On demand water pump for cabin

[snagbro1]

Hello,
I was wondering if anyone can tell me if an on demand water pump (like in an RV) would work for a cabin. I have a cabin with electricity but currently no running water. I could use either an AC or DC pump. I was thinking of putting in a holding tank plumbed to this pump and then from there to the hot water heater and on to the rest of the fixtures. It would be a pretty simple set up with the holding tank right outside the bathroom. The tank could even be elevated to help with some gravity flow. Would there be any need for a pressure tank - I don't beleive an RV has one? It would just be a small bathroom and a kitchen sink with all the plumbing within 10 feet of the holding tank.
Thanks for any input you can provide.
P.S. We do have a well but it would be difficult to run a line from there to the cabin and then to deal with a pressure tank. I think it would be much easier to use a holding tank that I can just fill with a hose and then drain when we leave. The cabin is only used for about 2 weeks during the summer. I plan on running the drains to a log crib system that is already on the property and plumbed close to the cabin.
If this will work, how many gallons per minute would a pump need to generate for enough pressure for a shower?
Andy

 

[MacGyver]

With out further information, I see no problem using an rv water pump. The shower would be a problem if you wanted the water to be running full time; on my shower it has a on-off shower head to conserve water. The water pump presser up the water line not the water tank.

 

[KelvinG]

I've since upgraded my system, but it originally had a 12 Vdc RV water pump and a small pressure tank. I think having a pressure tank is a good idea.

Motors take an inrush of current to get them started. Once they are running the current draw drops down to the normal running current. The magnitude of inrush depends on several factors. I thought generally it 4 or 5 times the running current. A quick Google search gave me some websites saying up to 20 times. Anyway the point is given two pumps moving the same amount of water, one stopping and starting a lot, and a second stopping and starting just a few times. The first pump will have a shorter life and use more current.

Adding a pressure tank would minimize the cycling of thus decrease the current used and extending the life of the pump.

Now, with all that said SHURflo makes some kind of super duper water pump designed to work without an accumulator tank.

I've also install a low flow shower head to reduce that particular water consumption.

Good luck

 

[marcd]

I use 12v DC ShurFlo pump in my cabin that draws from a small holding tank that runs a kitchen faucet and a shower.Similar to a RV system. It is powered by a small solar system and have not had any trouble running the batteries down The pump has a built in pressure switch.When showering I put the pick-up tube in a 5 gal bucket of warm water. Shower pressure is great! I use a ball valve for the shower head for easy off/on. I am very pleased with the system.

 

[NRick]

We put one in our boat that was designed to work without an accumulator tank (small pressure tank). Worked great when it worked. Replaced it three times (under warranty) before going with a different brand. It would provide enough flow for a small shower head. Enough to take care of business but in no way the same as on city water. No problems on battery usage (12v).

 

[alaskamokaiman]

We built a system in the cabin that uses a 55 gallon drum as a holding tank it is pressurized with a tire inflater pump set to less than 20 lbs it moves the water thought the water heater and works great. We did over inflate one it rounded the drum, we learned to use less pressure.

 

[snagbro1]

Thanks for the info guys. I am thinking of trying the Shurflo pump that is designed to not need an accumulater tank. Probably will get the bigger one that pumps 5.7 gpm and will use a low flow shower head like in an RV. However, I am still open to other ideas, so keep them coming.
Alaskamokaiman, your pressurized 55 gallon drum is pretty cool. I will file that away for future reference.

 

[alaskamokaiman]

Built the first version of it in 85 out of a 5 gallon gas can wife would not go camping unless she could take a shower every night. Then she wanted it hot too. Worked great with the little ones you could leave it pumped up so they could wash their hands.
Took it hunting was nice to clean up after the kill before you crawled in to the sack.

 

[257wby]

We built a system in the cabin that uses a 55 gallon drum as a holding tank it is pressurized with a tire inflater pump set to less than 20 lbs it moves the water thought the water heater and works great. We did over inflate one it rounded the drum, we learned to use less pressure.

I bet an old beer keg would work sweet. Light aluminum yet strong enough to take some higher pressures.

 

[millersreach]

View attachment 46610

Low tech but it works. 12 Volt Shurflo, 55 gal. drum, $145.00 on demand heater, cheap shower stall....not pretty but it works.
Good Luck all the advice given by the others is good.

This type of heater is good for a single source. It will not run a sink and shower at the same time.
If you are on the grid use a 120 volt pump. But with either 12 volts or 120 volts use a switch to turn off the pump when not in use.
This is from a few bad experiences.

Good Luck Again

 

[sheep man]

I'm using the shurflo with the internel 35 psi switch.Tied into 2, 55 gallon drums that feed a excel on demand water heater that is powered by a D cell batterey, when water flows the on demand heater fires up,no propane usage when water isn't flowing...unreal...my excel cost me 125.00 to the house, the shuflo is powered by a DC which has a solar charger on it.

 

[snagbro1]

I like the thought of using a on demand water heater along with a shurflo pump with the built in pressure switch. I think that will probably work out pretty nicely for what I need it for. Now if I can just figure out how to keep someone from stealing it when I am not there.
Thanks to all of you for the info, I really do appreciate it.
Andy

 

[La Pine]

Pumps

Pumps

Here are two of the shurflo pumps you could go with, depends on the flow rate you will need, and your electric power available to you. Good luck.

Name : SHURflo® Premium Plus Pump
Model Numbers OEM/Aftermarket : 2088-453-144, 2088-453-444
Voltage : 12 VDC
Dimensions Inches/Millimeters : 8.6" x 5.0" x 4.45" [218 x 127 x 113mm]
Flow Rate GPM/LPM : 3.5 GPM [12.5 LPM]
Amps (Max.) : 5
Shut-Off Pressure : 45 PSI [3.1 BAR]

Or you could go with this pump.
Name : SHURflo® Park Model Pump
Model Numbers OEM/Aftermarket : 2088-492-144, 2088-492-444
Voltage : 115 VAC
Dimensions Inches/Millimeters : 8.7" x 5.0" x 4.5" [221 x 127 x 113mm]
Flow Rate GPM/LPM : 3.3 GPM [12.5 LPM]
Amps (Max.) : 0.9
Shut-Off Pressure : 45 PSI [3.1 BAR]

 

[La Pine]

The Excel on demand water heater sounds like a great thing. Where did you purchase it?

I'm using the shurflo with the internel 35 psi switch.Tied into 2, 55 gallon drums that feed a excel on demand water heater that is powered by a D cell batterey, when water flows the on demand heater fires up,no propane usage when water isn't flowing...unreal...my excel cost me 125.00 to the house, the shuflo is powered by a DC which has a solar charger on it.

 

[Mr. Pid]

I've used a simple 12v on-demand pump for 15 years. No pressure tanks or other stuff that would make it harder to drain down before we leave. If you can put a holding tank above the level of your plumbing you can get along really well with gravity feed, too, including for a on-demand water heater. Just make sure you can drain it completely if you let your cabin go cold in the winter.

 

[millersreach]

Image did not come through, this is a second try. View attachment 47414