Question about Culligan Sales #SY-750S Under Sink Water Filter

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Air tank (underneath house) does not push water out of spigot in sinke or refridgerator.

There is 70 psi of air pressure in the culligan (underneath the house) air tank, but no air pressure comes out of the bottom to push the water through the spigot in the kitchen sink. What should I do if I'm positive that this has nothing to do with the under sink filters? I'm positive that the issue is with the air tank. Thanks for your help, DH

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  • jdthefixer May 11, 2010

    See if the pressure gauge on the tank is stuck. They can sometimes fail and appear to have pressure when they do not.

    However, if you have pressure elsewhere in plumbing fixtures, this probably isn't the case. If you have no pressure anywhere, then look for plugging of the discharge air piping from the tank.

    Othewise, look for any blockages in other parts of the system. Can you test for pressure before the sink filter(s)?



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I had the same problem on two different systems. Finally a Culligan lady gave me the answer. The tank should have no more than 7-10 PSI when empty, and when the tank fills up with water, it should register no more than 35 PSI. The bladder inside the tank will expand with high PSI to fill the whole tank thus restricting water to fill the tank. Simply bleed off the air at the valve and set the pressure at 7-10 PSI and you will hear water start filling the tank and within minutes water pure water at your spigot:-)

Posted on Aug 20, 2009

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You need to test the air pressure with the tank totally empty, remove the tube that is going into the tank and open the tank valve to release all water, if water is in tank and does not come out your bladder is finished and you will need a new tank, if you are able to get all the water out then you need to test PSI again and it needs to be between 7-10 psi, this way when the bladder fills up again with water that pressure will be the ideal 40-50 psi.

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Posted on May 25, 2009


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There can be many reasons for no water in tank.
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There may be several causes for this. Here is a list of things to look for.
1. If an activated carbon filter was installed many times carbon fines will plug up the head of the RO housing. Pull the filters out and flush the whole assembly with NO filters in it.
2. The capillary tube (which puts back pressure on the membrane to create water) may be worn out and all the water will run to the drain. Replace capillary tube
3. The automatic shutoff may not be opening to allow for water flow.
4. Shut the water off at RO tank and take the line off from RO filters to see if any water is flowing from housings.
5. The RO tank may also need air. If the air charge is low in tank (7 psi for 3 gal tank) no water can be forced from the tank.
6. If the RO is fed by a piercing valve make sure their is water coming from it.
7. Depending on what type of RO it is their may be a flow restrictor in head of membrane housing that can get plugged also.
I hope these tips may help you,

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