BioShieldUV® Magnetic (SL) Series
SL18-WallPlug, SL36-WallPlug, SL18-HVAC & SL36-HVAC. Complete installation with safety precautions, wiring, and maintenance.
Did You Order the Right Model?
This guide covers: SL18-WallPlug, SL36-WallPlug, SL18-HVAC, and SL36-HVAC. Select your model type below to see the correct installation steps. New to UV-C air purification? Read our Homeowner's Guide or see how BioShieldUV compares.
SL18-WallPlug & SL36-WallPlug
Plugs directly into a standard 110V–220V power outlet. No electrician needed. DIY-friendly — most installs completed in 20–30 minutes.
SL18-HVAC & SL36-HVAC
Direct wire to a dedicated 24VAC transformer. Ballast mounts outside the duct. Requires a licensed HVAC technician or electrician.
Warning & Safety Precautions
Follow all safety and building codes. Read carefully before installation.
UV Germicidal Lamp Safety Warning
THIS LUMINAIRE IS DESIGNED FOR USE WITH GERMICIDAL LAMPS AND MUST BE INSTALLED IN COMPLIANCE WITH COMPETENT TECHNICAL DIRECTIONS TO PREVENT THE USER'S EYE AND BARE SKIN FROM EXPOSURE TO HARMFUL UV RADIATION.
CE LUMINAIRE EST CONÇU POUR ÊTRE UTILISÉ AVEC DES LAMPES GERMICIDES ET DOIT ÊTRE INSTALLÉ EN STRICTE CONFORMITÉ AVEC LES INSTRUCTIONS AFIN D'ÉVITER QUE LES YEUX OU LA PEAU DE L'UTILISATEUR NE SOIENT EXPOSÉS AUX EFFETS NÉFASTES DES RAYONS UV
Electrical Safety
- Turn off the main power switch before plugging in or performing any maintenance.
- Electrical shock can cause injury or death.
- There may be more than one disconnect switch — check them all.
Lamp Handling
- Do not touch the lamp glass without gloves.
- If touched, wipe clean with isopropyl alcohol.
- Hand oils cause reduction in light intensity.
UV Eye Protection
- Never expose eyes directly to UV light.
- Looking at the UV lamp may cause eye damage.
- Wear safety glasses during installation.
Broken Lamp Hazard
- Never touch a broken lamp — contains mercury.
- If substance contacts skin, wash with mild soap.
- Clean up carefully and dispose properly.
UV Material Exposure
- UV-C light follows line-of-sight. Materials in direct exposure — plastic drain pans, flex duct liner, foam insulation, filter media, and wiring — may degrade over time.
- Shield any susceptible materials with aluminum foil tape before installing.
- Metal ductwork and components are unaffected.
Location Restrictions
- Dry locations only. Install in supply or return ductwork only. Do not install on the direct output side of an evaporator coil where moisture blow-off may contact the unit.
- Not for supplemental heating. Do not install in ductwork where supply air regularly exceeds 105°C (221°F). Not rated for installation adjacent to gas heat exchangers or electric heat strip elements.
- Improper installation, adjustment, alteration, service, or maintenance may cause fire or electrical shock.
Items Included
Parts included vary by model. Reference letters (A, B, C...) are used throughout this guide.
TruBlu™ UV-C Lamp
Magnetic Bracket
Power Supply
Lamp Cable
Cable Gland
Step Drill Bit
Warning Sticker
Sight Glass Lens
Self-Tapping Screws (×4)
Tap-In IDC (×2)
Safety Precautions
Magnetic Bracket & Lamp Installation
Find a Suitable Location
Open the air handler cabinet door. Identify a mounting position on the interior wall (back or side panel) with direct line-of-sight to the evaporator coil. The lamp should point toward the coil face, ideally 12–14 inches away.
- Upflow system (furnace below, coil above): Mount lamp on the return side for direct coil cavity access.
- Downflow system (furnace above, coil below): Mount on the supply side.
- Horizontal system: Mount on either side with line-of-sight to coil face.
- Heat pump (no furnace): Mount inside the air handler, aiming at the coil.
Attach the UV Lamp to the Magnetic Bracket
Using gloves, pass the lamp base [A] through the hole in the magnetic mounting bracket [B]. Fasten the lamp base to the bracket using the included quick nuts. The lamp should seat snugly without gaps.
Connect the 4-Pin Lamp Cable
Connect the lamp cable [D] to the 4-pin connector on the UV lamp [A]. Align the keys on the connector and press firmly until you feel a positive click. Do not force; if resistance is felt, recheck alignment.
Position the Magnetic Bracket
Place the magnetic base [B] against your chosen steel wall surface (back or side of air handler). The magnet will snap into place. Confirm it is positioned at the angle needed to aim the lamp toward the coil. Adjust position if needed — the magnet allows repositioning before the cable is routed.
Wiring Installation
Select your model type below for the correct wiring steps.
Drill the Cable Exit Hole
Using the included step drill bit [F], drill a 1″ hole through the air handler cabinet wall near an accessible power outlet. Keep the hole as low as practical to prevent condensation drainage issues.
Install the Cable Gland (Strain Relief)
Thread the cable gland [E] into the drilled hole from the exterior side. Place the locknut on the interior side and tighten against the cabinet wall to create a sealed, strain-relieved cable penetration. Do not overtighten.
Route the Power Cord
Thread the power cord from the wall adapter [C] through the cable gland [E] from the exterior side into the cabinet interior. Leave enough slack to connect to the lamp cable [D] without tension. Tighten the cable gland compression nut finger-tight to hold the cable and seal against air leakage.
Pour éviter les chocs électriques, introduire la lame la plus large de la fiche dans la fente la plus large.
Connect Power Cord & Plug In
Inside the cabinet, connect the power cord from the wall adapter [C] to the lamp cable [D] by aligning the square connectors and pressing firmly until the latch catches. Ensure all connections are dry and away from any condensate drip paths. Plug the wall adapter [C] into a nearby power outlet.
Dedicated Transformer Required
- A dedicated 24VAC transformer (minimum 40VA) is required. Do NOT connect to the existing HVAC system transformer secondary. Adding load to a certified HVAC transformer voids its safety certification.
- For communicating or smart thermostat HVAC systems (Nest, Ecobee, etc.), a separate transformer is always required.
- Must be wired to constant power. Do NOT connect to the blower relay. Mold growth is most aggressive when the system is off — disconnecting power when the fan stops removes protection exactly when it is needed most.
Mount the Ballast on the Duct Exterior
Find a suitable location on the outside surface of the duct wall, close to the lamp position inside. Mount the ballast unit [C] to the duct wall exterior using the included self-tapping screws. The ballast must remain outside the duct at all times.
Drill the Cable Entry Hole
Using the included step drill bit [F], drill a 1″ hole through the duct wall at a position that allows the lamp cable [D] to reach the lamp bracket [B] inside. Keep the hole as low as practical to prevent condensation drainage into the cable gland.
Install the Cable Gland (Strain Relief)
Thread the M16×1.5 cable gland [E] into the 1″ hole. Tighten the locknut against the duct wall to create a sealed, strain-relieved cable penetration. Do not overtighten.
Route the Lamp Cable
Pass the lamp cable [D] from the external ballast [C] through the cable gland [E] into the duct interior. Leave sufficient slack for the lamp to be positioned and the cable to be connected without tension.
Connect the Lamp Cable to the Lamp
Connect the lamp cable [D] to the 4-pin connector on the UV lamp [A]. Align the connector keys and press firmly until you feel a positive click.
Connect to Dedicated 24VAC Transformer
Connect the ballast [C] input wires to a dedicated 24VAC transformer (minimum 40VA). Wire connections: Black (L1/Hot), White (L2/Neutral), Green (Ground). Use wire nuts and ensure connections are secure and insulated.
Use thermally protected ballast for the lamp type specified.
Utiliser un ballast protégé thermiquement pour les lampes de type spécifié.
Alternative: Use Tap-In IDC Connectors (no wire cutting required)
If the installation location has existing constant-power 24VAC wiring nearby, you may use the included tap-in IDC connectors [J] instead of a direct wire splice:
- Identify a suitable constant-power 24VAC wire in the air handler control panel. Do not use a switched wire or relay circuit.
- Open the IDC connector and place the existing wire into the larger slot.
- Place your ballast lead wire into the smaller slot.
- Press the connector cap firmly closed until it clicks — the metal teeth pierce both wire insulations simultaneously, making the connection without cutting either wire.
- Repeat for the second wire (Neutral).
Warning Sticker & Safety Sight Glass
The combined warning sticker [G] and sight glass lens [H] allow you to monitor lamp operation from outside the duct without opening the cabinet. This section applies to HVAC models only. WallPlug models use the built-in LED indicator on the power adapter to confirm lamp status.
Apply the Warning Sticker
Find a location on the exterior of the duct wall near the UV lamp position. Clean and dry the surface. Apply the warning sticker [G] firmly to the duct exterior. The printed circle on the sticker is your drill guide.
Drill the Sight Glass Hole
Using the included step drill bit [F], drill a ½″ hole through the center circle printed on the sticker and through the duct wall.
Install the Sight Glass Lens
Press the sight glass lens [H] firmly into the hole through the sticker until it seats flush with the duct wall.
Power On & Verify Through Sight Glass
Turn on power. A visible blue glow through the sight glass [H] confirms the lamp is operating. Close the air handler cabinet door.
Power Supply LED Indicators:
Replace Bulbs Every 10 Months
- Lamp bulb is rated for about 8,000 hours of use under continuous operation.
- UV lamps continue to emit visible light but lose germicidal effectiveness over time. Replace on schedule.
- WallPlug models: Check the LED indicator — blue = working, red = replace.
