Water Setup Opinions?

[j3ffr3y]

Hello all,

I currently have an off-grid vacation cabin with a conventional water setup (see attached pic):

Deep Well (220v pump), Pressure Tank, and propane hot water heater (no electric). We have it all plumbed so that it is easy to drain everything down via gravity. (No worries about having to blow the lines out)

Hindsight being 20-20, I think I would have done things differently. But, at the time, we wanted to prepare for the chance that we might get electric utility run up the mountain...

Obviously, since I have a 220 pump, I need to run the generator to take showers and otherwise keep water in the Pressure Tank. I've been running this way for 2 years. However, it is getting increasingly annoying to have to walk out and start the generator every 4-5 toilet flushes just to pump the pressure tank back up.

I've been thinking about ways to make this easier and/or more efficient:

One option was to just upgrade to a remote start genny. However, I feel like if I do that, I should also go to a Honda EU7000is so I can reap the benefits of a much quieter and more fuel efficient generator. (Part of the annoyance factor is the noise). Unfortunately, that is dang expensive!!! (I also worry about theft)

Another option, is to get a plastic storage tank to keep inside (have to deal with freezing temps). If I did this, I would change the deep well pump to pump into the storage (hopefully with a float switch) and then use something like a shurflo (12v or 120v) to pump into the pressure tank. Question: Is the shurflo powerful enough to pump up the existing pressure tank?

This second option would allow me to use more water before having to fire up the deep well pump. I could also run the smaller Shurflo on either a small battery setup, my existing solar setup, or even just a smaller generator (like the EU2000). My only issue with this is that I don't have much room in my utility room for anything larger than about a 50 gallon container. 50 Gallons will get me quite a bit more flushes and hand washing. But, depending on what's left, probably only 1 quick shower. This leaves me wondering if the added complexity is worth it? I suppose I could eliminate the large hot water heater and replace with an on demand unit to free up a bunch of space. But, that also adds more cost and more complexity (especially for draining down)

Just looking for opinions or other ideas I haven't thought about?

Thanks,

Jeff

IMG_0367.JPG

[Mike90250]

I'd say get a 1,000 gall outdoor tank and fill it from the well once or twice a week (w/generator power)
Then you can use a small pressure building pump to produce 30 psi to run the appliances. Look at what's available in boating gear stores or conventional booster pumps. you may want to lower the pressure in your pressure tank to match the capacity of the small booster pump

[j3ffr3y]

Mike,

I may have entertained that option when I had the excavator there doing the trenching for the well line. I would have had him burry it. But, now I'm afraid it would cost too much to bring him back up. I wouldn't want to set it above ground and have to deal with the hassle/expense of keeping it and the lines from freezing in the winter either.

Good thought on lowering the pressure on the tank...

Thanks,

Jeff

[peakbagger]

A large storage tank is the way to go. Obviously install a low flow toilet. If you don't want to do a tank install a battery bank and inverter and only run the generator when the batteries are low. This will cut way down on your gas usage for the generator. I have an former coworker with camp on lake that is only accessed by boat, he used to lug a lot of fuel until he put in battery bank. He eventually added some PV to charge up the batteries during the week and cut his gas runs way down. If your well pump is a 3 wire across the line starter consider switching it to a Franklin Electric mono flow variable speed drive, that cuts way down on startup surges.

[j3ffr3y]

peakbagger,

Wow, how big of a battery bank and inverter (and cost) would I need to run a 220 pump at 500+' depth? I had hoped when we were drilling for water that we would have found it between 100-200 feet and then could have used a 120v pump...

[Mike90250]

How much flow do you need from 500' , and how much pressure to generate at the surface ? That gives the size/power of the pump, and then we can caculate how much power is needed from the chosen pump spec. Your pump dealer should have depth/head charts:
Grundfos_10_SO5-9_pumpCurvesC.jpg

[peakbagger]

The problem I expect is you bought the pump from the well driller with the intent of running grid power and now you are trying to use that solution for an off grid use. You have the wrong solution for your current use. Ideally you yank out the well pump and replace it with a DC positive displacement pump sized to be less than your well yield so your static lift is less. That then pumps to a large storage tank that supplies your surge loads. Its not the depth of the well as much as the static water level and the well yield. If you have a low yield well with a high volume pump (like a typical well pump), the depth has to be deeper so that there is some reserve storage in the hole which means a larger pump as the pump has to be sized for a lower depth in case you pump the storage in the casing down. In general if someone has a low yield well, a deep hole is a very expensive way of avoiding a large storage tank. The pump HP formula is (GPM*PSI)/1713*pump efficiency. At that depth, you have many stages to the pump so the efficiency is low so a lot of your power you are sending to the pump is wasted. Go with positive displacement pump and the efficiency is darn close to 100%.

You don't seem inclined to want to yank the existing pump so the variable speed option is a fix to cut down on surge load so you can run a smaller generator or a battery bank with a far smaller inverter. Once we get a lot of details we could size a battery bank which will be costly and then you will come to a conclusion that no matter what you do this isn't a cheap fix and a big storage tank is the way to go.

[j3ffr3y]

The problem I expect is you bought the pump from the well driller with the intent of running grid power and now you are trying to use that solution for an off grid use. You have the wrong solution for your current use. Ideally you yank out the well pump and replace it with a DC positive displacement pump sized to be less than your well yield so your static lift is less. That then pumps to a large storage tank that supplies your surge loads. Its not the depth of the well as much as the static water level and the well yield. If you have a low yield well with a high volume pump (like a typical well pump), the depth has to be deeper so that there is some reserve storage in the hole which means a larger pump as the pump has to be sized for a lower depth in case you pump the storage in the casing down. In general if someone has a low yield well, a deep hole is a very expensive way of avoiding a large storage tank. The pump HP formula is (GPM*PSI)/1713*pump efficiency. At that depth, you have many stages to the pump so the efficiency is low so a lot of your power you are sending to the pump is wasted. Go with positive displacement pump and the efficiency is darn close to 100%.

