RVGRINGO Posted August 12, 2015 Report Share Posted August 12, 2015 We had a pressure system and installed a solar hot water system on our Chapala house. We plumbed it so that we could switch a couple of valves and be on the on demand gas heater, if needed. It was never really needed; we did get down to luke warm a few times and went over to gas, but that always caused the sun to come out. In a few hours, we would have near boiling water again. So, we just used the solar system and were patient, since three cloudy days in a row were very, very rare. The pressure system is more expensive, but it payed for itself in two years of saved propane. We loved it. Link to comment Share on other sites More sharing options...
Serenity6 Posted August 12, 2015 Report Share Posted August 12, 2015 Very useful info. Thank you. So you kept your existing propane-powered on-demand hot water heater in place, and added the 2nd (solar heater)? That means if I did buy a solar heater, I wouldn't have to necessarily remove the gigantic hot water heater currently in place? Link to comment Share on other sites More sharing options...
Mainecoons Posted August 12, 2015 Report Share Posted August 12, 2015 No but you might want to since those are poorly insulated and use a lot of gas when running. We have Calorex water heaters with the flue dampeners. I added external insulation to them since they aren't well insulated IMO. These heaters are sold as high efficiency but really aren't very good. They don't have pilotless ignition for example and really are substandard in insulation. I am surprised given how expensive propane is here that better water heaters aren't available. Link to comment Share on other sites More sharing options...
RVGRINGO Posted August 12, 2015 Report Share Posted August 12, 2015 Note that we installed our solar water heater so that we could use either it or the on demand propane water heater, not both. Running solar hot water through your existing hot water heater is not a good idea. Start at the cold water supply point for your existing propane heater. Disconnect it and plumb it to two valves; one to feed the gas heater and the other to feed the new solar heater. Then, plumb the hot water from the solar heater into the closest hot water line. Now, using the valves, you may select either one to be open, gas or solar, keeping the other closed. It worked beautifully. Link to comment Share on other sites More sharing options...
mudgirl Posted August 13, 2015 Report Share Posted August 13, 2015 One 400 peso cylinder of gas lasts me a year on my normal (not on-demand), small water heater. I light the heater (including pilot) 15 minutes before I want a hot shower, and shut it off when I am done. I have a separate tank for my cook stove- that tank also lasts me a year. I am amazed at how much you all spend for these things! Link to comment Share on other sites More sharing options...
ComputerGuy Posted August 13, 2015 Report Share Posted August 13, 2015 I don't know what the physics are that apply to gas usage, but I know for certain that my $426 pesos worth of tall cylinder gas lasts me a LOT longer on my BBQ than putting $1,000 pesos into my rooftop tank, which averages 3 months. I, too, only turn on the hot water "boiler" before showering, and turn it off afterwards. Other than that, the gas stovetop and the clothes dryer (once a week). In a previous house, I could do the same with just one cylinder of gas: cook, dry, shower, etc. Link to comment Share on other sites More sharing options...
NLU Posted August 13, 2015 Report Share Posted August 13, 2015 I know a few people like mudgirl & ComputerGuy who turn the hot water heater on when they need it and off again right after. Since gas usage for cooking is relatively minimal, their gas bill is, as they say, very very low. The last thing these people need is a solar hot water system. I applaud them for their frugality. Link to comment Share on other sites More sharing options...
Go Solar Posted August 13, 2015 Report Share Posted August 13, 2015 For Serenity6: a large tank gas boiler can be left in place and plumbed with a "puente" (bypass valve setup) so you can either turn it off and bypass it (most of the time) or bring it online as needed, quickly and easily. For non-solar folks who wish to only use gas when they want to take a shower, an on-demand unit like a Rheem or a Bosch is a lot easier way to go than turning a tank boiler on and off all the time.....and these types can be tied in to function as automatic backup to the solar, as well. Link to comment Share on other sites More sharing options...
Serenity6 Posted August 13, 2015 Report Share Posted August 13, 2015 How much propane is lost if, for example, my gigantic hot water heater has the pilot light on all the time and the temp is set at the hottest level? Sounds much easier and just like common sense to only turn the pilot light on shortly before you want to shower. But given that my heater is huge, I think I would need at least 30 minutes, if not more, to heat it up so I'd have enough water for a nice, long hot shower. Go Solar: thank you for the tip! Link to comment Share on other sites More sharing options...
RVGRINGO Posted August 13, 2015 Report Share Posted August 13, 2015 I suggest that you turn the temperature settings down to 120ºF, or equivalent. That should give you good showers but will reduce the propane demand to keep the hot water heater at a higher temperature. Even with an older on-demand heater with a pilot, we found that it used half of our total propane consumption. That is why we went solar, and it paid for itself in 2 years. Link to comment Share on other sites More sharing options...
ComputerGuy Posted August 13, 2015 Report Share Posted August 13, 2015 I'm curious as to how much a hot water tank pilot light burns. Link to comment Share on other sites More sharing options...
mudgirl Posted August 14, 2015 Report Share Posted August 14, 2015 For Serenity6: a large tank gas boiler can be left in place and plumbed with a "puente" (bypass valve setup) so you can either turn it off and bypass it (most of the time) or bring it online as needed, quickly and easily. For non-solar folks who wish to only use gas when they want to take a shower, an on-demand unit like a Rheem or a Bosch is a lot easier way to go than turning a tank boiler on and off all the time.....and these types can be tied in to function as automatic backup to the solar, as well. The on-demand heaters I have seen have a pilot on constantly. It is not a big deal to turn the boiler on and off when I need it- takes about 2 minutes. And to answer Computer Guy's curiosity- when I used to just leave the pilot on all the time, I went through a cylinder in 2 months, by only lighting it when i need it, it lasts a year. Big dif, I'd say. Then there are the folks who just leave their computers turned on all the time, the electric toothbrush, the stereo, etc., claiming it uses "hardly any electricity". All those things that have a little red light on all the time suck power. Link to comment Share on other sites More sharing options...
Go Solar Posted August 14, 2015 Report Share Posted August 14, 2015 No pilot light on the Rheem or the Bosch type units; they "spark up" using electronic ignitions, when the water flows. Link to comment Share on other sites More sharing options...
ComputerGuy Posted August 14, 2015 Report Share Posted August 14, 2015 It is such a pain to relight my pilot (I've had the gas guys spend a full five minutes or more, and they know what they're doing), I just leave the thermostat at its lowest setting, but that's still a pretty strong flame. Link to comment Share on other sites More sharing options...
lcscats Posted April 27, 2016 Report Share Posted April 27, 2016 Water heaters (all kinds) come with pilot lights, or battery pack that sparks, or plug in AC to spark. Size of pilot light varies and gets smaller over time. I like the battery pack that allows quick restarts without putting your face near the opening. I have two on demand water heaters one uses a pilot light and one uses a battery pack to spark and do not need 30psi (or whatever) to work. Your mileage may vary with the fancier new on demand heaters as mine are older mexican designs. Read the instructions for limitations on the newer fancier tankless heaters like low pressure or clean filtered water being needed without sand. Mine work all the time with no problems but not sure how efficient they are when running compared to newer systems. Link to comment Share on other sites More sharing options...
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