(206) 949-5683, Top Rated Plumber, Seattle
Page 1 of 4 1234 LastLast
Results 1 to 15 of 59

Thread: 3M recommends pressure tank size for their CBF100 carbon filter

  1. #1
    DIY Junior Member hcw3's Avatar
    Join Date
    Oct 2011
    Location
    Los Angeles, CA
    Posts
    26

    Default 3M recommends pressure tank size for their CBF100 carbon filter

    I have a new water system, including a new pump & pressure tank, chlorinator & carbon filter, and softener.

    The carbon filter is a 3M CBF100 "Backwash Filtration System".

    3M's documentation for the carbon filter specifies the following:

    "A PROPERLY SIZED PRESSURE TANK WILL REQUIRE A MINIMUM PUMP CYCLE OF 60 SECONDS TO REFILL FROM PUMP ON-TO-OFF PRESSURE"
    link: http://www.3mwater.com/media/catalog...CBF_Manual.pdf

    Can anyone tell me what problems might occur if the pump-on to pump-off period is generally only 12 seconds (with all taps closed)?

    Thanks.

    --
    Harry

  2. #2
    That's all folks! Gary Slusser's Avatar
    Join Date
    Aug 2004
    Location
    Wherever I park the motorhome.
    Posts
    6,790

    Default

    That will burn up the pump motor very quickly and run up your electric bill.

    To solve the problem adjust the pressure switch too provide at least 20 psi between on and off.

    Check the well and pumps forum for instructions if you don't know how to do that.
    Gary Slusser Retired (= out of business)
    Click Here to learn how to correctly size or program a water softener.
    CAUTION, as of Nov 12 2013 all YouTube videos showing how to rebuild a Clack valve have an error in them that can cause damage.

  3. #3
    DIYer, not in the trades LLigetfa's Avatar
    Join Date
    Feb 2011
    Location
    NW Ontario, Canada
    Posts
    3,675

    Default

    A pump motor builds up heat during the start current draw phase and should stay running for at least 60 seconds to cool off. Install a Cycle Stop Valve to stop the pump from short cycling and to give you higher constant pressure.

  4. #4
    DIY Junior Member hcw3's Avatar
    Join Date
    Oct 2011
    Location
    Los Angeles, CA
    Posts
    26

    Default

    Well, I apologize for not seeing your replies guys, thanks. I guess forum notification isn't working for me.

    I'm still struggling with the problem, and I hope I haven't damaged my pump by now.

    Gary, my pump is operating with a 20psi on/off differential. I believe the problem is that the pump and pressure tank were sized improperly. I'm thinking the installer simply screwed up.

    He's now installed a 5gpm 'flow reducer', that's got to go. It has an awful scream, which calls for hearing protection, when it comes on and for the 1st 20 seconds or so. After that the sound drops to tolerable, but still pretty noisy. Noise is one reason I installed a submersible!

    And still, the duty cycle is only 45 seconds or so. Argh.

    Is a flow reducer the right answer? Can it be installed in the well instead? It looks simple enough, about the size and shape of a 1" coupler.

    LLigetfa, I've looked into the cycle stop valve a little. From what info I could find, they seem like an excellent solution. Why are they so controversial in the plumbing world?

    Is a CSV going to be noisy like this nasty 'flow restrictor'?

    Thanks again for your help.
    Last edited by hcw3; 03-21-2012 at 05:01 AM.

  5. #5
    That's all folks! Gary Slusser's Avatar
    Join Date
    Aug 2004
    Location
    Wherever I park the motorhome.
    Posts
    6,790

    Default

    Your pressure tank is too small. It's draw down is too few gallons for the pressure the pump is being operated at; I.E. 30/50 psi.

    Your driller or plumber that installed the 5 gpm flow control needs to remove it and refund all the money you paid for it. All it does is limit the volume of water you get out of the pump. He did that to make the pump stay off longer but you see it still isn't off for a minimum of 60 seconds (that is also required by all sub pump manufactures for regular less than 1.5hp pumps AND he should have seen that his 'fix' didn't fix anything after installing it and testing it.

    You probably have a 20 gal nominal captive air pressure tank, at 3/50 it will have a draw down of about 5.x galls. You need a larger tank that has a draw down of like 10 gals. Or you use a lot more power and eventually burn up the pump motor.
    Gary Slusser Retired (= out of business)
    Click Here to learn how to correctly size or program a water softener.
    CAUTION, as of Nov 12 2013 all YouTube videos showing how to rebuild a Clack valve have an error in them that can cause damage.

  6. #6
    DIYer, not in the trades LLigetfa's Avatar
    Join Date
    Feb 2011
    Location
    NW Ontario, Canada
    Posts
    3,675

    Default

    Quote Originally Posted by hcw3 View Post
    Is a flow reducer the right answer? Can it be installed in the well instead? It looks simple enough, about the size and shape of a 1" coupler.

    LLigetfa, I've looked into the cycle stop valve a little. From what info I could find, they seem like an excellent solution. Why are they so controversial in the plumbing world?

    Is a CSV going to be noisy like this nasty 'flow restrictor'?
    The flow reducer is not the right answer. The CSV is a much more adaptive flow reducer that lets you use all available GPM.

    You would be best to ask CSV questions in the pumps and wells forum where valveman will see them. They do make a model that fits in the well if noise is a concern.

    Your current tank size would be OK if you used a CSV.

  7. #7
    DIY Junior Member hcw3's Avatar
    Join Date
    Oct 2011
    Location
    Los Angeles, CA
    Posts
    26

    Default

    Thanks much for your inputs. I'm interested in the CSV, but am cautious because I've seen disagreement about them.

    Gary, I can't tell from your comments. What size tank does your figuring suggest? The way I figured it, the tank would need to be 4 times larger, because the pump runs for 15 seconds now with the 20 gallon tank and needs to run for 60 seconds. Is an 80 gallon tank appropriate then?

  8. #8
    That's all folks! Gary Slusser's Avatar
    Join Date
    Aug 2004
    Location
    Wherever I park the motorhome.
    Posts
    6,790

    Default

    The draw down gals at the pressure you operate the pump dictates the size of tank and that all depends on the gpm rating of the pump and the static water level in the well. So you need to know the gpm and hp of the pump and what depth it is set at in the well, then find the pump chart for it and plug in those figures to find out what draw down gallons you need, then you find the tank that provide them at the psi you run the pump at.
    Gary Slusser Retired (= out of business)
    Click Here to learn how to correctly size or program a water softener.
    CAUTION, as of Nov 12 2013 all YouTube videos showing how to rebuild a Clack valve have an error in them that can cause damage.

  9. #9
    Moderator valveman's Avatar
    Join Date
    Mar 2006
    Location
    Lubbock, Texas
    Posts
    4,154

    Default

    The CSV is a globe pattern, and only makes about as much noise as a open faucet.
    Last edited by valveman; 03-22-2012 at 08:23 PM.

  10. #10
    DIY Junior Member hcw3's Avatar
    Join Date
    Oct 2011
    Location
    Los Angeles, CA
    Posts
    26

    Default

    Well, if that isn't a lot to chew on.

    What would a residential csv cost me, roughly?

    I've found that a new tank would cost me @ $ 450 not installed, as would a new pump, but the pump should be a bit easier - less pipe work to deal with.

  11. #11
    DIYer, not in the trades LLigetfa's Avatar
    Join Date
    Feb 2011
    Location
    NW Ontario, Canada
    Posts
    3,675

    Default

    The MSRP is on their web site - between $90 and $245.

    http://www.cyclestopvalves.com/pdf/d...ist-prices.pdf

  12. #12
    DIY Junior Member hcw3's Avatar
    Join Date
    Oct 2011
    Location
    Los Angeles, CA
    Posts
    26

    Default

    I've looked into the CSV, and the cost will be more than replacing either the pump or the tank.

    The cost of the CSV was quoted at $236, but then I would need to change my chlorinator pump which now simply turns on with the pump. Since the CSV would vary the flow rate, with the pump running all the while, I would need some kind of variable rate pump for the chlorinator. I spotted some in the $300-$400 range. Not sure how they work, but that's too much $$$.

    It looks like switching out the pump would be the best place to start (and then hoping the pressure tank is the right size).

    Is the well-driller's GPM rating the appropriate way to determine the correct pump size for my well?

  13. #13
    Water systems designer, R&D ditttohead's Avatar
    Join Date
    Jan 2012
    Location
    California
    Posts
    1,707
    Blog Entries
    1

    Default

    Check out the Chemilizer HN55 pump, it uses the water flow to pump, and it has a set ratio. it is approximately $200 plus a chemical storage tank. The most common is 128-1 ratio. For every 128 gallons of water the house uses, it will pump 1 gallon from the chemical tank. Mixing a gallon of bleach with 35-45 gallons should get you into the 5-10 PPM range.

  14. #14
    DIY Junior Member hcw3's Avatar
    Join Date
    Oct 2011
    Location
    Los Angeles, CA
    Posts
    26

    Default

    Thanks Ditttohead. That one looks promising.

    How would I know what the ratio should be in my system? I can test the water coming out of the contact tank, which will tell me what ppm chlorine I have now in the tank, but the way the installer set it up was totally unscientific ("oh just mix a gallon with 3 or 4 gallons of water"). I called the guy who designed the system, and he said 'if you're getting 0ppm chlorine out your tap, then don't worry about it.'

    The water coming out of the well is high in iron and sulfur, though I couldn't tell you how high.

    Can I figure this out using the water test results that the designer used (if he still has them), or is it trial and error?

    Thanks.

  15. #15
    That's all folks! Gary Slusser's Avatar
    Join Date
    Aug 2004
    Location
    Wherever I park the motorhome.
    Posts
    6,790

    Default

    Quote Originally Posted by hcw3 View Post
    It looks like switching out the pump would be the best place to start (and then hoping the pressure tank is the right size).

    Is the well-driller's GPM rating the appropriate way to determine the correct pump size for my well?
    Finding the correct size tank to get the right draw down gallons is much easier than replacing a pump while hoping the too small tank will be OK for at least a minute off for the pump between starts.

    If the gpm the driller has is for the pump yes, but if the recovery rate gpm is for the well then no. That's the gpm of water refilling the well after using water. That has nothing to do with how many gpm the pump can deliver to the house. Call the driller and get the gpm and hp of the pump you have and ask him what size tank you need to get the pump to stay off for 60 seconds.
    Gary Slusser Retired (= out of business)
    Click Here to learn how to correctly size or program a water softener.
    CAUTION, as of Nov 12 2013 all YouTube videos showing how to rebuild a Clack valve have an error in them that can cause damage.

Similar Threads

  1. Carbon filter before or after water softener
    By Bloom80 in forum Water Softener Forum, problems, installation and reviews
    Replies: 7
    Last Post: 09-29-2011, 07:52 AM
  2. Rebedding a Culligan Carbon Filter / General Water Treatment System Questions
    By scrupul0us in forum Water Softener Forum, problems, installation and reviews
    Replies: 8
    Last Post: 09-11-2011, 08:23 AM
  3. seeking fridge filter without carbon
    By jeremytl in forum Pumps and Tanks Well Forum & Blog
    Replies: 6
    Last Post: 06-15-2011, 09:36 PM
  4. Carbon tank not working
    By Mrs. Smith in forum Pumps and Tanks Well Forum & Blog
    Replies: 3
    Last Post: 11-07-2008, 07:47 AM
  5. Whole house carbon filter installation with softener
    By dabiz7 in forum Plumbing Forum, Professional & DIY Advice, Tips & Tricks
    Replies: 1
    Last Post: 02-27-2008, 03:36 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •