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How to wire off-peak water heater

Altered wiring will void product warranty.
Tip: Change wiring back to make warranty claim
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 / 110-160°
Water heater thermostats
Camco thermostats
More thermostats
Test upper thermostat
Adjust temperature using screwdriver. Typical residential 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
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
Water heater cover
Larger image
Thermostats must sit flat against tank, and be covered with insulation

Without insulation, thermostat is exposed to room temperature and will misread temperature and cause overheating.

Thermostat must sit flat against tank wall to read correct temperature. Wiggle thermostat. Check that bracket is not rusted and loose.

Steel cover should be reinstalled.

Plastic protector should be snapped over thermostat if available



Off-peak water heater/ Option #1
Buy from manufacturer, or rewire tank
Off-peak thermostat wiringSee image
Off-peak
Purpose of off-peak
Save energy during peak electric prices.

How it works
> Upper thermostat operates normally to keep top 2/3 tank hot.
> Lower thermostat heats bottom 1/3 of tank when ordered by off-peak meter or timer

Compare:
Off-peak water heater thermostats vs
Ordinary water heater thermostats

1. Lower thermostat is replaced with ECO-protected thermostat identical to upper thermostat. ECO safety red reset cuts off power when water in tank reaches dangerously high 170°F

2. Upper thermostat: the Red wire is moved from L4 to T4, so lower thermostat and element can only receive power if upper part of tank is heated. Color of wires vary.

3. Black wire from L1 on lower thermostat does not connect to upper thermostat T4 screw.

4. Black wire from L1 on lower thermostat runs to top of water heater for connection to output from off-peak meter, or off-peak timer.

5. At top of tank, Black L1 and Yellow L1 come from the same leg on 240V breaker, and the Black Hot 2 comes from other leg on 240V breaker. See image

Buy
36" drill bits
Fish bits

Resources:
See Off-peak operation sequence
How to wire thermostats
See all thermostat wiring diagrams
Tork DTU timer Off peak operation
Larger image
DPDT Timer wiring for OFF peak
DPDT timers can be wired to toggle water heater between peak and off-peak operation.
40 amp digital and mechanical timers with Nema3R indoor-outdoor enclosure

Wire water heater so lower part of tank is OFF during peak price times.
Less hot water is available.
Tank will probably not run during peak times unless hot is drawn from tap

Buy:
GM40AV Timer

Resources:
How to wire DPDT timers
How to wire thermostats
How electric water heaters work
EH40 ... 30 amp 7-day programmable Timer wiring for OFF peak
 Lower thermostat receives power only when timer is ON
Upper thermostat receives power full time

30 amp digital timer with Nema1 indoor enclosure
6 programs/ SPDT timer
Buy:
EH40
30 amp timers
EH40 timer

Resources:
Compare timers



Resource:

EH40 off-peak water heater timer
Tork DTU timer Off peak operation
Larger image
Timer wiring for OFF peak
Heavy duty 40 amp mechanical timer with Nema3R indoor-outdoor enclosure
Up to 12 programs per 24-hour day


T106R / outdoor metal box/ 240 Volt
40 amp/ NO NC
Buy
T106R indoor/ outdoor timer

Resources:
How to wire T106 timer

Off-peak option 2:
toggle water heater between 240 volt and 120 volt
How to wire T106 timer
Larger image
Toggle water heater between 240 and 120 Volt using timer or switch

1) Wires inside water heater are NOT changed.
2) Requires Neutral wire from any nearby outlet or from breaker box.
3) Objective: Save electricity by heating water slowly.
4) Water heater will not 'recover' as quickly. Will heat 5-15 gallons per hour instead of 20-30 gallons per hour.
5) No need to change breaker.
Just run additional neutral wire to timer.

240Volt Elements and thermostats will work with 120Volt or 240Volt

Element watt consumption drops when voltage drops


T106R / outdoor metal box/ 240 V
Buy
T106R outdoor

Resources:
How to wire T106 timer

Off-peak option 3:
DIY home WiFi or Zwave 
off-delay-water-heater
Larger image
Off peak Home automation
Use any zwave, wifi, insteon, or programmable timer rated for inductive load. Connect to DTST 30-40 amp open frame power relay.
Or use on-delay timer, off delay timer, cycle timer, twin timer etc.


Magnecraft relay with NO NC terminals 120 volt coil or 24 volt coil
Buy from my affiliate links
Magnecraft box and cover
Magnecraft w199 relays
Siemens power relays
Programmable timers
Zwave contactor
WiFi contactor

Resources:
Programmable timers
On-off-delay timer
\
Off peak sequence of operation
Off peak water heater sequence
Larger image

Off-peak option 4:
Add another water heater to store hot water

 ...so more hot water available at usage time
Add timer to either water heater -or- both water heaters
Two water heaters Install tanks in series:
Cold water enters heater #1 and then feeds into heater #2.

