{"product_id":"weil-mclain-591-391-821","title":"Weil McLain 591-391-821 Wiring Harness","description":"\u003cp\u003eThe \u003cstrong\u003eWeil McLain 591-391-821 Wiring Harness with Junction Box\u003c\/strong\u003e is a factory \u003cstrong\u003ewiring harness\u003c\/strong\u003e that includes its own \u003cstrong\u003ejunction box\u003c\/strong\u003e. The part number appears in \u003cstrong\u003eWeil McLain\u003c\/strong\u003e's \u003cstrong\u003eGV Series 1 and 2\u003c\/strong\u003e parts list and again in the \u003cstrong\u003eGV Series 3\u003c\/strong\u003e parts list, which makes it a manufacturer-listed component for those gas \u003cstrong\u003eboiler\u003c\/strong\u003e families. It is not a universal \u003cstrong\u003eharness\u003c\/strong\u003e, and it is not listed for every \u003cstrong\u003eGV\u003c\/strong\u003e model, so the part number should be matched against the \u003cstrong\u003eboiler\u003c\/strong\u003e's own parts list.\u003c\/p\u003e\n\n\u003cp\u003eA \u003cstrong\u003ejunction box\u003c\/strong\u003e on a \u003cstrong\u003eboiler\u003c\/strong\u003e \u003cstrong\u003eharness\u003c\/strong\u003e gives the wiring a defined connection point, so field connections are made in an enclosure rather than in the open. When that box is cracked, the \u003cstrong\u003eharness\u003c\/strong\u003e insulation is brittle from years of heat, or terminals inside are corroded, the whole assembly is better replaced as a unit. Using the factory \u003cstrong\u003e591-391-821\u003c\/strong\u003e keeps the wire gauges, lengths and terminations the way the manufacturer built them and avoids the problems that come from patching a \u003cstrong\u003eharness\u003c\/strong\u003e with mismatched wire or loose connectors.\u003c\/p\u003e\n\n\u003cp\u003eCheck the old \u003cstrong\u003eharness\u003c\/strong\u003e and \u003cstrong\u003ejunction box\u003c\/strong\u003e against the part number before you order. \u003cstrong\u003eWeil McLain\u003c\/strong\u003e uses different \u003cstrong\u003eharness\u003c\/strong\u003e numbers on other \u003cstrong\u003eboiler\u003c\/strong\u003e lines, including the \u003cstrong\u003eGV90+\u003c\/strong\u003e family, so a \u003cstrong\u003eGV Series 1\u003c\/strong\u003e, 2 or 3 \u003cstrong\u003eboiler\u003c\/strong\u003e is the match for this one. If you are not sure which series you have, send the \u003cstrong\u003eboiler\u003c\/strong\u003e model and serial number and our team will help confirm the right \u003cstrong\u003eharness\u003c\/strong\u003e before you buy.\u003c\/p\u003e\n\n\u003cp\u003e\u003cstrong\u003eKey Benefits\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eListed for GV Series 1, 2 and 3:\u003c\/strong\u003e \u003cstrong\u003e591-391-821\u003c\/strong\u003e appears in the \u003cstrong\u003eWeil McLain\u003c\/strong\u003e \u003cstrong\u003eGV Series 1 and 2\u003c\/strong\u003e parts list and in the \u003cstrong\u003eGV Series 3\u003c\/strong\u003e parts list.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eHarness and Junction Box Together:\u003c\/strong\u003e The \u003cstrong\u003eharness\u003c\/strong\u003e comes with its \u003cstrong\u003ejunction box\u003c\/strong\u003e, so the wiring connection point is replaced along with the wire.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFactory Wire and Terminations:\u003c\/strong\u003e Built to the manufacturer's layout, which avoids the mismatched wire and loose connectors that field repairs invite.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eOne Part Number to Match:\u003c\/strong\u003e \u003cstrong\u003e591-391-821\u003c\/strong\u003e is the number to check against the old \u003cstrong\u003eharness\u003c\/strong\u003e or the \u003cstrong\u003eboiler\u003c\/strong\u003e parts list.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003e\u003cstrong\u003eCommon Questions\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eWhat is the 591-391-821?\u003c\/strong\u003e It is a \u003cstrong\u003eWeil McLain\u003c\/strong\u003e \u003cstrong\u003ewiring harness\u003c\/strong\u003e with a \u003cstrong\u003ejunction box\u003c\/strong\u003e, listed in the \u003cstrong\u003eGV Series 1 and 2\u003c\/strong\u003e parts list and in the \u003cstrong\u003eGV Series 3\u003c\/strong\u003e parts list.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eWill it fit a GV90+ boiler?\u003c\/strong\u003e We do not list it for the \u003cstrong\u003eGV90+\u003c\/strong\u003e. That family uses different \u003cstrong\u003eharness\u003c\/strong\u003e numbers, so please send your \u003cstrong\u003eboiler\u003c\/strong\u003e model and serial number and our team will confirm.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eShould I replace the junction box with the harness?\u003c\/strong\u003e Yes, when the \u003cstrong\u003eharness\u003c\/strong\u003e and box are supplied together. A cracked box or brittle insulation is the usual reason to replace the whole assembly.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eDisclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.\u003c\/p\u003e\n","brand":"Weil McLain","offers":[{"title":"Default Title","offer_id":68008918352050,"sku":"591-391-821","price":28.38,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1838\/2375\/files\/ac-parts-1000x1000_d8f6c0df-eeb5-4a7f-8ee2-4f92681ea310.webp?v=1755632728","url":"https:\/\/www.gsistore.com\/products\/weil-mclain-591-391-821","provider":"GSIstore","version":"1.0","type":"link"}