SLEX-100 / REX-100 Installation, Operation & Maintenance
Halogen & HI-LED Explosion-Proof Sightglass Lights — Bulletin SL-IOM
Warning: These fixtures are for use in hazardous (classified) locations. Installation must be performed by a qualified electrician in accordance with the National Electrical Code (NEC), NFPA 70, and all applicable local codes. Verify that the fixture's hazardous location rating matches the area classification before installation. Failure to do so may result in fire, explosion, serious injury, or death.
Warning: De-energize the circuit before installation, maintenance, or lamp replacement. Do not open the fixture enclosure in a hazardous atmosphere unless the area has been verified gas-free. The fixture must be operated via a customer-supplied, separately listed hazardous-location switch.
Receiving, Storage & Handling
Inspect the fixture upon receipt for any shipping damage. If damage is found, file a claim with the carrier immediately before proceeding with installation. Retain all packing materials until the claim is resolved.
Store units in a dry, protected area free from corrosive fumes. Keep the borosilicate glass lens and conduit entries protected from impact. Do not place objects on top of the fixture.
Note: Verify the fixture model number and voltage rating on the nameplate match your application requirements before installation.
Components & Accessories
The SLEX-100 / REX-100 series consists of the following main components:
Fixture Body
Heavy-wall copper-free aluminum alloy casting (No. 356T6). Separate, individually explosion-proof lamp and wiring compartments.
Borosilicate Glass Lens
Precision-machined seal. Provides bright, glare-free light transmission into the sightglass or vessel.
Lamp
Halogen (100 W or 50 W) or HI-LED (8 W / 100 W equivalent). Lamp compartment is separately explosion-proof.
Mounting Brackets
Slotted brackets for easy installation on 3-1/4", 4", or larger circular sightglass flanges. Supplied with fixture.
Conduit Entries
½" FNPT conduit entries (3 places). Supply wire must be rated 150°C minimum.
Internal Reflector (REX-100 only)
Highly polished internal reflector increases illumination intensity over the standard SLEX-100 model.
Mounting Instructions
The SLEX-100 / REX-100 mounts completely externally to the sightglass flange — entirely outside vessel pressure. The fixture can be installed on new or existing sightglasses without modifying the vessel or process piping.
Caution: Confirm the sightglass flange diameter is 3-1/4", 4", or larger before proceeding. The supplied slotted mounting brackets are designed for these standard circular flange sizes. Contact Northeast Controls for non-standard flange configurations.
Standard Flange Mounting
Verify the area classification matches the fixture's hazardous location rating. De-energize the circuit before proceeding.
Position the fixture centered on the sightglass flange. The lens face must be flush against the sightglass window for maximum light transmission.
Slide the slotted mounting brackets into position on both sides of the sightglass flange. The brackets accommodate 3-1/4" and 4" standard circular flanges.
Tighten the bracket fasteners securely. The fixture must be rigidly mounted — vibration can reduce lamp life, particularly for halogen models.
Verify the fixture is centered on the sightglass and the lens is making full, even contact with the sightglass window.
SVTC Sanitary Clamp Model
The SLEX/SVTC and REX/SVTC models integrate the sightglass lens directly into the fixture body. The lens is an integral part of the unit — not a loose component. Install directly onto existing standard 3" or 4" sanitary clamp ferrules.
Clean the sanitary clamp ferrule seating surface. Inspect the PTFE gasket for damage — replace if necessary.
Position the SVTC assembly onto the ferrule. Align the sanitary clamp and hand-tighten.
Tighten the sanitary clamp to the torque specified for your clamp size and gasket material. Do not overtighten — the PTFE gasket requires only moderate torque.
Verify the assembly is secure and the clamp is fully seated before proceeding to electrical installation.
Note: The fixture can also be used as a dedicated illumination port paired with a separate viewing sightglass — for example, for TV camera or video monitoring applications. In this configuration, mount the fixture on the illumination port and position the camera at the viewing port.
Electrical Installation
Warning: All electrical installation must be performed by a qualified electrician in accordance with NEC Article 501 (Class I locations), NEC Article 502 (Class II locations), and all applicable local codes. The fixture must be operated via a separately listed hazardous-location switch — do not use a standard switch.
Caution: Supply wire must be rated for 150°C minimum. Use only approved conduit fittings and sealing fittings suitable for the area classification. Install a conduit sealing fitting within 18 inches of the fixture's conduit entry.
Verify the circuit is de-energized. Confirm the supply voltage matches the fixture nameplate voltage (120 V or 240 V).
