Greensand System Installed... Low Pressure?

Discussion in 'Water Softener Forum, problems, installation and r' started by szuba, Oct 8, 2011.

  1. szuba

    szuba New Member

    Messages:
    5
    Location:
    Bryant, AL
    Hey everyone, I have a question.

    I just installed a 1.5cf Greensand iron filter last night and am experiencing very low water pressure. If I bypass the system, the water pressure in the house is fantastic. Once the flow is through the Greensand filter, I can't flush the toilet and run a sink faucet at the same time.

    I have a pressure tank at the well, before the iron filter. Would it be unheard of to put another pressure tank AFTER the iron filter? Has anyone heard of a greensand filter bogging pressure down like this?

    Any help would be appreciated.
    Thanks!
  2. Cookie

    Cookie .

    Messages:
    5,660
    Location:
    .
    Are you sure the potassium permanganate is being injected properly.
  3. Cookie

    Cookie .

    Messages:
    5,660
    Location:
    .
    ...and, are you sure the proper amount is being injected.
  4. szuba

    szuba New Member

    Messages:
    5
    Location:
    Bryant, AL
    Would that effect the pressure? To be honest, no i'm not sure. I followed the instructions that came with the filter and watched for most of the backwash process. It said to make sure it pulled in the potassium; it did draw most of the potassium permanganate but not the entire tank. That was actually going to be my next question. I JUST installed it yesterday, so i'm not too familiar with it. How much is supposed to be pulled in? Every last drop?
  5. Cookie

    Cookie .

    Messages:
    5,660
    Location:
    .
    yes, not enough injected it won't remove the iron and will clog your filter. Too much is just waste.

    There is another thread I just noticed, called, Greensand Filter-frequent clogging, if you look for it, there are a few other replies, too.
  6. szuba

    szuba New Member

    Messages:
    5
    Location:
    Bryant, AL
    This is a brand new system... surely it wouldn't be clogged with iron instantly? I may run another backwash tonight and see if it's any better in the morning.
    Thanks for your input.
  7. Cookie

    Cookie .

    Messages:
    5,660
    Location:
    .
    It was nothing. I hope it works out well for you.
  8. szuba

    szuba New Member

    Messages:
    5
    Location:
    Bryant, AL
    Any opinions on installing a second pressure tank after the filter?
  9. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,838
    Location:
    NW Ontario, Canada
    A second tank after the filter is only stop-gap. It would have to be a large tank to get a decent drawdown. Under high usage, the pump would be slow to respond since it would be governed by the tank before the filter. Also, you would need to install a checkvalve so that the flow cannot reverse through the filter and loosen the pack.

    What are the specs on the filter for service flow rate? Have you measured the actual flow rate? Is it providing the specified flow rate? It sounds like either a faulty or undersized unit.

    I have a birm type iron filter and the flow rate through it is higher than the flow rate through the micronizer. The 30 gallon precipitation tank buffers the difference.

    You can partially close the stops on the toilet to rate-limit the refill time. This could mitigate a potential scald issue should a toilet be flushed while someone is having a shower.
  10. rjh2o

    rjh2o New Member

    Messages:
    75
    Location:
    Michigan
    What is the gpm produced by your well, submersible pump or jet pump, pressure switch at well (20/40,30/50, 40/60)?
    It takes about 40 psi and at least 10gpm to backwash a 1.5 cu ft greensand filter effectively. That filtration system will only provide about 5-7gpm flow rate. If your well is only producing 10gpm the system will never work and your home will never operate with that low flow rate. There will also be about a 20psi pressure drop across the media. A second pressure tank won't accomplish anything, before or after the filter. Who ever recommended that system did NOT do their home work and did you and injustice.
    RJ
  11. szuba

    szuba New Member

    Messages:
    5
    Location:
    Bryant, AL
    I have a 40/60 pressure switch with a submersible pump.

