Lochinvar Electric Water Heater Not Heating
On this page (6 sections)
The Short Answer: A Lochinvar electric storage heater that stops heating usually has a tripped breaker or blown fuse, a tripped high-limit, or a failed element, thermostat or contactor. First confirm it really is an electric tank. Lochinvar also makes gas heaters, boilers and indirect tanks that have no elements. Check the breaker and disconnect once, then leave the internal testing to an electrician or service technician.
Make sure it’s an electric tank
Lochinvar sells a wide range of equipment, and the troubleshooting is completely different for each. Read the rating plate:
| What the rating plate or cabinet shows | What it is | Where to look instead |
|---|---|---|
| Voltage, phase and element wattage; no gas connection | Electric storage water heater | This page |
| Gas input rating and a vent pipe | Gas water heater or boiler | Gas troubleshooting for that model |
| Two pipe connections to a boiler, no elements or burner | Indirect tank (for example, Squire) | The boiler and tank controls; see indirect tank problems |
| Compressor and fan on top | Heat pump water heater | Heat pump section of the manual |
Residential electric tanks usually have two elements with a thermostat for each. Commercial electric models can have several elements, contactors, fuses and an electronic control, and may run on 208, 240 or 480 volts, single- or three-phase. Element ratings and fault messages are model-specific, so use the rating plate and that model’s manual.
What the symptom suggests
| What happens | Likely cause |
|---|---|
| No hot water at all, nothing on the display (if it has one) | No power: breaker, fused disconnect, or control fuse |
| No hot water, power on | High-limit tripped, or upper element or thermostat failed |
| Hot water runs out quickly | Lower element or thermostat (residential), or some elements out (commercial) |
| Breaker trips as soon as it’s reset | Short circuit in an element or wiring |
| Breaker trips after running a while | Element failing to ground, loose connection, or undersized circuit |
| Fault message on an electronic control | Use the model’s manual to look it up |
| Water inside an element access area | Element gasket leak or tank leak; leave power off |
What you can check safely
- Find every disconnect. Electric water heaters often have a breaker in the panel and a separate disconnect switch near the heater. Commercial units may have a fused disconnect. All must be on.
- Reset a tripped breaker once. If it trips again, immediately or after a few minutes, leave it off. See trips breaker after a few minutes.
- Read the display on models with an electronic control and write down any message before cycling power.
- Confirm the tank is full if it was recently drained or serviced. A hot water faucet should run with no air sputtering. An empty tank must not be powered.
- Check whether the problem is the heater or the fixtures. If the pipe leaving the heater is hot but taps are cool, a mixing valve or a crossover in the plumbing is more likely.
The high-limit (ECO) reset buttons are behind the access covers next to live terminals. Don’t press them yourself. Repeated high-limit trips mean something is overheating, and the technician needs to find the cause.
What the technician will check
An electrician or service technician will lock out power and verify it’s off. Then they test the supply voltage on each leg, test each element’s resistance and its insulation to ground, check the thermostats and high-limit switches, and, on commercial units, check contactors, fuses and the control’s fault history. They also inspect the wiring for heat damage at the terminals, which is a common cause of nuisance tripping. If an element has failed, they check for scale, which shortens element life in hard water. What causes a thermostat to burn up explains the heat-damage pattern they look for.
Repair or replace
Elements, thermostats, high-limits, contactors and fuses are normal repair parts. A burned control board or wiring harness is a larger repair. A leak from the tank itself, as opposed to an element gasket or fitting, means the heater needs replacing. On commercial units, check the warranty terms with Lochinvar using the serial number before buying parts.
Frequently Asked Questions
Q: Where is the reset button on a Lochinvar electric water heater? A: On most models, each thermostat has a high-limit reset behind its access cover, next to live wiring. Because the cover has to come off and the trip usually has a cause, a technician should do the reset after testing.
Q: Why does my Lochinvar heat a little, then go lukewarm? A: On a two-element heater, that usually means the lower element or its thermostat has failed, so only the top of the tank heats. On a commercial unit, one or more elements, or a contactor, may be out. A technician can test each one.
Manuals and supporting references
These links distinguish general safety information from model-specific documentation. A manual directory helps you locate your unit’s instructions; it does not establish that every model uses the same parts, codes, or test values.
- A. O. Smith: standard electric no-hot-water diagnostic chart (opens in a new tab)Professional diagnostic context for standard electric storage heaters; not instructions to open or test your appliance.
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