- SL18-HVAC & SL36-HVAC: Use the sight glass [H] (the small viewport lens in the duct wall) to confirm the lamp is operating. A visible blue glow through the sight glass indicates the lamp is on.
Bulb Replacement Procedure:
- Turn off power to the unit (unplug the adapter or disconnect transformer).
- HVAC models: Check the sight glass [H] to confirm no glow — verify the lamp is off before reaching inside.
- Open the air handler cabinet door. Wear gloves and safety glasses.
- Disconnect the 4-pin connector from the old lamp. Remove the lamp from the bracket [B].
- Insert the new TruBlu™ replacement lamp into the bracket. Reconnect the 4-pin connector.
- Close the cabinet, restore power.
- Verify: blue LED indicator (WallPlug) or blue glow through the sight glass (HVAC) confirms the new lamp is operating.
Scan to order bulbs
www.bioshielduv.com/bulbs
Common Issues
UV C-Lamp Disposal
Visit www.lamprecycle.org for information about proper mercury lamp recycling and to find a recycling location near you.
You may also visit www.earth911.com for your local or state waste management program and information about where to dispose of the used UV lamp.
Contact your local hardware, home improvement stores, and other retailers selling UV and fluorescent bulbs. Many stores allow customers to drop off used bulbs for recycling.
If you cannot recycle, and it is acceptable with your local waste management agency, you may seal the bulb in a plastic bag and put it in the trash for collection.
Lifetime Warranty
Sign up for Lifetime Warranty! Get 10% Discount on Bulbs.
Lifetime Unit Warranty
Register within 30 days of purchase to activate your lifetime warranty coverage on the ballast and housing unit. Covers manufacturing defects for as long as you own the product.
What's Covered:
- Ballast / driver unit — lifetime
- Magnetic bracket — lifetime
- Manufacturing defects
- UV lamp bulbs (consumable — replace every 10 months)
- Damage from misuse, accidents, or non-approved lamps
- Installation by non-licensed contractors
BioShield Guardian Club
Never worry about bulb replacement again. Join for free and get exclusive benefits.
Learn about The Clean Coil Promise™ · Club Policy
Installation FAQ
SL18-HVAC & SL36-HVAC: Requires a certified HVAC technician or licensed electrician. Wiring into a dedicated 24VAC transformer is not a DIY task. Installation by unlicensed persons voids warranty.
Find a certified installer near you →
1. Unplug the adapter or disconnect the transformer. Open the cabinet (power off).
2. Confirm the 4-pin connector is fully seated — push firmly until it clicks.
3. Confirm the lamp is properly seated in the bracket.
4. Plug back in. If red light persists, the bulb has likely reached end of life — order a replacement.
Learn more about UV-C and your HVAC components →
Read the full explanation: Why UV-C units smell on first use →
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Required Safety Markings
Images Referenced in This Guide
All images below are required. Numbers correspond to placeholders throughout the guide. Provide these descriptions to the photographer/illustrator.
- Product hero — UV lamp with blue glow inside air handler
- WallPlug model plugged into power outlet
- HVAC model with external ballast mounted on duct exterior and wire-to-transformer connection
- TruBlu™ UV-C Lamp — elongated tube
- Magnetic bracket — metal U-shaped bracket with lamp holder
- Wall outlet adapter — power brick (WallPlug)
- External ballast/driver unit — rectangular box with wires (HVAC)
- 4-pin keyed lamp cable connector — close-up
- Cable gland M16×1.5 — threaded fitting with locknut
- Step drill bit — showing both 1″ and ½″ steps labeled
- Warning + sight glass sticker — UV warning text and center drill circle
- Sight glass lens — small round plastic viewport
- Four self-tapping screws
- Two IDC tap-in connectors — spade style
- Technician turning off HVAC system with gloves
- Certified HVAC technician with electrical tools
- Interior of air handler — UV lamp mounted near coil with blue UV glow + placement diagram overlay
- Lamp base being passed through magnetic bracket hole — gloves shown
- 4-pin connector alignment and click — close-up
- Magnetic bracket snapping to steel duct wall surface
- Screw-mount alternative — bracket secured with screws to aluminum surface
- Drilling 1″ hole in duct wall — step drill bit
- Cable gland being threaded into 1″ hole — locknut on interior
- Power cord threaded through cable gland (WallPlug)
- Lamp cable routed through cable gland into duct (HVAC)
- Square connectors being pressed together — latch click
- Wiring diagram — transformer → ballast → lamp with wire color labels
- IDC tap-in connector being snapped over existing wire — close-up
- Warning sticker being applied to duct exterior
- Drilling ½″ hole through center circle on sticker
- Sight glass lens [H] being pressed into hole
- Blue glow visible through installed sight glass on duct exterior
- QR code — bioshielduv.com/bulbs
- Recycling symbol with UV lamp
- Lifetime Warranty badge
- QR code — warranty registration