Run conduit to the fixture using one of the three ½" FNPT conduit entries. Plug unused entries with listed explosion-proof plugs.
Install a conduit sealing fitting (Crouse-Hinds EYS or equivalent) within 18 inches of the fixture conduit entry, as required by NEC 501.15.
Open the wiring compartment cover. The lamp and wiring compartments are separately explosion-proof — do not open the lamp compartment during wiring.
Connect the supply wires to the terminal block inside the wiring compartment. Connect the ground wire to the grounding screw provided.
Replace the wiring compartment cover and tighten all cover screws fully. All threaded covers must be fully engaged — do not leave partially open.
Fill the conduit sealing fitting with approved sealing compound per manufacturer's instructions. Allow to cure fully before energizing.
Energize the circuit and verify the fixture illuminates. If the lamp does not light, de-energize and check wiring connections before proceeding.
Conduit Entry Specifications
- →½" FNPT — 3 entries provided
- →Unused entries: plug with listed XP plugs
- →Sealing fitting required within 18" of entry
- →Supply wire: 150°C minimum rating
- →Ground through conduit or grounding screw
Electrical Ratings
- →Voltage: 120 VAC standard (220/230/240 VAC available)
- →Max power: 100 W (UL & C-UL listed maximum)
- →HI-LED actual draw: 8 W
- →Approx. output: ~1,800 lumens
- →Listings: UL-844, C-UL/CSA C22.2 No. 137
Operation
The SLEX-100 / REX-100 is designed for continuous operation. Once properly installed and wired, the fixture requires no operator intervention during normal service.
Halogen Models
Halogen lamps operate at high temperatures. Allow the fixture to cool for at least 15 minutes before opening the lamp compartment for any reason. Avoid touching the halogen bulb with bare hands — skin oils will cause premature lamp failure. Use a clean cloth or gloves when handling replacement bulbs.
HI-LED Models
HI-LED models generate no significant heat and can run continuously without concern for overheating. The LED array is rated for 40,000–50,000 hours of continuous operation. No warm-up period is required — the fixture reaches full output immediately upon energizing.
Note: The fixture can be used as an illumination port for TV camera or video monitoring systems. In this application, the fixture provides the light source while a separate sightglass serves as the viewing port for the camera.
Routine Maintenance
The SLEX-100 / REX-100 requires minimal routine maintenance. The following tasks should be performed periodically:
Lens Cleaning
Clean the borosilicate glass lens periodically using a commercial glass cleaner (Windex® or equivalent). Never use abrasive cleaners, wire brushes, metal scrapers, or any material that could scratch the lens. The lens may be cleaned while the fixture is energized. A clean lens maximizes light transmission into the sightglass.
Bracket Inspection
Inspect mounting brackets periodically for looseness, corrosion, or damage. Tighten any loose fasteners. A loose fixture can vibrate against the sightglass flange, potentially damaging the lens seal or reducing lamp life in halogen models.
Conduit & Cover Inspection
Inspect conduit connections and cover screws periodically. All threaded covers must be fully engaged. Replace any damaged cover screws or gaskets immediately. Do not operate the fixture with a partially open or damaged cover in a hazardous location.
Lamp Replacement — Halogen Models
One of the key design advantages of the SLEX-100 / REX-100 is that the lamp can be replaced without removing the fixture from the sightglass or disturbing any wiring. The lamp and wiring compartments are separately explosion-proof.
Warning: De-energize the circuit and allow the fixture to cool for at least 15 minutes before opening the lamp compartment. The halogen lamp and fixture body reach high temperatures during operation.
Caution: Verify the area is free of flammable gases or vapors before opening any fixture compartment. If the area cannot be verified gas-free, the circuit must remain de-energized until the area is cleared.
De-energize the circuit at the hazardous-location switch. Wait at least 15 minutes for the fixture to cool.
Open the lamp compartment cover (separate from the wiring compartment). The lamp compartment is independently explosion-proof — wiring is not disturbed.
Remove the burned-out lamp. Do not touch the new halogen bulb with bare hands — use a clean cloth or gloves. Skin oils cause premature halogen lamp failure.
Install the replacement lamp. Verify it is the correct wattage and voltage for the fixture (see nameplate). Do not exceed the rated maximum wattage.
Replace the lamp compartment cover and tighten all cover screws fully.
Re-energize the circuit and verify the new lamp illuminates correctly.
Replacement Lamp Reference
Contact Northeast Controls to order replacement lamps. Always verify the replacement lamp wattage and voltage against the fixture nameplate before installation.
