{"product_id":"pentaircomportexpansionmodule520818pen520818","title":"Pentair Com Port Expansion Module | 520818","description":"\u003cdiv\u003e\n  \u003ch2\u003ePentair Serial COM Port Expansion Board Kit (Adds RS-485 Communication Ports) | 520818\u003c\/h2\u003e\n\n  \u003cp\u003e\n    The Pentair \u003cstrong\u003e520818\u003c\/strong\u003e is a \u003cstrong\u003eSerial COM Port Expansion Board kit\u003c\/strong\u003e used to add additional RS-485 communication\n    ports to compatible Pentair pool\/spa automation systems. It’s commonly installed when you need more connection points for\n    equipment such as variable-speed pumps, salt systems, heaters, or other RS-485 devices that communicate with the control panel.\n  \u003c\/p\u003e\n\n  \u003ch3\u003eKey Features\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eAdds more COM ports:\u003c\/strong\u003e expands available RS-485 connection points for supported automation systems.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eHelps eliminate “no open COM port” issues:\u003c\/strong\u003e useful when adding devices to an already-populated controller.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eClean install:\u003c\/strong\u003e mounts inside the control enclosure using the included brackets and hardware.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eIncludes 12\" (1 ft) cable:\u003c\/strong\u003e pre-made interconnect cable to link the expansion board to the automation system.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eOEM Pentair kit:\u003c\/strong\u003e designed for correct fit, wiring layout, and long-term reliability.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eCompatible Systems\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePentair EasyTouch\u003c\/strong\u003e automation systems\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePentair IntelliTouch\u003c\/strong\u003e automation systems\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eSelect ComPool \/ TimeMaster \/ LX-10 power center\u003c\/strong\u003e automation applications (where specified)\u003c\/li\u003e\n  \u003c\/ul\u003e\n  \u003cp\u003e\n    \u003cem\u003eTip:\u003c\/em\u003e Compatibility can vary by system revision and configuration. Confirm your automation model and wiring layout before ordering.\n  \u003c\/p\u003e\n\n  \u003ch3\u003eWhat’s Included\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003e(1) Serial COM Port Expansion Board\u003c\/strong\u003e (multi-terminal RS-485 expansion PCB)\u003c\/li\u003e\n    \u003cli\u003e\u003cstrong\u003e(1) 12\" (1 ft) 4-conductor cable assembly\u003c\/strong\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cstrong\u003e(2) Mounting brackets\u003c\/strong\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003cstrong\u003e(4) Mounting screws\u003c\/strong\u003e\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eCommon Uses\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003eAdding a second (or additional) RS-485 device when all existing COM ports are already in use\u003c\/li\u003e\n    \u003cli\u003eExpanding automation to control more equipment (pump, salt system, heater interface, accessories)\u003c\/li\u003e\n    \u003cli\u003eReplacing a damaged or corroded COM expansion board inside an automation load center\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eInstallation Notes\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePower off first:\u003c\/strong\u003e shut off all power to the automation panel at the breaker before opening the enclosure.\u003c\/li\u003e\n    \u003cli\u003eMount the expansion board securely with the included brackets and screws to prevent vibration-related connection issues.\u003c\/li\u003e\n    \u003cli\u003eRoute the included cable cleanly and keep low-voltage communication wiring separated from high-voltage conductors when possible.\u003c\/li\u003e\n    \u003cli\u003eUse correct polarity\/terminal labeling for RS-485 connections and tighten terminals securely (loose terminals can cause intermittent comm faults).\u003c\/li\u003e\n    \u003cli\u003eAutomation wiring should be performed by a qualified pool professional or electrician.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eTroubleshooting Notes\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eIntermittent communication:\u003c\/strong\u003e check terminal tightness, wire strain, corrosion, and correct RS-485 polarity.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eNo device detected:\u003c\/strong\u003e confirm the device is RS-485 capable, wired to the correct terminals, and enabled\/configured in the automation settings.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eMultiple devices offline:\u003c\/strong\u003e inspect the shared communication bus, look for pinched cables, and verify there are no splices with poor connections.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eRelated Products\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/pages\/search-results-page?q=520818\"\u003eSearch Aqua Pool Supply for 520818\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/pages\/search-results-page?q=EasyTouch%20parts\"\u003ePentair EasyTouch parts\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/pages\/search-results-page?q=IntelliTouch%20parts\"\u003ePentair IntelliTouch parts\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/pages\/search-results-page?q=IntelliFlo%20RS-485%20pump%20parts\"\u003ePentair IntelliFlo RS-485 pump parts\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/pages\/search-results-page?q=IntelliChlor%20parts\"\u003ePentair IntelliChlor parts\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/pages\/search-results-page?q=RS-485%20cable\"\u003eRS-485 communication cable \u0026amp; accessories\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/pages\/search-results-page?q=pool%20automation%20accessories\"\u003ePool automation accessories\u003c\/a\u003e\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eMaintenance Tips\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003eOnce per season, inspect low-voltage terminals for corrosion and confirm all screws remain snug.\u003c\/li\u003e\n    \u003cli\u003eKeep the automation enclosure dry and properly sealed to reduce corrosion on boards and terminals.\u003c\/li\u003e\n    \u003cli\u003eIf you service wiring, label each RS-485 cable to prevent mix-ups when adding future devices.\u003c\/li\u003e\n    \u003cli\u003eAvoid running communication wires tightly alongside high-voltage conductors to reduce interference.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/div\u003e\n","brand":"Pentair","offers":[{"title":"Default Title","offer_id":52589952008508,"sku":"520818","price":99.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0736\/3280\/9276\/files\/pentair-com-port-expansion-module-520818-pool-automation-8107943.jpg?v=1771561336","url":"https:\/\/aquapoolsupply.com\/products\/pentaircomportexpansionmodule520818pen520818","provider":"Aqua Pool Supply","version":"1.0","type":"link"}