Cabin Water System Components

[ezwryder]

I am trying to figure out if I have a generally-correct set of components for an off-grid cabin water system. I don't think it needs to be complicated, but I haven't worked with a plumbing system before. If you have experience with these types of systems, your input would be appreciated.

Our needs are simple; decent water pressure for a sink, shower and a toilet. Right now our toilet is a 5 gallon bucket and the shower is a Joolca. Expectations are not high, just about anything would be better!

The well is currently plumbed with a windmill driven pump, which I will continue to use for now. Later I'd like to install a solar-driven pump with a low water level switch that can auto-refill the tank.

The pump and accumulator are the style used in RV systems, and I figured this is basically an RV/marine-type system.

Hot water would come from a propane instant water heater.

Does this look relatively on track, or would you do things differently? Use different components or different-sized components?

Thank you.

 

[dcg9381]

I've extensively done off grid water and have experience with wells and tanks. You can also PM me.
There is no real reason for a storage buffer unless you have a low flow well or have well water that needs to off gas. You'll need a 2nd pump (like you have) after the tank... So you're adding a lot of hardware here - and ideally pump protection, so it's going to get expensive.

I don't know where you are but that tank (if above ground) is going to be subject to freeze. Unless you can get it indoors/insulated.

Tell me more about what you've got - generally you can minimize this stuff with a stop-cycle-valve and good pump control / protection.

FYI - these guys are excellent. I use both their stop cycle valve instead of pressure tanks and I use their pump protection.

Cycle Stop Valves, Inc

Constant pressure pump control kits, constant pressure pump control valves, and pump monitors

cyclestopvalves.com

 

[ezwryder]

Thanks dcg, I appreciate the feedback. Right now I have none of this. I have the well, and that's it.

The driller rated the well at 10 GPM and the solar water pump system I'm looking at is rated for 5 GPM at 220 feet. The water does not need to off gas, it's pretty decent.

Would you just go from the well into a pressure tank of some kind?

One detail I left off is that I want to install a sillcock at a point where I can drain the system in the fall. It is a 3 season cabin.

 

[OzSolar]

FWIW: We avoid on demand water heaters in general but particularly in off grid applications. They tend to be finicky about water pressure and gpm plus be can prone to clogging up.

Edit: "we" is my company just in case anyone though I was trying to speak for everyone in this forum.

Would you just go from the well into a pressure tank of some kind?

That the most common set up we see. You just need to make sure that your pump has enough head pressure left over to both lift the water and to pressurize the tank. Each PSI will add 2.31 feet of head to your system. EG 45 PSI x 2.31 FT/PSI = 104 ft of additional head

 

[dcg9381]

The driller rated the well at 10 GPM and the solar water pump system I'm looking at is rated for 5 GPM at 220 feet. The water does not need to off gas, it's pretty decent.

10 GPM is "moderate flow" here. That's enough for most homes (larger) as long as it's consistent. You already have a "buffer" of water. What's the level of the pump compared to the level of the water? That's your water storage.

Would you just go from the well into a pressure tank of some kind?
One detail I left off is that I want to install a sillcock at a point where I can drain the system in the fall. It is a 3 season cabin.

I would go into an insulated well house (or insulated location for a pump). I use Stop Cycle Valves (see my link above) rather than pressure tanks - a very small pressure tank is still required. Sure, you can set a silcock or otherwise low point drain that's appropriate. I would assume you'd need to drain or otherwise winterize the pump.

 

[ezwryder]

That the most common set up we see. You just need to make sure that your pump has enough head pressure left to both lift the water and to pressurize the tank. Each PSI will add 2.31 feet of head to your system. EG 45 PSI x 2.31 FT/PSI = 104 ft

Thanks for the feedback. Is there an alternative you would use for generating hot water? I appreciate the calculation. That is very handy to know.

 

[ezwryder]

10 GPM is "moderate flow" here. That's enough for most homes (larger) as long as it's consistent. You already have a "buffer" of water. What's the level of the pump compared to the level of the water? That's your water storage.

