Electric water heater not heating? Element and thermostat checks

Why is the electric water heater cold or running out too soon?

An electric water heater that is not heating needs its supply, high-limit control, elements and thermostat switching checked in circuit order. On a conventional two-element, non-simultaneous heater, the upper element heats first and the lower element receives power after the upper thermostat is satisfied, as Bradford White explains in its May 2022 service manual. A 240 V, 4,500 W element calculates to 12.8 ohms; test its isolated terminals with power verified off, then screen each terminal to the flange for a conductive fault. Finish the repair by proving upper-to-lower transfer and recovery at the actual supply voltage and water-temperature rise.

A fully cold tank puts supply, the energy cut-off high limit (ECO) and the upper path first. A short hot draw puts transfer, the lower path and mixing first. Symptoms select tests, not replacement parts.

Ask whether every fixture is affected and whether failure followed a power interruption, drain/refill or element replacement. Compare heater-outlet temperature with mixed fixture temperature. A hot tank and a cold shower describe a different job from a tank that never heats.

Bradford White 238-51544-00D, Rev. 5/22, pp. 12 to 18 supplies these competing fault paths. Sediment work belongs in water-heater maintenance; first identify the water-heater type before applying a resistance-tank procedure.

What should you record before opening the covers?

Photograph the complete model/serial plate, wiring label, phase, supply rating, upper and lower element markings, thermostat settings and utility-control arrangement. Keep nominal capacity separate from rated storage volume.

Write down the local thermal state for each control test: cold upper zone, satisfied upper zone with cold lower zone, or both satisfied. An output reading without that condition is incomplete evidence.

How does a non-simultaneous water-heater circuit work?

Bradford White's May 2022 residential electric service manual describes non-simultaneous operation as upper-element heating followed by transfer to the lower thermostat, so an inactive lower element during an upper heat call is normal.

After a small draw, cold inlet water reaches the lower zone through the dip tube, so the lower element can restart while the upper stays satisfied. A large draw that cools the upper zone restores upper priority and interrupts lower heating.

All feeds isolated, absence of voltage verified
  -> full tank, purge complete, barriers restored -> enable supply
  -> ECO closed?
       No: no heating; diagnose ECO cause
       Yes: upper zone calls?
              Yes: UPPER ACTIVE, lower blocked
                    -> upper satisfies -> lower zone calls?
              No: --------------------> lower zone calls?
                                         Yes: LOWER ACTIVE
                                              -> large draw cools upper
                                                 -> UPPER ACTIVE (return)
                                         No: STANDBY, both inactive
Standby retains live supply; it is not isolation.

Functional heating-current paths, not replacement wiring:
Leg A -> ECO pole -> upper changeover common
                      | upper call -> upper element -> protected leg B
                      | upper satisfied -> lower thermostat
                                           | call -> lower element
                                                     -> protected leg B
                                           | satisfied -> open path
Leg B -> other ECO pole -> common side of both elements

The two ungrounded supply legs complete the 240 V heating loop; equipment ground is not its normal return. During standby, the upper control still selects the lower feed, the lower thermostat is open and the common element leg remains energized.

Two 4,500 W markings mean one 4,500 W active load on this circuit. Simultaneous operation would change the connected load.

What changes on other heater circuits?

Bradford White Rev. 5/22, pp. 6 to 11 distinguishes single-element, simultaneous, three-phase and off-peak arrangements. A single-element tank has one heating path; simultaneous and four-wire designs can have multiple active paths or independent feeds. Identify and isolate every feed, and use the actual three-phase configuration to distinguish line current from element current.

Record which off-peak circuit the utility controls and whether its schedule permits operation. An unavailable controlled lower feed is a supply/control condition, not proof of lower-thermostat failure. Do not apply this diagram to heat-pump, tankless or electronic equipment.

A. O. Smith 2000620230 Rev. C, December 2023 uses model-specific mode, sensor, relay and fault-code procedures for its hybrid families. Those procedures govern that equipment.

