Honeywell Sensepoint XCD SPXCDULNRX – Fixed CH₄ Detector (0-100%LEL, Infrared (dual-beam), UL, LM25, 3/4" NPT)
SPXCDULNRX is the dual-beam infrared methane LEL point on Sensepoint XCD, 0–100 %LEL, LM25 epoxy-coated aluminium, 2 × 3/4" NPT, UL / CSA. It is the SKU for gas-transmission compounds and biogas roofs where catalytic poison or oxygen-free streams rule out a pellistor.
Same gas, swap enclosure/approval: aluminium SPXCDALMRX, 316SS SPXCDASMRX, UL SPXCDULNRX. SPXCDALMRX · SPXCDASMRX · SPXCDULNRX
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 |
| RX | Gas methane, Infrared (dual-beam) | RX |
Same gas, swap enclosure/approval: aluminium SPXCDALMRX, 316SS SPXCDASMRX, UL SPXCDULNRX.
Technical specifications
| Target gas | CH₄ / methane |
|---|---|
| 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
Methane is lighter than air and rises to roof vents and canopy corners. Dual-beam IR is used because it does not need oxygen and ignores silicone poisons that kill catalytic beads. Mount high, under the eaves or at the compressor hall ridge, and keep the optical window out of direct wash-down.
Sensor and replaceable parts
OEM cartridge SPXCDXSRXSS. Calibration cap S3KCAL. Collecting cone follows buoyancy—see installation. Pipe/duct kits: SPXCDMTBR / SPXCDDMK.
Typical applications
City-gate stations, LNG boil-off rooms and anaerobic digester roofs need a methane-specific IR point. XCD holds the trip while operators stay outside the classified shed—something a portable survey cannot guarantee.
Selection contrast
| P/N | Gas | Range | Principle |
|---|---|---|---|
| SPXCDULNRX | CH₄ | 0-100%LEL | IR |
| SPXCDULNPX | C₃H₈ | 0-100%LEL | IR |
| SPXCDULNFX | LEL | 0-100%LEL | Catalytic bead |
| SPXCDULNB1 | CO₂ | 0-2.00%Vol | IR |
| SPXCDALMRX | CH₄ | 0-100%LEL | IR |
| SPXCDASMRX | CH₄ | 0-100%LEL | IR |
Installation and wiring
Wall-mount SPXCDULNRX (methane, 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 SPXCDULNRX. Land SPXCDULNRX 4–20 mA as three-wire and set Modbus address from the menu only. Magnetic wand calibration on the SPXCDULNRX lid stays non-intrusive. Park the SPXCDULNRX methane IR at the ridge and out of wash-down.
FAQ
- SPXCDULNRX: Does the RX IR cell see propane?
- SPXCDULNRX — Poorly. Propane has its own PX SKU. Do not substitute RX on an LPG skid.
- SPXCDULNRX: Why not use catalytic LEL for methane?
- SPXCDULNRX — If the stream can be inert or silicone-contaminated, the pellistor goes to sleep. IR keeps working at 0 % oxygen.
- LM25 or 316SS for SPXCDULNRX (methane)?
- SPXCDULNRX ships in LM25 epoxy aluminium (~4.4 lb). For methane in salt spray, caustic CIP or sour-water splash, switch to 316SS sibling SPXCDASMRX instead of painting this lid.
- Why is SPXCDULNRX NPT instead of M20?
- SPXCDULNRX is the UL/CSA methane body and ships 3/4" NPT. Do not tap M20 on this lid—order ATEX sibling SPXCDALMRX if metric glands are mandatory.
- Can I retrofit Modbus on SPXCDULNRX after it ships?
- Modbus RTU on SPXCDULNRX is a transmitter sales option, not a jumper on the methane 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 SPXCDASMRX or UL SPXCDULNRX rather than a dead SKU.