{"product_id":"macurco-gbc-24-2-gas-detection-controller","title":"Macurco GBC-24-2 Gas Detection Controller (2 Relays)","description":"\u003c!-- PRODUCT B0GHSGJMNW | tag fixed-gas-detector | TODO: add matching Product Review + best-of guide links when those silo layers exist --\u003e\n\n\u003cdiv style=\"background:#1a1a1a;border-left:4px solid #ff9800;padding:14px 18px;margin:0 0 18px 0;color:#f5e6d3;font-size:0.95em;\"\u003e\n\u003cstrong style=\"color:#ffb74d;\"\u003eEditor’s note:\u003c\/strong\u003e the Macurco GBC-24-2 is one of the instruments we curate in our \u003ca href=\"\/collections\/fixed-gas-detection-systems\" title=\"Fixed Gas Detection Systems\"\u003eFixed Gas Detection Systems\u003c\/a\u003e buyer’s hub. Compare it with the \u003ca href=\"\/products\/forensics-ex-lel-gas-detector-wall-mount\" title=\"Forensics EX\/LEL Wall-Mount\"\u003eForensics EX\/LEL Wall-Mount\u003c\/a\u003e below before you order.\u003c\/div\u003e\n\n\u003ch2 id=\"top\"\u003eMacurco GBC-24-2 Gas Detection Controller — 2 Relay Outputs\u003c\/h2\u003e\n\n\u003cp\u003eThe \u003cstrong\u003eMacurco GBC-24-2\u003c\/strong\u003e is a gas-detection controller with two relay outputs that turns connected detector heads into a coordinated \u003ca href=\"\/collections\/fixed-gas-detection-systems\" title=\"fixed gas detection system\"\u003efixed gas detection system\u003c\/a\u003e — driving ventilation and alarms from one panel, with staged response on its two relays.\u003c\/p\u003e\n\n\u003cp style=\"font-size:0.9em;color:#bdae9d;margin:10px 0 18px 0;\"\u003eJump to: \u003ca href=\"#features\" style=\"color:#ffb74d;\"\u003eFeatures\u003c\/a\u003e · \u003ca href=\"#specs\" style=\"color:#ffb74d;\"\u003eSpecs\u003c\/a\u003e · \u003ca href=\"#compatibility\" style=\"color:#ffb74d;\"\u003eWhat it detects\u003c\/a\u003e · \u003ca href=\"#comparison\" style=\"color:#ffb74d;\"\u003eComparison\u003c\/a\u003e · \u003ca href=\"#faq\" style=\"color:#ffb74d;\"\u003eFAQ\u003c\/a\u003e\u003c\/p\u003e\n\n\u003cp\u003eThe Macurco GBC-24-2 is a fixed gas-detection controller with two relay outputs that drives ventilation and alarms from connected gas detectors in boiler and equipment rooms.\u003c\/p\u003e\n\n\u003ch3 id=\"features\"\u003eKey features\u003c\/h3\u003e\n\n\u003cul\u003e\n\u003cli\u003eCentral controller that drives ventilation and alarms from connected gas detectors\u003c\/li\u003e\n\u003cli\u003eTwo relay outputs for staged action — e.g. ventilation on low, shutdown\/alarm on high\u003c\/li\u003e\n\u003cli\u003eCoordinates a fixed gas-detection system from one panel\u003c\/li\u003e\n\u003cli\u003eDesigned for boiler and equipment-room gas control\u003c\/li\u003e\n\u003cli\u003ePairs with fixed detector heads for a complete system\u003c\/li\u003e\n\u003cli\u003eFrom Macurco, a established fixed gas-detection brand\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cdiv style=\"display:flex;gap:14px;flex-wrap:wrap;margin:18px 0;\"\u003e\n\u003cdiv style=\"flex:1;min-width:240px;background:#1b3a2a;border:1px solid #4caf50;border-radius:6px;padding:14px 18px;\"\u003e\n\u003cstrong style=\"color:#81c784;\"\u003ePros\u003c\/strong\u003e\u003cul style=\"margin:8px 0 0 0;\"\u003e\n\u003cli\u003eCentralises control of a fixed system\u003c\/li\u003e\n\u003cli\u003eTwo relay outputs for staged response\u003c\/li\u003e\n\u003cli\u003eCoordinates ventilation and alarms\u003c\/li\u003e\n\u003cli\u003ePanel\/fixed