{"product_id":"honeywell-rm7840l1018-control-relay-module","title":"Honeywell RM7840L1018 Control Relay Module","description":"\u003cp\u003eThe \u003cstrong\u003eHoneywell RM7840L1018\u003c\/strong\u003e, also cataloged as the \u003cstrong\u003eRM7840L1018\u003c\/strong\u003e Burner Control Relay Module, operates as a dedicated hardware component for automatic burner sequencing and safety shutoff execution within Honeywell 7800 Series platforms.\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\u003eRM7840L1018\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\u003eUnited States\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e0.8 kg (1 lb 13 oz net; 2.5 kg shipping)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDimensions\u003c\/td\u003e\n\u003ctd\u003e127 mm W x 127 mm H x 133 mm D (Q7800A Subbase) \/ 155 mm D (Q7800B Subbase)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Temp\u003c\/td\u003e\n\u003ctd\u003e-40 to 60 deg C (Storage: -40 to +60 deg C)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Consumption\u003c\/td\u003e\n\u003ctd\u003e120 VAC (+10, -15%), 50\/60 Hz (+\/-10%) logic supply\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eIgnition \u0026amp; Pilot\u003c\/td\u003e\n\u003ctd\u003eInterrupted pilot, interrupted 2nd stage pilot valve, 5 sec early spark termination\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTiming Cycles\u003c\/td\u003e\n\u003ctd\u003ePilot flame period (4 or 10 sec), Main flame period (10 or 15 sec), Fixed 15 sec post-purge\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eVibration Limit\u003c\/td\u003e\n\u003ctd\u003e0.5 G continuous operating environment\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 Loop Protocol and Diagnostics Dynamics\u003c\/h3\u003e\n\u003cp\u003eConfigured for combustion management, the module interface processes inputs from plug-in R78XX flame signal amplifiers to continuously decode flame signal strength and detect signal degradation. Internal optocouplers enforce galvanic isolation between high-voltage ignition outputs, safety interlock switches, and low-voltage solid-state logic microprocessors. The system uses dynamic self-check routines to validate airflow switch contacts and pre-ignition interlocks, forcing an immediate fail-safe lock-out upon loss of flame or detection of contact faults.\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003eQ: Can the RM7840L1018 module be installed without an external purge timer card?\u003c\/p\u003e\n\u003cp\u003eA: No, the module requires an ST7800A plug-in purge timer card inserted into the faceplate to establish the required pre-purge timing period.\u003c\/p\u003e\n\u003cp\u003eQ: How does the module react if an airflow fault is detected during operation?\u003c\/p\u003e\n\u003cp\u003eA: The user-selectable airflow check circuit evaluates line continuity; an open circuit condition on the airflow switch triggers a safety shutdown sequence.\u003c\/p\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003cp\u003eMount the RM7840L1018 strictly into a compatible Q7800A or Q7800B universal wiring subbase with line power completely de-energized. Ensure the subbase grounding terminal is connected directly to panel earth using a heavy-gauge copper conductor to satisfy FCC Class B noise requirements. Maintain physical separation by routing high-voltage ignition wires and line power in separate conduits away from low-voltage flame amplifier inputs. Verify that ambient vibration at the mounting surface does not exceed 0.5 G.\u003c\/p\u003e","brand":"Honeywell","offers":[{"title":"Default Title","offer_id":45422064205939,"sku":"RM7840L1018","price":88.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0644\/4348\/2227\/files\/RM7840L1075_a384fb6d-6621-406b-8f31-0c526ca3aa4f.png?v=1788147475","url":"https:\/\/www.dcssupplier.com\/ar\/products\/honeywell-rm7840l1018-control-relay-module","provider":"DcsSupplier Limited","version":"1.0","type":"link"}