Small demand pumps and their brushes... who knew?

vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
I have been researching a replacement for my failing Shurflo 2088 series pump (115 volt AC model). After two years (estimated 375 hours) one of its non-replaceable brushes is worn out. I am not too impressed with its longevity. It's had an easy life... it lives in a cool basement and pumps water to an unpressurized storage tank in the attic. It's never had to produce more than about 6 psi.

I've been researching other brands of diaphragm pumps and spoke today with a technician at one of the other brands. In his long career he has worked for a couple of different pump manufacturers.

Here's what he told me:

These cheap pumps all have DC motors. The AC pumps rectify AC into DC for the motor.

High voltage arcing is what damages the brushes, especially the negative brush.

The longest lived pumps are the 12 and 24 volt DC pumps. The 115 volt AC pumps make very high voltage DC which arcs and consumes the negative brush.

Who knew? (I didn't). If I buy another small diaphragm pump it will be 12 or 24 volt. I've got to decide whether to run 24 volt DC to a 24 volt pump, or use a 12 volt pump with a power supply to make 12 volts from AC. I am leaning slightly towards the 12 volt power supply because my batteries are about 80 ft of cable away from the pump.

Anyone have a suggestion for my next pump? Maybe something with replaceable brushes?

--vtMaps

postscript: As of this moment, the pump will work for a few minutes if I whack it with a screwdriver. And it is the negative brush that wore out.
4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i

Comments

  • solarixsolarix Solar Expert Posts: 713 ✭✭
    Re: Small demand pumps and their brushes... who knew?

    Guess what? the diaphrams are no Sure thing either. They (Shurflo) say you have to replace the diaphram every 1 to 2 years (hopefully before it leaks and ruins the motor) I've given up using cheap pumps - especially in submersible applications.
  • Blackcherry04Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Small demand pumps and their brushes... who knew?

    Having had DC pumps in the Marine environment for many years the shurflo is 30 year old technology. Here is the best IMO in 12V, 24V or 120V ac. it's 5.5 gpm and has a adjustable pressure switch.

    http://www.energybay.org/aquatec-550-pressure-pump-24vdc
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: Small demand pumps and their brushes... who knew?
    . Here is the best IMO in 12V, 24V or 120V ac. it's 5.5 gpm and has a adjustable pressure switch.

    Thanks for the tip BC04, I've seen you recommend those pumps in other threads. I did speak with their tech support and learned that, like the shurflo, the aquatec brushes are not replaceable:cry:

    The aquatec technician I spoke with said the 120 volt models do not last as long as the DC models.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • Texas WellmanTexas Wellman Solar Expert Posts: 153 ✭✭
    Re: Small demand pumps and their brushes... who knew?

    What are you pumping from and into? Why not look at the groundfos SQ that will run on 110V and not have a surge current? It would have to be submerged into the source tank.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Small demand pumps and their brushes... who knew?
    What are you pumping from and into? Why not look at the groundfos SQ that will run on 110V and not have a surge current? It would have to be submerged into the source tank.

    Grundfos pump: $2,000
    Shurflo pump: $200

    That could be why.
  • Texas WellmanTexas Wellman Solar Expert Posts: 153 ✭✭
    Re: Small demand pumps and their brushes... who knew?

    Not SQ Flex. SQ. About $400-600 online. Slow-start built in and they fit in a 3" well if need be.
    Grundfos pump: $2,000
    Shurflo pump: $200

    That could be why.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Small demand pumps and their brushes... who knew?
    Not SQ Flex. SQ. About $400-600 online. Slow-start built in and they fit in a 3" well if need be.

    Yes, 3X the price would be an improvement over 10X.
    But still more expensive by far.
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: Small demand pumps and their brushes... who knew?
    What are you pumping from and into? Why not look at the groundfos SQ that will run on 110V and not have a surge current? It would have to be submerged into the source tank.

    I have gravity water (from a shallow spring) into my basement. I use the pump to push water up to a non-pressurized storage tank in my attic. The pump does not need to be submersible. It's efficient and serves my needs very well, but I wish it had replaceable brushes.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • Blackcherry04Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Small demand pumps and their brushes... who knew?
    vtmaps wrote: »
    Thanks for the tip BC04, I've seen you recommend those pumps in other threads. I did speak with their tech support and learned that, like the shurflo, the aquatec brushes are not replaceable:cry:

    The aquatec technician I spoke with said the 120 volt models do not last as long as the DC models.

    --vtMaps
    I'v been using them for 5-6 years and must have 20 or so in service and never had a problem with one, @ $80 I would consider them expendable and not worth the time to repair.
  • SCharlesSCharles Solar Expert Posts: 123 ✭✭
    Re: Small demand pumps and their brushes... who knew?

    The Dankoff pumps are pricey. I believe my model is probably in the range of $550, though I haven't checked prices in a while. Also, I don't know what head you [OP] need to service. But my Flowlight model has been in use since about 1990. Last year, I replaced the brushes just because I'd been ordering some other stuff from them and decided to do some preventive maintenance. The old brushes were about half the size of the replacements after 20+ yr.

    I have the 12 v. model. It has been trouble-free and flawless in operation. I use it to pressurize water for our house, taking water from an underground cistern what is filled from a well with a Grunfos AC pump to get the water up the 100 feet vertical run from the well. My Dankoff isn't going to work for pushing water up to an attic or something with that much head. But you might want to check out their other pumps, if you are in the mood to spend that much money. Considering I haven't had trouble with mine in about 24 years, might be worth a look.
  • ILFEILFE Solar Expert Posts: 364 ✭✭
    Re: Small demand pumps and their brushes... who knew?

    For the money, I would just go back with a another Shurflo. There is a reason they are in so many camping trailers and motor coaches around North America. I had one in my last camper. It lasted years and years. For the money you can replace it with, it is really that necessary to buy one with replaceable brushes?

    Last year, I ordered a 3.0 GPM (11 LPM) ShurFlo Revolution (Model 4008), 55 PSI pump from the states. It keeps on keepin' on. I paid less than $150 USD, for the pump and a strainer, shipped to Cambodia. It's also very quiet when running. When I first connected it, I thought it was not functioning, until I saw the water coming from the ends of the pipes in the toilet.

    The Revolution Series come in both 12vdc and 24vdc versions. (I figure you don't want to go back with an AC pump?) They do offer a 115vac version, as well.

    Pump: $74.95
    Strainer: $12.95
    Shipping: $58.45 (Domestic shipping in the US would be $20.00.)
    Customs: $2.00

    Grand Total: $148.35
    Paul
  • VicVic Solar Expert Posts: 3,038 ✭✭✭✭
    Re: Small demand pumps and their brushes... who knew?

    Hi vt ..,

    Am a bit tardy in a reply ...

    But, first, believe that this is just a Universal Motor. As such, it should work directly from AC or DC. The commutation is done in the motor.

    I have two 120 V jobs and two 12 V ones. None have yet failed. Am surprised that you did not get better service from this one.

    You MIGHT be able to pull off the back of the motor when is really fails, and perhaps find some brushes somewhere, BUT, it might be a challenge getting it back together, have never been inside one.

    It might be possible to put some spark suppression while inside, but normally these (capacitor or cap/resistor) suppressors would need to be "tuned".

    Will try to try one of my 12 V units on 12 VAC. Doubt that AC power would result in much lower sparking or longer life, but never know.

    Have you replaced it yet? If so, what did you use, or which way are you leaning on the replacement model?

    Who would have guessed?! Thanks, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: Small demand pumps and their brushes... who knew?
    Vic wrote: »
    Have you replaced it yet? If so, what did you use, or which way are you leaning of the replacement model?

    I used a 12 volt shurflo that I had on the shelf. I once used it to pump water from a barrel on my truck. Problem is, I'm powering it with AC through a 12 volt car battery charger... not the most efficient power supply. I'm keeping my eyes open for an efficient 12 volt supply. I won't go back to using 120 volt pumps.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • VicVic Solar Expert Posts: 3,038 ✭✭✭✭
    Re: Small demand pumps and their brushes... who knew?

    Hi vt..,

    Thanks for the info. Hope the 12 V pump lasts much longer than the 120 VAC one.

    Will try running my 12 v DC pump on AC -- just a transformer, later this week.

    Thanks, Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • Dave AngeliniDave Angelini Solar Expert Posts: 5,501 ✭✭✭✭✭
    Re: Small demand pumps and their brushes... who knew?

    Having had DC pumps in the Marine environment for many years the shurflo is 30 year old technology. Here is the best IMO in 12V, 24V or 120V ac. it's 5.5 gpm and has a adjustable pressure switch.

    http://www.energybay.org/aquatec-550-pressure-pump-24vdc


    I have a question for you. One of my clients has had 2 of the Aquatec 24V pumps fail by the input strainer cracking. The pump is fine but this is weird. They do have a tank with 30 feet of vertical height when full feeding the pump. This has never cause a problem before in 10 years with a Shureflo pump with strainer. I have a phone call into Aquatec but thought I would ask you if you have had any issues? Both of the strainers with cracks were impossible to open without a pipe wrench. This makes me think they were over titghtened at the factory and then stress cracked after a few months.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

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