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Dekagoldwingers
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# Posted: 8 Mar 2014 11:50
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Reaching out to the collective brain trust here for some help on my hot water options.
The cabin property has electricity, but as we are off the main line it can take up to a week to get power back sometimes, though presently we are not usually there at those time. Our water requirement right now, for 95% of the time 2 people, will be a bathroom with shower, and sink in kitchen. We will also be plumbing in for a washer/dryer.
We are leaning towards a tankless hot water heater, either electric or propane, or a small electric tank. Any opinions? Pros/cons to either, and for tankless any brand recommendations.
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bldginsp
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# Posted: 8 Mar 2014 14:54 - Edited by: bldginsp
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If you trust the elec power enough have an elec water heater, you'll pay a fair amount for the elec, and if its a tank water heater it has to be drained when you leave. There are some electric on demand heaters that will handle a shower, don't know about those.
Most people go with propane. There are a lot of different models and features to choose from. The 75000 btu models will handle only one use at a time which seems right for a small cabin.
A lot of people like the ecotemp propane on demand heaters. They are meant for outdoor use because they don't have a flu that can go thru the roof, they exhaust thru the side wall of the unit. Some people use these indoors and believe that the fumes are no more harmful than using a kitchen stove. I question that.
Where there is freezing, and you want your heater indoors, the other option is a unit with a flu. Many units with flus require 110v power to operate, many do not. I'm looking at the Bosch 330 propane, which does not require 110, has a pilot light, and uses a natural draft 'B' type vent.
If you will leave the heater in place in winter where it will freeze, it must be drained because the heater element traps water and when it expands it can break the element. Some are made to drain, those that are not must be blown out with compressed air.
The residential code requires that a water heater located in a closet in a sleeping area have the closet sealed off, and combustion air supplied to the heater from outside. If the woodstove is going it is pulling air out of the room, and can mess with the firing and draft of the heater if they are in the same body of air.
So I plan to have a small closet with my Bosch 330 inside it, with a door sealed with weatherstrip, and several ducts leading combustion and drafting air into the closet for the heater from the outside. I don't want to mount it on the wall outside, cause it would freeze when I sleep in winter. The closet is essentially unconditioned space and will get outside air, so could freeze, but I won't insulate it so it will get heat from the space to keep the unit from freezing. I'll set up the whole water system to drain when I leave and the building is not heated, and I must have a small compressor to blow out the trapped air in the pipes, water heater, and shower mixing valve. That's the only way I figure I can have a drafting water heater available for use in winter in an off grid situation.
Marey makes similar off grid water heaters and evidently are worth a look.
Marey 220v electric on demand water heater, 50 amp:
http://www.amazon.com/Marey-Electric-Tankless-Water-Heater/dp/B008C3X0O0/ref=sr_1_39? ie=UTF8&qid=1394309379&sr=8-39&keywords=tankless+on+demand+water+heaters
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Dekagoldwingers
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# Posted: 9 Mar 2014 00:28
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Thanks bldnsp. Obviously you gave spent some time doing research. I appreciate your sharing!
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MtnDon
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# Posted: 9 Mar 2014 00:52
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If the cabin is part time use & if the cabin will endure freezing weather and not be heated, being able to easily drain the water heater is a must. It does not take much water to cause a big problem if it freezes. Many on demand heaters are a challenge to drain and blow out completely. I know a few people who have had freeze problems; maybe it was because of sloppy winterizing, I don't know for sure.
I really wish there were small (10 gallon+) propane fueled tank style water heaters, as there are small electric tank types. They are easy to drain. Electric might be okay even with power outages if you apply extra insulation and if you are lucky. Depends.
A tank type RV propane fueled water heater (6 & 10 gallon) can be used if there is no inspection as they are not residence approved. We use one in our cabin. They are not as efficient as a good residential on demand heater or a good standard residential tank water heater, but they are pretty simple and above all else easy to drain. They do need to be placed in an exterior wall.
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bldginsp
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# Posted: 9 Mar 2014 03:12
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Youre welcome Deka actually I got most of that info from others here on this forum. Helped me solve my problem.
Some of the on demand water heaters claim to have a drain plug for freeze protection, such as the Bosch 330, but I have no idea how effective they are. Compressed air is the best way to go, I think.
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ILFE
Member
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# Posted: 9 Mar 2014 07:58
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Dekagoldwingers, I live in a region that wouldn't know what the words "cold" or "snow" even mean. So, that will never be an issue for me. (Cambodia.)
Being completely off grid, and considering going with a propane refrigerator anyway, has helped me to seriously consider adding a propane instant water heater. Our bathroom is separated, while still part of the main house. The room has cinder block vents on two walls, making it so ventilation would not be an issue.
Considering possible electric problems that you mentioned in your original post, helps me come to the conclusion that you would probably be much better off with an LP gas water heater as well.
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beachman
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# Posted: 9 Mar 2014 10:10
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Deka - we have a Bosch 1600 propane on-demand water heater with a type B vent up through the roof. I have heard, and this makes sense, that cold air can be drawn down the vent and freeze the unit. Ours has a drain too but I disconnect the unit in the Fall and keep it in our basement over the Winter. I also have a small Zodi water heater that works with two small Coleman propane camp tanks. It works quite well and might be an alternative for the Winter as it is easier to drain.
