch
How to wire whole house surge protector
Figure volts amps and watts
Figure correct wire and breaker
electric thermostat on gas water heater Add another thermostat to water heater

For example turn off power to recirculation pump that pumps water from solar panel or secondary tank...or control electric water heater from the gas water heater... or turn off solenoid valve that turns off gas line... or connect to indicator light to notify when tank reaches set point... or connect to solenoid water valve that turns on hot water. Thermostat is mechanical and will work with 12-12 Volt AC-DC, 120-208-240, 277 volt AC electricity.

Resource
Add another thermostat to gas or electric water heater

How to install and troubleshoot gas water heater

How to wire off-peak water heater

Anode rods
Solar water heater
9+ ways to save with water heater
Recirculation system
Hot water circulation system
Do it yourself
Do it yourself water heater




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