    Ok, so the website I purchased this system from stated,
    "The recommended flow rate for maximum filtration performance is 5.0 gallons per minute but peak flow rates of 18 gallons per minute are possible. The backwash flow rate is 5.0 gallons per minute."

    Your saying I can only get about 5-7gpm max? Does it not mean I can get up to 18gpm of filtered water?
    What could I possibly do to increase this pressure? Would I have to upgrade to a 2.5CF unit, or would this make matters worse?

    Thanks!
  12. LLigetfa

    LLigetfa DIYer, not in the trades

    Messages:
    3,838
    Location:
    NW Ontario, Canada
    So they are saying 5 GPM to provide enough "hang time" for the PP to interact, and that the max GPM you can draw through the unit is 18. Have you filled a big bucket and timed it to calculate the GPM.

    A larger CF unit has a larger diameter tank and provided the head and dip tube assembly are properly sized, should provide greater service flow rates.

    You could try jacking the pressure up to 50/70 or 60/80 if it can produce the needed GPM at the higher pressures.
  13. rjh2o

    rjh2o New Member

    Messages:
    75
    Location:
    Michigan
    That unit will never get 18gpm peak flow rate. With 1.5 cu ft the peak flow rate will be a max of 10gpm. A larger capacity greensand filter will not help, it will only cause more pressure/flow rate loss. Manganese greensand is extremely dense (85lb per cu ft), this is one of the properties that makes it work (contact time). Consequently the flow rates through this media are extremely low and it has a very limited application in modern homes. Performance is also dependent on the GPM from well. Forcing higher pressure through filter will cause higher pressure drop and the system to not work properly, iron bleeding through. Depending on the size of home, floors, fixture count, a bathroom on a second story may only be getting 2-3 gpm flow rate and won't work if any water is being used elsewhere in the home.
    RJ
  14. Gary Slusser

    Gary Slusser That's all folks!

    You mean the output of the well pump and not the recovery rate gpm of the well right?
  15. Gary Slusser

    Gary Slusser That's all folks!

    It sounds as if the dealer is confusing the peak SFR (service flow rate) of his control valve as the SFR of his filter, and that is a serious mistake, and incorrect.

    You should be backwashing a 1.5 cuft greensand filter at a higher gpm than his 5 gpm.
  16. rjh2o

    rjh2o New Member

    Messages:
    75
    Location:
    Michigan
    Well pump output yes. It should be on the pressure tank, well pump control and/or with the paperwork you got with the well installation. You are only going to get 5-7 gpm with this system. If you have a well that is producing low output (gpm) the gpm through greensand system will be even less. As Gary stated the sfr through the "valve" alone may be 18gpm but not the the media tank with 1.5 cu ft of greensand.
    RJ
  17. Akpsdvan

    Akpsdvan In the Trades

    Messages:
    1,480
    Location:
    Alaska
    Just double check any number of the books that I have for the Greensand units with a 10x54 or 1.5 cubic foot and they all have 5.0gpm on the backwash...

    They also have a max service flow rate through the greensand at 5gpm.... for the same 1.5 cubic ..
  18. mialynette2003

    mialynette2003 Member

    Messages:
    720
    Location:
    Ocala, Florida
    according to the manuals I have the max backwash flow rate for a 1.5 cf Greensand is 5.0 GPM.
  19. rjh2o

    rjh2o New Member

    Messages:
    75
    Location:
    Michigan
    I would agree with Gary. The dealer quoted you the flow rate through the valve alone. The max flow through the 1.5 greensand will be 7gpm. Just a bad application for any modern home. That unit requires 10gpm backwash flow rate. Yes I meant the output of the well.
    RJ
  20. Gary Slusser

    Gary Slusser That's all folks!

    The backwash gpm is a drain line flow control (DLFC) that can be changed and usually most control valves can go to 10 gpm and if you need more you remove the DLFC from the control valve and add an inline flow control in the drain line itself.

    RJ, then I assume you mean the output of the well pump and not the recovery rate of the well.
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