BajaNomad - Water pressure pumps

Water pressure pumps

Pescador - 4-5-2007 at 04:05 PM

Ok, water pressure is 2.3 lbs per foot of elevation., so to get 45 obs of pressure you need 19 1/2 feet of height. Consequently most systems I see with buried tinacos or ground level use some type of pressure pump system. If you have one did you buy a mexican system and install or did you bring one from the states. Approximate costs?

David K - 4-5-2007 at 04:16 PM

Pescador, the gain (or loss) of water pressure is 0.443 pounds per foot of change. If you want 45 PSI, the top of the water in the tank will need to be just over 100 feet HIGHER than the point of use.

20 feet would give you just under 9 PSI.

This information is on page 42 of the book I co-authored in 1992 called 'Irrigation Design'.

comitan - 4-5-2007 at 04:44 PM

In La Paz you can buy, US, Mexican systems all sizes all prices. and yes every system I know has a pressure tank.

David K - 4-5-2007 at 06:46 PM

Only 20 photos Larry? Heck, I dodn't know if I can tell a story with less than that!

Drip irrigation needs less pressure than typical sprinklers. The emitterline (dripperline) from Netafim works between 5 and 50 PSI... has an emitter factory installed every foot in the tube. So if your lines aren't too long you may get by with 10 PSI... to start the system. The length, elevation change, and emitter flow per foot will determine if your pressure is enough... or Your starting pressure will determine how long the drip system can run per valve.

The bigger trick is if you want to have an automatic system (battery operated or AC) as you will need valves that operate at very low pressure... So do the research to find the operating pressure range for the valve and for the irrigation devices.

With the water pressure known and a landscape plan, somehow it can be made to work... lot's of variables and choices in irrigation! I love it!

[Edited on 4-6-2007 by David K]

Mexitron - 4-5-2007 at 06:58 PM

I'll second the Netafim drip tubing suggestion for low pressure irrigation--good stuff!

Alan - 4-5-2007 at 07:46 PM

Quote:

Originally posted by Pescador
Ok, water pressure is 2.3 lbs per foot of elevation.,

Quote:

Originally posted by David K
Pescador, the gain (or loss) of water pressure is 0.443 pounds per foot of change.

Pescador, your numbers are right. your units of measurements are just reversed.

A column of water 1' tall exerts a pressure at its base of .434 psi. A column of water 2.3' high exerts a pressure of 1 psi.

Unless you have a very tall hill nearby and are willing to run the necessary pipe, get a pressure pump.

longlegsinlapaz - 4-5-2007 at 08:28 PM

Pescador

How these guys hijacked your thread & turned it into an irrigation question is beyond me!! :lol:

Virtually all gringos that I know who have built do use a water pressure holding tank. I've built twice & had them in both casas...I also add an auto shut-off float to the cistern that's tied directly into the electrical circuit of the pressure tank, so when the water level is at a pre-determined point, it'll shut off the pressure tank pump rather than burn it out. You'd have to check with hardware stores in your area to see what makes, models, capacities & pricing is available near you.

Russ - 4-6-2007 at 08:02 AM

Pescador, I've used both AC & DC pumps here. I bought an AC pump with pressure tank from Guero and it has worked for two years without problems. The 12volt pumps (Sureflow Blaster types) don't last as long for general use and seem to be a little noisier. The AC one with a half horse pump uses about 8 amps so it really isn't too bad. I kept the factory settings for the pressure regulator and I'm happy with that. You'll want to but fixtures that have a removable water saver devices.

Marie-Rose - 4-6-2007 at 08:38 AM

We just installed an new water pressure tank... 82 gallons (310 litres) "Flotec" and bought it in TS for $250.

Bob and Susan - 4-6-2007 at 11:08 AM

you get 2 flushes before the motor starts
we have about 80 feet of 3/4 inch pipe to keep pressureized

pump1.jpg - 45kB

losfrailes - 4-6-2007 at 11:10 AM

Pescador,

10 years ago I installed an underground 2500 liter tank that fills till a float valve stops the flow.

