Radiantec makes a heat dump valve that activates at a temp you set via a controller that may be a safer way to divert over heated water... http://www.radiantec.com/pdf/End_Uses_of_the_Solar_Energy.pdf pp4 -Glenn Burt
_____ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Roy Butler Sent: Tuesday, November 11, 2008 11:15 AM To: RE-wrenches Subject: Re: [RE-wrenches] Pt valves as overheat control Hi guys, I have been using the SS water loop in my Amish wood cookstove for my domestic hot water for 9 years now. My tank is a 40 gallon electric water heater (space saver unit) and is configured for thermo siphon operation. The P/T valve is all I have for protection and I have to be honest, I kind of knew this was probably not a great idea right from the start! But it works....the valve opens up and discharges into a piping system located under a raised bed planting area in our attached green house. So we get the benefit of the 'waste' heat. The valve opens, on average, about 1 or 2 times a week during the coldest part of the winter. I replace the P/T valve every other heating season because it does begin to weep a bit. So that may be what's saved my ignorant butt from being blown to bits.....maybe. My question....is there a more robust version of that P/T valve that I should be using? Something that you would use in a boiler perhaps? I'm hoping to not have to change the system too much....I love the long, guilt free showers....more so because the electricity for the pump comes from my off-grid hybrid system. I'm so much better at PV and wind systems....hot water scares me! Roy Butler NABCEP Certified Solar PV InstallerR NYSERDA eligible PV & wind installer Four Winds Renewable Energy, LLC 8902 Route 46 Arkport, NY 14807 607-324-9747 www.four-winds-energy.com www.nationalsolarsupply.com Although no trees were killed in the sending of this message, a large number of electrons were terribly inconvenienced. Todd Cory wrote: Sure, but the discussion was about preventing hot water storage tanks from exploding. Putting BTUs into a tank, whether that be from a wood stove loop or 5 kW electric heating element is not the issue. Relying on a P/T valve to regulate overheating is of course not a good idea, but it will prevent the tank from exploding. Todd Conrad Geyser wrote: Todd, I'm afraid that any PT valves that I've ever known have continued to weep indefinitely after one or two overheat triggers. I would not recommend relying on them for heat control devices. Conrad Cotuit Solar NABCEP thermal cert. <!--[endif]--> _____ _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
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