Honeywell Sensepoint XCD SPXCDULNPX – Fixed C₃H₈ Detector (0-100%LEL, Infrared (dual-beam), UL, LM25, 3/4" NPT)
SPXCDULNPX is the Sensepoint XCD infrared propane LEL transmitter, 0–100 %LEL, LM25 epoxy-coated aluminium, 2 × 3/4" NPT, UL / CSA. Order it for LPG bullet farms and cylinder filling halls where methane IR would under-read.
Same gas, swap enclosure/approval: aluminium SPXCDALMPX, 316SS SPXCDASMPX, UL SPXCDULNPX. SPXCDALMPX · SPXCDASMPX · SPXCDULNPX
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 |
| PX | Gas propane, Infrared (dual-beam) | PX |
Same gas, swap enclosure/approval: aluminium SPXCDALMPX, 316SS SPXCDASMPX, UL SPXCDULNPX.
Technical specifications
| Target gas | C₃H₈ / propane |
|---|---|
| Principle | Infrared (dual-beam) |
| Default range | 0-100%LEL |
| User FSD window | 20-100%LEL |
| Resolution | 10%LEL |
| 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
Propane is heavier than air and slides along floors toward pits. Dual-beam IR tuned for C₃ is used so a methane-calibrated pellistor or RX cell cannot hide a rich LPG layer. Mount 200–400 mm above grade, at the pit lip, not on the roof.
Sensor and replaceable parts
OEM cartridge SPXCDXSPXSS. Calibration cap S3KCAL. Collecting cone follows buoyancy—see installation. Pipe/duct kits: SPXCDMTBR / SPXCDDMK.
Typical applications
LPG tank farms, bottle-filling halls and kitchen-gas manifolds need a propane-specific IR trip. XCD gives a hard-wired 4–20 mA to the tank ESD; a handheld only proves the aisle you walked.
Selection contrast
| P/N | Gas | Range | Principle |
|---|---|---|---|
| SPXCDULNPX | C₃H₈ | 0-100%LEL | IR |
| SPXCDULNRX | CH₄ | 0-100%LEL | IR |
| SPXCDULNFX | LEL | 0-100%LEL | Catalytic bead |
| SPXCDULNB1 | CO₂ | 0-2.00%Vol | IR |
| SPXCDALMPX | C₃H₈ | 0-100%LEL | IR |
| SPXCDASMPX | C₃H₈ | 0-100%LEL | IR |
Installation and wiring
Wall-mount SPXCDULNPX (propane, 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 SPXCDULNPX. Land SPXCDULNPX 4–20 mA as three-wire and set Modbus address from the menu only. Magnetic wand calibration on the SPXCDULNPX lid stays non-intrusive. SPXCDULNPX propane belongs at the pit lip, not the roof.
FAQ
- SPXCDULNPX: Can I use methane IR (RX) on an LPG skid?
- SPXCDULNPX — No. Response curves differ. Specify PX or you will under-alarm a propane release.
- SPXCDULNPX: Does PX work in oxygen-free vapour spaces?
- SPXCDULNPX — Yes. IR does not combust the sample, so inerted LPG vapour spaces remain measurable.
- LM25 or 316SS for SPXCDULNPX (propane)?
- SPXCDULNPX ships in LM25 epoxy aluminium (~4.4 lb). For propane in salt spray, caustic CIP or sour-water splash, switch to 316SS sibling SPXCDASMPX instead of painting this lid.
- Why is SPXCDULNPX NPT instead of M20?
- SPXCDULNPX is the UL/CSA propane body and ships 3/4" NPT. Do not tap M20 on this lid—order ATEX sibling SPXCDALMPX if metric glands are mandatory.
- Can I retrofit Modbus on SPXCDULNPX after it ships?
- Modbus RTU on SPXCDULNPX is a transmitter sales option, not a jumper on the propane 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 SPXCDASMPX or UL SPXCDULNPX rather than a dead SKU.