mount\u003c\/li\u003e\n\u003cli\u003eEstablished Macurco brand\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"flex:1;min-width:240px;background:#3a1e1e;border:1px solid #ef5350;border-radius:6px;padding:14px 18px;\"\u003e\n\u003cstrong style=\"color:#e57373;\"\u003eCons\u003c\/strong\u003e\u003cul style=\"margin:8px 0 0 0;\"\u003e\n\u003cli\u003eController only — needs detector heads\u003c\/li\u003e\n\u003cli\u003eThin published spec detail online\u003c\/li\u003e\n\u003cli\u003eHard-wired install required\u003c\/li\u003e\n\u003cli\u003eNot a standalone detector\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\n\u003ch3 id=\"specs\"\u003eSpecifications\u003c\/h3\u003e\n\n\u003cdiv style=\"overflow-x:auto;\"\u003e\u003ctable style=\"width:100%;border-collapse:collapse;background:#1a1a1a;margin:14px 0;\"\u003e\n\u003cthead\u003e\u003ctr style=\"background:#2a2a2a;\"\u003e\n\u003cth style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;text-align:left;\"\u003eSpecification\u003c\/th\u003e\n\u003cth style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;text-align:left;\"\u003eDetail\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eRole\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003eGas detection \/ boiler controller\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eRelays\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003e2 relay outputs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eFunction\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003eDrives ventilation \u0026amp; alarms from connected detectors\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eMounting\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003eFixed \/ panel\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003ePower\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003e24 V class\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#ffb74d;padding:8px 10px;border:1px solid #3a3a3a;white-space:nowrap;\"\u003eModel\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:8px 10px;border:1px solid #3a3a3a;\"\u003eMacurco GBC-24-2\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003c\/div\u003e\n\n\u003ch3\u003eWhere the Macurco GBC-24-2 fits\u003c\/h3\u003e\n\n\u003cul\u003e\n\u003cli\u003eBoiler and mechanical rooms\u003c\/li\u003e\n\u003cli\u003eParking-garage CO ventilation control\u003c\/li\u003e\n\u003cli\u003eMulti-detector plant systems\u003c\/li\u003e\n\u003cli\u003eStaged ventilation\/shutdown logic\u003c\/li\u003e\n\u003cli\u003eCoordinating several fixed heads from one panel\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"compatibility\"\u003eWhat the Macurco GBC-24-2 detects (and what it doesn’t)\u003c\/h2\u003e\n\n\u003cp\u003eThe GBC-24-2 is a \u003cstrong\u003econtroller, not a detector\u003c\/strong\u003e — it coordinates fixed detector heads and drives ventilation and alarms through its two relays. Pair it with fixed heads such as the \u003ca href=\"\/products\/macurco-pm100-co-fixed-carbon-monoxide-monitor\" title=\"Macurco PM100-CO\"\u003eMacurco PM100-CO\u003c\/a\u003e or the Forensics \u003ca href=\"\/products\/forensics-ex-lel-gas-detector-wall-mount\" title=\"EX LEL Detector\"\u003eEX LEL Detector\u003c\/a\u003e and \u003ca href=\"\/products\/forensics-4-gas-wall-mount-monitor\" title=\"4 Gas Wall-Mount Monitor\"\u003e4 Gas Wall-Mount Monitor\u003c\/a\u003e. Use the two relays for staged action — ventilation at a low set point, shutdown or full alarm at a high one. The system protects the space; entrants still use a \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"Portable Gas Detectors\"\u003ePortable Gas Detectors\u003c\/a\u003e instrument for pre-entry testing.\u003c\/p\u003e\n\n\u003cp\u003eCross-shopping? This unit sits in our \u003ca href=\"\/collections\/fixed-gas-detection-systems\" title=\"Fixed Gas Detection Systems\"\u003eFixed Gas Detection Systems\u003c\/a\u003e hub alongside \u003ca href=\"\/products\/forensics-ex-lel-gas-detector-wall-mount\" title=\"Forensics EX\/LEL Wall-Mount\"\u003eForensics EX\/LEL Wall-Mount\u003c\/a\u003e, \u003ca href=\"\/products\/forensics-hydrogen-gas-detector-wall-mount\" title=\"Forensics Hydrogen Wall-Mount\"\u003eForensics Hydrogen Wall-Mount\u003c\/a\u003e, \u003ca href=\"\/products\/forensics-4-gas-wall-mount-monitor\" title=\"Forensics 4 Gas Wall-Mount\"\u003eForensics 4 Gas Wall-Mount\u003c\/a\u003e, \u003ca href=\"\/products\/macurco-pm100-co-fixed-carbon-monoxide-monitor\" title=\"Macurco PM100-CO\"\u003eMacurco PM100-CO\u003c\/a\u003e. For other gas-detection form factors see \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"Portable Gas Detectors\"\u003ePortable Gas Detectors\u003c\/a\u003e, \u003ca href=\"\/collections\/personal-gas-detectors\" title=\"Personal \u0026amp; Wearable Gas Detectors\"\u003ePersonal \u0026amp; Wearable Gas Detectors\u003c\/a\u003e, \u003ca href=\"\/collections\/area-gas-monitors\" title=\"Area \u0026amp; Transportable Gas Monitors\"\u003eArea \u0026amp; Transportable Gas Monitors\u003c\/a\u003e, or browse the full \u003ca href=\"\/collections\/gas-detectors\" title=\"Gas Detectors\"\u003eGas Detectors\u003c\/a\u003e range.\u003c\/p\u003e\n\n\u003ch2 id=\"comparison\"\u003eMacurco fixed gas-detection family\u003c\/h2\u003e\n\n\u003cdiv style=\"overflow-x:auto;\"\u003e\u003ctable style=\"width:100%;border-collapse:collapse;background:#1a1a1a;margin:14px 0;\"\u003e\n\u003ccaption style=\"color:#bdae9d;font-size:0.85em;text-align:left;padding:4px 0;\"\u003eMacurco fixed gas-detection family\u003c\/caption\u003e\n\u003cthead\u003e\u003ctr style=\"background:#2a2a2a;\"\u003e\n\u003cth style=\"color:#ffb74d;padding:9px;border:1px solid #3a3a3a;text-align:left;\"\u003eModel\u003c\/th\u003e\n\u003cth style=\"color:#ffb74d;padding:9px;border:1px solid #3a3a3a;text-align:left;\"\u003eRole\u003c\/th\u003e\n\u003cth style=\"color:#ffb74d;padding:9px;border:1px solid #3a3a3a;text-align:left;\"\u003eGas\u003c\/th\u003e\n\u003cth style=\"color:#ffb74d;padding:9px;border:1px solid #3a3a3a;text-align:left;\"\u003eNotable\u003c\/th\u003e\n\u003cth style=\"color:#ffb74d;padding:9px;border:1px solid #3a3a3a;text-align:left;\"\u003eStreet price\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003e\u003ca href=\"\/products\/macurco-pm100-co-fixed-carbon-monoxide-monitor\" title=\"PM100-CO\"\u003ePM100-CO\u003c\/a\u003e\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003ePoint monitor\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eCarbon monoxide\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eCompact fixed CO\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003e~$128\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background:#2a2520;\"\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003e\u003cstrong\u003e\u003ca