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Small Cabin Forum / Off-Grid Living / Recommendation on tankless propane H20 heater
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Alpine_Junky
Member
# Posted: 11 Mar 2021 19:03
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Looking for a recommendation on an indoor tankless propane H20 heater; here is what I am working with:

-Offgrid cabin build; hoping for pilot light or battery ignition unit. (I have probably went though 100+ units on all the box store websites and various other searches - can't seem to locate a current production unit). All units seem to be about 50 watts of 120v A/C when being used.

-120 gallon well tank with 40/60 cut in / out pressure.

-Water will need to be heated from high 30 degree mark during coldest days in winter; water is pulled from surface and stored in a cistern underground.

-Nothing fancy; dishes, washing machine, shower, etc. Single bathroom house.

Nobadays
Member
# Posted: 11 Mar 2021 19:48
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There are many out there that do not require 120vac. This Marey one is what we bought as others have had good luck with it at higher elevations.

Alpine_Junky
Member
# Posted: 11 Mar 2021 20:04
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Thanks for that! I actually was looking at this one and it shows that it isn't up to the task of raising the H20 temps from the high 30s - that has been one of the challenges. Never having used one before their documentation suggests the output isn't high enough. Where is your install at? One of the colder climates?

Fanman
Member
# Posted: 11 Mar 2021 20:38
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I don't think they still make that model, but we have a Bosch Aquastar tankless heater that has no pilot and needs no power... the water flow spins a tiny generator that provides the electricity to open the gas valve and light the igniter. Previously, we had one that used a standing pilot, no electric.

100° temperature rise is a lot for any heater. You might be able to get that at a reduced flow rate, though.

Nobadays
Member
# Posted: 11 Mar 2021 22:26
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We haven't installed it yet.... sorry.

Irrigation Guy
Member
# Posted: 11 Mar 2021 23:25
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The unit that Nobadays posted won’t give the desired temperature rise but it isn’t very expensive either. Has any one ever plumbed two of these in series to get higher temps? I realize it might be unorthodox but I don’t imagine there are many options for water heaters that don’t require constant power.

Brettny
Member
# Posted: 12 Mar 2021 05:40
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Quoting: Alpine_Junky
Thanks for that! I actually was looking at this one and it shows that it isn't up to the task of raising the H20 temps from the high 30s - that has been one of the challenges. Never having used one before their documentation suggests the output isn't high enough. Where is your install at? One of the colder climates?

You are an informed consumer! All these 5L, 7L and 10L rating dont mean any thing. The only thing that matters is a specific temp rise at a specific GPM. Some dont even show this spec available.

If you are willing to loose GPM your temp will rise. I have an iheat brand one from HD but it's not rated for indoor use.

Steve_S
Member
# Posted: 12 Mar 2021 06:48
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I have TWO On-Demand systems, both are LPG fueled and run off 120VAC.

1st one is a Takagi TH-3M used for my Radiant Heating system. Standby it uses 120V 4.2W including thermostat controls.

2nd One is an EccoTemp FVI12 which also uses 120VAC which also uses about 2W on standby. This works well and can generate really hot water without issues BUT it is extremely persnickety with sensitive temp adjustments IE: when getting into a shower. This Model has been updated/replaced and apparently better now.

The Takagi's are NOT cheap but well worth it. I chose a dedicated system for the radiant heating but this could have done both, hot water & radiant heating had I designed my system that way.

The EccoTemps are cheaper Chinese Imports (they also own Marey) but are not bad. They have low-end battery operated outdoor ones to higher-end whole-house capable models. The pricing is not bad at all.

Couple of points on On-Demand systems.
You will need a proper installation kit with valves etc.
https://www.watts.com/products/plumbing-flow-control-solutions/shutoff-valves/tankles s-water-heater-valves/lftwh

A "Pre-Mix" valve may be warranted. This injects a small amount of the hot coming out back into the cold input, raising the temp and lowering the amount of energy required to bring it up to temp. DO NOT Confuse this with a Post Mix Valve which is pressure & temp balancing.

Install the On-Demand system "central" or as close to where the water outlets are to reduce the amount of distance from heater to faucet. Do use foam pipe insulation on both hot & cold water lines.

ketchgould
Member
# Posted: 12 Mar 2021 09:37
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What if you made a loop in the plumbing with a tank inside the cabin too. Mix the outside water with the warm water in the indoor holding tank to get hot water coming out in the end?

