Posted by Josepi on January 5, 2010, 10:31 pm
What was the reason it is the "wrong pump"?
- Many solar systems are only 120volt
- Perhaps the starting surge or running surge takes out the solar inverter
- Harmonics from the inverter may interfere with signal communications or
hurt the pump motor.
Now the client has called and says his "solar guy" says it's the wrong pump
for a solar setup.
Any ideas.
--
Robert Olin
Bob's Water & Septic LLC
jolin@whidbey.net
http://soilsandseptic.com/bobs.html
Posted by dold on January 6, 2010, 2:16 am
> I was asked to replace a well pump for a client who has an off grid
> aviarey. The well was drilled about 130'. I could see a 1.5 hp pump in
> the corner of the well house that must have gone bad. It's a typical 4"
> centrifugal pump with a Franklin 240 motor. The pump I pulled out of the
> well was one I had never seen before. It was long and thin. It was also
> a 1.5hp pump, but this was a 120 volt.
...
> Now the client has called and says his "solar guy" says it's the wrong
> pump for a solar setup.
I suspect the "typical" pump was still good, but replaced for solar
operation.
The smaller pump may have failed, or maybe something else failed, since you
don't seem to understand the system.
Manufacturers? Models? How did the solar guy get involved again? Did the
new pump not operate correctly, and you didn't realize it, or were you
supposed to replace a pump, and the solar guy was checking to see if the
subcontracted job was done properly. Bummer that he didn't specify that
the pump was to be replaced with the same model that was in there.
So little data.
--
Clarence A Dold - Hidden Valley Lake, CA, USA GPS: 38.8,-122.5
Posted by wmbjkREMOVE on January 6, 2010, 9:41 am
On Wed, 6 Jan 2010 03:16:54 +0000 (UTC), "Robert Olin"
>I was asked to replace a well pump for a client who has an off grid aviarey.
>The well was drilled about 130'. I could see a 1.5 hp pump in the corner of
>the well house that must have gone bad. It's a typical 4" centrifugal pump
>with a Franklin 240 motor. The pump I pulled out of the well was one I had
>never seen before. It was long and thin. It was also a 1.5hp pump, but
>this was a 120 volt.
>The well is less that 5 years old so to have two pumps go out in this period
>of time is unusual.
It all sounds strange. When calculating head, you use the static water
level, not the well depth, unless the static level drops when pumping,
in which case you generally use the depth the pump is set at. If the
well is 130' deep, then the pump (or suction pickup) is likely set at
perhaps 120', and the water level might be, say, 60'. A 1/2 hp 10 gpm
submersible pump in that circumstance will deliver about 10gpm into a
pressure tank, and that sort of setup is usually considered good for a
home and light irrigation. A standard submersible isn't the most
efficient choice, but it can still be a good choice in some
circumstances like my own. http://www.citlink.net/~wmbjk/04water.htm
But water consumption should be considered as volume, not just gpm,
especially when powered by solar. If volume demands are higher than
average, or if the solar setup is marginal, then it's common to switch
to a higher-efficiency (and more expensive) specialty pump.
>The power is supplied from a battery bank that is charged by solar panels
>and a battery.
>I checked the breaker panel and it showed 240 volts to the main breaker, so
>I installed my typical centrifugal 4" pump with a Franklin 240 volt motor
Common failure modes are - pressure tank failed first, causing the
pump to cycle on and off excessively - water level in the well
dropped, perhaps on a seasonal basis - there was a leak and the pump
ran endlessly, although there's generally less chance of that with a
solar setup.
>however, I only used a 1 hp pump since it could supply as much water as the
>well could produce, according to the well log. I set it at the same level
>of pump I pulled out, and then turned it on. It quickly started gulping
>air. I then lowered it to the bottom of the well (another 6') and then
>there was plenty of water a the 10 gpm the pump and well yielded.