href=\"\/products\/macurco-gbc-24-2-gas-detection-controller\" title=\"GBC-24-2\"\u003eGBC-24-2\u003c\/a\u003e\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eController\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003eMulti-channel\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003e2 relay outputs\u003c\/td\u003e\n\u003ctd style=\"color:#e0e0e0;padding:9px;border:1px solid #3a3a3a;\"\u003e~$888\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003c\/div\u003e\n\n\u003cul\u003e\n\u003cli\u003eChoose the \u003cstrong\u003eGBC-24-2\u003c\/strong\u003e to centralise control and staged relays for a fixed gas-detection system.\u003c\/li\u003e\n\u003cli\u003eAdd detector heads — start with the \u003ca href=\"\/products\/macurco-pm100-co-fixed-carbon-monoxide-monitor\" title=\"Macurco PM100-CO\"\u003eMacurco PM100-CO\u003c\/a\u003e for CO.\u003c\/li\u003e\n\u003cli\u003eFor combustible and multi-gas heads, see the Forensics \u003ca href=\"\/products\/forensics-ex-lel-gas-detector-wall-mount\" title=\"EX LEL\"\u003eEX LEL\u003c\/a\u003e and \u003ca href=\"\/products\/forensics-4-gas-wall-mount-monitor\" title=\"4 Gas Monitor\"\u003e4 Gas Monitor\u003c\/a\u003e.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2 id=\"faq\"\u003eFrequently asked questions\u003c\/h2\u003e\n\n\u003ch3\u003eWhat does the Macurco GBC-24-2 do?\u003c\/h3\u003e\u003cp\u003eIt is a gas-detection controller — it takes signals from connected detector heads and drives ventilation and alarms through two relay outputs. It is not itself a gas sensor.\u003c\/p\u003e\n\u003ch3\u003eWhat are the two relays for?\u003c\/h3\u003e\u003cp\u003eStaged response — for example, energise ventilation at a low gas level on one relay, then trigger shutdown or a full alarm at a higher level on the other.\u003c\/p\u003e\n\u003ch3\u003eDo I need detector heads with it?\u003c\/h3\u003e\u003cp\u003eYes — the controller coordinates heads. Pair it with fixed detectors such as the \u003ca href=\"\/products\/macurco-pm100-co-fixed-carbon-monoxide-monitor\" title=\"Macurco PM100-CO\"\u003eMacurco PM100-CO\u003c\/a\u003e or a Forensics \u003ca href=\"\/products\/forensics-ex-lel-gas-detector-wall-mount\" title=\"EX LEL Detector\"\u003eEX LEL Detector\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eWhere is the GBC-24-2 used?\u003c\/h3\u003e\u003cp\u003eBoiler and mechanical rooms, parking-garage CO ventilation control, and any plant space where several fixed detectors need coordinated relays from one panel.\u003c\/p\u003e\n\u003ch3\u003eCan it control building ventilation?\u003c\/h3\u003e\u003cp\u003eYes — driving exhaust ventilation is a primary function; the relays energise fans or shutdown circuits based on the connected detectors' readings.\u003c\/p\u003e\n\u003ch3\u003eIs it a standalone gas detector?\u003c\/h3\u003e\u003cp\u003eNo — it is a controller. For a single standalone fixed detector, see the \u003ca href=\"\/products\/forensics-4-gas-wall-mount-monitor\" title=\"Forensics 4 Gas Wall-Mount Monitor\"\u003eForensics 4 Gas Wall-Mount Monitor\u003c\/a\u003e.\u003c\/p\u003e\n\u003ch3\u003eHow is it mounted and powered?\u003c\/h3\u003e\u003cp\u003eIt is a fixed\/panel-mounted, hard-wired controller; installation and relay wiring should follow local electrical code.\u003c\/p\u003e\n\u003ch3\u003eHow many detectors can it coordinate?