{"product_id":"camco-10421-t-p-relief-valve-150-psi-1-2-inch-npt","title":"Camco 10421 T\u0026P Relief Valve | 150 PSI 1\/2 Inch NPT","description":"\u003cp class=\"nvn-hero\"\u003eThe Camco 10421 is the temperature and pressure relief valve that keeps your RV or marine water heater safe. It's factory set to vent at 150 PSI, threads into a standard 1\/2 inch NPT port, and reaches 4 inches into the tank. Corrosion-resistant metal and an epoxy-coated probe mean it holds up to salt air, with no gaskets to dry out and leak.\u003c\/p\u003e\n\n\u003cdiv class=\"nvn-description\"\u003e\n\u003cp\u003eA temperature and pressure relief valve isn't glamorous, but it's the one part on your water heater you never want to skip. The Camco 10421 is a T\u0026amp;P safety valve that opens automatically if your tank ever climbs past its safe pressure. It's factory set to relieve at 150 PSI, so the moment internal pressure gets there, the valve vents and protects the tank, the plumbing, and everyone aboard. Think of it as the last line of defense on your hot water system. Small part, big job.\u003c\/p\u003e\n\u003cp\u003eThis one uses a 1\/2 inch NPT threaded body, which is the standard fitting on the vast majority of RV and marine water heaters. The probe runs 4 inches into the tank, so it reads the actual water temperature and pressure inside, not just what's happening out at the fitting. That probe length is a good match for typical 6 to 10 gallon heaters. If you're working with a compact tank, measure your existing valve first so you know the probe won't bottom out against the far wall.\u003c\/p\u003e\n\u003cp\u003eWhere this valve earns its money is the build. The body is corrosion-resistant metal, and the probe is epoxy-coated, so it stands up to the damp, salty air that eats ordinary hardware alive in a bilge or engine bay. And there are no gaskets in the design. That matters, because gaskets are usually the first thing to dry out, crack, and start weeping after a couple of seasons. Fewer failure points means fewer surprise drips under the heater.\u003c\/p\u003e\n\u003cp\u003eInstallation is straightforward if you've done any threaded plumbing before. Shut off the water and power, drain enough from the tank to clear the valve port, and thread the new valve in with a few wraps of Teflon tape on the threads. A little anti-seize helps too, especially in a hot engine room where metal can seize up over time. Snug it down, restore pressure, and check for weeping before you call it done. Point the discharge where a release won't spray gear or wiring.\u003c\/p\u003e\n\u003cp\u003eA couple of habits will keep this valve honest. Test it once a year by lifting the lever and letting it snap back, which flushes any mineral buildup off the seat and confirms it reseats cleanly. If your boat runs a closed-loop system, pairing the heater with a small expansion tank keeps normal thermal expansion from nudging the valve open and dribbling every heat cycle. And if your current valve is weeping, seeping, or won't reseat, don't nurse it along. Replace it. A relief valve that won't close is just as much a problem as one that won't open.\u003c\/p\u003e\n\u003cp\u003eSo how do you know when a relief valve has gone bad? The usual tells are a steady drip from the discharge, a hiss under normal operating pressure, or a lever that feels stuck when you flip it to test. Any of those, and the valve is done. A little seepage right after a heat cycle can be normal thermal expansion, but a constant drip is not. On a boat that sits for weeks between trips, that slow leak can drain a tank and soak the compartment before you're even back aboard. Catching it early is cheap. Ignoring it is how you end up with a rusted-out heater and a wet locker. When in doubt, swap the valve. It's a few dollars of insurance against a much bigger headache.\u003c\/p\u003e\n\u003cp\u003eOne heads-up on the packaging: this ships in bulk, so it comes as the bare valve without a retail box or a printed instruction sheet. That's fine if you know what you're doing, and it keeps the cost down. But if you're installing several across a couple of boats, label them as you go so you don't mix up which tank got the fresh valve. For a standard 1\/2 inch NPT water heater, the Camco 10421 is a simple, honest fix you can trust.