Wiring goes in reverse order:
Wire from circuit breaker arrives at heater #2, and then goes to heater #1 (as shown diagrams below)

IF WATER HEATER HAS FOAM INSULATION the wiring may not be possible without drilling hole to drop additional wire into lower part of tank.
This action will void water heater warranty.
Remember, for water heater to work correctly, the thermostats and element must be covered with insulation or thermostat will misread temperature.
Reduntant thermostats - two water heaters
Larger image
Add timer to either water heater or both water heaters
Redundant thermostats control 2 water heaters
Set upper thermostats at lower temperature than lower thermostats

Purpose:
Add additional tank so more hot water available at peak times, without adding additional wiring from breaker.

Heater #1 must be satisfied before power is sent to heater #2.
Heater #2 may not fully heat before heater #1 needs to turn ON again. This will happen IF water heater is poorly insulated or cold water is drawn from heater #1 or incoming water is very cold.

Sequence:
1) Power  from circuit breaker arrives at ECO-protected upper thermostat on heater #1
2) ECO protection required on upper part of tank to prevent overheating event since heat rises
3) Typical lower thermostat on heater #1 is replaced with ECO thermostat so power can be transferred to heater #2 when heater #1 thermostats are satisfied.
4) Once heater #1 is satisfied, power goes to heater #2.

Either heater can be wired for redundant or typical non-simultaneous operation.
The key is adding ECO-protected thermostat to lower part of heater #1, and adding wire from lower thermostat so power can be transferred to heater #2.


Resource:
Read about two water heaters
Two water heaters
Non-simultaneous thermostats control 2 water heaters

Simultaneous wiring will heat top of tank first.
Redundant will turn ON as soon as cold water enters tank. How electric water heater works

Purpose:
Add additional tank so more hot water available at peak times, without adding additional wiring.

Heater #1 must be satisfied before power is sent to heater #2.
Heater #2 may not fully heat before heater #1 needs to turn ON again. This will happen IF water heater is poorly insulated or cold water is drawn from heater #1 or incoming water is very cold.

Sequence is generally same as above.


Resource:
Read about two water heaters

Add timer to either water heater or both water heaters
Why does this work?
240volt water heaters have two hot wires from breaker. Each element is permanently connected to one hot wire, and will always test hot for 120Volt to ground.
Thermostat opens and closes second hot wire to element. This action turns element ON-OFF
Resource:
Basic water heater circuit
Thermostat is either Hot on T2 or Hot on T4, but never both.
Some ECO thermostats are numbered 2 and 4.
So the lower thermostat on water heater #1 will either send power to lower element on heater #1, or it will send power to heater #2.
Water heater #2 will not turn ON unless water heater #1 is OFF
When water heater #1 turns OFF, then heater #2 has 240V power available.

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

When not to use:
Do not remove ECO protection on upper part of tank.
On simultaneous and single-tank off-peak water heaters, the ECO is require for lower thermostat operation.
ECO protects you in case of overheating and is required for safe operation of water heaters.

If you cannot rewire water heater:
  WHQ water heater timer WHQ4 Water heater timerIf you cannot rewire water heater because of foam insulation or other factor such as warranty:

Re-plumb water heaters in series, and run additional 30 amp circuit to additional heater. Then put both water heater on a GM series timer

Buy:
GM40AV       120-208-240-277V
GM40AVQ       w/ back-up battery

Resources
How to wire GM40 series timers
See basic water heater circuit

Water heater timer for two water heaters
Both water heaters have same schedule & turn on-off at same time

More box-type water heater timers

Other Off-peak ideas
Adding home energy system is more expensive option.
Automated home energy system can regulate all appliances during peak pricing. Basically same as adding programmable timer to each appliance.
Difference is more control tweaks available with home energy system. For example, instead of turning heat OFF and water heater OFF, the system can decide to run one or the other so both do not operate at same time.
Example system: Brayden Energy Sentry
    Water heater element Change elements to lower wattage for slower heating
Good for homes with lower consumption and homes with peak electric pricing

Resource:
How to replace element
3-element tank from Giant Water Heater & Hydro-Quebec
Manual & specs
Product manual
Elk remote control contactor Elk remote control contactor (relay)

Works on 120Volt.
Plug into outlet.
Relay works with automated hardware.
Rated up to 60 amps.
Buy:
Elk relay contactor

Resource:
Elk-9200 manual
Intermatic CA3750
Larger image

Control water heater or pool pump with telephone or compute

Control water heater with Z-wave

Intermatic CA3750 contactor module
Contactor controlled by remote Z wave
5-year warranty/ 30 amp

Buy:
WiFi and Zwave contactors
Zwave hub
Zwave contactor
WiFi contactor

Resource:
How to wire and set up CA3750
How to wire wifi contactor
More contactors




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