The driller said the static water level was 160 feet. That is something I need to confirm on my next trip because that was 5 years ago.

I will check out the link, I overlooked that before.

Related to what OzSolar mentioned about hot water, do you have an opinion or suggestion on the best method for generating hot water in a setup like this? Have you done any on demand products in this type of setup?

 

[Mattb4]

If your water supply comes from a surface tank (however the tank is filled) it can be quite simple to use a simple jet pump and pressure tank, or RV styled DC voltage demand pump, to supply your modest needs. They even sell fractional HP jet pumps with attached tanks ready to go.

I run such a setup at my home. From rain water collection tanks it is plumbed to the suction of a 120vAC 1/2hp jet pump and than to a 30gal pressure tank before it supplies the home. I have been using a 240vAC hot water tank with 3500w elements with an off switch so that I can turn off the tank when not needed and reduce energy usage. This Spring I am plumbing in a new tank that is going to have 120vAC 2000w elements so that I can use my PV setup to heat the water. it will be switchable from grid to PV inverter with its own manual transfer switch.

 

[OzSolar]

Thanks for the feedback. Is there an alternative you would use for generating hot water? I appreciate the calculation. That is very handy to know.

A standard tanked water heater is what I would suggest. While they might be a bit less efficient than a tankless the are very reliable which a pretty fair trade. Keep in mind I'm speaking from the perspective of a US based contractor. Tankless water heaters have been a big source of complaints and call backs over the years.

 

[dcg9381]

A standard tanked water heater is what I would suggest. While they might be a bit less efficient than a tankless the are very reliable which a pretty fair trade. Keep in mind I'm speaking from the perspective of a US based contractor. Tankless water heaters have been a big source of complaints and call backs over the years.

The driller said the static water level was 160 feet. That is something I need to confirm on my next trip because that was 5 years ago.

I will check out the link, I overlooked that before.

Related to what OzSolar mentioned about hot water, do you have an opinion or suggestion on the best method for generating hot water in a setup like this? Have you done any on demand products in this type of setup?

I may disagree here with @OzSolar . But I'll also say that a standard tanked water heater will certainly work.

To me, it depends on the availability of your fuel/electrical supply AND the quality of your water.

If your water is "hard" absolutely stay away from tankless (unless you're willing to do the annual de-scale).
For us, when we built - essentially bare bones barndo with limited electrical power, but "clean" water, I put in a tankless 3-4GPM, propane, vented unit. Indoor mounted, vent out the side of a vertical wall. Cost me under $400 and works absolutely great for moderate use - meaning 1 shower + a sink, laundry + sink, etc. How WELL these work is also a function of your water temperature, so if you have cold water, they have to work harder.

For us it's easy to refill a 100 lb propane bottle that would last 3-4 months doing hot water and running a clothes dryer.

Another downside of tankless is that they need to be drained if subjected to a possible freeze, but I assume that's the same for a tanked hot water unit that's powered down in freezing weather.

 

[ezwryder]

To me, it depends on the availability of your fuel/electrical supply AND the quality of your water.

I can see where calcium buildup would create a problem. I was thinking of adding an inline filter. Since I already have the Joolca, it won't cost me anything extra to try that.

 

[dcg9381]

I can see where calcium buildup would create a problem. I was thinking of adding an inline filter. Since I already have the Joolca, it won't cost me anything extra to try that.

You can't filter dissolved solids, well, not by the means you're thinking of. Media filters won't work.
You need to know your total hardness of your water. You can have it tested or buy a simple hardness meter.
You have to "soften" the hard water (typically with salt) or you have to run it through reverse osmosis (which is very wasteful) to get the dissolved solids down.

 

[ezwryder]

I was just reading about that. My bad. I did have the water tested last year. I just pulled up the report.

 

[dcg9381]

I was just reading about that. My bad. I did have the water tested last year. I just pulled up the report.

You have very reasonable dissolved solids. I'd be willing to run tankless with that and simply descale every few years. Where I'm at, wells have readings in the 1000 PPM range, about 10X higher than yours.

