LED DownlightsRecessed
ConTech Lighting R4NC540K12D LED Downlight Manual
Setup, everyday use, maintenance and troubleshooting for the 4 in. recessed LED downlight, with verified specifications.
- Light output3,671 lumens
- Power38 W
- Efficacy96.6 lm/W
- Color temp.2700–4000K (selectable)
About the ConTech Lighting R4NC540K12D
ConTech Lighting model R4NC540K12D is a 4 in. recessed LED downlight that meets ENERGY STAR requirements for light output, efficacy and color quality. It produces 3,671 lumens from 38 W of input power, an efficacy of 96.6 lumens per watt. That efficacy is better than 83% of the 3,089 Recessed models in our database.
Light quality: the fixture offers selectable color temperatures of 2700K, 3000K, 3500K, or 4000K and a color rendering index of 82.
Notable features include continuous dimming (0–10 V supported). The rated light-source life is 55,000 hours.
Specifications
| Brand | ConTech Lighting |
|---|---|
| Model number | R4NC540K12D |
| Fixture type | Recessed |
| Nominal size / aperture | 4 in. |
| Light output | 3,671 lumens |
| Input power | 38.0 W |
| Efficacy | 96.6 lm/W |
| Color temperature(s) | 2700K, 3000K, 3500K, 4000K |
| Color rendering index (CRI) | 82 |
| Rated light-source life | 55,000 hours |
| Power factor | 0.99 |
| Continuously dimmable | Yes |
| Dimming control | 0–10 V |
| Indoor / outdoor use | Indoor/Outdoor |
| Tunable / selectable white | No |
| Full-color tunable | No |
| Selectable light output | No |
| Occupancy sensor | No |
| Connected (smart) capable | No |
Safety information
- Turn off power at the circuit breaker — not just the wall switch — before installing, removing or servicing the fixture, and confirm the circuit is dead with a non-contact voltage tester.
- Installation must comply with the National Electrical Code (NEC) or Canadian Electrical Code (CEC) and local codes. Many jurisdictions require a licensed electrician and a permit for new fixture locations or new wiring; if you are not comfortable with household wiring, hire one.
- Use only the junction box, housing, or mounting hardware specified in the installation instructions, and do not exceed the box-fill limits of the junction box.
- Install the fixture only on a circuit whose voltage matches the label, and never modify the LED driver or module.
- Connect dimmable fixtures only to dimmers the manufacturer lists as compatible, and keep the total connected LED load within the dimmer's LED rating (often much lower than its incandescent rating).
Installation and first-time setup
Recessed downlights mount above the ceiling, either in a new-construction housing fixed to joists before the drywall goes up or in a remodel housing that clips into a cutout in an existing ceiling. This model is a 4 in. fixture; use the cutout template from the manufacturer — never estimate the hole size.
- Plan the layout
Check for joists, ducts and pipes before cutting. As a starting point for general lighting, space fixtures about as far apart as the ceiling is high, and keep them about half that distance from walls; use closer spacing or more lumens for task areas.
- Turn off power
Switch off the breaker feeding the circuit and verify it is dead.
- Cut the opening
Trace the template and cut the opening with a drywall saw or hole saw. Keep the cut clean so the trim covers it fully.
- Wire the junction box
Feed the supply cable into the fixture's junction box through a cable clamp. Connect line to line, neutral to neutral and ground to ground with listed connectors, and close the box cover.
- Set options
Set the color-temperature selector before the fixture goes into the ceiling.
- Install the fixture
Push the housing or canless module into the opening until the mounting clips or springs grip the drywall and the trim sits flush.
- Restore power and test
Turn on the breaker and check operation through the full dimming range.
Using your downlight
Dimming
The fixture dims continuously. In addition to phase-cut (wall-box) dimming where supported, the certification data lists 0–10 V dimming. Check the manufacturer's compatibility list: most LED drivers work best with trailing-edge (ELV) or LED-rated dimmers, and some dimmers have a low-end trim adjustment that stops flicker at the bottom of the range.
0–10 V dimming uses a separate pair of low-voltage control wires (usually purple and gray, or purple and pink) run to a 0–10 V dimmer or lighting controller. Keep the control wiring separated from line-voltage conductors as the instructions and code require.
Choosing a color temperature
This fixture can be set to 2700K, 3000K, 3500K, or 4000K. Set every fixture in a room to the same setting — mismatched color temperatures are very noticeable.
| Setting | Appearance | Typical use |
|---|---|---|
| 2700K | Warm white, similar to incandescent | Living rooms, bedrooms, dining areas |
| 3000K | Soft warm white, similar to halogen | Kitchens, living spaces, hospitality |
| 3500K | Neutral warm | Kitchens, retail, offices |
| 4000K | Neutral / cool white | Offices, laundry rooms, garages |
Light output and placement
At 3,671 lumens, this is a high-output fixture suited to tall ceilings, lobbies, retail and other commercial spaces. LED fixtures reach full brightness instantly and are not shortened by frequent switching.