You don't seem inclined to want to yank the existing pump so the variable speed option is a fix to cut down on surge load so you can run a smaller generator or a battery bank with a far smaller inverter. Once we get a lot of details we could size a battery bank which will be costly and then you will come to a conclusion that no matter what you do this isn't a cheap fix and a big storage tank is the way to go.

Yep, you're right. We went with everything standard for running on grid power. At the time, (and my current knowledge) that was all cheaper than other more off grid efficient setups. If I remember correctly, the well's recovery rate is between 15-20 gallons per minute and the static water lever is around 100 -150' down.

You are correct also, in that I'm not planning on yanking the pump. However, I'm curious about this "variable speed option" that you are referring to? How, would that be retrofitted to the existing pump?

In the meantime, I'm working up a plan to possibly pump from the well to 100-150 gallon poly tank(s) upstairs in the eves. Then from there I could use a shurflo (or something similar) to pressurize the pressure tank (yes, I realize I might not need that. But, it's already there...). In addition, I think I could get gravity feed pressure to wash hands and flush toilets without any power needs at all?

The 100-150 gallons should get me several days when I'm on my own and maybe I have to run the big genny once or twice a day to fill the poly tanks when there's a group of us. I'd be very happy with that setup if it works the way I'm thinking it would?

Thanks again for all the feedback!

[Mike90250]

Your 100 gallon tank hanging from the eves, is going to weigh about 800 pounds. That's going to take some work, to be safe

[AzRoute66]

I have been keeping my eyes open on something to store rainwater in and am considering an AquaTank 2. It is a potable grade pillow bladder. Good price and the interesting thing is the 150 gallon version has a 6' x 4' footprint at 12" tall, making it easy to spread those pounds per square foot over a larger-ish area. I originally got interested because the 300 gallon version was less than $1/gallon (very rare), but no matter how many times I remeasured the space I couldn't come up with a 12' x 4' frame to hold it. Am now considering daisy-chaining a 150 gallon with a 60 gallon (preferred) or putting the 300 gallon bladder in a 240 gallon frame.

[j3ffr3y]

Mike,

The tank(s) won't be hanging. They'll be inside the envelope of the house behind the knee walls of our second floor sitting on the plywood subfloor. The ceiling joists on the first floor that would be supporting it are 2x10's. I was under the impression this should be strong enough?

[Mike90250]

Mike,

The tank(s) won't be hanging. They'll be inside the envelope of the house behind the knee walls of our second floor sitting on the plywood subfloor. The ceiling joists on the first floor that would be supporting it are 2x10's. I was under the impression this should be strong enough?

If your building engineer says it is, is must be. I had to install a steel column for a 80 gal water tank.

[J.P.M.]

Mike,

The tank(s) won't be hanging. They'll be inside the envelope of the house behind the knee walls of our second floor sitting on the plywood subfloor. The ceiling joists on the first floor that would be supporting it are 2x10's. I was under the impression this should be strong enough?

The tank will weigh ~~ 800 lbs. when full. As Mike suggests, if the AHJ is OK with that loading and arrangement, it's OK, but Id run some numbers just for goofs/giggles.

[peakbagger]

If you have a three wire well pump with an external capacitor box, all you do is replace the capacitor box with a Franklin Electric monodrive. A pressure transmitter replaces the typical high low water pressure switch. Instead of cycling the pump on and off between a high and low setup the motor speed varies the pump speed to maintain constant pressure. It is programmed to start slowly so the startup surge is far lower than an across the line start that a typical pump uses. Most people can set a lower overall pressure as its constant. Plenty of documentation out on the web on the monodrive.

[mtjag]

We have a full time off grid home with a 500' deep well. Currently we have a soft start Grundfos 5SQ-410 pump that runs at 6.6 gallons per minute into three pressure tanks for a total of 98 pressurize gallons . It takes just over 15 minutes of running to pressurize the house at 30/50# of pressure. The problem is the well pump comes on at night which really hammers our batteries. The current well pump draws 11.2 amps and shows about 2.5 kw while running. I'm thinking of going to a 1000 gallon cistern with a smaller pressure pump so that it can run at night if needed. I will have the solar to use the well pump during the day to pump into the cistern. By the way, our household uses 230-260 gallons of water per day and our elevation is 8,600'. The options I have are as follows: 1)I've found a Grundfos JP05D-CI jet pump that is 1/2 hp and is rated at 3.61 amps at 115v or 7.06 amps at 230v that pumps at 12.5 gallons per minute and uses about 770 watts while running. It is not a soft start pump but will pump up my 98 gallon pressurized tanks in just under 8 minutes which will save some power.
Option 2) is a Grundfos scala2 "on demand" pressure pump that would not need the pressure tanks I currently have in place. It would power up every time you open a water valve or flush a toilet. This pump can be plugged into a 115v outlet and uses 5.7 amps and pumps at a rate of 13 gpm and uses about 550 watts while running. It has a variable smart control that "learns" your plumbing to control speed and power necessary to maintain a pressure you select up to 60#.
So, my question is which of these two alternative would offer the least impact on the health of my battery bank? Or do you have a recommendation for a pump or setup that will reduce my battery usage in the evenings?