What setup makes element and thermostat checks reliable?

OSHA 29 CFR 1910.333, 2025 annual edition requires deenergizing exposed live parts unless an applicable exception is demonstrated, securing the disconnect under the electrical work-practice procedure and verifying absence of voltage. Apply these provisions within their general-industry workplace scope.

Identify every source, disconnect and lock/tag under the workplace procedure, then verify exposed circuits line-to-line and line-to-ground with appropriate contact test equipment. Thermostat settings and utility control commands are not disconnecting means. Anvilfield's field sequence checks the meter on a known source before and after this verification. OSHA's specific before/after instrument-check clause for circuits over 600 V is not a universal 240 V clause.

Only after verification, photograph and label connections and disconnect both element wires. Resistance mode uses the meter's own source and belongs on an isolated circuit. Restore connections before authorized energized diagnosis. Under OSHA 1910.333(a)(2) and (c)(2), qualified personnel use protective work practices, shielding and equipment appropriate to the exposed electrical hazards; a voltage test is not permission to repair live wiring.

Use the full electrical isolation and lockout procedure and multimeter testing guide. OSHA 1910.334(c), 2025 annual edition restricts electrical testing to qualified persons and requires inspected, suitably rated instruments and accessories.

Which instruments and test conditions belong on the job?

Bring a contact multimeter rated for the circuit and environment, intact leads, a clamp ammeter, thermometer, timer and the model wiring diagram. Clamp one conductor to measure element current; clamping the complete cable combines opposing currents. Never connect an ordinary meter's current input across the supply.

A continuity beep does not establish the correct element resistance. A noncontact indicator is a preliminary screen, not the absence-of-voltage record for exposed service work.

A DMM terminal-to-flange screen differs from a specified insulation-resistance test with a megohmmeter. Apply the model procedure before additional insulation testing, especially around electronic controls; do not impose an arbitrary test voltage or megohm pass limit.

Is the fault in the supply, high limit or heater circuit?

On the circuit depicted in Bradford White RE-I, Rev. 5/22, p. 14, supply is tested across upper-control L1 and L3 and ECO output across L1 and L4. Use those labels only after reconciling the installed wiring diagram to that circuit.

A 240 V split-phase supply requires the appropriate line-to-line reading. Record both line-to-ground values and the line-to-line value under the state being diagnosed. Two separate 120 V readings to ground do not by themselves prove a working 240 V supply across the heater.

Correct input with absent ECO output sends diagnosis through the manual's cool-down/reset branch. Isolate power before touching the reset. Investigate grounded elements, thermostat switching and thermostat contact with the tank; repeated resets are not a service repair.

For the covered Bradford White assembly, rated input with absent ECO output after the prescribed reset and with cool water directs replacement of the upper thermostat/ECO assembly. Repeated breaker operation is a separate symptom.

OSHA 1910.334(b)(2), 2025 annual edition requires establishing that the equipment and circuit can be safely energized before manual reclosing and prohibits repetitive manual breaker reclosing. Bypassing the ECO, jumpering controls or increasing breaker size does not correct the fault.

When is a missing voltage reading expected?

On an intact circuit, voltage across the lower element is absent during upper priority, and voltage across both elements is absent after satisfaction. Terminals can still be live to ground. A closed control contact has little voltage drop across that contact, while its output measured to the opposite supply leg can show rated voltage. Record both reference terminals so these measurements cannot be confused.

An unloaded supply reading can collapse during a heat call through a damaged connection. Compare input and active-element voltage in the same loaded state. With power isolated, inspect discolored, loose or heat-damaged terminations, repair the connection and its cause, then retest under load.

How many ohms should a water-heater element read?

For a 240 V, 4,500 W element covered by Bradford White's May 2022 RE-II test, nominal resistance is 12.8 ohms and the manual's ±6% criterion calculates to 12.03 to 13.57 ohms with the element isolated and power verified off.

Divide the element's rated voltage squared by rated watts to obtain nominal resistance: R = V_rated² / P_rated. Use rated voltage here even when actual supply is lower. Actual voltage enters the delivered-power calculation later.

These are Anvilfield estimates using Bradford White Rev. 5/22, pp. 3 and 15.

Resistance testing does not require draining. Keep the tank full for subsequent powered tests; drain below the opening only when replacing an element. With both wires removed, OL across the element indicates an open path after lead contact and meter operation are proved. Near-zero ohms calls for range/lead checks and element investigation, not acceptance as a normal heater.

How do you check for an element grounded to the tank?

With power verified off and both wires removed, test each terminal to the metal element flange. Bradford White's RE-II screen requires no conductive reading; a confirmed finite path directs element replacement. Prove contact on clean flange metal so corrosion or insulation cannot create a false OL, and record the actual display and range.

Normal coil resistance does not establish intact sheath insulation. Record the terminal-to-terminal result and both terminal-to-flange results separately. DMM OL describes this screen on the selected range; use the applicable additional manufacturer procedure for intermittent hot or wet faults.

Why do manufacturers give different resistance limits?

The Smith legacy nominal values differ from direct nameplate arithmetic; retain them only with that table’s procedure. Its hybrid screen does not authorize accepting a 20 ohm conventional 240 V/4,500 W element.

Criteria sources: Bradford White Rev. 5/22; A. O. Smith 320991-000, ©2006, pp. 47 and 55; A. O. Smith hybrid handbook Rev. C, December 2023, p. 18.

What power and current should an element draw at 208 or 240 V?

Anvilfield estimates that a nominal 240 V, 4,500 W element supplied at 208 V produces 3,380 W and draws 16.25 A, increasing ideal recovery time by about one-third for the same water mass and temperature rise.

For the same resistance, current changes directly with applied voltage and power changes with voltage squared. Divide actual volts by resistance for current; divide actual volts squared by resistance for watts: I_actual = V_actual/R; P_actual = V_actual²/R.

Anvilfield estimates use the electrical relationships in Bradford White Rev. 5/22, p. 3. The 120 V row means voltage actually applied across the element, not an assumption about every lost-leg fault.

Read every side of the element's terminal block for dual-voltage markings. Different printed wattages at 208 V and 240 V can describe the same coil in intended service. Establish the approved supply/element combination before declaring a voltage mismatch.

How do you distinguish an upper thermostat fault from a lower one?

Bradford White's May 2022 non-simultaneous thermostat procedure checks upper transfer and lower input before lower output, so absent power at the lower element alone does not prove a failed lower thermostat.

Verify supply, ECO function and isolated element results first. This matrix synthesizes Bradford White RE-III, pp. 17 to 18; numbered terminals must match the installed single-phase, non-simultaneous circuit.

Isolate and verify absence of voltage before accessing or changing mechanical thermostat settings. Reenergize only for qualified measurements under the required work practices, then isolate again for further adjustment. Record the local water condition beside each reading.

What proves upper-to-lower transfer?

Observe upper current stop and lower current start with the upper zone satisfied and the lower zone calling. Prove the transfer output, lower input and lower output in that order.

Turning a dial alone does not establish the thermal condition. The water must be on the specified side of the setting. Restore approved settings after testing.

What explains overheating or repeated ECO trips?

Separate continued control output, an element conducting to ground and a surface thermostat lifted off the tank. A surface control needs flush thermal contact to sense tank-wall temperature correctly. Bradford White Rev. 5/22, p. 12 explains that a grounded element can continue heating without drawing enough current to trip the breaker; an untripped breaker does not clear the element.

In Bradford White's prescribed above-setpoint test, continued rated output directs the applicable thermostat branch; below-rated readings direct a grounded-element recheck. Partial voltage is not a thermostat-only verdict. Use the installed control's markings and manual for high-limit temperatures rather than applying a universal ECO trip value.

What if the electrical tests pass but the hot water still runs out?

Compare tank outlet, mixed main and affected fixtures during the complaint. A hot heater outlet with one cool fixture directs the next test toward that fixture's mixing device. Hot storage with a cool tempered main directs it toward the master mixing valve and distribution.

Check a damaged or missing dip tube, reversed piping and cross-connections before declaring a correctly powered tank undersized. Keep required protection in service during isolation tests.

Use the mixing-valve guide at that branch and record the recirculation heat load when the loop removes heat during recovery.

Anvilfield estimates 26.56 gallons per hour (GPH) recovery from 4,500 W over a 70°F rise. A continuous hot-only 2 GPM draw takes 120 GPH, so stored water supplies the difference until depleted. For a mixed shower, multiply total flow by the mixed-to-cold temperature rise divided by the hot-to-cold rise. Using Smith’s 2006 handbook, p. 4 relationship, Anvilfield estimates that 2 GPM delivered at 105°F from 120°F storage and 50°F cold water draws 1.57 GPM, or 94.29 GPH, from storage before distribution losses.

Measure flow and duration, inlet temperature and unintended draws before changing capacity. Sediment inspection follows the maintenance branch; flushing does not repair an electrically open element.

After proving output, use water-heater sizing and selection to compare the measured load with storage and recovery.

How long should recovery take, and how do you test it?

Using Rheem's May 2024 recovery relationship and its XE50T06ST45U1 rated volume of 45 gallons, Anvilfield estimates 102 minutes to raise the water from 50°F to 120°F at a continuous 4,500 W, without draws and before heat losses.

The same 240 V element supplied at 208 V gives an estimated 135 minutes. Multiply gallons by temperature rise and the water-heating energy factor, then divide by delivered watts for hours. In the units below, the factor is 2.42 watt-hours per gallon per degree Fahrenheit.

GPH = P_actual / (2.42 × ΔT); t_minutes = 60 × 2.42 × gallons × ΔT / P_actual.

Rheem THD-PE06 N Rev. 10, May 2024, p. 2 lists XE50T06ST45U1 at 50 nominal gallons, 45 rated gallons, 21 GPH recovery at a 90°F rise and 61 gallons first-hour rating (FHR). Recovery rate, full-volume cold-start time and first-hour delivery are different quantities. Its 0.93 uniform energy factor (UEF) is a prescribed-cycle efficiency rating, not an instantaneous multiplier for element output.

How do you perform a no-draw recovery check?

Define the finish before starting: final upper and lower satisfaction, followed by recovered outlet and delivery temperatures against approved job settings. Upper shutoff alone proves transfer, not full-tank recovery. Fill and purge, close draws, and record any remaining recirculation load.

Log start time, inlet temperature, available initial upper/lower temperatures, settings, actual voltage and active-element current. Observe transfer and final satisfaction in the permitted service configuration with live parts guarded. Use installed or safely attached external sensors, recording location and whether each reading represents water or tank surface.

Anvilfield recommends a 10 to 15 minute logging interval plus transfer and finish entries. Opening a tap for a sample creates a draw: record its flow or volume separately. Do not remove a pressurized fitting to create a temperature point.

The energy model assumes uniform initial bulk temperature, uninterrupted input and no losses or draw. With unequal element ratings, use each stage’s actual watts and energized duration; upper and lower ratings cannot be added as continuous input. A top-outlet reading does not establish whole-tank average temperature. Investigate timing differences through cycling, actual voltage, draw and distribution loss; use OEM and project acceptance rather than an invented percentage tolerance.

How do you prove hot-water delivery after recovery?

Run a separate controlled draw with the site's required flow, duration and delivery temperature established beforehand. Record starting storage/outlet and inlet temperatures, test location, actual flow, duration, temperature trend and heater response. Keep mixing and scald controls operating and route discharge safely.