\u003c\/p\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eKey Features\u003c\/h2\u003e\n\u003cul class=\"nvn-features\"\u003e\n  \u003cli\u003eFactory set to relieve at 150 PSI to protect the tank, plumbing, and crew from over-pressure\u003c\/li\u003e\n  \u003cli\u003e1\/2 inch NPT threaded body fits the standard relief port on most RV and marine water heaters\u003c\/li\u003e\n  \u003cli\u003e4 inch probe reads true tank temperature and pressure, sized for typical 6 to 10 gallon heaters\u003c\/li\u003e\n  \u003cli\u003eCorrosion-resistant metal body stands up to damp, salty engine-bay and bilge air\u003c\/li\u003e\n  \u003cli\u003eEpoxy-coated probe adds a second layer of corrosion protection where it counts\u003c\/li\u003e\n  \u003cli\u003eGasket-free design removes the part most likely to dry out and weep over time\u003c\/li\u003e\n  \u003cli\u003eBulk packaged as a bare valve to keep the cost down on straightforward replacements\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cdiv class=\"nvn-trust\"\u003e\n  \u003ch2\u003eWhy Buy from NVN Marine\u003c\/h2\u003e\n  \u003cul\u003e\n    \u003cli\u003eAuthorized Camco reseller, full manufacturer warranty\u003c\/li\u003e\n    \u003cli\u003eNMEA member and ABYC certified, advice from real boat techs\u003c\/li\u003e\n    \u003cli\u003eSame-day shipping before 3 PM ET on in-stock items\u003c\/li\u003e\n    \u003cli\u003eNY headquarters and Fort Lauderdale flagship retail store\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eFrequently Asked Questions\u003c\/h2\u003e\n\u003cdiv class=\"nvn-faq\"\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat does a temperature and pressure relief valve actually do?\u003c\/summary\u003e\n    \u003cp\u003eIt's a safety valve. If your water heater's internal pressure climbs to the valve's set point, it opens and vents to protect the tank and plumbing from bursting. The Camco 10421 is factory set to relieve at 150 PSI.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat pressure does this valve release at?\u003c\/summary\u003e\n    \u003cp\u003eIt's factory set at 150 PSI. There's no adjustment needed, it's ready to install as it comes.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWhat thread size is it?\u003c\/summary\u003e\n    \u003cp\u003eThe body uses a 1\/2 inch NPT thread, which is the standard fitting on the large majority of RV and marine water heaters.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow long is the probe?\u003c\/summary\u003e\n    \u003cp\u003eThe probe is 4 inches long, so it reaches into the tank to read actual water temperature and pressure. That length suits most 6 to 10 gallon heaters.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eWill it fit my water heater?\u003c\/summary\u003e\n    \u003cp\u003eIf your heater uses a 1\/2 inch NPT relief valve port, it'll thread right in. Before you order, pull your old valve and confirm the thread size and that a 4 inch probe won't bottom out in a very compact tank.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eIs it okay for saltwater and marine use?\u003c\/summary\u003e\n    \u003cp\u003eYes. The corrosion-resistant metal body and epoxy-coated probe are built for damp, salty air, and the gasket-free design removes a common leak point. It holds up well in a bilge or engine bay.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eDo I need Teflon tape to install it?\u003c\/summary\u003e\n    \u003cp\u003eYes, a few wraps of Teflon tape on the threads is standard practice. A little anti-seize helps too, especially in a hot engine room where threads can seize over time.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eHow often should I test the valve?\u003c\/summary\u003e\n    \u003cp\u003eOnce a year, lift the lever and let it snap back to flush mineral buildup off the seat and confirm it reseats cleanly. If it won't reseat or it weeps, replace it.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eDoes it come with instructions?\u003c\/summary\u003e\n    \u003cp\u003eNo. This ships in bulk packaging as the bare valve, without a retail box or printed instructions, which helps keep the price down. Installation is standard threaded plumbing.\u003c\/p\u003e\n  \u003c\/details\u003e\n  \u003cdetails\u003e\n    \u003csummary\u003eMy old valve keeps dripping. Should I just replace it?\u003c\/summary\u003e\n    \u003cp\u003eIf a relief valve weeps or won't reseat, replace it rather than nurse it along. On closed-loop systems, adding a small expansion tank also helps stop normal thermal expansion from nudging the valve open.