Water Well Pump

Thermal cycling is harder on incandescent light bulbs than motors.

This may draw comments to the contrary, but it's the run time more than the number of starts that age a motor. A properly sized and maintained motor can last a long time.

It's usually bearing lubrication or insulation breakdown that causes motors to fail, not start-up.

I think a larger tank won't hurt anything, but it won't pay back in longer motor life that would pay for the conversion.

You may have to look for it, but motor data often specifies how many starts per hour are permissible. The inrush current heats the motor windings. If not dissipated between successive starts, this heat can accumulate, to the detriment of motor life.

The 450HP screw compressors in the plant where I work are programmed with anti-recycle provisions to prevent restarting too soon, as well as keeping track of "hot starts" and preventing too many of them.

As I said, "This may draw comments to the contrary". I discounted inrush current heating as a factor. Maybe I was wrong to do so. You should be able to find data on your motor on the manufacturer's web site.

I'm one of the people that believe that frequent starts and stops put wear on the well pump components. I put in a 52 gallon tank for a household of 3, which works fine. I would say to size your tank to usage, and bigger will never hurt.

This guy overkilled it a little, but it's a pretty good read.

http://www.frugal-living-freedom.com/water-pressure-tank.html

The reserve capacity in case of power failure is a good point.

Yeah, comes in handy when the power goes out. Just have to make sure the tank is cycled up and not toward the end of a cycle.

If we have a big storm coming in, I'll run my water until I hear the pump kick on, and shut the water off to make sure I've got a fully charged tank. That gives me plenty of drinking/cooking water. I fill up a tub and use a 5 gal. bucket to keep toilet tanks full.

I heat the house with wood and cook with propane, so winter power outages are no big deal.

I was going to say, pumps are designed to take the frequent switching... but this is a worthwhile idea anyway! I have a very deep artesian well, and don't have a backup system for power outages - except jugs of water set by for that purpose. An extra tank would be handy... thanks for the tip.

Like most things it's a compromise.
you don't want it switching on and off every few seconds and conversely you don't want it running 24/7 unecesarilly.
So yes, better to run it for 5 minutes every now and then rather than off/on once a minute.

Yes,

I agree that, the more often the motor starts the earlier the starting contacts will get dirty or wear out.

I only have a 5 gal tank on our pump and about once a year have to go and clean the contacts. They are not really worn that much (after 7 ears), but they get arced a bit and I clean them. I also have a small backup power system, so my wife doesn't get caught with soap in her hair when the power grid goes off. We live in the bush and the power is not very reliable. I also have a small set of solar panels (55W) feeding a 100amphour deepcycle battery driving a 1Kw inverter and it is quite sufficient for us.

Jens

The issue of rapid cycling and winding warm-up has been sell- covered.

Check out cost of a small VFD for the motor of the booster, and forget about the storage.

When there is no load, the pump will spin at minimal loading- less than 5%- and will immediately ramp up to meet ANY demand while being cooled during the run period.

If you want to save as much energy as possible, program a shut-down over night or other times of minimal load. The VFD will provide a low-energy ramp up when it starts running the booster again- minimizing the winding heating.

A simpler solution will be to have an overhead storage tank of sufficient capacity to last for at lease 24hrs.

Yes, and it depends on location. If gravity is abundant, gravity is king. If space is limited, but energy is available for a basement located 2-5 atmospheric pressure vessel, that is the way to go. I have used both.

What do you think a VFD for a 1 HP 115 volt water pump would cost?

Grainger's lists a few (1 to 2 HP) for $368 to $421 list.

I am sure that other supply houses- including HVAC or pump services- will have at least equal or better pricing.

You will still need a pressure sensor for output to the drive (4-20 ma) and set the drive for your desired pressure output signal.

Thanks.

I like the VFD route, you can also use the pressure switch to give the drive a run command for simplicity and ramp up and down as you wish. Westinghouse Teco single phase units start at $99.00 @automationdirect.com

Good luck

For a normal household owner, a large (20-60 gallons, 50-150liters) tank is the cheapest way to limit the pump cycling, that finally will kill the pump in all likelihood. And that is expensive.

There is one thing to do, and nobody mentioned yet. A tank has a pressurized rubber membrane protected air in it, to maintain pressure within limits. When you simply lose air volume, or the membrane fails, the air volume markedly decreases. THE PUMP IS CYCLING FREQUENTLY ON/OFF. You need to check it yearly for correct diagnostic and correct action. Luckily, there is no hurry there. You can pump it up every few months for years, no problem. Guess, how do I know it? The winner gets the best beer in my favorite pub.

Here's a nice write up on pressure tanks.

A few posts here would have you thinking that pressure tanks are a scam. They're not.

Kram, you earned a GA from me for that post.

This is sort of a OT, but the OP should also determine if the well pump has a "thermo protection relay" that will force the pump into a shut-down mode if the motor overheats. OP needs to check his Owner's Manual for this info. High quality well pumps, like Gould's or Franklin or an equivalent, are almost always equipped with this sensor and relay. When in doubt check with the pump installer, as his/her records may allow you to make a determination or at least the manufacturer's name, address, and the well pump model number...then the OP can contact tech support. I cannot stress enough the importance of this overheat sensor & relay being installed in the pump motor (factory installed that is....).

The OP's tank size is obviously way undersized. I agree with the others that a much larger single tank or a set of medium sized tanks in parallel is warranted......sized to adequately provide the daily water consumption (ie, demand). It is very important to make sure that all of the pressure settings for the new and old tank are identical, otherwise the system will operate "unbalanced" and not provide the required water.