 

[ezwryder]

You have very reasonable dissolved solids. I'd be willing to run tankless with that and simply descale every few years. Where I'm at, wells have readings in the 1000 PPM range, about 10X higher than yours.

Thanks for the feedback. Your input and comments from others have all been very helpful in clarifying my thinking.

 

[OzSolar]

I may disagree here with @OzSolar . But I'll also say that a standard tanked water heater will certainly work.

To me, it depends on the availability of your fuel/electrical supply AND the quality of your water.

If your water is "hard" absolutely stay away from tankless (unless you're willing to do the annual de-scale).
For us, when we built - essentially bare bones barndo with limited electrical power, but "clean" water, I put in a tankless 3-4GPM, propane, vented unit. Indoor mounted, vent out the side of a vertical wall. Cost me under $400 and works absolutely great for moderate use - meaning 1 shower + a sink, laundry + sink, etc. How WELL these work is also a function of your water temperature, so if you have cold water, they have to work harder.

For us it's easy to refill a 100 lb propane bottle that would last 3-4 months doing hot water and running a clothes dryer.

Another downside of tankless is that they need to be drained if subjected to a possible freeze, but I assume that's the same for a tanked hot water unit that's powered down in freezing weather.

Actually it sounds like we're on pretty much the same page. I think they are great for certain applications but I'll never install one for a customer again. Too many complaints, calls backs and costly repairs for not that much gain in efficiency. That's just offered as my view point from 30 years of experience in doing off grid projects.

 

[sgtidaho]

check out RPS solar pumps. I have 360ft well. I pump into a cistern, and pump out of it to my house. it was under 5k and I did it myself.
no need to over think it.

 

[ezwryder]

Actually it sounds like we're on pretty much the same page. I think they are great for certain applications but I'll never install one for a customer again. Too many complaints, calls backs and costly repairs for not that much gain in efficiency. That's just offered as my view point from 30 years of experience in doing off grid projects.

I appreciate that perspective and I don't doubt it. I can see where an instant system could be more fiddly. Right now I have a Joolca (alias Camplux, alias Eccotemp) and once you get the hang of it, it works great. But it is not always a "facuet on, water hot" experience.

I think since I already have that and understand its quirks, I will just integrate it into my version 1.0 setup and see how it goes.

 

[ezwryder]

check out RPS solar pumps. I have 360ft well. I pump into a cistern, and pump out of it to my house. it was under 5k and I did it myself.
no need to over think it.

I have been looking at RPS for some time and that is exactly the system I am considering. What do you do to control the water level in the cistern? Do you have a float switch or something that controls the pump? Did you use RPS panels or did you already have enough solar capacity that you did not need to?

 

[sgtidaho]

I have been looking at RPS for some time and that is exactly the system I am considering. What do you do to control the water level in the cistern? Do you have a float switch or something that controls the pump? Did you use RPS panels or did you already have enough solar capacity that you did not need to?

to control the water level there is a sensor that stops the pump when the water level hits it. yes a float switch.
we bought the complete RPS deep well kit, with panels (100w x10) It was on sale so it was not cost effective at the time to use my panels.
I have the well as its own self contained system. I bought the AC kit for it as well. so if i need to run it off my house system i can.
I also use their tankless pressure pump. (220v) wow does that work great. it came with its own inverter and i have 2 100ah gelcells for it. for it i did not use their panels but 2 of my own 395w bifacels.
i have 2 tanks i can pump into, main tank is 250 gallons in my pump house, the other is 1500 gallon. in full sun the 1500 gallon fills in an hour or so, some times 45 mins. the P pump system charges tops off the batteries in about an hour.
most of the time i have enough solar. being in WA where i live its hard from nov - feb. I am also still building my homestead so things are setup to get a job done.. but the well system has been completed and working well for 6 months. dark weeks i run off the house. but when the sun is out.. that stuff does not take long to fill and charge. very impressed and happy .

their support is good too, mostly by text but they are quick.