\u003c\/p\u003e\n  \u003c\/details\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specifications\u003c\/h2\u003e\n\u003ctable class=\"nvn-specs\"\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n\u003cth\u003eTitle\u003c\/th\u003e\n\u003ctd\u003eCamco 10421 Temperature and Pressure Relief Valve\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003ctd\u003eCamco\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eManufacturer Part Number\u003c\/th\u003e\n\u003ctd\u003e10421\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eUPC\u003c\/th\u003e\n\u003ctd\u003e014717104210\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eValve Type\u003c\/th\u003e\n\u003ctd\u003eTemperature and Pressure (T\u0026amp;P) Relief Valve\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003ePressure Relief Setting\u003c\/th\u003e\n\u003ctd\u003e150 PSI (factory set)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eThread Size\u003c\/th\u003e\n\u003ctd\u003e1\/2 Inch NPT\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eProbe Length\u003c\/th\u003e\n\u003ctd\u003e4 Inch\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eValve Body Material\u003c\/th\u003e\n\u003ctd\u003eCorrosion-Resistant Metal\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eGasket\u003c\/th\u003e\n\u003ctd\u003eNone (gasket-free design)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003eProbe Coating\u003c\/th\u003e\n\u003ctd\u003eEpoxy-Coated\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003ctr\u003e\n\u003cth\u003ePackaging\u003c\/th\u003e\n\u003ctd\u003eBulk\u003c\/td\u003e\n\u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e\n{\n    \"@context\": \"https:\/\/schema.org\",\n    \"@type\": \"FAQPage\",\n    \"mainEntity\": [\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What does a temperature and pressure relief valve actually do?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It's a safety valve. If your water heater's internal pressure climbs to the valve's set point, it opens and vents to protect the tank and plumbing from bursting. The Camco 10421 is factory set to relieve at 150 PSI.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What pressure does this valve release at?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"It's factory set at 150 PSI. There's no adjustment needed, it's ready to install as it comes.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"What thread size is it?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"The body uses a 1\/2 inch NPT thread, which is the standard fitting on the large majority of RV and marine water heaters.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"How long is the probe?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"The probe is 4 inches long, so it reaches into the tank to read actual water temperature and pressure. That length suits most 6 to 10 gallon heaters.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Will it fit my water heater?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"If your heater uses a 1\/2 inch NPT relief valve port, it'll thread right in. Before you order, pull your old valve and confirm the thread size and that a 4 inch probe won't bottom out in a very compact tank.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Is it okay for saltwater and marine use?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Yes. The corrosion-resistant metal body and epoxy-coated probe are built for damp, salty air, and the gasket-free design removes a common leak point. It holds up well in a bilge or engine bay.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Do I need Teflon tape to install it?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Yes, a few wraps of Teflon tape on the threads is standard practice. A little anti-seize helps too, especially in a hot engine room where threads can seize over time.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"How often should I test the valve?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"Once a year, lift the lever and let it snap back to flush mineral buildup off the seat and confirm it reseats cleanly. If it won't reseat or it weeps, replace it.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"Does it come with instructions?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"No. This ships in bulk packaging as the bare valve, without a retail box or printed instructions, which helps keep the price down. Installation is standard threaded plumbing.\"\n            }\n        },\n        {\n            \"@type\": \"Question\",\n            \"name\": \"My old valve keeps dripping. Should I just replace it?\",\n            \"acceptedAnswer\": {\n                \"@type\": \"Answer\",\n                \"text\": \"If a relief valve weeps or won't reseat, replace it rather than nurse it along. On closed-loop systems, adding a small expansion tank also helps stop normal thermal expansion from nudging the valve open.\"\n            }\n        }\n    ]\n}\n\u003c\/script\u003e\n","brand":"Camco","offers":[{"title":"Default Title","offer_id":45076626505821,"sku":"2009758","price":27.59,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0299\/7266\/0317\/files\/ImageServerAPI_0c56b7c2-8e97-45db-9948-e3a0798a251d.jpg?v=1789893345","url":"https:\/\/nvnmarine.com\/products\/camco-10421-t-p-relief-valve-150-psi-1-2-inch-npt","provider":"NVN Marine","version":"1.0","type":"link"}