\u003c\/h3\u003e\u003cp\u003eIt centralises control and provides two relay outputs for staged action; size your system with the heads and zones your space requires.\u003c\/p\u003e\n\u003ch3\u003eDoes it replace portable testing?\u003c\/h3\u003e\u003cp\u003eNo — even with fixed detection and control, pre-entry testing of a space uses a \u003ca href=\"\/collections\/portable-gas-detectors\" title=\"Portable Gas Detectors\"\u003ePortable Gas Detectors\u003c\/a\u003e instrument.\u003c\/p\u003e\n\u003ch3\u003eIs it in stock and how does it ship?\u003c\/h3\u003e\u003cp\u003eUse the Amazon buy button for current availability and delivery timing through our fulfillment partner.\u003c\/p\u003e\n\u003ch3\u003eDoes it need professional installation?\u003c\/h3\u003e\u003cp\u003eAs a hard-wired controller wired to detectors and ventilation\/shutdown circuits, it should be installed to local electrical code, often by a qualified contractor.\u003c\/p\u003e\n\u003ch3\u003eWhat gases does the system detect?\u003c\/h3\u003e\u003cp\u003eThat depends on the heads you connect — CO from the \u003ca href=\"\/products\/macurco-pm100-co-fixed-carbon-monoxide-monitor\" title=\"PM100-CO\"\u003ePM100-CO\u003c\/a\u003e, combustibles or multi-gas from the Forensics \u003ca href=\"\/products\/forensics-ex-lel-gas-detector-wall-mount\" title=\"EX LEL\"\u003eEX LEL\u003c\/a\u003e and \u003ca href=\"\/products\/forensics-4-gas-wall-mount-monitor\" title=\"4 Gas\"\u003e4 Gas\u003c\/a\u003e heads.\u003c\/p\u003e\n\n\u003cdiv style=\"background:#1a1a1a;border:1px solid #3a3a3a;border-radius:6px;padding:16px 18px;margin:22px 0;\"\u003e\n\u003cp style=\"margin:0 0 10px 0;color:#f5e6d3;\"\u003eReady to order the \u003cstrong\u003eMacurco GBC-24-2\u003c\/strong\u003e? Add it to your cart above, or check the current Amazon price below. Compare it against the rest of our \u003ca href=\"\/collections\/fixed-gas-detection-systems\" title=\"Fixed Gas Detection Systems\"\u003eFixed Gas Detection Systems\u003c\/a\u003e lineup before you buy.\u003c\/p\u003e\n\u003cp style=\"display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin:0;\"\u003e\u003ca href=\"https:\/\/www.amazon.com\/dp\/B0GHSGJMNW?tag=wcsafety04-20\" rel=\"sponsored nofollow noopener\" target=\"_blank\" style=\"display:inline-block;background:#FFD814;color:#0F1111;padding:13px 26px;text-decoration:none;font-weight:bold;border-radius:4px;border:1px solid #FCD200;\"\u003eCHECK PRICE ON AMAZON →\u003c\/a\u003e\u003cspan style=\"font-size:0.8em;color:#bdae9d;\"\u003eAs an Amazon Associate, WC Safety earns from qualifying purchases.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003cdiv style=\"background:#1a2733;border:1px dashed #4fc3f7;padding:16px 20px;margin:30px 0 18px 0;color:#cfd8dc;font-size:0.92em;\"\u003e\n  \u003cstrong style=\"color:#4fc3f7;\"\u003eWhy trust this Macurco page?\u003c\/strong\u003e WC Safety is an independent industrial safety-equipment retailer serving safety managers, procurement teams and field supervisors. The specifications here are taken from the manufacturer’s published listing for Macurco GBC-24-2 and framed against \u003ca href=\"https:\/\/www.osha.gov\/laws-regs\/regulations\/standardnumber\/1910\/1910.146\" rel=\"noopener\" target=\"_blank\" style=\"color:#4fc3f7;\"\u003eOSHA 29 CFR 1910.146\u003c\/a\u003e and \u003ca href=\"https:\/\/www.osha.gov\/annotated-pels\" rel=\"noopener\" target=\"_blank\" style=\"color:#4fc3f7;\"\u003eOSHA Permissible Exposure Limits\u003c\/a\u003e. Disclosed: WC Safety earns Amazon affiliate commissions on outbound clicks; that does not influence the specs shown or our lineup.