HI-LED Models — Maintenance
HI-LED models (SLEX-HI-LED, REX-HI-LED) are designed for maintenance-free operation. The LED array is rated for 40,000–50,000 hours of continuous service — approximately 5–6 years of 24/7 operation. Under normal conditions, no lamp replacement is required during this period.
LED Array Replacement
If the LED array fails before the rated service life, contact Northeast Controls for a replacement LED module. The LED array is a field-replaceable component. De-energize the circuit before opening any compartment.
Upgrading from Halogen to HI-LED
Existing SLEX-100 and REX-100 halogen fixtures can be retrofitted with the HI-LED lamp module. Contact Northeast Controls for retrofit kit availability and compatibility with your existing fixture model.
Specifications
Halogen Models
| Voltage | 120 VAC standard; 220/230/240 VAC available |
| Max Power | 100 W (UL & C-UL listed maximum) |
| Lamp Life | 1,000–2,000 hours (typical halogen) |
| Output | ~1,800 lumens |
| Conduit Entries | ½" FNPT (3 places) |
| Supply Wire | 150°C minimum rating required |
| Listings | UL-844, C-UL/CSA C22.2 No. 137 |
| Hazardous Rating | Class I Div. 1 & 2, Groups C, D; Class II Div. 1, Groups E, F, G |
| Temp Code | T4A (120°C) — Class I; T3C (160°C) — Class II |
| Housing | Copper-free aluminum alloy No. 356T6 |
| Lens | Borosilicate glass, precision-machined seal |
| Mounting | 3-1/4" or 4" circular sightglass flange (slotted brackets) |
HI-LED Models — Recommended
| Voltage | 120 VAC or 240 VAC |
| Actual Power Draw | 8 W (100 W equivalent output) |
| Lamp Life | 40,000–50,000 hours (continuous) |
| Output | ~1,800 lumens (22% more than 100W halogen) |
| Conduit Entries | ½" FNPT (3 places) |
| Supply Wire | 150°C minimum rating required |
| Listings | UL-844, C-UL/CSA C22.2 No. 137 |
| Hazardous Rating | Class I Div. 1 & 2, Groups C, D; Class II Div. 1, Groups E, F, G |
| Temp Code | T4A (120°C) — Class I; T3C (160°C) — Class II |
| Housing | Copper-free aluminum alloy No. 356T6 |
| Lens | Borosilicate glass, precision-machined seal |
| Energy Savings | 93% less energy vs. 100W halogen |
Dimensions
Typical Dimensions — SLEX-100 / REX-100
| Overall Width (across brackets) | 10-7/8" (276 mm) |
| Body Diameter | 4-1/2" (114 mm) |
| Body Height | 4-1/8" to 4-13/16" (depending on viewing angle) |
| Conduit Entries | ½" FNPT — 3 places |
| Mounting Flange Compatibility | 3-1/4", 4", or larger circular flanges |
| SVTC Sanitary Clamp Sizes | 3" or 4" sanitary clamp (standard) |
For certified dimensional drawings or factory prints, contact Northeast Controls. Refer to factory drawing SLEX-100-SVTC-DWG for SVTC sanitary clamp assembly details.
Spare Parts & Ordering Information
Contact Northeast Controls to order replacement lamps, LED modules, mounting brackets, or other spare parts. Have the fixture model number and nameplate information available when ordering.
Common Spare Parts
| Description | Notes |
|---|---|
| Halogen Lamp — 100 W, 120 V | For SLEX-100-00 / REX-100-00 |
| Halogen Lamp — 100 W, 240 V | For SLEX-100-01 / REX-100-01 |
| Halogen Lamp — 50 W, 240 V | For SLEX-100-02 / REX-100-02 |
| HI-LED Retrofit Module | Upgrades existing halogen SLEX/REX-100 to HI-LED — contact factory for compatibility |
| Mounting Bracket Set | Slotted brackets for 3-1/4" or 4" circular flanges |
| SVTC Gasket — PTFE | Replacement gasket for SVTC sanitary clamp models (3" or 4") |
| Borosilicate Glass Lens | Replacement lens assembly with precision-machined seal |
| Cover Screws | Replacement cover screws for lamp or wiring compartment |
Order Replacement Parts
Contact Northeast Controls with your fixture model number and nameplate information.
Listings & Certifications
UL-844
Electric lighting fixtures for hazardous (classified) locations
C-UL / CSA C22.2 No. 137
Canadian listing for hazardous location lighting fixtures
Made in USA
UL & cUL listed explosion-proof lighting for hazardous locations since 1969
SLEX-100 / REX-100 — Technical Support & Pricing
1-201-419-6111 · [email protected]
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