Honeywell Sensepoint XCD SPXCDULNB1 – Fixed CO₂ Detector (0-2.00%Vol, Infrared (dual-beam), UL, LM25, 3/4" NPT)
SPXCDULNB1 is the Sensepoint XCD infrared carbon dioxide transmitter at 0–2.00 %vol, LM25 epoxy-coated aluminium, 2 × 3/4" NPT, UL / CSA. Use it on beverage carbonation rooms and small inerting cabinets—not the 5 %vol B2 SKU.
Same gas, swap enclosure/approval: aluminium SPXCDALMB1, 316SS SPXCDASMB1, UL SPXCDULNB1. SPXCDALMB1 · SPXCDASMB1 · SPXCDULNB1
Part-number decode
| Segment | Meaning | This SKU |
|---|---|---|
| SPXCD | Sensepoint XCD series | SPXCD |
| A / U | Approval A=ATEX/IECEx/GB; U=UL | U |
| L / S | Enclosure L=LM25 aluminium; S=316SS | L |
| M / N | Entry M=M20; N=3/4" NPT | N |
| B1 | Gas carbon dioxide 2 %vol, Infrared (dual-beam) | B1 |
Same gas, swap enclosure/approval: aluminium SPXCDALMB1, 316SS SPXCDASMB1, UL SPXCDULNB1.
Technical specifications
| Target gas | CO₂ / carbon dioxide 2 %vol |
|---|---|
| Principle | Infrared (dual-beam) |
| Default range | 0-2.00%Vol |
| User FSD window | Fixed 2.00%Vol |
| Resolution | n/a |
| Output | 4–20 mA sink/source + optional Modbus RTU |
| Supply | 16–32 VDC (24 VDC nominal) |
| Power | 3.7 W |
| Enclosure | LM25 epoxy-coated aluminium |
| Entries | 2 × 3/4" NPT |
| Display | Tri-colour backlight LCD |
| Relays | 3×5A@250VAC |
| Ingress | IP66 |
| Approvals | UL / CSA |
| Temperature | −40~+65 ℃ |
| Mass | approx. 2.0 kg (4.4 lb) |
Why this principle for this gas
CO₂ is heavier than air and fills cellars from the floor up. Dual-beam IR is the correct principle at %vol levels; an electrochemical toxic cell cannot span 2 %. Mount 300 mm above the lowest floor in the carbonation room and keep the optical path off wet drains.
Sensor and replaceable parts
OEM cartridge SPXCDXSB1SS. Calibration cap S3KCAL. Collecting cone follows buoyancy—see installation. Pipe/duct kits: SPXCDMTBR / SPXCDDMK.
Typical applications
Soft-drink carbonation, brewery cellars and small CO₂-inerted cabinets need a 2 %vol trip before asphyxiation. XCD provides the hard-wired extract start; a portable wand is only a leak survey tool.
Selection contrast
| P/N | Gas | Range | Principle |
|---|---|---|---|
| SPXCDULNB1 | CO₂ | 0-2.00%Vol | IR |
| SPXCDULNRX | CH₄ | 0-100%LEL | IR |
| SPXCDULNO1 | O₂ | 0-25.0%Vol | EChem |
| SPXCDALMB1 | CO₂ | 0-2.00%Vol | IR |
| SPXCDASMB1 | CO₂ | 0-2.00%Vol | IR |
Installation and wiring
Wall-mount SPXCDULNB1 (carbon dioxide 2 %vol, LM25 epoxy-coated aluminium) through the one-piece plate with M8 bolts sized for that mass. This SKU uses 2 × 3/4" NPT entries: pipe kit SPXCDMTBR covers Ø1.5–3″, duct kit is SPXCDDMK, and glands must match—do not retap SPXCDULNB1. Land SPXCDULNB1 4–20 mA as three-wire and set Modbus address from the menu only. Magnetic wand calibration on the SPXCDULNB1 lid stays non-intrusive. SPXCDULNB1 2 %vol CO₂ hugs the cellar floor.
FAQ
- SPXCDULNB1: Should I order B1 or B2?
- SPXCDULNB1 — B1 is 0–2.00 %vol for occupied carbonation rooms. B2 is 0–5.00 %vol for process-rich spaces. Do not mix them.
- SPXCDULNB1: Why not an electrochemical CO₂ cell?
- SPXCDULNB1 — Surecell™ toxic cells are ppm devices. Percent-level CO₂ is an IR measurement on XCD.
- LM25 or 316SS for SPXCDULNB1 (carbon dioxide 2 %vol)?
- SPXCDULNB1 ships in LM25 epoxy aluminium (~4.4 lb). For carbon dioxide 2 %vol in salt spray, caustic CIP or sour-water splash, switch to 316SS sibling SPXCDASMB1 instead of painting this lid.
- Why is SPXCDULNB1 NPT instead of M20?
- SPXCDULNB1 is the UL/CSA carbon dioxide 2 %vol body and ships 3/4" NPT. Do not tap M20 on this lid—order ATEX sibling SPXCDALMB1 if metric glands are mandatory.
- Can I retrofit Modbus on SPXCDULNB1 after it ships?
- Modbus RTU on SPXCDULNB1 is a transmitter sales option, not a jumper on the carbon dioxide 2 %vol lid. Confirm the option before the box leaves; 4–20 mA sink/source is already on this SKU.
Documents
Honeywell Sensepoint XCD datasheet / manual · On-site XCD selection matrix
Availability and enquiry
Stock is lot-based. If this aluminium ATEX box is out, jump to 316SS SPXCDASMB1 or UL SPXCDULNB1 rather than a dead SKU.