Hey Ian, The key is that you want "temperature modulated", not "flow modulated". There are a number of temperature modulated units out there, the Rinnai and Takagi probably being the most popular. We have had one problem with a solar preheat through one of these and that is if the solar water is pretty close (around 115 or so) the unit doesn't come on. The factory settings don't let you take the temperature higher than 125 to try to overcome this. Both the Rinnai and Takagi have electric ignition, no pilot! Cheers, Conrad Cotuit Solar
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ian Woofenden Sent: Friday, November 14, 2008 12:05 PM To: RE-wrenches Subject: Re: [RE-wrenches] tankless hot water and pumping question Hi Todd and all, Since this is a renewable energy list, I think it's worth mentioning that installing a modulating demand heater will make the installation "solar ready". I'm only aware of one tankless heater that accepts pre-heated water and has no electrical usage, and that's the Bosch 1600PS (which I live with). I'd love to know if there are others, since this is a common need in off-grid systems. Some of the other modulating heaters on the market have significant electrical demand, which is a deal breaker for us poor off-gridders. Ideally, we'd have such a unit that doesn't have a standing pilot, but I've never heard of such a product, though there are non-modulating heaters that run on piezo igniton and a couple of D-cells. Bosch's hydro unit is a neat concept, but it's not modulating. I hope others will share their knowledge and experience. Ian -- Ian Woofenden <[EMAIL PROTECTED]>, Senior Editor, Home Power magazine Subscriptions: $24.95 per year PO Box 520, Ashland, OR 97520 USA 800-707-6585 (US), 541-512-0220 or download free sample issue at <http://www.homepower.com> _______________________________________________ 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 _______________________________________________ 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