So you came up with something that works, but it sounds like you
haven't given any consideration to efficiency, which is generally
paramount in a solar setup.
>Since two pump has already failed in just 5 years, I talked my client into
>installing a PumpTec, which shuts down the pump if it senses no water and
>also won't let the pump start if the voltage is low.
The PumpTec protects against low water by sensing a reduction in motor
current. They're a really good idea, but they can be fooled in the
case of the water drawing down to the suction level and hovering
there. You should have a low-water cutoff pressure-switch as well.
That way, if for any reason the system pressure drops below about ~20
PSI, the switch will cut off the power and the pump won't restart
without manual intervention. Those switches only cost a couple bucks
more than the standard type, and can be identified by the lever on the
side. Some caution is advised however. If there's any reason that the
pump doesn't run sometimes (grid power failure, or marginal setup
off-grid), then the customer might not like having a manual reset,
especially if the control location requires, say, walking through a
snowbank. :-) There are also fully-programmable motor-protection
devices to allow sensible but limited automatic restarts, but they're
usually considered too expensive for modest installations.
>Now the client has called and says his "solar guy" says it's the wrong pump
>for a solar setup.
The water system is probably over-taxing the solar setup, and the
solar guy is likely miffed that you've added an unnecessarily
inefficient load. He might also have preferred to keep the well pump
on 120 with a more efficient submersible. On the other hand, if the
original setup was designed for what sounds like a poorly chosen pump,
the solar guy could be blaming you for his problems. A third
possibility is that the customer is asking more than the setup could
possibly supply (very common, especially if it's a new owner), and
he's looking to blame anybody but himself.
>Any ideas.
I doubt that it's possible for you to supply all the necessary
information to evaluate this setup properly. If one were starting from
scratch, he'd want to know all the well details including recovery
rate. That may or may not be available from the drilling log, may or
may not be current, and is best verified by testing. You'd also need
to know the planned or desired water consumption rate, as well as
pretty much all the solar setup details, including the customer's
usage patterns. It seldom happens that there's one guy who knows
everything in these situations, so the various contractors each do
their best and success is determined only by whether or not the
customer is satisfied. In this case, if you protect the installation
against low water, and if it doesn't run out, and if the solar setup
can keep up, then you can claim success. But if what you've done
causes the customer to burn more backup fuel, or put more wear and
tear on his batteries, or to have to forego the use of other
appliances, then you've done them a disservice whether they realize it
or not.
Wayne
Posted by wmbjkREMOVE on January 8, 2010, 2:32 pm
On Fri, 8 Jan 2010 18:27:29 +0000 (UTC), "Robert Olin"
>Thanks guys for all the good info.
>I discovered that the last pump was set too high in the well and was drawing
>air. But along with that, there were leaks in the plumbing going to the
>house which is about 300 feet away. So the pump must have been trying to
>run continually - gulping air and with no way to shut off when the batteries
>drew down.
>My understanding is that 240 volt is always more efficient than 120.
That's incorrect. The main thing you want to know is the watt-hours
per gallon of the various options.
> It
>takes 1/2 the amperage and 1/4 the line loss. What am I missing?
The actual efficiency. And you'd want to know the obvious things such
as whether the entire system is 240, or if there's just a branch on a
transformer that may have other loads on it. You could ask the guy who
put in the 120V pump to tell you why he did that.
> The pump
>I put in is 1/4 hp less that the last one, so I would guess any efficiency
>would be negated by the extra hp????
Nope. From the info so far, it sounds like you could cut the load
substantially with a 1/2 hp conventional submersible, and shave more
again by using a specialty pump.
> Everything works fine when he has the
>batteries charged up.
Check out the curve for the 11 SQF-2 here
http://lib.store.yahoo.net/lib/wind-sun/SQFlex.pdf . On the setup
you've described (pump needs to run at any time), getting the energy
down might extend battery life span considerably. That's an expensive
pump though, and the benefits might depend on the customer's usage
habits.