IMO and experience, short cycling of the well pump will greatly decrease its life. Installing an inexpensive but high quality VSD, as one of the other posters had suggested, really should be contemplated.....highly recommended in my professional judgement!

A pressure tank needs constant monitoring whether a) the bladder burst 2) air pressure drops c)pressure switch malfunctioning etc. But an overhead tank has no such issues.

Well I think it falling through the ceiling or springing a leak counts as a concern.

As far as my experience with pressure tanks I grew up out in the country where every household had their own private well and pumps systems and I can say that any decent quality and correctly installed pumping system is near zero maintenance!

To match the pressure that a pressure tank can provide, a gravity feed system would have to be about 1000 feet in the air. I wonder how much that would cost?

1000 foot head- at 2.42 feet per PSI- is over 400 PSI.

100 feet- OK, but most booster pumps would have a problem with a 1000 foot boost.

I have a tendency to exaggerate, but you get the the point.

Okay Einstein, lets have a little fun. With my pressure tank, my average water pressure inside the house is around 65 psi.

What size and height would my gravity feed system have to be, to provide that kind of pressure?

Once we've got that one answered, we can compare the price to my $350 pressure tank.

It's a 52 gallon tank. Assuming it's a non-pressurized, gravity feed system, how high in the air would it have to be to feed my second story bathroom, which is about 12'-14' above ground level?

The well is 250' deep. Pump is at 200' deep.

If it sounds like I'm being a smartass, I am. But it's also an interesting question.

65 x 2.31 ≈ 150 ft.

Thanks Tornado-

I was a little busy with other issues.

Kramarat-

160 feet of 4 inch PVC would hold about 35 gallons above you bathroom, and would cost about $250, with no bladder to fail

And- you could use it as a REALLY COOL flagpole or a very effective digital antenna standard so you could pick up stations about 100 miles away.

The new pressure tanks don't use a bladder. But at least the OP now has another option.

With the overhead tank just above the upper floor ,why don't you fix a small in-line circulating pump to be switched on when required by a pressure switch.

Good point Kramarat. They can have a gravity feed tank on the ground with a "Water Puppy" like we had on our sailboat.. A 12VDC diaphragm on demand pump, not much pressure, but good enough for showers, sinks, toilets and luxury items like that.

Yes you will need to keep the "Bugs" out of it (Bleach works).

I love your avatar... not so much your answer.

Another pump, bleaching, batteries... by the end of the day More maintenance,more complicated than pressure tank, and probably more expensive.

Is this a Pitts?

Wangito.

Read your first answer and didn't bother to answer, but couldn't help on the second.

Over head tanks are now forbidden in most civilized countries due to bio-contamination.

pressure tanks are pressurized and hermetically sealed, which overhead tanks usually are not.(Vents of some sort), they are less esthetically intruding,(surface mount) you can get much higher line pressure unless you are willing to put a 120 feet tower, and you can use the pressure tank as some emergency water supply also., Zero maintenance for years, no cleaning and chlorinating of OH tank...and more reasons... I have a Square-D Press-O-Stat for the last 17 years. It works flawlessly.

You are definitely wrong my friend. Go, change to pressure tank. You will love it, and thank me later.

Wangito

.

Wangito said,

"Over head tanks are now forbidden in most civilized countries due to bio-contamination."

I beg to differ, One of the largest cities in the world, New York City. 90% of the buildings that are 6 stories or higher have simple wooden water tanks on the roof for their water supply.

There are currently between 10,000 and 15,000 of these wooden tanks in New york City alone.

Here is a page all about them in New York,

http://www.fogonazos.es/2007/06/new-york-rooftop-water-tanks.html

Beautiful photos!!! all on 100-200 years old buildings, 1800 technologies... and all are 6 stories and higher buildings. For your up-to-date knowledge I suggest you google NYC 2011 building codes.(no more wooden tanks on public/community buildings)

The original poster is, to my understanding talks about a single home with a small well with at best 15PSI of water pressure. do you want this water pressure at your shower?,

I kindo doubt this.

Wangito.

HEY! You two behave. Who ever said NYC was part of a civilized world?

Won't there be bio-contamination in pressure tanks where water is in contact with rubber?. In a home where water from a deep well is directly sent to a pressure tank, is it necessary to add some chemicals like chlorine depending on water analysis report?. In TV I saw in South africa ornamental fish in tap water died in 14minutes while in bottled water it survived. Is that tap water safe for bathing?. Are deep well waters not contaminated/.

you wrote:"Water well pump,

I remember a motor being like a lightbulb.

When what causes a motor to fail is mostly turning it on and off often. Is this true?

YES! Don't switch it on, and it will never fail!

Most Deep water well pumps manufacturers, (Google Franklin, In-rush current) be it submeredged or not, recommend the use of DOL (direct on line) start or VFD's (Frequency drive units.)

Variable torque is number 1 enemy of all rotating devices.

In pressure tanks why don't they incorporate a pressure gauge to check the air pressure when the tank has no water?. This will assist maintaining a required pressure and flow.

I think what you would need is a way to determine the ratio of air to water within the tank, which would increase the price quite a bit

a pressure gauge is going to help in that endeavor

The air pressure gauge will indicate the pressure of air plus the water pressure when the tank is with water. That's why we check the air pressure(recommended value) when there is no water in the tank after draining it.

Ratio is: 33/66 water/air.

You wrote: "In pressure tanks why don't they incorporate a pressure gauge to check the air pressure..."

Reading your question I Finally I understood what is your problem! You Seem to have never seen a pneumatic (pressure) tank.

Wangito.

The air pressure in pressure tank has some relationship to the cut-in pressure of the pump,that's why we monitor the air pressure(for leaks).