I then put a small 5 gallon pressure tank, the type with a bladder inside, connected with a 1/2 HP pressure regulated 120 volt motor. The draw comes up from about 9 feet and maintains a solid 55 psi.

Have only had one small problem with it, the starting solenoid on the motor gave up the ghost. Easily replaced and still running strong.

All parts were purchased in the local hardware store in Santa Rosalia.

Hey, thats a picture of the identical item from Bob and Susan, however I think their tank is a 10 gallon one.

[Edited on 4-6-2007 by losfrailes]

Bob and Susan - 4-6-2007 at 11:10 AM

here is the data...

pump2.jpg - 41kB

Sharksbaja - 4-6-2007 at 11:36 AM

Yes, ours was the same only with a 45 gal tank. It now has a home somewhere in the SOC.
Now, however, water pressure is a constant 20-25 psi from the city so Iam not sure if well install a new one. Probably will, I plumbed the new system for one.
Bob, what is the drawdown in gals with the switch set for 20psi/40psi?

Is that a water meter sitting on the ground?????

bigboy - 4-6-2007 at 04:42 PM

I use the Sears Hydro Glass shallow water jet pump at my house in Baja. I have about a 30 gal pressure tank like Bob and Susan's set up. The pump starts up at 40 psi and shuts off at 60 psi.

A lot of my neighbors have the same pump and are pleased with the performance of the system. The pump retails for less than $300 at Sears.

Pescador - 4-6-2007 at 06:11 PM

By golly you are right, it was early morning and I did reverse the numbers, and to think "I are a certified water operator".
Guess the question is what size pressure tank is appropriate for the amount of usage. Wayne is using a smaller tank, Bob and Susan have a larger tank but are expecting more water usage.
I think I might lean toward buying a system in Santa Rosalia so that I don't have more stuff to haul down.
Thanks for catching me in my error and for all the great info.

Bob and Susan - 4-6-2007 at 08:17 PM

good eye corky...

that's a badger 1" water meter
we're tired of bending down and opening the tank to see the level
we'll just do the math...
ebay about $80
3/4" is about $40

i think the advertised drawdown is 19 gallons
but the thing turns on with 4 gallons used
but i have lots of lines to pressurize

every casita will have a pump like that...
you NEED water pressure for the shower or you can't get the soap off :lol:

your hair (if you still have it) will go flat!!! :lol:

the tank we are using now will hold the water for washing only ~2100 gallons

the casita tanks when installed will hold another ~2800 gallons

i also need the "power" when i wash the truck on sundays :lol:

Bob and Susan - 4-7-2007 at 05:47 AM

it's not about the expansion of the lines but the total volume of the lines...

the more volume the bigger the pump need to be

the pump in my picture would easily pressurize and entire house

Bob and Susan - 4-7-2007 at 09:06 AM

david k help me here...

you are the irrigation guy....

losfrailes - 4-7-2007 at 09:24 AM

This seems like 'much ado about nothing'.

The pressure tank and pump setup that Bob and Susan have is certainly adequate to supply the needs at their location.

This started simply, but seems to be getting technicalized (sp??) in a hurry.

It works, works fine. What more is needed?

Bob and Susan - 4-7-2007 at 01:52 PM

i understand...
i'm not the expert here...

i wish i could explaine like the "bedman" :lol:

i'm just applying the principals that would happen in a sprinkler system.
the more pipe the less pressure...the harder it is to "pump it up" :lol:

maybe david k will assist

Lencho is right

Sharksbaja - 4-7-2007 at 02:13 PM

The volume factor is only relevant while the system is open and being used. Of course you could overwhelm your pump by have too many lines open and running.
There is a factory set or recommended air precharge number. It is usually set for a specific drawdown. Ususally set at either 20-40 psi or 40-60psi. The more air you put in the bladder the larger the drawdown. It's just a big balloon pushing the water out.
Read the literature on the system. It is not paramount to use their stated precharge psi. Which obviously is not what is in your tank.
Empty the tank completely then close outlet.. Charge air bladder(fitting on top of tank) till you have 20-30 psi. Next, start pump it should shut off at the setting of the pressure switch(which you also can adjust but only if you know what yer doin').
Check drawdown, if not enough repeat or just add a little air at a time till you like what you see.

sidenote: tank bladder get saturated sometimes or develop tiny leaks. It's smart to empty the tank and check that every so often. Especially if the drawdown keeps creaping up.