>When he last called his batteries were at 50%. He hasn't called since so it
>seem they must have gotten everything charged up.
The first assumption I make with off-grid folks is that they rarely
know their true battery SOC. It's very common that people seriously
overestimate SOC for long periods, and because of that end up with
short-lived batteries. Unless you know for sure that these people have
a reliable system monitor, then considering the circumstances
described I'd be over there with a hydrometer. Just because they
aren't calling you now doesn't mean they won't be irate a year later
when their solar guy hands them a giant bill for new batteries.
Wayne
Posted by ghio on January 9, 2010, 11:21 pm
> Thanks guys for all the good info.
> I discovered that the last pump was set too high in the well and was drawing
> air. But along with that, there were leaks in the plumbing going to the
> house which is about 300 feet away. So the pump must have been trying to
> run continually - gulping air and with no way to shut off when the batteries
> drew down.
> My understanding is that 240 volt is always more efficient than 120. It
> takes 1/2 the amperage and 1/4 the line loss. What am I missing? The pump
> I put in is 1/4 hp less that the last one, so I would guess any efficiency
> would be negated by the extra hp???? Everything works fine when he has the
> batteries charged up.
> When he last called his batteries were at 50%. He hasn't called since so it
> seem they must have gotten everything charged up.
> Bob
> --
> Robert Olin
> Bob's Water & Septic LLC
> jo...@whidbey.net
> > On Wed, 6 Jan 2010 03:16:54 +0000 (UTC), "Robert Olin"
> >>I was asked to replace a well pump for a client who has an off grid
> >>aviarey.
> >>The well was drilled about 130'. I could see a 1.5 hp pump in the corner
> >>of
> >>the well house that must have gone bad. It's a typical 4" centrifugal
> >>pump
> >>with a Franklin 240 motor. The pump I pulled out of the well was one I
> >>had
> >>never seen before. It was long and thin. It was also a 1.5hp pump, but
> >>this was a 120 volt.
> >>The well is less that 5 years old so to have two pumps go out in this
> >>period
> >>of time is unusual.
> > It all sounds strange. When calculating head, you use the static water
> > level, not the well depth, unless the static level drops when pumping,
> > in which case you generally use the depth the pump is set at. If the
> > well is 130' deep, then the pump (or suction pickup) is likely set at
> > perhaps 120', and the water level might be, say, 60'. A 1/2 hp 10 gpm
> > submersible pump in that circumstance will deliver about 10gpm into a
> > pressure tank, and that sort of setup is usually considered good for a
> > home and light irrigation. A standard submersible isn't the most
> > efficient choice, but it can still be a good choice in some
> > circumstances like my own.http://www.citlink.net/~wmbjk/04water.htm
> > But water consumption should be considered as volume, not just gpm,
> > especially when powered by solar. If volume demands are higher than
> > average, or if the solar setup is marginal, then it's common to switch
> > to a higher-efficiency (and more expensive) specialty pump.
> >>The power is supplied from a battery bank that is charged by solar panels
> >>and a battery.
> >>I checked the breaker panel and it showed 240 volts to the main breaker,
> >>so
> >>I installed my typical centrifugal 4" pump with a Franklin 240 volt motor
> > Common failure modes are - pressure tank failed first, causing the
> > pump to cycle on and off excessively - water level in the well
> > dropped, perhaps on a seasonal basis - there was a leak and the pump
> > ran endlessly, although there's generally less chance of that with a
> > solar setup.
> >>however, I only used a 1 hp pump since it could supply as much water as
> >>the
> >>well could produce, according to the well log. I set it at the same level
> >>of pump I pulled out, and then turned it on. It quickly started gulping
> >>air. I then lowered it to the bottom of the well (another 6') and then
> >>there was plenty of water a the 10 gpm the pump and well yielded.
> > So you came up with something that works, but it sounds like you
> > haven't given any consideration to efficiency, which is generally
> > paramount in a solar setup.
> >>Since two pump has already failed in just 5 years, I talked my client into
> >>installing a PumpTec, which shuts down the pump if it senses no water and
> >>also won't let the pump start if the voltage is low.
> > The PumpTec protects against low water by sensing a reduction in motor
> > current. They're a really good idea, but they can be fooled in the
> > case of the water drawing down to the suction level and hovering
> > there. You should have a low-water cutoff pressure-switch as well.
> > That way, if for any reason the system pressure drops below about ~20
> > PSI, the switch will cut off the power and the pump won't restart
> > without manual intervention. Those switches only cost a couple bucks
> > more than the standard type, and can be identified by the lever on the
> > side. Some caution is advised however. If there's any reason that the
> > pump doesn't run sometimes (grid power failure, or marginal setup
> > off-grid), then the customer might not like having a manual reset,
> > especially if the control location requires, say, walking through a
> > snowbank. :-) There are also fully-programmable motor-protection
> > devices to allow sensible but limited automatic restarts, but they're
> > usually considered too expensive for modest installations.
> >>Now the client has called and says his "solar guy" says it's the wrong
> >>pump
> >>for a solar setup.
> > The water system is probably over-taxing the solar setup, and the
> > solar guy is likely miffed that you've added an unnecessarily
> > inefficient load. He might also have preferred to keep the well pump
> > on 120 with a more efficient submersible. On the other hand, if the
> > original setup was designed for what sounds like a poorly chosen pump,
> > the solar guy could be blaming you for his problems. A third
> > possibility is that the customer is asking more than the setup could
> > possibly supply (very common, especially if it's a new owner), and
> > he's looking to blame anybody but himself.
> >>Any ideas.
> > I doubt that it's possible for you to supply all the necessary
> > information to evaluate this setup properly. If one were starting from
> > scratch, he'd want to know all the well details including recovery
> > rate. That may or may not be available from the drilling log, may or
> > may not be current, and is best verified by testing. You'd also need
> > to know the planned or desired water consumption rate, as well as
> > pretty much all the solar setup details, including the customer's
> > usage patterns. It seldom happens that there's one guy who knows
> > everything in these situations, so the various contractors each do
> > their best and success is determined only by whether or not the
> > customer is satisfied. In this case, if you protect the installation
> > against low water, and if it doesn't run out, and if the solar setup
> > can keep up, then you can claim success. But if what you've done
> > causes the customer to burn more backup fuel, or put more wear and
> > tear on his batteries, or to have to forego the use of other
> > appliances, then you've done them a disservice whether they realize it
> > or not.
> > Wayne
Point - The question of 240V vs 110V is moot. The supply voltage is
what ever the battery voltage is(12, 24 or 48).
The formula is - Watts divided by Voltage = Amps. While 750Watts(1Hp)
at 240V = 3.125Amps and 1125Watts(1.5Hp) at 110volts = 10.23Amps
neither of these voltages is appropriate to the situation.
If, for the sake of this argument, the battery voltage is 48V then the
actual answer for your 1Hp pump is 750Watts divided by 48Volts =
15.6Amps, (31.3Amps for 24V battery voltage and 62.5Amps for 12Volt
battery)
For all waynes elusive efficiency claims, what you are faced with is
finding a pump that delivers the most number of gallons per minute for
the least number of Amp hours consumed from the battery supply,
balanced against how fast the well can be replenished.
From what you have said the failure of the pumps in question is caused
by trying to take water out faster than the source can replenish the
well. Running pumps dry will almost certainly destroy them.
XML site map
> aviarey. The well was drilled about 130'. I could see a 1.5 hp pump in
> the corner of the well house that must have gone bad. It's a typical 4"
> centrifugal pump with a Franklin 240 motor. The pump I pulled out of the
> well was one I had never seen before. It was long and thin. It was also
> a 1.5hp pump, but this was a 120 volt.