Hi Bill, I'm still running an Aquastar 125BS (original French model, before Bosch bought them) that I installed in 1990. I've had to rebuild the water valve once (after a freeze up; it's in an unheated outside closet on the north side of my house), the high-temp sensor once, and I needed to replace the thermocouple a few times when I was just using a small propane tank to run it. I installed a 250 gallon propane tank in the late nineties and haven't had to replace the thermocouple since.
The Aquastar still works great, even when my incoming water temp is near freezing. I just have to use less cold-water mix during the winter. Are you finding the new Bosch models to be this reliable? Brian Teitelbaum AEE Solar -----Original Message----- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bill Loesch Sent: Monday, September 30, 2013 5:00 AM To: RE-wrenches Subject: Re: [RE-wrenches] On demand WH Hi Bill, et al, There are two major categories of tankless water heaters-natural draft (which work very similar in control aspect to a conventional tank i.e.. no electric required, some form of pilot light) and power vented (all power vented machines have need for at least a fan, most a computer with some form of display included - if your own body is incapable of telling you if the water is sufficiently hot). Of the Big Five (major players in the tankless market) all manufacture one or more models of power vented tankless. Today, only Bosch markets a natural draft tankless. Bosch offers more than one model of natural draft tankless, standing pilot and intermittent pilot. If you like simple, trouble free, and low life cycle cost, you have but one choice. http://www.bosch-climate.us/files/201304181918370.520PN_English_06.2011.pdf What must be properly addressed with _any_ tankless is intake and exhaust venting, gas line sizing, and water quality. Since this isn't a tank, the pilot flame does almost nothing in terms of freeze prevention. Some manufacturers state flow rate for their heaters without also providing temp rise. Flow rate without temp rise is meaningless. The above is a 117,000 BTU/h machine. Sometimes winter ground water temperatures are significantly colder than summertime temps. If you want hot water in the winter, too, make sure you use the appropriate temp rise. Hardness is the biggest issue with water quality, if you scale the heat exchanger you won't get the performance advertised. If you have hard water, a water softener or descaling _as required_ is necessary. I am a big fan of tankless and have been since '89 when I was first introduced to them as a user. Today, I install and troubleshoot all five major manufacturers. Co-located with the load, tankless provides you not only endless hot water but also instant hot water. Good luck, Bill Loesch Solar 1 - Saint Louis Solar 314 631 1094 On Sat, Sep 28, 2013 at 10:19 PM, frenergy wrote: > Off-grid Wrenches, > > I'm working on a load sheet and am having a hard time finding > standby and while firing electrical usage for a propane-fired on > demand water heater. Do they some/all have standing pilots, glow > bars, something else? I'm guessing the standby power needs are very > low but we all know how even 10-15 watts adds up over 24 hrs when > you're off-grid. > > If any body has some actual numbers rather than just pdf.specs > (though manus specs might help some), I would be most grateful. > Thanks in advance. > > Bill > Feather River Solar Electric > > ------------------------------ > > _______________________________________________ > List sponsored by Home Power magazine > > _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & 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 Change email address & 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