\n\u003c\/div\u003e\n\u003cdiv style=\"background:#1a2733;border-left:4px solid #4fc3f7;padding:18px 22px;margin:18px 0;color:#cfd8dc;font-size:0.92em;\"\u003e\n  \u003cstrong style=\"color:#4fc3f7;\"\u003eBy Steven Eaton, WC Safety Editorial\u003c\/strong\u003e — Industrial safety-equipment desk · specialization: atmospheric monitoring, gas detection and instrument selection.\u003cbr\u003e\n  \u003cstrong\u003eLast updated:\u003c\/strong\u003e \u003ctime datetime=\"2026-06-22\"\u003eJune 22, 2026\u003c\/time\u003e · \u003cstrong\u003eSources reviewed:\u003c\/strong\u003e manufacturer product listing \u0026amp; specifications, OSHA 29 CFR 1910.146, OSHA Annotated PEL tables, ACGIH Threshold Limit Values.\u003cbr\u003e\n  \u003cstrong\u003eEditorial standard:\u003c\/strong\u003e \u003cem\u003eZero sponsored listings. No manufacturer input. Specs verified against the manufacturer’s published data.\u003c\/em\u003e\n\u003c\/div\u003e\n\u003cdiv style=\"background:#1a2733;border-left:4px solid #4fc3f7;padding:16px 20px;margin:18px 0;color:#cfd8dc;font-size:0.92em;\"\u003e\n  \u003cstrong style=\"color:#4fc3f7;\"\u003eHow this page is maintained.\u003c\/strong\u003e Specifications and pricing are reviewed against the manufacturer’s current listing and re-checked whenever the lineup changes. Gas-detection guidance follows \u003ca href=\"https:\/\/www.osha.gov\/laws-regs\/regulations\/standardnumber\/1910\/1910.146\" rel=\"noopener\" target=\"_blank\" style=\"color:#4fc3f7;\"\u003eOSHA 1910.146\u003c\/a\u003e and \u003ca href=\"https:\/\/www.osha.gov\/annotated-pels\" rel=\"noopener\" target=\"_blank\" style=\"color:#4fc3f7;\"\u003eOSHA PELs\u003c\/a\u003e, cross-referenced with ACGIH TLVs.\n\u003c\/div\u003e\n\u003cdiv style=\"background:#2a2520;border-left:4px solid #ff9800;padding:16px 20px;margin:18px 0;color:#f5e6d3;font-size:0.92em;\"\u003e\n  \u003cstrong style=\"color:#ffb74d;\"\u003eDisclosure.\u003c\/strong\u003e WC Safety participates in the Amazon Associates Program and earns commissions on qualifying purchases through outbound links on this page (tag wcsafety04-20). We are not sponsored by any instrument manufacturer. This page is buyer guidance, not medical, legal or regulatory advice — confirm gas-detection requirements for your site against the applicable OSHA standard and, for commercial monitoring programs, a Certified Industrial Hygienist (CIH).\n\u003c\/div\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\"@context\": \"https:\/\/schema.org\", \"@graph\": [{\"@type\": \"Product\", \"@id\": \"https:\/\/wcsafety.com\/products\/macurco-gbc-24-2-gas-detection-controller#product\", \"name\": \"Macurco GBC-24-2 Gas Detection Controller (2 Relays)\", \"description\": \"Macurco GBC-24-2 gas detection controller with 2 relay outputs — drives ventilation and alarms from connected fixed gas detectors. Order at WC Safety.