Bob, put more air in it. :yes:

Pescador - 4-7-2007 at 05:07 PM

Lencho is right, if the tank is not starting with enough pressure then drawdown causes it to start up more frequently. I think Corky is correct when he tells Bob how to pressure the tank correctly.

Bajalero - 4-7-2007 at 07:33 PM

Seems like this subject is going in a few different directions. Hopefully what I have to say doesn't confuse matters more.

A basic pressure system has 3 components. A pump motor, a pressure switch to that pump motor and a bladder tank. For purposes of simplicity , assume you have a negligible head of water , no air in the system , and all the piping and connections add minimal resistance to what your trying to accomplish pressure wise.

The bladder tank is there for energy storage and to provide a quantity of water before your pump kicks in so the motor doesn't wear out constantly cycling every time someone turns on a faucet. Most bladder tanks come "precharged " ,but depending on your pressure requirements this is not necessarily the proper charge for your system. Most manufacturers recommend a charge of air set to 2psi. under the desired kick in pressure (the low side). From experience , we usually set the air pressure 3-4 lbs. under the low pressure kick in . So, if you want to run your pressure at say 40 to 70 psi, I would set the bladder tank precharge at 37 psi. This helps prevent rapid cycling of the pressure switch (thus motor) if the differential is too sensitive . Also, a minimal amount of water hammering can cause rapid cycling but now I'm getting too detailed. The make of the pressure switch you use will determine how sensitive this setting is.

Pressure switches: a good pressure switch will have 2 adjustments . One , the kick in and kick out pressure are both changed without changing the spread between the two pressures. The second , changes the differential between the two,ie. - gives more or less of a spread between the two pressures . In effect if you wanted a more consistent psi. in your system, you would decrease the spread - but then your pump works more to keep a more constant pressure and not usually a good idea. To take advantage of the bladder tanks potential- within reason of course, you can increase the spread to create more volume drawdown before the pump cycles again.

Bladder tanks: first off , don't buy a small tank thinking you're going to pressurize it to the limit to get more volume draw down. It doesn't quite work that way and is not efficient . In fact , the maximum possible draw down of a bladder tank is its total volume minus the volume of the bladder at a set psi . so the MORE pressure you put in it the LESS the draw down volume . If you have a small house you can get away with a small tank . If you have a small development like Bob and Susan , it would be more efficient to go with a larger tank to supply many guests at once. Tanks are rated by gallons tank capacity at a given psi. range. I run a 80 gal. tank and get about 10 gal. drawdown (I think) , at a pressure setting of 70 to 95 psi before the pump kicks in.

I use a switch from Grainger # 6B446

and a pressure tank simular to Grainger # 4MY63

Bob and Susan - 4-7-2007 at 08:10 PM

see... i didn't even know this stuff...

that link was great...lots of info

i'll be checking the tank tomorrow :saint:

this month i learned about beds AND water pressure pumps :light:

Bob and Susan - 4-8-2007 at 05:40 AM

i did the math and i think Bajalero is correct... :lol:

... and
i read the entire thing...twice :lol:

my drawdown is a little over 5 gallons with the 42 gallon pressure tank...

to me...this subject is interesting stuff for building in a place without services...oh yea...i'm typing this from my garage where i currently live :lol:

Bob and Susan - 4-8-2007 at 05:54 AM

now...

i really need someone to explaine this to me...
i have a 42 gallon pressure pump...

i have 150 feet of 3/4" pipe to pressurize to 45 pounds.
(that's alot of volume of water in a pipe)

wouldn't the pump run less time if it only had 10 feet of 3/4" pipe to pressurize and i used 5 gallons at a time?

comitan - 4-8-2007 at 07:35 AM

Most important item to bring from the states if buying a pressure system here is the pressure switch because the ones I've seen here do not have the cutoff if your out of water, you have to buy a separate cutoff that costs more. you can tell if the switch has a little arm on the side if has the cutoff feature.