Christian-WI

FishHog
Member
# Posted: 12 Mar 2021 18:51
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My eccotemp L10 takes water from my tank that has ice on top and makes it hotter than I can handle for a shower. I do run it on low flow but I do that year round as it’s more than enough water and I don’t see the need to waste more

It’s not an indoor heater but I do have it indoor to prevent freezing. For the few minutes it runs I’ve never registered a CO reading on my monitors.

mj1angier
Member
# Posted: 12 Mar 2021 19:23
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We have outside shower with a heater like those posted. In the winter we have to take the shower head and drop back in the supply barrel to recirculate the water to get it warm enough to shower. Works but it does use so lp...

DartNorth
Member
# Posted: 17 Mar 2021 01:37 - Edited by: DartNorth
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I've been thinking about the Camplux CA318. 42 watts in use, 2.4 watts in standby ( I had to email them for that info)

42 watts seems like a lot, but you'd be surprised how little it's actually running. Prob less than 30 mins a day for a couple, including showers and dishes.

silverwaterlady
Member
# Posted: 17 Mar 2021 09:57 - Edited by: silverwaterlady
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Quite a bit of water has to run through the on demand if any piping is involved, depending how far the water has to travel and how cold the ground water is.
You will be rinsing dishes and washing your hands in cold water because you don’t want the heater to turn on for the small amount of water required. It’s a waste because it won’t get hot until you run about five gallons through.
This on demand system I’m writing about is for a entire house and in our basement. It required a bunch of work by a HVAC company to set up. Venting to the outside (holes drilled through) a electrical outlet added, water piping and gas hookup.
That’s the up to code and legal way to install a indoor on demand.
At camp it’s a Marley with batteries. Used above freezing. Taken down and stored in the heated cabin at the hint of freezing temperatures. Venting out of the top that gets extremely hot. Almost instant hot water because there is no piping involved. Outside. I would never use it indoors. If anything happened indoors with that unit, our homeowners policy would be void.

cjm
Member
# Posted: 17 Mar 2021 11:59
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This is all super interesting and not something I'd considered. Do any of you use a tankless heater with water from a raised rain barrel? I'm curious to look if that would be enough water pressure.

NBNK
Member
# Posted: 17 Mar 2021 12:16 - Edited by: NBNK
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We use an eccotemp L10 from an outside tank. Water sometimes has ice on the edges. Have it set at a low speed and have a low flow head to get as many showers as possible from the tank. We have it plumbed to have hot and cold out of the tank and the water out of the tank will burn you if you don't get the mix or speed thru the heater correct. Tanks is 28 gallons, get 4+ showers. Tank is in the back of a pickup. I think the shower head is ~1 1/2 gallons a minute. We use a jet pump plugged into a converter that plugs into a 110 outlet.

DartNorth
Member
# Posted: 17 Mar 2021 15:27
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I don't use a rain barrel, but I used a 1000L IBC tote. We fill it from the lake with the big pump, then use an RV pump from that for all our water need.

3.6 gpm RV pump is more than enough for a shower. But we don't try to do anything else while using that shower.


Currently, we have a Camplux 8L outside, set to it's lowest flow setting to compensate for colder water. Runs off 2 D batteries. Hardly uses any propane.

We are looking to get a different one that we can install inside though, for hot water in freezing later fall/winter conditions.

gcrank1
Member
# Posted: 17 Mar 2021 16:20
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If anyone is running a gen sometime during the day or has enough solar-elec, an old elec coffee perc with the perc stuff out makes a great water heater. Cheap at the resale shops or free from your home basement or that of a relative.
Mine is a 30cup/1000w and having it full of water and ready for whenever the gen runs we have a big pot-o-hot-water for whatever.
Almost too easy.

silverwaterlady
Member
# Posted: 17 Mar 2021 20:07 - Edited by: silverwaterlady
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cjm-not enough water pressure. We use a RV water pump hooked up to a Goal Zero Yeti.
Edited to include: We built a water tower and have a 250 gallon water tank. There is enough pressure to run cold water into our cabin. As stated above, not enough water pressure to run the Marley in our outside shower.

rachelsdad
Member
# Posted: 18 Mar 2021 04:52
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I've been eyeing this for my water system redo this spring.

https://www.homedepot.com/p/Eccotemp-Eccotemp-i12-4-0-GPM-WholeHome-Residential-80-00 0-BTU-Liquid-Propane-Indoor-Tankless-Water-Heater-i12-LP/206262177#product-overview

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