Care and maintenance
| When | What to do |
|---|---|
| Every 3–6 months | Dust the trim and lens with a soft, dry microfiber cloth with the light off and cool. Do not spray cleaner directly onto the fixture. |
| Every year | Check that the trim still sits flush and the springs or clips hold it firmly. A sagging trim can leave a gap that lets attic air leak. |
| When cleaning greasy kitchens | Wipe the lens with a cloth dampened in mild soapy water, then dry it. Avoid solvents and abrasive pads, which can cloud the lens. |
The integrated LEDs are not user-replaceable bulbs. The rated light-source life of 55,000 hours works out to roughly 50 years at 3 hours a day, or about 13 years at 12 hours a day. Over time the LEDs gradually dim rather than burning out; when output becomes too low, or if the driver fails, replace the fixture or LED module as the manufacturer directs.
Troubleshooting
Most downlight problems trace back to dimmer compatibility or wiring connections. Always turn off the breaker before opening the fixture or the junction box.
| Problem | Possible cause | What to try |
|---|---|---|
| Light does not turn on | Breaker off or tripped; loose wire connection; switch or dimmer failure. | Check the breaker; with power off, confirm connections in the junction box are tight; test with a standard switch. |
| Flickers or buzzes when dimmed | Dimmer not compatible with the LED driver; dimmer low-end trim set too low; too many or too few fixtures on the dimmer. | Use a dimmer on the manufacturer's compatibility list; adjust the dimmer's low-end trim; keep the load within the dimmer's LED rating. |
| Faint glow when switched off | Illuminated or smart switch leaking a small current; shared neutral wiring issue. | Try a standard switch; use a smart switch that has a neutral connection; have an electrician check the wiring. |
| Does not dim smoothly or turns off at low settings | Dimmer range not matched to the driver. | Raise the dimmer's minimum setting; consult the dimmer and fixture compatibility notes. |
| Color looks different from the other fixtures | Color-temperature selector set differently from neighboring fixtures. | Turn off power, check the selector setting and match it to the other fixtures. |
| Trim falls or hangs below the ceiling | Springs or clips not engaged; opening cut too large. | Reseat the springs in the receivers; use a trim with a wider flange or repair the drywall. |
| Turns off by itself after running a while | Driver overheating, often from insulation packed around a fixture or a loose connection. | Turn off power and check the installation. Do not cover Non-IC fixtures with insulation; call an electrician if the problem continues. |
Energy use and running costs
The ConTech Lighting R4NC540K12D draws 38 W. Used 3 hours a day — a typical home assumption — it consumes about 41.6 kWh a year, roughly $7.07 per year at an electricity price of $0.17 per kWh. In a commercial space lit 12 hours a day, the same fixture uses about 166 kWh, or $28.29 a year.
Efficacy — lumens of light per watt of electricity — is the best single measure of a fixture's efficiency. This model delivers 96.6 lm/W. That figure is better than 83% of the 3,089 Recessed models in our database.
| Daily use | Energy per year | Cost per year |
|---|---|---|
| 1 hour | 13.9 kWh | $2.36 |
| 3 hours | 41.6 kWh | $7.07 |
| 6 hours | 83.2 kWh | $14.15 |
| 12 hours | 166.4 kWh | $28.29 |
The listed power factor is 0.99, high enough that the fixture draws current efficiently from the supply — useful in commercial buildings with many fixtures on one circuit.
Dimming reduces power roughly in proportion to light output.
Frequently asked questions
How bright is the ConTech Lighting R4NC540K12D?
It is rated at 3,671 lumens while drawing 38 W, for an efficacy of 96.6 lumens per watt.
Is the ConTech Lighting R4NC540K12D dimmable?
Yes. It is continuously dimmable, and the certification data also lists 0–10 V dimming. Use a dimmer the manufacturer lists as compatible for flicker-free operation.
What color temperature is the ConTech Lighting R4NC540K12D?
It is selectable between 2700K, 3000K, 3500K, and 4000K. Set the selector before installation.
What size is the ConTech Lighting R4NC540K12D?
Its nominal size is 4 in. Confirm the exact cutout or housing dimensions in the manufacturer's installation sheet before purchasing.
How much does it cost to run the ConTech Lighting R4NC540K12D?
At 3 hours a day and $0.17/kWh, it costs about $7.07 a year to operate.
Sources and disclaimer
Specifications on this page come from the ENERGY STAR certified led downlights dataset published by the U.S. Environmental Protection Agency (record certified January 28, 2025), retrieved October 7, 2026.
The setup, operating, maintenance and troubleshooting guidance is written by ManualHarbor's editors for this specific product type and configuration. It is an independent guide — not a reproduction of the manufacturer's manual — and ManualHarbor is not affiliated with ConTech Lighting. Always follow the safety instructions, installation requirements and warranty terms supplied with your unit, and contact ConTech Lighting or an authorized service provider for warranty repairs and replacement parts.
Running-cost figures use assumed U.S. average utility prices and are estimates for comparison only. See our editorial methodology for details.
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