Bajalero - 4-8-2007 at 08:32 AM

Quote:

Originally posted by comitan
Most important item to bring from the states if buying a pressure system here is the pressure switch because the ones I've seen here do not have the cutoff if your out of water, you have to buy a separate cutoff that costs more. you can tell if the switch has a little arm on the side if has the cutoff feature.

Comitan : when you have a supply tank aka pila, that problem is solved by putting in a reverse float switch that works by cutting the electrical supply to the motor when the water level is low. The manual cutoff switches are ok if you are always there to monitor the water level. If you run out of water and your pump motor runs , some of them burn up in a short time running dry

http://www.capump.com/catalog/11-basin-float-switches-and-ac...

part# F5006

Lero

comitan - 4-8-2007 at 08:38 AM

Lero

The switch I'm explaining above came from Grainger and it eliminates the need for the system you describe. When my cistern runs dry the switch turns the motor off. It is part of the the pressure switch,. It has to have the low pressure cut off. As per below.
wiley

http://www.grainger.com/Grainger/wwg/itemDetailsRender.shtml...

[Edited on 4-8-2007 by comitan]

Bajalero - 4-8-2007 at 09:19 AM

Comitan : that looks like a good alternative.

The commercial style switch I use doesn't come with a low pressure cut off but I think they are better sealed to the elements /bugs and seem to last much longer.

By the way , important

Bajalero - 4-8-2007 at 09:37 AM

When reading these "how to" articles on residential ,do it yourself etc., keep in mind that there are 2 basic types of air - charged pressure storage tanks.

1, The bladder tank which is what is most common today and what we are mainly talking about ,

2, - a "stand " tank that has no bladder in it so the air charge you put in it comes in contact with the water you are pressurizing. In these tanks , as the pump cycles , over time the air charge dissolves into the water . So these bladderless tanks require period maintenance to keep the air pressure charge at the proper setting so your pump switch detects conditions properly.

JZ - 4-8-2007 at 09:40 AM

Quote:

Originally posted by Bajalero
The bladder tank is there for energy storage and to provide a quantity of water before your pump kicks in so the motor doesn't wear out constantly cycling every time someone turns on a faucet.

I was wondering what the tank was for. I had a pump installed but not a tank separate from the cistern.

longlegsinlapaz - 4-8-2007 at 04:12 PM

JZ

With your system, the pump comes on every time there's a demand for water. With a water pressure holding tank, you use less electricity because the tank fills & allows for a set amount of water usage before the pump comes on to refill the tank. Smaller tanks come on a lot more frequently. Also...I've discovered, there is a LOT less noise transferred through the concrete to adjacent areas if you mount the tank on a separate slab than the casa floor! :yes:

Even with the little rubber "footies" underneath! The only up side would be if someone leaves a hose on, you HEAR it!! :lol:

JZ - 4-8-2007 at 07:51 PM

Got it, thanks.

Do you need a cistern to use a pressure pump? I.e. can you use it with water feed from the city?

David K - 4-8-2007 at 08:02 PM

Quote:

Originally posted by Bob and Susan
now...

i really need someone to explaine this to me...
i have a 42 gallon pressure pump...

i have 150 feet of 3/4" pipe to pressurize to 45 pounds.
(that's alot of volume of water in a pipe)

wouldn't the pump run less time if it only had 10 feet of 3/4" pipe to pressurize and i used 5 gallons at a time?

=============================================================

Quote:

Originally posted by Bob and Susan
david k help me here...

you are the irrigation guy....

***************************************************************

Sorry I was not here for you sooner...

I just now quickly read the posts after this one of yours and your second question, too...

Pressure is the force on water and it is created only two ways, by gravity or by a pump.

A 10 foot long pipe and a 100 foot long pipe (on level ground) would require the same 'power' to pressure it up to 45 psi... STATIC (no water moving)... with a gauge on the pipe to test.

This is because water is NOT compressible (you can not 'squeeze' water to increase pressure). You can only 'push' water with the force of gravity or the force of a pump.