\", \"sku\": \"B0GHSGJMNW\", \"mpn\": \"GBC-24-2\", \"image\": [\"https:\/\/wcsafety.com\/cdn\/shop\/products\/macurco-gbc-24-2-gas-detection-controller.jpg\"], \"brand\": {\"@type\": \"Brand\", \"name\": \"Macurco\"}, \"category\": \"Fixed Gas Detector\", \"isPartOf\": {\"@type\": \"CollectionPage\", \"@id\": \"https:\/\/wcsafety.com\/collections\/fixed-gas-detection-systems#collection\", \"name\": \"Fixed Gas Detection Systems\", \"url\": \"https:\/\/wcsafety.com\/collections\/fixed-gas-detection-systems\"}, \"isRelatedTo\": [{\"@type\": \"Product\", \"name\": \"Forensics EX LEL Gas Detector (Wall-Mount)\", \"url\": \"https:\/\/wcsafety.com\/products\/forensics-ex-lel-gas-detector-wall-mount\"}, {\"@type\": \"Product\", \"name\": \"Forensics Hydrogen Gas Detector (Wall-Mount)\", \"url\": \"https:\/\/wcsafety.com\/products\/forensics-hydrogen-gas-detector-wall-mount\"}, {\"@type\": \"Product\", \"name\": \"Forensics 4 Gas Wall-Mount Monitor\", \"url\": \"https:\/\/wcsafety.com\/products\/forensics-4-gas-wall-mount-monitor\"}, {\"@type\": \"Product\", \"name\": \"Macurco PM100-CO Fixed CO Monitor\", \"url\": \"https:\/\/wcsafety.com\/products\/macurco-pm100-co-fixed-carbon-monoxide-monitor\"}], \"offers\": {\"@type\": \"Offer\", \"url\": \"https:\/\/wcsafety.com\/products\/macurco-gbc-24-2-gas-detection-controller\", \"priceCurrency\": \"USD\", \"price\": \"888.10\", \"availability\": \"https:\/\/schema.org\/InStock\", \"seller\": {\"@type\": \"Organization\", \"name\": \"WC Safety\"}}}, {\"@type\": \"BreadcrumbList\", \"@id\": \"https:\/\/wcsafety.com\/products\/macurco-gbc-24-2-gas-detection-controller#breadcrumb\", \"itemListElement\": [{\"@type\": \"ListItem\", \"position\": 1, \"name\": \"Home\", \"item\": \"https:\/\/wcsafety.com\/\"}, {\"@type\": \"ListItem\", \"position\": 2, \"name\": \"Gas Detectors\", \"item\": \"https:\/\/wcsafety.com\/collections\/gas-detectors\"}, {\"@type\": \"ListItem\", \"position\": 3, \"name\": \"Fixed Gas Detection Systems\", \"item\": \"https:\/\/wcsafety.com\/collections\/fixed-gas-detection-systems\"}, {\"@type\": \"ListItem\", \"position\": 4, \"name\": \"Macurco GBC-24-2 Gas Detection Controller (2 Relays)\"}]}, {\"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"What does the Macurco GBC-24-2 do?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"It is a gas-detection controller — it takes signals from connected detector heads and drives ventilation and alarms through two relay outputs. It is not itself a gas sensor.\"}}, {\"@type\": \"Question\", \"name\": \"What are the two relays for?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Staged response — for example, energise ventilation at a low gas level on one relay, then trigger shutdown or a full alarm at a higher level on the other.\"}}, {\"@type\": \"Question\", \"name\": \"Do I need detector heads with it?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Yes — the controller coordinates heads. Pair it with fixed detectors such as the Macurco PM100-CO or a Forensics EX LEL Detector.\"}}, {\"@type\": \"Question\", \"name\": \"Where is the GBC-24-2 used?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Boiler and mechanical rooms, parking-garage CO ventilation control, and any plant space where several fixed detectors need coordinated relays from one panel.\"}}, {\"@type\": \"Question\", \"name\": \"Can it control building ventilation?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"Yes — driving exhaust ventilation is a primary function; the relays energise fans or shutdown circuits based on the connected detectors' readings.\"}}, {\"@type\": \"Question\", \"name\": \"Is it a standalone gas detector?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"No — it is a controller. 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