{"product_id":"honeywell-rm7850a1019-relay-module","title":"Honeywell RM7850A1019 Relay Module","description":"\u003cp\u003eThe \u003cstrong\u003eHoneywell RM7850A1019\u003c\/strong\u003e serves as the primary \u003cstrong\u003eRM7850A\u003c\/strong\u003e Burner Control Unit utilized to execute flame safeguard sequencing, pre-ignition logic, and airflow validation across 7800 Series platforms. Operating on a nominal line voltage of 120 VAC at 50\/60 Hz, this microprocessor-based control module manages interrupted pilot types and intermittent second-stage pilot valve timing. It incorporates user-selectable airflow check switches, a mandatory 15-second post-purge cycle, and hardwired lockout interlock inputs to ensure safe light-off and continuous operational monitoring in industrial burner assemblies.\u003c\/p\u003e\n\u003ch3\u003eHardware Specifications\u003c\/h3\u003e\n\u003cfigure class=\"table\"\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003e\u003cstrong\u003eParameter\u003c\/strong\u003e\u003c\/th\u003e\n\u003cth\u003e\u003cstrong\u003eSpecification\u003c\/strong\u003e\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eModel\u003c\/td\u003e\n\u003ctd\u003eRM7850A1019\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eHoneywell\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOrigin\u003c\/td\u003e\n\u003ctd\u003eUSA\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e1.98 lbs\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDimensions\u003c\/td\u003e\n\u003ctd\u003ePlug-in form factor for 7800 Series subbases\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Temp\u003c\/td\u003e\n\u003ctd\u003e-40 deg C to 60 deg C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Consumption\u003c\/td\u003e\n\u003ctd\u003e10 W maximum\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVoltage Rating\u003c\/td\u003e\n\u003ctd\u003e120 VAC (+10%, -15%)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInput Frequency\u003c\/td\u003e\n\u003ctd\u003e50\/60 Hz (+\/- 10%)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePost Purge Period\u003c\/td\u003e\n\u003ctd\u003e15 seconds\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePilot Type\u003c\/td\u003e\n\u003ctd\u003eInterrupted \/ Intermittent Second Stage Pilot Valve\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAirflow Check\u003c\/td\u003e\n\u003ctd\u003eUser Selectable\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eSafety Timing\u003c\/td\u003e\n\u003ctd\u003ePre-ignition \u0026amp; Lockout Interlocks\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/figure\u003e\n\u003ch3\u003e4-20 mA HART \u0026amp; Channel-to-Channel Isolation Profiles\u003c\/h3\u003e\n\u003cp\u003eThe Honeywell RM7850A1019 integrates high-integrity channel-to-channel isolation between its low-voltage logic circuitry, external 4-20 mA HART loop interfaces, and line-voltage output contacts. To prevent signal distortion from nearby motor drives or transformers, the onboard signal conditioning circuit isolates optical, flame rod, or UV detector inputs from backplane noise. Relay output channels controlling safety shutoff valves and ignition transformers maintain physical galvanic separation from internal microprocessors, ensuring deterministic lockout response times upon flame failure or system trip events.\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003eQ: What happens if the user-selectable airflow check switch fails to prove closed during start-up?\u003c\/p\u003e\n\u003cp\u003eA: If the airflow switch input does not close within the specified pre-ignition timing window, the module aborts the light-off sequence and initiates a safety lockout condition, requiring a manual reset before re-attempting ignition.\u003c\/p\u003e\n\u003cp\u003eQ: Can the RM7850A1019 module be removed or inserted while the wiring subbase is powered?\u003c\/p\u003e\n\u003cp\u003eA: No. The 120 VAC main power source must be completely de-energized prior to inserting or removing the module to prevent electrical arcing across terminal pins and to avoid un-sequenced relay actuation.\u003c\/p\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003col\u003e\n\u003cli\u003eMount the subbase vertically within a protective NEMA enclosure to allow proper natural convection cooling across the housing and internal power dissipating components.\u003c\/li\u003e\n\u003cli\u003eRoute low-voltage flame sensor wires in separate grounded metallic conduits away from line-voltage ignition transformer leads to prevent inductive noise pickup; ensure standard 5-thread engagement for all threaded NPT conduit fittings.\u003c\/li\u003e\n\u003cli\u003eAlign the RM7850A1019 connector guide rails with the subbase socket, push firmly to seat all pins, and tighten side lock screws to ensure subbase ground continuity before applying 120 VAC line power.\u003c\/li\u003e\n\u003c\/ol\u003e","brand":"Honeywell","offers":[{"title":"Default Title","offer_id":45414752780403,"sku":"RM7850A1019","price":88.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0644\/4348\/2227\/files\/RM7888A1027_3a3da9e8-93f1-461a-853f-1eac62ac7ed1.png?v=1787898515","url":"https:\/\/www.dcssupplier.com\/ar\/products\/honeywell-rm7850a1019-relay-module","provider":"DcsSupplier Limited","version":"1.0","type":"link"}