When water is moving, it is called DYNAMIC and everything except going downhill takes away pressure from the water when it is moving (fittings/ turns, valves, pipe friction).

The other properties of water (besides pressure) are velocity (the speed of water in feet per second) and volume (the flow of water in gallons per minute)...

All three are inter-connected... change one and it affects the other two.

A lot of people get velocity and pressure confused... For example, some think by running water through a smaller pipe it will increase the pressure! The opposite is true since smaller pipe has a greater amount of friction pressure loss than bigger pipe. The water will move FASTER, but will lose pressure (force) and have reduced flow (gallons).

Most of my personal irrigation business is done on gravity systems (city water, from tanks on hilltops)... so I am not a pump expert.

If you think I can help further, then please ask away!

Bob and Susan - 4-8-2007 at 08:07 PM

then why when i've use city water and ran a sprinkler line 200 ft the power at the end is nothing but a trickle?

David K - 4-8-2007 at 08:45 PM

Quote:

Originally posted by Bob and Susan
then why when i've use city water and ran a sprinkler line 200 ft the power at the end is nothing but a trickle?

Friction Pressure Loss!

As I said above, except for going downhill, everything else takes pressure away from the water!

As water is moving through a pipe/ hose... every foot pressure is lost, every turn, every valve, everything the water touches takes away pressure. Going uphill will cause pressure to drop, as well.

You can reduce the amount of loss (lose less pressure) by either using a larger pipe or reducing the flow in the pipe.... like with a lower gallon device at the end.

You can only gain pressure with a pump or by going downhill.

Bob and Susan - 4-9-2007 at 03:59 AM

"every foot pressure is lost"
so now going back...

if i'm using 150 feet of pipe...

my pump works more than if i was using 10 feet of pipe.
so...

if you are pressuring a house the amount of pipe in the house is important to have constant acceptable pressure

pressure.jpg - 4kB

longlegsinlapaz - 4-9-2007 at 07:34 AM

Quote:

Originally posted by JZ
Got it, thanks.

Do you need a cistern to use a pressure pump? I.e. can you use it with water feed from the city?

If you've got "city water" on a reliable 365-day-a-year basis, you could probably forego a cistern...BUT most places in Baja only turn water on for a few hours each day, then move to another area & turn it on for a few hours & the reliability of when you'll have water, how much, how much pressure & how long is very unpredictable. Because of that unpredictability, everyone I know uses either a cistern or smaller tinacos to store water for use 7 x 24. I'm currently in the beginning phase of new const & in a rental where ALL the outside water is only tied to the city water, which means I'm dependent on the city water being turned on to water plants & alas, to wash clothes. So all laundry must be done in the morning & inevitably, when I plan to wash, that's the day they miss turning the water on; the pressure is so low it takes an hour for the washer to fill....or my all-time favorite; the water is turned off before the full cycle, so I have to bucket water from inside (from the roof tinaco) to complete the load of laundry! By having your own cistern and water pressure holding tank, you can avoid the hassles of both availability & dependable pressure 7 x 24.

David K - 4-9-2007 at 07:55 AM

Quote:

Originally posted by Bob and Susan
"every foot pressure is lost"
so now going back...

if i'm using 150 feet of pipe...

my pump works more than if i was using 10 feet of pipe.
so...

if you are pressuring a house the amount of pipe in the house is important to have constant acceptable pressure

Constant pressure... ? Again, water pressure can be measured as dynamic or static...

The pump or pila height will create pressure which you can measure with a gauge. At the same elevation that pressure will be the same everywhere in the house or property, if the water is static (not moving).

Once you open a faucet, shower, sprinkler system, then the water is dynamic and will lose pressure for every foot it travels, every turn in the pipe it makes, every valve it goes through.

To have less pressure loss, use a bigger pipe (or flow less water). Otherwise use a pump and set the pressure higher so where you want more pressure, you will have it.

Pumps I have seen will provide 'X' number of gallons per minute at 'Y' to 'Z' pounds per square inch of pressure.

You need to get the pump that will provide the pressure and flow required at the end of the pipe.

