{"product_id":"mcdonnell-miller-142400-model-63-mechanical-low-water-cut-off","title":"McDonnell \u0026 Miller 142400 Model 63 Mechanical Low Water Cut-Off","description":"\u003cp\u003eProtect your boiler system from dry-firing damage with the reliable \u003cstrong\u003e142400\u003c\/strong\u003e mechanical low water cut-off from McDonnell \u0026amp; Miller. Designed specifically for the \u003cstrong\u003eModel 63\u003c\/strong\u003e series, this component provides essential automatic burner shut-off when boiler water levels drop below a critical threshold, preventing potential overheating and system failure.\u003c\/p\u003e\u003cp\u003eThe mechanism utilizes a high-sensitivity float switch assembly that responds precisely to water level fluctuations within the boiler. When the water drops, the float triggers the switch to interrupt the burner circuit, maintaining system integrity through proven mechanical logic that has been a standard in the industry for decades.\u003c\/p\u003e\u003ch4\u003eKey System Performance Baselines:\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eAutomatic Safety Shut-off:\u003c\/strong\u003e Reliably cuts power to the burner during low-water events.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeavy-Duty Construction:\u003c\/strong\u003e Engineered to withstand the rigors of commercial and residential hydronic heating environments.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePrecision Float Design:\u003c\/strong\u003e Ensures consistent response times and long-term operational durability.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEasy Maintenance:\u003c\/strong\u003e Simplified design allows for efficient inspection and replacement.\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e⚠️ \u003cstrong\u003eApplication Profile:\u003c\/strong\u003e Recommended for use in hot water heating boilers to prevent dry firing, improve system longevity, and comply with standard safety codes for hydronic installations.\u003c\/p\u003e","brand":"McDonnell \u0026 Miller","offers":[{"title":"Default Title","offer_id":43125823504478,"sku":"142400","price":768.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0663\/7151\/8558\/files\/142400_image_367a1538-7d3d-49d1-a359-ba349438a769.png?v=1786038945","url":"https:\/\/nationalboilersupply.com\/products\/mcdonnell-miller-142400-model-63-mechanical-low-water-cut-off","provider":"National Boiler Supply","version":"1.0","type":"link"}