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bldginsp
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# Posted: 9 Mar 2014 12:52 - Edited by: bldginsp
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The Bosch 1600 water heater has what they call hydro-generated ignition, which means the gas is fired by a small turbine that spins when you turn on the water. The advantage to this is no 110v is required, no batteries are required for ignition (like Eccotemp and others), and no pilot light is required (Bosch 330 and others). That's great, but they cost a lot more, and I wonder how well the turbine will work after a period of use with high mineral content well water. I've seen instruction manuals for these units that include instructions on how to repair the turbine, which tells you that the manufacturer is expecting that it will need repair.
The units with pilot lights have one more advantage, which is that the pilot creates a slight amount of heat on the heater element, which hopefully avoids the potential problem of cold air coming down the flu and freezing the element. I have no idea how effective this really is, it's a guess on my part, but even though the pilot is very small it's located right under the element and burns constantly.
One other thing I read about freezing air coming down the flu and freezing the element, is that this is more likely to happen in a situation where you have another appliance in the building that is sucking combustion air out of the cabin, like a woodstove. That would create negative air pressure in the cabin, and if the water heater flu is the only access to the outside, cold air will be pulled down the flu directly onto the element. This is another reason to install the water heater in a sealed closet with it's own combustion air ducts.
Another issue to consider with on demand gas heaters is that the elements gradually build up calcification or other mineral deposits which gradually reduces their efficiency and ability to heat water. The instruction manuals include procedures for decalcification, which generally involves running a vinegar solution thru the unit. One more thing to keep on your maintenance list, and one more reason to favor collected rainwater, since it has very low mineral content and a slightly acidic balance, which would discourage mineral build up I guess.
When designing the piping system at an on demand heater, it's probably a good idea to think about how you would get a vinegar solution into the heater without removing it, or completely disconnecting the piping. Some sort of valve arrangement on the piping should be effective. I think kits are manufactured for the purpose, or maybe it's an expensive plumbers tool I'm thinking of, that facilitates flushing a piping system. But also you may want to incorporate a means of connecting compressed air to the piping system for draining before winter.
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ILFE
Member
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# Posted: 9 Mar 2014 12:56
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bldginsp, do you know an average cost for one of those units? (The Bosch 1600 water heater.)
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bldginsp
Member
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# Posted: 9 Mar 2014 13:04 - Edited by: bldginsp
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The Bosch 1600 lists on Amazon for $707, the 330 for $430. The 1600 is 117,000 btus, enough to run two applications at a time probably. The 330 is 75000 btus, not enough for two.
One thing to remember is that if you get an on demand water heater that requires a stainless steel vent, your vent costs will be high. The Bosch 1600 and 330 both use standard B vents, which cost a lot less.
Eccotemps range from $120, 170 to 270 depending on model. Again these are all designed strictly for outdoor use and cannot be used indoors since they are not designed to draft with a vent. I've never heard people complain of reliability problems with these units, cheap as they are.
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ILFE
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# Posted: 9 Mar 2014 13:14
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No electricity is what I would want, if possible. We only use piped hot water, currently, for showers.
Thanks for the information, i will do some more searching. I posted that, because I couldn't find the 1600 online at the time. Then, I found where it is supposedly replaced with a 520HN NG or a 520HN LP. Well, I assume (there's that word) we are talking about the same unit. It was a 1600H that I found.
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bldginsp
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# Posted: 9 Mar 2014 13:21
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It's amazing how many different choices and design options there are on these things. I was baffled at first. I ended up reading the installation/use manuals to get the information I needed, because the advertising fluff was not as complete as I would have preferred.
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ILFE
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# Posted: 9 Mar 2014 13:33 - Edited by: ILFE
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In 2006, I was visiting New Zealand. Stayed with a guy who had one, similar to this 1600. But, it had electric ignition. Quite modern, actually. Control panels in the bath and kitchen, both you could adjust for temperature, and even use it to fill the tub. Just set the number of liters you wanted. Then, you could walk out, finish anything else you needed to do, and the tub would automatically cut off when full - at the right temperature for you. (I thought I was livin' in high cotton, back then.)
Unfortunately, I wasn't really good with the liters to gallons conversion thing, though. So, it wasn't a pretty sight when I returned to the bath / swimming pool the first time I had set it. His cat wasn't very happy either. (Don't ask.) But, I made amends, cleaned the bathroom, paid for the whiskey and wine (Kiwi's like wine), dried the cat off, and he was happy again.
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bldginsp
Member
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# Posted: 9 Mar 2014 13:42
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Ha Ha!
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Dekagoldwingers
Member
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# Posted: 9 Mar 2014 18:45
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THanks again folks, this is helpful info. I will look into these options. For the bosch 330 did I read here that it is only good for one outlet. Does that mean 1 tap at a time? When I looked at it on line, it didn't seem to show a fpm rate. I know I looked at a small unit locally but it had very low capacity. The local Propane guy had it hooked to a washroom outlet, but the supply travelled under the building in the cold and the supply line to the unit was a standard sink pigtail. The output (GPM) was very poor in my opinion.
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bldginsp
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# Posted: 9 Mar 2014 19:59
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You could pull enough water thru a Bosch 330 to feed three showers, but the water wouldn't get hot enough for any. On demand water heaters can only raise the temperature of water passing thru them a certain number of degrees at a certain rate of flow. The lower the rate of flow, the higher the temp increase, and vice versa. Larger capacity units can literally put more fire on the firebox and heat water to a higher temp at a higher rate of flow.
Most on demand water heaters for on grid residential use are 200,000 btus, and these will handle two showers and the kitchen sink at the same time. Less than 100,000 btus, I'm guessing one shower and maybe a sink, but you might give the person showering a cold wake up call when you turn on the sink, then they adjust the temp accordingly, then you shut off the water and they get burned.
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MtnDon
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# Posted: 9 Mar 2014 21:03
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Do remember that if the on demand heater will be used in cold weather, and IF the propane supply is small 2-# cylinders, you may run into problems with a heater demanding more propane volume than can be provided by that cylinder.
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drb777
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# Posted: 9 Mar 2014 22:21 - Edited by: drb777
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I choose the eccotemp with power vent, natural gas, but LP is also available. Stainless vent fittings were included, 'only had to add a relief valve and normal hook-up fittings. The photos show the pex piping which may be eventually shrouded and the outside of the vent.
I was able to find the unit at a sale price of only $225 a couple of years ago, a bit higher now. This model does require AC power, but at a low level easily achievable with a power inverter in a pinch.
ecotemp with power vent
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external vent
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drb777
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# Posted: 9 Mar 2014 22:35 - Edited by: drb777
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The model shown is a Eccotemp FV112-NG, 74,000 BTU, 3.6 gpm rating. They are now available under $300 delivered, also as a propane, LP unit. www.eccotemp.com shows all of the different units they offer, lots of choices.
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Dekagoldwingers
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# Posted: 10 Mar 2014 02:34
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Hi drb777, what kind of temperature rise do you get on the ecotemp unit. When I look at the website, I can find no specifications, only a description. What us the water temp at input side and what us it on the output side given a shower flow? Cheers and thanks
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tverga
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# Posted: 10 Mar 2014 18:28
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http://www.grainger.com/product/BOSCH-Tankless-Water-Heater-2KJH4?s_pp=false
The good thing about this water heater it needs no electric, it has a gas pilot.
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bldginsp
Member
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# Posted: 10 Mar 2014 21:21
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Tverga- yes that's a good heater but grainger is the wrong place to buy it. $200 less on amazon.
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ramloui
Member
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# Posted: 11 Mar 2014 15:17
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Hello all,
I'm a bit late joining this thread but here is what I'm experiencing with my on-demand water heater (Bosch- forget model number) at my cabin.
This water heater is propane and has a standing pilot. It requires 2 conditions for the burner to light off: minimum flow and minimum pressure. Minimum pressure has not been an issue since the cabin is equipped with a pressurized water system (pump water from lake to large tank with gasoline pump, gravity to 12V Shurflo pump, 20G pressure tank then cabin).
The minimum required flow is what has been bugging me most and the reason is that the faucets are 1 lever type. When I open a faucet fully to hot, no problem. The flow is high enough and the heater lights and I (eventually) get hot water. However, when I want warm water, the lever is turned towards cold which decreases the flow on the hot side. At some point, the minimum flow to the water heater is too low and it turns off. Since the faucet is a bit far from the heater, it takes many seconds before I realize that the heater has turned off, so I swing the lever back towards hot all the while screaming like a little girl because I am getting a cold shower! I know that the water temperature can be adjusted at the heater, but it is not very practical as the water temperature in the large tank varies constantly.
So, my plan is to eventually change all the faucets to 2 knobs type. If I could, I would also move the water heater closer to the users.
Cheers!
Louis R.
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drb777
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# Posted: 11 Mar 2014 17:51 - Edited by: drb777
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Louis, your on-demand water heater problems are common to many if not most brands. As you said, most people first try to adjust the output temperature lower to maximize the volume through the unit. Next, many have found that single lever control faucets simply don't work well with rate sensitive water heaters. Realizing this, I specifically choose an older design surface mount dual valve faucet shown in the photo below, and mounted the heater close the the shower and bath vanity. I suppose you could try a separate circulation pump to equalize the water temperature in the large tank, but that would likely be too much trouble & expense. 'Hope you get it worked out. David
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bobrok
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# Posted: 10 Jul 2014 11:34
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And I apologize to u because I meant no disrespect; I was just commenting on the general nature of spam on the internet.
After being somewhat silent on the forum I am once again trying to participate and i probably shot from the hip too quickly.
At any rate I am replying to you before this whole thing gets edited out of the thread.
Pretty cool talking to someone from that part of the world!
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ILFE
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# Posted: 10 Jul 2014 11:42
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LOL. No worries. Well, not so much from, as just being a resident. (I'm originally from the state of Gawga.)
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