If you measure the pressure with the water static (say it's 43 psi from a pump or pila or city water) and measure it again with the sprinkler sysytem or whatever running and it drops to 23 psi, you will need a pump that can be raised 20 psi more, to maintain 43 psi with the water running. That means a pump set at 63 psi (43 static + 20 dynamic pressure loss).

Most every water device has a rating of flow at a pressure... Sprinklers will be rated at so many GPM @ 50 PSI... Shower heads too...

There are tables that tell you how much pressure is lost through various sizes and types of pipes at different flows.

Anytime you have a long run and do not want to lose much pressure when the water travels through it, then size up the pipe. The tables will let you know what size pipe, so you don't waste money buying too big a pipe or lose pressure by using too small a pipe. You will need to know the estimated flow (GPM) through the pipe and the distance (FEET) to utilize the tables.

I have them in my book for 1/2" to 2" pipes (PVC sch. 40/ Class 200 and copper type M and L).

[Edited on 4-9-2007 by David K]

JZ - 4-9-2007 at 09:03 AM

Quote:

Originally posted by longlegsinlapaz
If you've got "city water" on a reliable 365-day-a-year basis, you could probably forego a cistern...BUT most places in Baja only turn water on for a few hours each day, then move to another area & turn it on for a few hours & the reliability of when you'll have water, how much, how much pressure & how long is very unpredictable.

Got you, I have a cistern for my place in Sonora.

I was wondering more about beefing up pressure in the US where there is a consistent supply.

David K - 4-9-2007 at 04:49 PM

Quote:

Originally posted by JZ

Quote:

Got you, I have a cistern for my place in Sonora.

I was wondering more about beefing up pressure in the US where there is a consistent supply.

It is done all the time to provide more pressure for those who live on mountain tops or next to water tanks... Check the yellow pages for water/ well pump dealers.

Sharksbaja - 4-9-2007 at 07:00 PM

Quote:

I was wondering more about beefing up pressure in the US where there is a consistent supply.

You could do that.
When you increase the pressure in a closed system like with a cistern and bladder tank you have a trade off. You will enjoy higher pressure for your shower but the pump will run longer and harder. That's why upping the pressure is best with a 1-2 hp motor. There is a reason for factory assembled settings. I use a system here that is set to cut-off at 60psi and cut-in at 35psi. The 55 gal tank is precharged to 35psi. The drawdown is something like 25 gallons. That is the amount used before it kicks in again. This lower cut-off with a greater differential setting with a higher bladder precharge means it will cycle fewer times and save you money.
I have tried many different settings and this is what works well for our home.
As Comitan says, the pressure switch is key to cycling and saving motor or seal burn-out. The switch I use is run thru a contacter and when pressure drops out it kills the whole system. I also installed an air-pump up top and a compressor pumps air to an aereator/bubbler in the bottom of the well. I have also installed bubblers in volume tanks. This system(which I developed) bubbles off sulfur as a dioxide and takes the smell out of water. This is a common problem in many places. It also make ordinary water taste better. So if you have clean but odorous water try this method.

Bob and Susan - 4-9-2007 at 07:59 PM

we use clorine...smells gooood :biggrin:

No drinky?

Sharksbaja - 4-9-2007 at 08:35 PM

Do you regulate that stuff or just pour it in?

Bob and Susan - 4-9-2007 at 08:42 PM

no "drinky"...

thursday is half price day at the water store in mulege
for the "drinky" stuff

we just pour it in to kill the critters :spingrin:

Sharksbaja - 4-9-2007 at 11:42 PM

Yeah Bob I do exactly the same thing. Just pour it in occasionally. They say that water is fit to drink in Mulege but I haven't yet. Except for with coffee.

Bob and Susan - 4-10-2007 at 05:02 AM

that's funny...
just about EVERYONE goes to the water purification store

Susan does wash dishes with it and the clothes are fine out of the washer

it seems to have a lot of minerals in it

Bob and Susan - 4-10-2007 at 05:32 AM

here is the "filling" station in Mulege...

it's a good thing i have susan to climb things :lol: