Pressurized water tank or use suction water pumps

[OzWanderer]

Looking into installing a fresh water tank system using one of two tanks, wondered if using PUSH method ( Pressurized tanks ) or PULL ( suction water pumps ) is better.

Could someone share their experiences?

cheers

 

[Joe917]

A good marine water pump (suction) is the simplest most dependable way to go.

 

[quickfarms]

Pressurized tanks are heavier and still need a way to pressurize the tank

 

[Howard70]

Looking into installing a fresh water tank system using one of two tanks, wondered if using PUSH method ( Pressurized tanks ) or PULL ( suction water pumps ) is better.

Could someone share their experiences?

My all time favorite system was on an Olson 40 sailboat we had from 1993 through 2004. It was a pump system but most of the pumps were foot operated so you could pump water "hands free". It was simple, efficient and I think used less water than a pressurized system (only because getting water took continuous action). Two added advantages: (1) you have complete access to your water without any power - in those hopefully rare times you have depleted batteries or other electrical problems. (2) in my experience they are quieter.

To me, pressurized systems seem designed for easier showering and/or to make things more similar to what someone is familiar with at home.

Howard

 

[SkiFreak]

I have to admit, I do not think I have ever encountered a pressurized water tank system in a RV. Why would you even consider something like this?
I think you may actually be a little confused here, or maybe you just described things poorly.

Pumps generally push liquid much better than they pull, so what you need to do is to put the pump as close as possible to the outlet of the tank.
Ideally, the pump would be lower than the tank outlet, as this would positively prime the the pump, but this is quite often not ideal, for numerous reasons.
The higher the pump is above the tank outlet the harder it has to work, but in an RV scenario having your pumps up higher reduces the possibility of them being submerged when doing something like a river crossing, so it's a bit of a juggling act between efficiency and functionality.
Increasing the size of the pump inlet hose will give you significantly better efficiency. Personally, I run 3/4" hose into the pumps and 1/2" out.

Also, if you wish to use taps with ceramic disks, the pipework needs to remain pressurized, because that type of tap seal requires water pressure to work.

Despite many manufacturers saying that "on demand" pumps do not need an accumulator, I would disagree. At low flow rates, the water flow will be significantly smoother if there is an accumulator in the system.
In a system that has an accumulator, the pump will normally run longer, but less frequently. Less startups normally equates to better longevity and ultimately the pump will use less power. (it takes more power to start a pump than it does to keep it running)

 

[OzWanderer]

Thanks, SkiFreak. My only experience with a water tank is using rental Troopies, my Landcruiser only use a manual system. Troopies seem pressurised to me, but perhaps there is an accumulator where the pump operates when the level is below a certain threshold.

See if I understand it correctly, the accumulator will be positioned somewhere above the water tap, and water will be drawn from it to the tap via gravity. And the pump would fill it up when it reaches a certain level. So there'll be a water level switch of some sort in the accumulator to turn on the pump when the water level is low?

Is that the idea?

cheers

 

[SkiFreak]

See if I understand it correctly

No, you don't.
You should Google what an accumulator is and what it does.

If the Troopie had a pressurized water tank you would need to vent the tank (remove the pressure completely) before you could fill it. I highly doubt that this was the case.

On demand pumps, like you would use in an RV, have a pressure switch built in. There will normally be pressure in the system, between the tap and the pump. When this pressure drops to a predefined level, the pump will turn on automatically.

It ain't rocket science.

 

[OzWanderer]

No, you don't.
You should Google what an accumulator is and what it does.

If the Troopie had a pressurized water tank you would need to vent the tank (remove the pressure completely) before you could fill it. I highly doubt that this was the case.

On demand pumps, like you would use in an RV, have a pressure switch built in. There will normally be pressure in the system, between the tap and the pump. When this pressure drops to a predefined level, the pump will turn on automatically.

It ain't rocket science.

Thank you. Learning it. Will be back for more questions after reading more.

cheers

 

[BeNimble]

A fella used air pressure for his water tanks. He had a few of the 5 gallon corny kegs. There is a video on how he did it along with the entire DIY camper build.
I am planning to do something similiar? Why? Water pumps tend to fail regularly is what I've learned from boating. They are noisy too.
Air compressors tend to last a very long time, like decades. And you can use one for other things like inflating rafts, tires, running air tools, etc.
They can be really loud, some worse than others. If you regulate a high pressure tank down, they don't have to run every time you use water.

 

[SkiFreak]

I am planning to do something similar?

Or.... you could just use a larger accumulator.

As I eluded to previously, starting and stopping a motor frequently, which is what normally happens with an on demand water pump, will most likely reduce its longevity.
Also, as with most products, there are good pumps and bad ones. Buying a cheap, Chinese water pump off eBay will probably not justify the savings over a good, name brand pump, when it comes to reliability.
A water pump with a lower pressure will probably be more reliable too, as it does not work as hard.

As to pressurizing a water tank...
Yes, this will definitely work, but be mindful that the majority or air compressors do not produce "clean" air. Pressurizing a tank directly using such a compressor could contaminate the water, which could be dangerous to your health.
On the outlet side you would probably need to include a pressure regulator and/or flow regulator too, or you would get varying water flow and pressure.

Just because someone else has done something does not necessarily make it a good idea. Just sayin'.......

 

[shirk]

A fella used air pressure for his water tanks. He had a few of the 5 gallon corny kegs. There is a video on how he did it along with the entire DIY camper build.
I am planning to do something similiar? Why? Water pumps tend to fail regularly is what I've learned from boating. They are noisy too.
Air compressors tend to last a very long time, like decades. And you can use one for other things like inflating rafts, tires, running air tools, etc.
They can be really loud, some worse than others. If you regulate a high pressure tank down, they don't have to run every time you use water.

Everlander system.


Planning to copy this on a smaller scale, most weekends a single keg should cover our use.

 

[BeNimble]

Thanks for finding the video! Smart fella. I had the same idea for my 34ft catamaran project about 5-10 years ago.
I have a 2 gallon expansion tank with a bladder so there is no mixing of air with water, eliminating the air filtering.
On the boat, maybe having a dive compressor so that is another option, not so useful overland camping.

However, directing to the common water pump solution is the right answer for the OP.

 

[BeNimble]

Thanks for finding the video! Smart fella. I had the same idea for my 34ft catamaran project about 5-10 years ago.
I have a 2 gallon expansion tank with a bladder so there is no mixing of air with water, eliminating the air filtering.

 

[Howard70]

Just because someone else has done something does not necessarily make it a good idea. Just sayin'.......

The wisest statement of the week on Expedition Portal!

Howard

 

[John M.]

Considering the additional complications of pressurized system and the unique consequences of several different failure modes, I don't see any good reason to chose it over a standard pump system.