Odd Fleck 7000SXT configuration possible?

Discussion in 'Water Softener Forum, problems, installation and r' started by zver11, Jan 7, 2013.

  1. zver11

    zver11 New Member

    Messages:
    12
    Location:
    Philadelphia pa
    I have a Filox iron filter with a Fleck 7000SXT followed by a 200 gallon tank radon aerator with its own repressurization pump. Aerator follows iron filter (and backwashable sediment filter) to avoid fouling. However, during Iron filter backwash, it would be nice to have the aerator tank's additional flow of oxygenated water through the iron filter.

    Top of the Fleck control has a large 1" connector over inlet side which is used for exiting backwash water. With an attached 1" drain line, backwash flow drops pressure to zero so there is no new flow to aerator tank during backwash. I notice on the output side of the 7000SXT control head , there is a cover for what looks like another access port on top of the filter. Would attaching a line from the aerator output to this port cause aerator water to enter the filter during backwash? If not, is there another port that could be used? I, obviously, do not want constant flow in this route but want flow from this independently pressurized line to enter the filter to supplement during backwash.
  2. Gary Slusser

    Gary Slusser That's all folks!

    How do you control the well pump and is the control after or before these filters?
  3. zver11

    zver11 New Member

    Messages:
    12
    Location:
    Philadelphia pa
    Detail of configuration:
    Part I: Well pump to pressure switch/pressure tank then iron filter then sediment filter output into aerator tank.
    Part II: Aerator is sprayer type which fills its own 200 gallon tank. 1/2hp submersible pump in aerator tank controlled by second pressure switch feeds aerator's pressure tank which then outputs house water supply.

    The house is fed by the aerator even if the well pump were off. There is therefore no current loss of water pressure when the iron filter is backwashing as long as water draw not exceed aerator tank reserve. When the aerator tank drops below a certain level, an automatic valve opens accepting input from Part I system.
  4. Gary Slusser

    Gary Slusser That's all folks!

    If the backwash causes 0 pressure from the well, then something is wrong with the pipe from the well to the filter, like a water leak, worn out or undersized pump (gpm and/or hp) or a too large or missing DLFC in the filter control valve. Or both filters are backwashing at the same time. I suspect you might have a jet pump feeding the filters, no?

    The answer to your question is no, you can't add water from after the filters.
  5. zver11

    zver11 New Member

    Messages:
    12
    Location:
    Philadelphia pa
    Water pressure drops to near zero because very little resistance to flow--large diameter of all flow channels in Fleck 7000 series, 1" PVC feed, 1" ID backwash output line means little resistance to flow. A little surprised Filox does not provide more resistance, but there is strong water flow out backwash line during backwash. Both pumps are submersible.

    Water I want to add is from storage tank of aerator--there is no question that adding it helps boost backwash flow. I can do this manually with current ball valve configuration(configuration serves as a large manual bypass everything option--but opening correct sequence will feedback to input). I would just like to do it automated. When used in certain configurations, control heads allow feeds to enter the backwash stream (e.g. brine for water conditioner, potassium permanganate solution for greensand chlorine injection for iron filters etc.). These are typically low flow unpressurized streams. I would like to add a pressurized water stream instead. The source exists and works. It is just a question of if there is a simple input that will connect this source of water during backwash but cut it off when valve is in service position.
  6. Gary Slusser

    Gary Slusser That's all folks!

    My 25 years of sales, installations and servicing thousands of filters etc. says: If the backwash causes 0 pressure from the well, then something is wrong with the pipe from the well to the filter, like a water leak, worn out or undersized pump (gpm and/or hp) or a too large or missing DLFC in the filter control valve. Or both filters are backwashing at the same time.

    Plus now I'll mention the possibility that the backwash water isn't going through the mineral due to a broken distributor tube or no o-ring on the distributor tube. That would allow most/all of the water flow out the drain line instead of up through the mineral but.. the DLFC button should limit some of the total gpm output of the pump and that would prevent the pressure from falling to 0 psi.

    Also, the capative air in the well pressure tank may be low and/or... the pressure switch is set wrong. The air in the pressure tank, with no water in the tank, should be 29 psi for pressure switch settings of 30/50 or, 39 for 40/60, with no water in the tank.

    That plate you mention on the top of the control valve is where an injector would be to introduce a regenerate for a mineral that can be regenerated with potassium permanganate or bleach etc.. So you can not add aerator water to the valve anywhere other than the water inlet to the valve (as you already are), and millions of other filters over the last 60-70 years haven't needed that additional water flow so lucky you, since you believe there's nothing wrong with your filter, you got yerself a "special" one.
  7. Tom Sawyer

    Tom Sawyer In the Trades

    Messages:
    3,172
    Location:
    Maine
    Just for grins, change the pressure gauge
  8. zver11

    zver11 New Member

    Messages:
    12
    Location:
    Philadelphia pa
    Sorry if I sound as if I am arguing with you. My writing style leaves room for improvement. I am asking because you are the expert. I learn from your comments and do appreciate them.

    The loss of water pressure during backwash was not a concern to me since it did not affect service since at 3:30am, the aerator tank provides adequate water supply to the house even with the well flow interrupted.

    What I have observed:
    1) main pressure tank holds pressure, pressure switch works (based on behavior, pressure gauge, and a good tire pressure gauge measuring air pressure in the empty pressure tank.

    2) Well pump can move water at just under 8 gpm(at pressure tank based on tank fill volume/tank fill time test), no symptoms evident during normal use. Well pump is relatively weak for a deep well, but I suspect this was intentional since well production capacity was low during initial well installation testing. Pump uses a three wire system with above ground controls. It is likely that, on sustained flows, well output gpm could drop as the water level in the well drops. Initial well installation testing showed 400 foot drop in water level during the 30 minute test pump.

    3) zero pressure only on backwashing folox filter. Other filter has 1/2" backwash line and backwashes normal. There is significant water flow through the filox filter control head during backwash(I can not measure it easily but see and hear it flow). The "DLFC" is a straight 1" tube--maximum flowrate as provided by the seller of the filter. Since I have done manual backwash to observe, I know nothing else is running during this single filter's backwash.

    4) When doing a manual backwash and supplementing it with aerator pump flow (expect combined flow easily 20gpm), I can hear a sound I suspect is the filox media lifting in the tank at the start of flow(sound like sand or gravel moving).

    I believe well output is low. I interpreted this as the likely source of pressure collapsing during backwash. Filox filters are great at iron/manganese/sulphur removal but have the difficult requirement that ideal backwash flow is double service flow. I used a 1" inner diameter backwash line and 1" PVC plumbing to the filox filter i order to maximize this flowrate. A narrower diameter line or restrictive DLFC would have slowed flow and might have allowed pressure to remain for the bypass. The problem of achieving adequate backwash flow is common for all variations of high purity Manganese oxide filters. One solution I have heard is to put two small filters in parallel with different backwash times. I was hoping for an alternative solution given that I have an (admittedly limited) alternative source of backwash water in the aerator tank.
  9. Gary Slusser

    Gary Slusser That's all folks!

    It sounds as if someone possibly removed the DLFC button in the control valve. It goes in where the drain line connects to the valve. It has nothing to do with the ID of the drain line.

    Without a DLFC button you get all the water out the drain line that flow through the mineral will allow. That runs the risk of dumping mineral out the drain line.

    I don't know much about Filox but I do know a lot about greensand and Pyrolox and with a good flow control valve, you always use a DLFC button based on the cuft size of the filter Or you use an external flow control if the valve's choice of buttons don't go up high enough.

    The other possibility is the water level in the well falling so far and a pump that was fine for the system before adding this filter but isn't know.
  10. Bob999

    Bob999 In the Trades

    Messages:
    448
    Location:
    Pennsylvania
    Poster said his well pump only produces 8 gallons per minute. That isn't much for a filox filter except for the smallest size. With a larger media tank a 10, 12, or more gpm DLFC would be indicated and if the supply is only 8 gpm then the pressure is going to be very low--approaching zero.
  11. ditttohead

    ditttohead Water systems designer, R&D

    Messages:
    1,836
    Location:
    Ontario California
    Filox should be backwashed at 20+ gpm per sq. ft. of bed area, and the fact that he has a 1" drain connector indicates his DLFC button will be no smaller than 8 GPM. Assuming a 10" diameter tank, he probably has a 10-15 GPM button, obviously exceeding the pumps ability. BTW, backwash rates are not based on cu. ft. of media, backwash rates are based on Sq. Ft. of bed area, media type, water temperature, and manufacturers recommended bed expansion during backwash.
  12. Gary Slusser

    Gary Slusser That's all folks!

    Yeah that's what he said he measured but I doubt he has an 8 gpm pump. And we don't know how deep the water level was in the well when he got the 8 gpm.
  13. Gary Slusser

    Gary Slusser That's all folks!

    You are assuming he designed this filter instead of buying it from a dealer, or if he is a dealer, from a supplier that included the correct size DLFC for the type of mineral and cuft size filter he bought. Plus we don't know the cuft size yet.
  14. zver11

    zver11 New Member

    Messages:
    12
    Location:
    Philadelphia pa
    Filter was purchased from afwfilters. Web site claimed 6gpm backwash rate(which I do not believe). Per manufacturer of Filox and 10" tank diameter, need 14gpm x .55 sq ft=7.6gpm backwash. Of course, if anyone has real world experience on whether manufacturer claim of 14 gpm/sq ft is realistic, I would like to hear it

    One thing I did not take into account is that on sustained draw, well output drops dramatically. Water level at 100' from surface-> 8gpm. On sustained draw with 3/4hp pump water level drops to over 400' from surface and pump output drops to approx 2gpm!. I appreciate Gary's comment on DLFC. I suspect system shipped without one!. I can achieve flow rate well over 20 gpm by diverting aerator tank output to combine with well output. On doing this, there appears to be no restriction slowing flow down(amazing rate of water consumption!).

    I am planning on putting in a 10GPM button DLFC(should it be bigger?) in the Fleck 7000SXT filox filter and rearranging filters to: well->sediment filter->aerator->filox filter->water conditioner. Aerator will deliver oxygenated water @ 20gpm (which will be cut by new DLFC). Given space restrictions in installation area and directionality of various control heads, this will have water bouncing back and forth (to left then to right then left then right then left for output! I was trying to avoid this with my initial configuration, but it seems the simplest solution. As a further positive, there will be less load on the well pump (sediment filter and aerator sprayer only) with the oversized (1/2 hp aerator pump for 2 story building) pushing through the iron filter and water conditioner as well as all the extra elbows in the configuration.

    As always, though I may be stubborn, I look forward to any comments and criticism of my new plan
  15. ditttohead

    ditttohead Water systems designer, R&D

    Messages:
    1,836
    Location:
    Ontario California
    Due to time I will only comment on the Backwash flow rate of Manganese Dioxide ore medias. Filox, Pyrolox, etc all have varying backwash rate claims but real world experience tells us that more is definetly better. 14 GPM per Sq. Ft. is not recommended unless you have very cold water. The rate specified is at 60 degrees. Most companies prefer a more aggressive backwash rate of 15-25 GPM per Sq. Foot of bed area and Pyrolox recommends a backwash rate of 25-30 GPM per Sq. Ft. http://www.clackcorp.com/downloads/ion_exchange_resin_and_filter_media/pyrolox_2356.pdf

    From field experience, we usually push the backwash rate to the higher limits assuming the well and pump and pre-treatment can handle it. This will allow the media to perfom much better and longer.

    The bed expansion at 25-30 GPM per Sq. Ft. is still under 30%.

    A minor note, these higher backwash rated do not require as long of a backwash time, the time can be cut significantly. It is normal to do a 25 GPM per Sq. Ft. rate at 5 minutes instead of the more common 10 minutes.

    hope this helps.
    Last edited: Jun 24, 2013
  16. zver11

    zver11 New Member

    Messages:
    12
    Location:
    Philadelphia pa
    I have been doing a 5 min backwash in the old configuration simply to avoid drawing down well until flow rate slows to a crawl. A relief to hear that shorter is common if at high flow rates. In the new configuration will have pump from 200 Gal aerator tank running at 20 gpm, but tank refill significantly slower so keeping total under tank capacity good. A short high output run will work. With approx. 1/2 sq ft area(10" diameter 1.5 cu ft media) this would imply flow of approx 12GPM (DLFC 12gpm?). Well water @ approx 40 degrees but slightly warmer if sitting in aerator tank a while)

    Also concerned about excessive flow in that I am dumping backwash through septic system. House is in a steep dirt hill(no bedrock until 50' down) and the well head is on the uphill side of house, so dumping in front yard will cause water flow under house. This has already been a problem with storm gutters which I have had to reroute away from house. I suppose I could cut into pipe diverting downspout away from house for backwash water if really important.
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