Honeywell Sensepoint XCD SPXCDULNCX – Fixed CO Detector (0-300ppm, Electrochemical (Surecell™), UL, LM25, 3/4" NPT)
SPXCDULNCX is the Sensepoint XCD carbon monoxide variant, 0–300 ppm electrochemical default, LM25 epoxy-coated aluminium, 2 × 3/4" NPT, UL / CSA. Use it on boiler rooms, enclosed car parks and furnace galleries where CO is near-neutral buoyancy and a wall-mounted 4–20 mA point is safer than a clip-on badge.
Same gas, swap enclosure/approval: aluminium SPXCDALMCX, 316SS SPXCDASMCX, UL SPXCDULNCX. SPXCDALMCX · SPXCDASMCX · SPXCDULNCX
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 |
| CX | Gas carbon monoxide, Electrochemical (Surecell™) | CX |
Same gas, swap enclosure/approval: aluminium SPXCDALMCX, 316SS SPXCDASMCX, UL SPXCDULNCX.
Technical specifications
| Target gas | CO / carbon monoxide |
|---|---|
| Principle | Electrochemical (Surecell™) |
| Default range | 0-300ppm |
| User FSD window | 100-1000ppm |
| Resolution | 100ppm |
| 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
CO mixes through the occupied layer instead of pooling on the floor. Electrochemical Surecell™ is chosen for ppm resolution and cross-interference control versus catalytic beads that only see flammability. Mount at breathing height (1.5–1.8 m) on the downwind wall of the boiler or parking deck; a floor mount will under-read a stratified plume.
Sensor and replaceable parts
OEM cartridge SPXCDXSCXSS. Calibration cap S3KCAL. Collecting cone follows buoyancy—see installation. Pipe/duct kits: SPXCDMTBR / SPXCDDMK.
Typical applications
Specify this SKU for boiler houses, tunnel plant rooms, sinter galleries and enclosed loading docks. A fixed XCD point gives a hard-wired trip to the ventilation starter and a local tri-colour display; a portable only records the minute you walked past.
Selection contrast
| P/N | Gas | Range | Principle |
|---|---|---|---|
| SPXCDULNCX | CO | 0-300ppm | EChem |
| SPXCDULNHX | H₂S | 0-50ppm | EChem |
| SPXCDULNO1 | O₂ | 0-25.0%Vol | EChem |
| SPXCDULNG1 | H₂ | 0-1000ppm | EChem |
| SPXCDALMCX | CO | 0-300ppm | EChem |
| SPXCDASMCX | CO | 0-300ppm | EChem |
Installation and wiring
Wall-mount SPXCDULNCX (carbon monoxide, 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 SPXCDULNCX. Land SPXCDULNCX 4–20 mA as three-wire and set Modbus address from the menu only. Magnetic wand calibration on the SPXCDULNCX lid stays non-intrusive. On SPXCDULNCX hold CO at breathing height on the downwind wall.
FAQ
- SPXCDULNCX: Is the 0–300 ppm CO range field-adjustable?
- SPXCDULNCX — Yes, the user FSD window is 100–1000 ppm in 100 ppm steps. Leave 300 ppm for occupied rooms; lift FSD only if a process vent can exceed that.
- SPXCDULNCX: Will hydrogen interfere with the CO cell?
- SPXCDULNCX — Short H₂ transients can read as CO. If the room also handles hydrogen, add a dedicated G1 point rather than relying on this CX cell alone.
- LM25 or 316SS for SPXCDULNCX (carbon monoxide)?
- SPXCDULNCX ships in LM25 epoxy aluminium (~4.4 lb). For carbon monoxide in salt spray, caustic CIP or sour-water splash, switch to 316SS sibling SPXCDASMCX instead of painting this lid.
- Why is SPXCDULNCX NPT instead of M20?
- SPXCDULNCX is the UL/CSA carbon monoxide body and ships 3/4" NPT. Do not tap M20 on this lid—order ATEX sibling SPXCDALMCX if metric glands are mandatory.
- Can I retrofit Modbus on SPXCDULNCX after it ships?
- Modbus RTU on SPXCDULNCX is a transmitter sales option, not a jumper on the carbon monoxide 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 SPXCDASMCX or UL SPXCDULNCX rather than a dead SKU.