Shallow well pump

notes · December 2013

I have a 3/4 hp / 230 /1ph jet pump. Amperage running measured with fluke clamp on is 3.7, start amperage is 19.3. Name plate RLA is 4.6. Average water level in well is 5-8 feet. I am told there is a foot valve in bottom of pipe. Is there any other type pump I can use that has a soft start motor. I cannot find a pump with start capacitor. Cabin is off grid, only on generator currently, looking it to adding batteries and then panels at a later date. Thanks, Andy.

mike95490 · December 2013

Re: Shallow well pump

for water 8' down, I can't believe you NEED 3/4 hp motor. The 240V saves you on copper wire costs.

As for surface mounted pumps, I don't know if they have a "3 wire" version. Deep well pumps come in 2 wire and 3 wire versions, and 3 wire is a "less harsh" start, but not totally soft.

Or look in the Grainger catalog, for VFD controllers and motors
http://www.grainger.com/category/adjustable-frequency-drives/motor-supplies/motors/ecatalog/N-bom

BB. · December 2013

Re: Shallow well pump

Jet pumps tend to be least energy efficient type you can choose... However, they are cheap, pretty reliable, and easy to service as the motor is at ground level.

What is the maximum lift you need (if well, does the water get pumped down further than 8 feet)? Your maximum lift is around 20' for water at sea level, if you are in the mountains the lift is somewhat less (lower air pressure).

In practice, if you can avoid pulling a vacuum to lift water, you probably will be happier. If there is a screen/filter on the input (sand, debris from a lake, etc.), it reduces inlet pressure even more and can cause the pump to be noisy/fail to lift water, and even quickly wear out the pump (pump cavitation).

The standard solution is to put the pump below the surface of the water, and it will be more efficient and reliable. You have a choice of placing the pump below the water but using a drive shaft with the motor on the well head. Or using a submersible pump (and the issue of water leaking through seals, having to pull the pump to service, etc.).

With a surface mounted motor, you have the choice of motor type. Remote capacitor start and three phase can both use a VFD (Variable Frequency Drive--Basically a 3 phase AC inverter that starts at low frequency (soft start) and slowly spins the motor up to speed--and can have different final frequency set points based on your pumping needs). And you have a pretty good choice of motors for submersible pumps+motors too.

And there are pump mfg. that have integraded VFD's (Grundfos, Sun Pumps, others). Grundfos (for example) has an SQ series that will run from 120 VAC, and an SQ-Flex series that will run from ~48 to 300 VDC or 120/240 VAC--Very nice pumps, not cheap, soft start and lots of options.

Other questions will include pump flow rate (pump direct to home/water usage + pressure tank or pump to cistern with second pump for pressurization)... In the US Southwest (at least), there seem to be some pretty substantial requirements for fire fighting (cisterns, fire pumps for wildfires/building sprinklers).

I should also ask how far from your off grid system to the well head... Do you need 240 VAC for long power run, or can you stick with 120 VAC?

-Bill "more questions than answers" B.

waynefromnscanada · December 2013

Re: Shallow well pump

Don't know if you're in Canada or not, but there is a very efficient shallow well pump available through Home Hardware, It comes with a 1/3 hp motor, but will operate very well with 1/4 hp. In fact I have one (It's an old DURO design no longer made by DURO) I believe the Chinese bought out the rights. The one I have is probably over 60 years old, and still has the original 1/6 hp, yes, 1/6 hp 110 volt 3.8 A (nameplate) Wagner motor on it and I keep it as a backup. It belonged to my grandparents. There is also, or at least to be, a SS version of this same pump.
http://www.homehardware.ca/en/rec/index.htm/Plumbing-Electrical/Plumbing/Waterworks/Water-Pumps/Piston/1-3-Horse-Power-275-Gallons-Per-Hour-Piston-Pump/_/N-ntjbh/R-I3130757?Num=0

Here is link to video of a very similar pump, this one is older, but operates exactly the same way. The guy has way oversized the motor, he states 1/2 hp.
http://www.youtube.com/watch?v=epL8NBBJdmw

BB. · December 2013

Re: Shallow well pump

waynefromnscanada wrote: »

In fact I have one (It's an old DURO design no longer made by DURO) I believe the Chinese bought out the rights.

Oh--that is so sad on many levels.

-Bill

vtmaps · December 2013

Re: Shallow well pump

BB. wrote: »

Oh--that is so sad on many levels.

If the design is so old, I think the patents would have expired. --vtMaps

waynefromnscanada · December 2013

Re: Shallow well pump

vtmaps wrote: »

If the design is so old, I think the patents would have expired. --vtMaps

They may well have, but it was an awesome pump in it's day and those looked after and still running, still are awesome pumps. Cheap, one moving part, jet pumps priced the North American built versions out of business. Sad. The Duros were built to last, and last they did.

notes · December 2013

Re: Shallow well pump

Thanks for all your responses, Bill,

What is the maximum lift you need (if well, does the water get pumped down further than 8 feet)? Your maximum lift is around 20' for water at sea level, if you are in the mountains the lift is somewhat less (lower air pressure). The well is in crawl space, lift from pump to fixtures is max 6 feet,cabin is in Michigans upper peninsula.i removed suction side of pump and using old dip stick method had water at 6 feet, although foot valve may have something to do with that. Info from well driller has well drilled at 25 feet.

In practice, if you can avoid pulling a vacuum to lift water, you probably will be happier. If there is a screen/filter on the input (sand, debris from a lake, etc.), it reduces inlet pressure even more and can cause the pump to be noisy/fail to lift water, and even quickly wear out the pump (pump cavitation). Stainless steel mesh filter is installed with strainer.

The standard solution is to put the pump below the surface of the water, and it will be more efficient and reliable. You have a choice of placing the pump below the water but using a drive shaft with the motor on the well head. Or using a submersible pump (and the issue of water leaking through seals, having to pull the pump to service, etc.).

With a surface mounted motor, you have the choice of motor type. Remote capacitor start and three phase can both use a VFD (Variable Frequency Drive--Basically a 3 phase AC inverter that starts at low frequency (soft start) and slowly spins the motor up to speed--and can have different final frequency set points based on your pumping needs). And you have a pretty good choice of motors for submersible pumps+motors too. VFDs I am familiar with in commercial ventilation, quests I would need a presure transducer of some sort.

And there are pump mfg. that have integraded VFD's (Grundfos, Sun Pumps, others). Grundfos (for example) has an SQ series that will run from 120 VAC, and an SQ-Flex series that will run from ~48 to 300 VDC or 120/240 VAC--Very nice pumps, not cheap, soft start and lots of options.

Other questions will include pump flow rate (pump direct to home/water usage + pressure tank or pump to cistern with second pump for pressurization)... In the US Southwest (at least), there seem to be some pretty substantial requirements for fire fighting (cisterns, fire pumps for wildfires/building sprinklers).
Pump to pressure tank to fixtures. No fire fighting needed, we have a pond on site with a 6" pipe for pumper truck. Flow rate of pump at 25' is 400 gallons.
I should also ask how far from your off grid system to the well head... Do you need 240 VAC for long power run, or can you stick with 120 VAC?
Circuit breaker panel is about 25' from pump. Either voltage is ok just trying to keep power to a min. Also I think 3/4 is to large. Fixtures, kitchen sink,2 bathroom sink, shower, 2 low flow toilets, 1 outside faucet.

Shallow well pump

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