Anvilfield’s recording example specifies 2 GPM for 5 minutes, totaling 10 gallons. Measure actual flow, label it hot-only or mixed, and log temperature at the start and each minute.

A recovered outlet meeting target with one failing fixture returns diagnosis to mixing/distribution. Falling delivery throughout the building calls for comparing storage, measured hot-side demand, recovery, dip-tube condition and crossover.

Worked diagnostic exercise: a 240 V element on a 208 V supply

Use Rheem's published XE50T06ST45U1 inputs in a training exercise: 50 nominal/45 rated gallons and non-simultaneous 4,500 W/240 V elements. Select 50°F starting bulk water, 120°F target, nominal resistance, no draws and continuous active recovery without tank or distribution losses.

Use four records to distinguish reduced input from an open lower path: element marking, isolated element tests, lower-call voltage/current and upper transfer. Confirm model approval before changing supply or elements.

What is the diagnostic answer and repair proof?

1. Upper off while upper water is satisfied and lower water calls: normal transfer state; prove lower operation.
2. 12.8 ohms with 208 V and 16.25 A: consistent reduced input, giving the modeled 135-minute recovery.
3. Lower input present but output absent during a proved call: lower thermostat branch after prerequisite and wiring checks.
4. Element voltage present with zero current: isolate and investigate an open element or connection.
5. Finite terminal-to-flange path despite nominal coil resistance: grounded-element replacement branch.

Enter actual measurements in the repair verification record.

Which parts and settings belong in the repair?

Replace the component proved faulty. One open lower element does not establish failure of the upper element or either thermostat. Test both paths and controls, then document additional defects separately.

Match model/serial approval, voltage, wattage, mounting, insertion length, clearance, gasket and control function. An upper changeover thermostat is not interchangeable with a lower control. Low watt density reduces surface loading; a 4,500 W low-density element still supplies 4,500 W at rated voltage.

Fit and function sources are Bradford White Rev. 5/22, pp. 25 to 26, Smith 320991-000, p. 55 and Camco’s undated technical catalog. Bradford White specification 1201-0926 identifies the surface-control and immersed-element equipment context; actual model approval governs parts.

With power isolated and water cooled for handling/discharge, shut the cold inlet, open a hot faucet to relieve pressure and admit air, and route a drain hose safely and lower the tank water level below the element opening. Remove the old gasket, clean the seat, install a flat new gasket and tighten under the applicable instructions. Bradford White specifies a 1½ inch deep-well socket and warns against overtightening; it supplies no universal torque value.

Seat the thermostat flush under its retainer and reconnect to the label. Bradford White Rev. 08/26, p. 12 requires filling before power is restored: close the drain, open the cold inlet and open hot faucets until steady water flows. Close the faucets, leave the inlet open, inspect for leaks and restore protectors, insulation and covers before energizing. A proposed input change also requires the appropriate electrical load calculation and approved equipment configuration.

Should the thermostats be set to 120°F or 140°F?

Bradford White installation manual Rev. 08/26, p. 12 reports approximately 120°F U.S. factory settings and 140°F Canadian household-electric presets, attributing the latter to CSA C22.2 No. 110. DOE’s Energy Saver Guide, 2022 recommends 120°F for most people.

CDC’s Monitoring Building Water, March 26, 2026 recommends storage above 140°F and circulation at least 120°F for Legionella control, with scald controls at use. These sources address different operating objectives.

Restore approved storage and delivery settings under the building’s water-management requirements and applicable fixture limits. Verify actual temperatures with a thermometer: the dial is only a setting. Use the storage and tempered delivery control guide to keep those boundaries distinct.

What belongs in an element or thermostat repair scope?

Specify the failed component, approved replacement and verification work. Separate supply-circuit correction and tank replacement from element or thermostat service so the owner knows which fault each task addresses.

This scope table follows Bradford White’s component-specific service procedures. Access, drainage, seized fittings and utility scheduling affect labor; thermal recovery adds elapsed time, with attendance determined by the test plan.

Public-facility scopes should distinguish diagnosis, component allowances, supply correction and tank replacement so bidders cover the same work. Estimators building school and municipal water-heater service scopes use PorchRocket Bid Control to find public plumbing bids and past award records.

When does the tank need replacement?

A leaking tank shell opens the replacement branch; an element-gasket leak opens a repair branch. Identify the water source with power isolated before selecting either scope.

Repair verification record and handover checklist

Accept electrical operation against the installed model’s criteria, then record recovery and delivery against the site targets. A passed electrical test does not close an unresolved hot-water complaint.

Field checklist

• ☐ Identify model/serial, element ratings, circuit, phase and every feed.
• ☐ Record complaint location and separate storage/outlet/fixture temperatures.
• ☐ Inspect tank, gasket and wiring; identify any leak source.
• ☐ Isolate every supply; verify absence of voltage under the electrical procedure.
• ☐ Photograph/label connections before disconnecting.
• ☐ Calculate nameplate resistance; attach the OEM criterion.
• ☐ Record both coil resistances and four flange-screen results.
• ☐ Reconnect to label; restore required barriers for authorized energized diagnosis.
• ☐ Record supply/ECO pairs, readings and state.
• ☐ Prove upper call, transfer and lower call with voltage/current.
• ☐ Separate recurrent ECO ground/control/contact faults from breaker/supply faults.
• ☐ Record approved parts; renew gasket and seat thermostat flush.
• ☐ Fill/purge, leave inlet open, inspect leaks, restore protectors/insulation/covers; reenergize.
• ☐ Restore settings; verify outlet and tempered fixture temperatures.
• ☐ Log recovery through both final satisfactions, voltage, sensors, temperatures, timing, draws and recirculation.
• ☐ Test delivery against agreed flow/duration/temperature; separate electrical and delivery acceptance.
• ☐ Retain evidence, diagnosis, correction, remaining scope and maintenance due date.

Anvilfield’s checklist combines Bradford White service procedures, OSHA work practices, Rheem recovery arithmetic and CDC temperature guidance.

What does the owner receive?

Deliver the completed record with photographs and remaining work identified. “240 V good” without a terminal pair and circuit state cannot support the diagnosis.

Bradford White installation instructions Rev. 08/26, p. 14 call for at least annual qualified inspection and annual thermostat-operation checks, monthly sediment draw-off and two-year anode inspection shortened for conditions. Record the installed unit’s schedule rather than averaging it with the broader maintenance guide.

Give the next due date under the applicable manual and water-management program. Repeat diagnosis when symptoms return or after relevant repairs.

FAQs about electric water-heater elements and thermostats

How do you diagnose electric water-heater elements and thermostats?

Verify supply and high limit, test isolated elements for resistance and ground faults, then prove thermostat outputs in the correct heating state.

What is a non-simultaneous water-heater circuit?

It gives the upper element priority and transfers the heating call to the lower thermostat after the upper zone is satisfied.

How do I calculate heating-element resistance from the nameplate?

Divide rated volts squared by rated watts, then apply the installed model’s acceptance criterion.

How long does a no-hot-water recovery test take?

Anvilfield estimates 102 minutes for 45 gallons heated from 50°F to 120°F at continuous 4,500 W, before heat losses and draws; record actual conditions.

Can a water heater work with one failed element?

A failed lower path can leave limited upper-zone hot water; a failed upper path can prevent a cold upper-priority tank from heating.

Should both water-heater elements be on at once?

Only where the installed wiring design permits simultaneous operation; conventional non-simultaneous operation uses one at a time.

Does 120 V to ground mean a 240 V water heater has power?

No. Record the required line-to-line voltage, operating state and reference points.

Why does my water-heater reset button keep tripping?

Test for a grounded element, a thermostat that fails to open and a thermostat not seated against the tank; do not repeatedly reset it.

Can I use a 240 V element on 208 V?

The same resistance produces less heat at 208 V; the installed model’s approval and element markings govern that combination.

Can I replace a 4,500 W element with a 5,500 W element?

Only with manufacturer approval for the heater and supply circuit. Higher wattage changes current; matching the threads alone does not establish compatibility.

Do I have to drain a water heater to test the elements?

No. Isolated resistance/ground screening requires power verified off and wires removed; replacement requires draining below the element.

Should I replace both elements and thermostats at the same time?

Replace proved faulty components and document additional defects; one failed element does not establish failure of the other parts.

Anvilfield. Sources checked and page reviewed: 2026-11-05.

How to cite this page: Anvilfield, Electric water heater not heating? Element and thermostat checks, 2026, https://anvilfield.com/field-guides/plumbing/electric-water-heater-element-thermostat-diagnosis/

Update log: 2026-11-05: Reviewed source editions, electrical safety, circuit states, replacement procedure, recovery calculations and repair verification; added mixed-demand calculation and repair scope.

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Sources checked

• S1. Bradford White, Residential Electric Water Heaters Service Manual, 238-51544-00D, Rev. 5/22 pp. 3, 6 to 18, 25 to 27: formulas, circuits, fault tests and replacement. Reopened with curl and reviewed 2026-11-05.
• S2. A. O. Smith, Residential Gas and Electric Water Heater Service Handbook, 320991-000, ©2006 p. 4 mixing relationship; A-6/A-7, pp. 45 to 48 and 55: control testing and legacy resistance criterion. Reopened with curl and reviewed 2026-11-05.
• S3. Bradford White, Electric Water Heater Installation and Operation Manual, printed 238-44422-O0AB, Rev. 08/26 pp. 12 and 14: fill/purge, presets and maintenance. Reopened with curl and reviewed 2026-11-05.
• S4. Bradford White, Upright Electric Residential Water Heater specification, 1201-0926 Surface controls, manual-reset ECO and immersed-element equipment context. Reopened with curl and reviewed 2026-11-05.
• S5. Rheem, PERFORMANCE Electric Specifications, THD-PE06 N Rev. 10, 05/24 p. 2: XE50T06ST45U1 volume, input, recovery, FHR, UEF and 2.42 factor. Reopened with curl and reviewed 2026-11-05.
• S6. A. O. Smith, Hybrid Electric Heat Pump Water Heater Service Handbook, 2000620230 Rev. C, December 2023 p. 18: model-specific upper-element maintenance screen; hybrid procedure boundary. Reopened with curl and reviewed 2026-11-05.
• S7. OSHA, 29 CFR 1910.333, annual edition revised July 1, 2025 Official GovInfo text; deenergization, electrical lock/tag and verification within workplace scope. Reopened with curl and reviewed 2026-11-05.
• S8. OSHA, 29 CFR 1910.334, annual edition revised July 1, 2025 Official GovInfo text; (b)(2) breaker reclosing, (c) qualified testing and instruments. Reopened with curl and reviewed 2026-11-05.
• S9. Camco, Specialty Items technical catalog, undated Element fit, voltage/wattage, watt density and thermostat function; no printed revision identified. Reopened with curl and reviewed 2026-11-05.
• S10. U.S. Department of Energy, Energy Saver Guide, 2022 PDF p. 22: 120°F recommendation for most people. Reopened with curl and reviewed 2026-11-05.
• S11. CDC, Monitoring Building Water, March 26, 2026 Storage/circulation temperatures, measurement boundaries and scald controls for Legionella management. Reopened with curl and reviewed 2026-11-05.
• S12. University of Hawaii, Building Maintenance & Construction: Water Heating, undated live chapter Component terminology and instructional circuit overview. Reopened with curl and reviewed 2026-11-05.